Clinical Problem Solving Term 1...CS8.4 Case Study: No energy. .....81 . Clinical Problem Solving Term 1 Workbook Table of Contents ... Clinical Problem Solving Term 1 Workbook Introduction

MB ChB Intake 2021

MB ChB

Clinical Problem Solving Term 1

Student Workbook

Clinical Problem Solving Term 1 Workbook Table of Contents

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Table of Contents Table of Contents ............................................................................................. 1

Introduction to the Unit ................................................................................... 6

Aim of the Unit ............................................................................................. 6

GMC ‘Outcomes for Graduates’ Addressed by the Unit .............................. 6

Outcomes 1: Professional values and behaviours .................................... 6

Outcomes 2: Professional skills ................................................................ 6

Outcomes 3: Professional knowledge ...................................................... 7

Specific Learning Outcomes ......................................................................... 8

Specific Learning Outcomes ......................................................................... 8

The Curriculum Philosophy - Guided Learning ............................................. 9

Constructing understanding ..................................................................... 9

Learning in context ................................................................................... 9

Learning together ..................................................................................... 9

The key steps of guided learning .............................................................. 9

1.1.1 Resources for the Unit ............................................................ 10

Unit Lead..................................................................................................... 10

1 Session One: Introduction to Clinical Problem Solving............................... 11

1.1 Aim of the Session .......................................................................... 11

1.2 Learning Outcomes for the Session ................................................ 11

1.2.1 Specific unit outcomes addressed by the session .................. 11

1.2.2 Detailed outcomes for the session ......................................... 11

1.3 Structure of the Session .................................................................. 11

1.4 Lecture: Introduction to Clinical Problem Solving .......................... 12

Clinical Problem Solving .......................................................................... 12

1.5 Group Work: Concept Map for Chest Pain...................................... 15

Your Concept Map: ................................................................................. 16

1.6 Self-directed Study .......................................................................... 17

2 Session Two: Preparing for Assessments ................................................ 18

2.1 Aim of the Session ........................................................................... 18


2.2.1 Specific unit learning outcomes addressed by this session .... 18

2.2.2 Detailed outcomes for the session .......................................... 18


2.4 Lecture: Assessments in the Medical Course .................................. 19

2.5 Group Work: Outcomes of the Course ........................................... 21

Questions to test your understanding of concepts: ............................... 21

2.6 Group Work: Expressing Yourself Concisely ................................... 24

Questions to test your understanding of concepts ................................ 24

2.7 Self-directed Study: Literacy ........................................................... 26

Punctuation ............................................................................................. 26

Tautological Repetition ........................................................................... 27

Writing correctly ..................................................................................... 28



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3 Session Three: Cystic Fibrosis ................................................................. 29





3.3 Structure of the Session ................................................................. 29

3.4 Lecture: Cystic Fibrosis ................................................................... 30

Your Concept Map .................................................................................. 32

3.5 Group Work: Cystic fibrosis Questions ........................................... 33

3.6 Role Play: ........................................................................................ 36

3.7 Self-directed Study ......................................................................... 36

4 Session Four: Sickle Cell Disease ............................................................ 37






4.4 Lecture: Sickle Cell Disease ............................................................. 38

Your Concept Map .................................................................................. 40

4.5 Group Work: Sickle Cell Disease Questions .................................... 41

Setting ..................................................................................................... 41

4.6 Self-directed Study: Numeracy ....................................................... 45

Section A: Tables and Graphs ................................................................. 45

Section B: Equations ................................................................................ 47

Section C: Percentages ............................................................................ 47

Section D: Multiplication and Division .................................................... 48

Section E: Units and Scales ..................................................................... 49

Section F: Ratios and Logarithms ........................................................... 49


5 Session Five: Joint Pain ............................................................................ 50



5.2.1 Specific unit outcomes addressed by the session ................... 50



5.4 Lecture: Joint Pain ........................................................................... 51

Joints in the body .................................................................................... 51

Arthritis ................................................................................................... 51

Mono-arthritis ......................................................................................... 51

Poly-arthritis ............................................................................................ 51

Consulting with a patient who may have arthritis .................................. 52

Commonest types of arthritis ................................................................. 52

Osteoarthritis .......................................................................................... 52

Rheumatoid arthritis ............................................................................... 52


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5.5 Concept map: Joint pain ................................................................. 54

5.6 Group Work: Questions to test your understanding ...................... 55

Joint structure ......................................................................................... 55

Bone pathology ....................................................................................... 55

5.7 Case Studies .................................................................................... 57

CS5.1 Case Study: Chronic joint pain and/or swelling ...................... 57

CS5.2 Case Study: Acute joint pain and swelling. ............................. 58

CS5.3 Case Study: Acute joint pain and swelling. ............................. 59

CS5.4 Case Study: Acute joint pain and swelling. ................................... 60


6 Session Six: Pathological Fractures ......................................................... 61


6.1 Learning Outcomes for the session ................................................ 61


6.1.2 Detailed outcomes for this session ........................................ 61


6.3 Lecture: Pathological Fractures ...................................................... 62

Your Concept Map: ................................................................................. 65

6.4 Group Work: Fractures ................................................................... 66

Disease Definition ................................................................................... 66

Post-Translational Modification in Protein Synthesis ............................ 67

6.5 Public Health Poster ....................................................................... 69


7 Session Seven: Evidence Based Medicine ............................................... 70



7.2.1 Specific unit outcomes addressed by this session .................. 70



7.4 Lecture: Introduction to Evidence Based Medicine ........................ 71


8 Session Eight: TigreenAll the Time .......................................................... 73



8.2.1 Specific unit outcomes addressed by this session .................. 73



8.4 Lecture: TigreenAll the Time ........................................................... 74

Your Concept Map: ................................................................................. 76

8.5 Group Work: Questions - Tigreenall the time ................................. 77

CS8.1 Case Study: Abnormal blood glucose. ..................................... 77

CS8.2 Case Study: No energy ............................................................ 78

CS8.3 Case Study: No energy. ........................................................... 80

CS8.4 Case Study: No energy. ................................................................. 81


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9 Session Nine: Fever ................................................................................. 84






9.4 Lecture: Body Temperature Control and Fever .............................. 85

Heat inputs ............................................................................................. 85

Heat loss ................................................................................................. 85

The ‘thermo-neutral’ environment ........................................................ 85

Decreasing heat loss ............................................................................... 86

Increasing heat gain ................................................................................ 86

Decreasing heat gain .............................................................................. 86

Increasing heat loss ................................................................................ 86

Control of body temperature ................................................................. 86

The concept of ‘set point’ ....................................................................... 87

Fever ....................................................................................................... 87

Resolution of fever ................................................................................. 87

Pyrogens ................................................................................................. 87

Managing fevers ..................................................................................... 88

9.5 Group Work: Body Temperature Control & Fever ......................... 89

Questions to test your understanding of concepts ................................ 89

CS9.1 Case Study: Fever. ................................................................... 91



CS9.4 Case Study: Abnormal blood glucose. ........................................... 94

9.6 Public Health poster ........................................................................ 94

9.7 Write your own assessment questions: .......................................... 95


10 Session Ten: Mood disorders .............................................................. 98



10.2.1 Specific unit outcomes addressed by the session ................... 98



10.4 Lecture: Depression ........................................................................ 99

Symptoms ................................................................................................ 99

Causes ..................................................................................................... 99

Neurotransmitters................................................................................... 99

Psychological Factors ............................................................................ 100

Diagnosis ............................................................................................... 100

Pharmacological Treatment .................................................................. 101

Psychological Intervention .................................................................... 101

Clinical Problem Solving Term 1 Workbook

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10.5 Group Work: Depression .............................................................. 102

Notes/prompts for educators to guide students: ................................ 104

Questions to test your understanding of concepts: Mental health

problems ............................................................................................... 105

10.6 Self-directed Study ....................................................................... 108

11 Session Eleven: Headache ................................................................ 109

11.1 Aim of the Session ........................................................................ 109

11.2 Learning Outcomes for the Session .............................................. 109

11.2.1 Specific unit outcomes addressed by the session ................ 109

11.2.2 Detailed outcomes for the session ....................................... 109

11.3 Structure of the Session ............................................................... 109

11.4 Lecture: Headache ....................................................................... 110

Your Concept Map: Headache .............................................................. 111

11.5 Group Work: Role Play ................................................................. 112

CS11.1 Case Study: Headache ...................................................... 112



CS11.4 Case study: Headache .................................................................. 115

11.6 Self-directed Study ....................................................................... 116

12 Session Twelve: Revision .................................................................. 117

12.1 Aim of the Session ........................................................................ 117

12.2 Learning Outcomes for the Session .............................................. 117

12.2.1 Specific Learning Outcomes ................................................. 117

12.2.2 Detailed learning outcomes for the session ......................... 117

12.3 Structure of the Session ................................................................ 117

12.4 Self-directed Study ........................................................................ 117

Index .............................................................................................................. 118

Clinical Problem Solving Term 1 Workbook Introduction to the Unit

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Introduction to the Unit

Aim of the Unit

The aim of this unit is to enable you to develop the skills of integrating

understanding, and focussing that integrated understanding on problems

presented by your patients.

GMC ‘Outcomes for Graduates’ Addressed by the Unit

Like all the Units in the medical course this Unit helps you to meet the

outcomes defined by the General Medical Council in its document

‘Promoting Excellence: Standards for Medical Education and Training’ (2016)

and updated in 2018. The particular outcomes addressed are listed below,

but it is important to realise that no single Unit in the course will enable any

of these outcomes fully to be achieved, as they are addressed by multiple

Units across the course and you should explore where the information is

contextualised between Units. Graduates must be able to demonstrate all

of the ‘outcomes for graduates’ in the context of caring for patients in the

population they will serve as new doctors.

Outcomes 1: Professional values and behaviours

2. Newly qualified doctors must behave according to ethical and

professional principles. They must be able to:

b. demonstrate compassionate professional behaviour and their

professional responsibilities in making sure the fundamental needs of

patients are addressed.

d. maintain confidentiality and respect patient’s dignity and privacy.

e. act with integrity, be polite, considerate, trustworthy and honest.

f. take personal and professional responsibility for their actions.

g. manage their time and prioritise effectively.

h. recognise and acknowledge their own personal and professional

limits and seek help from colleagues and supervisors when

necessary, including when they feel that patient safety may be

compromised.

j. Recognise the impact of their own attitudes and perceptions

(including personal bias, which may be unconscious) on groups

within society or individuals belonging to particular groups and

identify personal strategies that might be adopted to address this.

m. act appropriately, with an inclusive approach, towards patients and

colleagues.

p. explain and demonstrate the importance of professional

development and lifelong learning and demonstrate commitment to

this.

r. respect patients’ wishes about whether they wish to participate in

the education of learners.

8. Newly qualified doctors must recognise the role of doctors in

contributing to the management and leadership of the health service.

They must be able to:

b. undertake various team roles including, where appropriate,

demonstrating leadership and the ability to accept and support

leadership by others.

c. identify the impact of their behaviour on others.

Outcomes 2: Professional skills

10. Newly qualified doctors must be able to communicate effectively,

openly and honestly with patients, their relatives, carers or other


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advocates, and with colleagues, applying patient confidentiality

appropriately. They must be able to:

a. communicate clearly, sensitively and effectively with patients,

their relatives, carers or other advocates, and colleagues from

medical and other professions, by:

• listening, sharing and responding

• demonstrating empathy and compassion

• demonstrating effective verbal and non-verbal interpersonal

skills

• making adjustments to their communication approach if needed,

for example for people who communicate differently due to a

disability or who speak a different first language

• seeking support from colleagues for assistance with

communication if needed.

11. Newly qualified doctors must be able to carry out an effective

consultation with a patient. They must be able to:

b. encourage patients’ questions, discuss their understanding of

their condition and treatment options, and take into account their

ideas concerns, expectations, values and preferences

c. acknowledge and discuss information patients have gathered

about their conditions and symptoms, taking a collaborative

approach.

13. Newly qualified doctors must be able to perform a range of diagnostic,

therapeutic and practical procedures safely and effectively, and identify,

according to their level of skill and experience, the procedures for which they

need supervision to ensure patient safety. They must be able to:

a. propose an assessment of a patient’s clinical presentation,

integrating biological, psychological and social factors, agree this

with colleagues and use it to direct and prioritise investigations and

care.

Outcomes 3: Professional knowledge

22. Newly qualified doctors must be able to apply biomedical scientific

principles, methods and knowledge to medical practice and integrate

these into patient care. This must include principles and knowledge

relating to anatomy, biochemistry, cell biology, genetics, genomics and

personalised medicine, immunology, microbiology, molecular biology,

nutrition, pathology, pharmacology and clinical pharmacology, and

physiology. They must be able to:

a. explain how normal human structure and function and

physiological processes applies, including at the extremes of age,

in children and young people and during pregnancy and

childbirth.

b. explain the relevant scientific processes underlying common and

important disease processes.

c. justify, through an explanation of the underlying fundamental

principles and clinical reasoning, the selection of appropriate

investigations for common clinical conditions and diseases.

f. analyse clinical phenomena and conduct appropriate critical

appraisal and analysis of clinical data, and explain clinical

reasoning in action and how they formulate a differential

diagnosis and management plan.

26. Newly qualified doctors must be able to apply scientific method and

approaches to medical research and integrate these with a range of


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sources of information used to make decisions for care. They must be

able to:

e. critically appraise a range of research information including study

design, the results of relevant diagnostic, prognostic and

treatment trials, and other qualitative and quantitative studies as

reported in the medical and scientific literature.

f. formulate simple relevant research questions in biomedical

science, psychosocial science or population science, and design

appropriate studies or experiments to address the questions.

Specific Learning Outcomes

To help you more specifically, we have also framed these outcomes into a list

of secondary outcomes that you should have achieved by the end of the

Clinical Problem Solving unit.

By the end of this Unit, you should be able to:

Specific Learning Outcomes

By the end of this unit you should be able to:

• Describe in general terms the process of clinical problem solving.

• Explain the process of constructing a ‘concept map’ and apply it to a

clinical presentation.

• Apply the information on the ‘concept map’ to link information and

ideas in multiple contexts.

• Identify topic areas relevant to a given clinical presentation or

condition

• Explain how concept maps will help you to prepare for assessments.

• Describe and explain the educational rationale for the format of

written questions.

• Apply the information on your concept map to identify important

questions that may be asked in assessments relating to any clinical

presentation or condition, and how you will prepare to answer them.

• Write example assessment questions using your concept maps

• Describe how a careful history can help you to differentiate one

medical condition from another.

• Evaluate the information gained during history taking, clinical

examination and appropriate investigations, and then applying it to

clinical problem solving.

• Synthesise the intellectual process that enables you to identify and

catalogue information relevant to individual clinical presentations or

conditions, as the course progresses.

• Evaluate clinical evidence and apply it to clinical problem solving.

Apply, in particular understanding of the concepts of the Clinical

Problem Solving Unit to the diagnosis and management of patients

who present with any one of the following from the 66 core

presentations described in the MB ChB programme, in this Unit we

will cover:

• Chest pain - acute

• Blood glucose - abnormal

• Bowel habit change

• No energy – TATT

• Malaena/blood loss GI

• Pallor and/or abnormal blood test

• Headache

• Falls

• Joint pain/ swelling - acute


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• Joint pain/ swelling – chronic

• Back pain and/ or sciatica

• Fractures/ dislocation

• Affective disorders

• Psychosis/ personality disorders

• Genetic and or congenital disorder

• Fever/ infection

• Apply understanding of the concepts in the Clinical Problem Solving Unit, where relevant, to the remaining key presentations on the list defined in the Code of Practice for Assessment, many of which are also indicated in the clinical scenarios presented in this workbook.

The Curriculum Philosophy - Guided Learning

This Unit is not a separate entity, but part of an integrated programme with a

clear educational philosophy – guided learning. This workbook provides

much of the material you will need to follow this process, though you will

also use other resources. Guided learning has three key features:

Constructing understanding

The Unit aims to present material to you in an easily digestible way, but you

must then work to develop the understanding that will allow you to apply it

effectively to the practice of medicine. You must continually explore and re-

visit ideas from all units as the course progresses, applying them repeatedly

in different ways. This way you will construct understanding for yourself

through systematic exploration and application of ideas. This requires active

learning, which is the antithesis of the passive acquisition and regurgitation

of material that you may have indulged in previously.

Learning in context

Building understanding requires appreciation of the context in which you will

use it - the practice of medicine. Guided learning therefore focuses your

understanding on patient problems by continually revisiting material in the

context of different patient problems. We use a list of common patient

problems both to structure problem solving tasks to help you learn, and

assessment tasks to test what you have learnt. ‘Cognitive re-organisation’ is

the essence of learning to be a doctor. You must move away from

“memorising” material as it has been presented to you, to understanding it

in ways that you are going to use it. You need to be able to take a given

concept and apply it in multiple different contexts.

Learning together

You are privileged to have your fellow medical students as companions on

your personal journey. Like all journeys, a medical course is easier and more

fun in company. Working with other students in group work will both

enhance your own learning, and ensure that you acquire valuable skills of

working with others.

The key steps of guided learning

Guided learning follows the same pattern in all Units, so you are guided

through repeated reflective cycles of learning.

1. We will present ideas and material to you mostly through lectures,

supplemented by guided reading of material in textbooks and other

resources.

2. You will then move rapidly into group work, where you will address,

as a group, structured problems relating to the material that has just

been presented, its relationships to other material and the

application of those concepts to common patient problems. Your


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work in groups will be supported by tutors, but not directly tutor-led.

In group work your performance will be assessed in terms of your

attention, focus, engagement and contribution to the activities, and

each term this will provide you with invaluable feedback as you

develop your team- working skills.

3. The group work is followed up by self-directed study, where you will

work on the ideas further using a variety of resources, some

suggested by us, others identified by yourselves, in order to enhance

your understanding, and link it to other material across the course so

you may apply it to a wide range of patient problems.

If you can see early how you are going to use material, however, it becomes

very much easier to cope with, because you can place your learning into

context. In this Unit we shall be considering the way in which different

patients present with problems. We will discuss how we gather the necessary

information, by speaking to the patient and learning about their “history”.

Further information is gathered by examining the patient, and then deciding

which investigations they need. Clinical Problem Solving is the intellectual

process involved in bringing all this information together to make an accurate

diagnosis and an appropriate management plan.

1.1.1 Resources for the Unit

Much of the content is presented in either concurrent or later Units and

the workbooks and reading prescribed for those Units will be your major

resource. You will need to search out some topics, in order to learn the skills

of doing so, as well as learn how to filter information from multiple sources.

Recommended Books:

Kumar and Clark Clinical Medicine, Paveen Kumar and Michael Clarke (9th

edition).

Further Reference:

Davidson’s Principles & Practice of Medicine, edited by Stuart H. Ralston et al

23rd edition

What is a concept map? J. Novak & A Canas www.ihmc.us (2008)

Unit Lead

http://www.ihmc.us/

Clinical Problem Solving Term 1 Workbook 1 Session One: Introduction to Clinical Problem Solving

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1 Session One: Introduction to Clinical Problem Solving

1.1 Aim of the Session

The aim of this session is that you should start to become familiar with the

process of collecting information about a patient’s problem and the

understanding and skills that you will need to diagnose and manage that

problem.

1.2 Learning Outcomes for the Session

1.2.1 Specific unit outcomes addressed by the session

• Describe in general terms the process of clinical problem solving.

• Explain the process constructing a ‘concept map’ and apply it to a

clinical presentation.

1.2.2 Detailed outcomes for the session

• By the end of this session you should be able to:

• Explain the terms ‘symptom’, ‘sign’, and ‘investigation’

• Explain the term ‘taking a history’ from a patient, and define the

elements of a complete history, including:

o Presenting complaint

o History of presenting complain

o Past medical & drug history

o Family history

o Social history

o Ideas, concerns & expectations

• Explain the process of concept mapping, and demonstrate it in the

context of a patient presenting with crushing chest pain

1.3 Structure of the Session

1330-1430 Lecture: Introduction to Clinical Problem Solving

1430-1600 Group work: Concept maps

1600-1645 Group work: Patient experience


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1.4 Lecture: Introduction to Clinical Problem Solving

Any medical student or doctor will tell you that the principal intellectual

challenge of a medical course is the breadth of the subject. There are few

individual concepts which are difficult to understand, but there are a huge

number of ideas to assimilate and interrelate. There are thousands of

doctors practising all over the world who have managed this challenging task,

so it can be done, but it is not easy.

There is a huge temptation to try and divide the material into isolated, bite-

sized chunks, each contained within its own impregnable silo. These may

easily be learned, but are only useable if applied in the precise context which

generated them. This is fine if you are learning to pass A-levels when the

question format and content is largely predictable, so you may learn material

only in the way which will subsequently be tested.

Such learning is shallow, context specific and not what is known as

‘generalizable’. That is to say it cannot be used in multiple different contexts,

which is exactly what you will have to do as a doctor. Generalizable

information can be used for problem solving and is what being a doctor is all-

about. It is completely different to writing answers in response to pre-

determined cues.

Clinical Problem Solving

Clinical problem solving is a process of merging information collected from a

patient with ideas and concepts in your head in order to make a diagnosis

which will facilitate the construction of a management plan that may be

implemented in collaboration with the patient.

Information collected from a patient is in three categories:

1. Symptoms: These are things that a patient reports to you, such as a

pain in some part of their body, feeling breathless, feeling tired, or

changes that they have noticed about themselves.

2. Signs: This is information you collect by examining a patient.

Examination involves looking at the patient (inspection), feeling the

patient with your hands (palpation), listening to some part of the

patient, usually with a stethoscope (auscultation) and tapping a

patient to elicit a sound or response (percussion). You may also

undertake a mental state examination by asking the patient to

perform a series of tasks.

3. Investigations: This is where equipment of some kind is used to

image some part of a patient, measure a physiological process

(breathing, hearing, heart function) or measure some biochemical

variable in the body.

The symptoms a patient reports are collected by talking with the patient,

which is known as ‘taking a history’. You will learn a structured approach to

this specialised communication skill as the course progresses, starting with

the Clinical Skills Foundation Course which runs alongside this unit.

You will need to identify a ‘presenting complaint’, often known as a

‘presentation’, which is a mixture of symptoms and signs which defines the

starting point for problem solving. For example, a patient may have ‘central

crushing chest pain’ or ‘acute epi-gastric pain’.

You will then collect the ‘history of the presenting complaint’ which will tell

you what events preceded and are associated with this clinical event, plus a

variety of other information about the patient’s previous medical history,

drug history, social history and what the patient already believes about the

condition, (‘ideas’) what they are worried about (‘concerns’) and what they

expect you to do about it (‘expectations’).

You will be problem solving as information is collected, so that you may focus

on relevant questions in the history, examine the patient appropriately and

order the appropriate investigations. This involves matching the evolving


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patient story to structures in your head which enable you to identify what is

wrong with the patient.

These structures are commonly called ‘illness scripts’ and they are the means

by which expert clinicians make diagnoses very quickly indeed. The process

is one of recognition, but it is not simple pattern recognition, rather a

process of exploring options very swiftly and deciding between them – a so

called hypothetico-deductive approach.

The process is strongly analogous to the recognition of objects in the world,

skills we all learn unconsciously at a very early age. The hypothetico-

deductive approach involves the testing of ideas, by asking ‘what if’

questions. The basis of these questions in medicine is a deep understanding

of how the body is put together, how it works and in what ways it can go

wrong.

This deep understanding needs to be in the form of what computer buffs

among you will understand as a ‘relational database’. That is to say any

piece of data may be accessed by a huge variety of routes and is linked to

potentially many different presentations or diseases.

Your task is to build these links. A useful tool for the purpose is the ‘concept

map’. Many of you will have used these before, and may have called them

‘spider diagrams’, or “mind maps”.

The clinical presentation or condition is placed in a central box and related

ideas in nearby boxes linked by lines. Each of these boxes identifies relevant

information, but does not necessarily contain it in detail. It is simply a flag

that indicates this information is relevant and in what way. Information may

be defined in a number of levels of detail by connecting boxes to others, so

that over the whole diagram the picture is complete.

The same concepts will recur in many different concept maps, and over time

you will begin to see that relatively few big ideas explain a great deal of what

you need to know. These then provide you a means of handling the mass of

information, and make it shrink overnight. The aim of our assessment

scheme is to reward those of you who develop the cognitive (i.e. mental)

structures that help you problem solve.

All questions in the assessments are related to a clinical presentation or

condition, and all open with a case scenario which relates, in a succinct form,

to aspects of a patient’s presenting complaint. This is then followed by a

series of questions relating to that scenario. These questions are chosen by

the examiners who use concept maps to identify relevant questions relating

to that presentation or condition.

If you understand, and have similar concept maps then the questions we may

ask are often predictable. You can therefore work out for yourself the best

way to revise for the assessments.

In summary, if you are to be a good doctor you must learn to think like a

doctor from day one, which is a skill that has to be acquired. The quicker you

change, the more successful you will be.


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The following diagram suggests a broad structure for your concept maps:


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1.5 Group Work: Concept Map for Chest Pain

Consider the presentation ‘Crushing Central Chest Pain’. This might be

presented as follows:

Deepak, aged 53, has enjoyed his life, consuming with relish his wife’s

excellent cooking. He is a little portly as a result, and a few years ago he was

diagnosed as diabetic, although he is reasonably well controlled with oral

drugs. He also has higher blood pressure than he should, but has been

resistant to suggestions that he should exercise and lose some weight. After

a stressful day at the office he develops sudden onset chest pain which is

severe, and feels like a band crushing his chest. He is pale and has vomited.

You are the first to see him when he arrives in the Emergency Department.

You suspect a myocardial infarction.

Your task is to construct an outline concept map of the topics you will need

to know about to confirm your suspicions and subsequently manage Deepak

with the aim of keeping him alive.

The essence of Deepak’s condition is:

1. Deepak has atherosclerosis of his coronary arteries, i.e. the blood

vessels which carry blood to the muscle of his heart. Atherosclerosis

is a thickening of the inner layer of the blood vessels, due to changes

in cells stimulated by the accumulation of oxidised LDL cholesterol

within them. This builds up over time and is exacerbated by high

blood cholesterol (affected by diet) and damage caused by smoking

and high blood pressure.

2. This thickening protrudes into the lumen (hole down the middle) of

the blood vessels and makes it harder for blood to flow to the heart

muscle, which must have a high blood flow to maintain its constant

activity. So long as the atherosclerosis is stable, the effect is to limit

blood flow to the heart muscle in exercise, which may lead to pain

called angina. Angina comes on with exercise and is normally

relieved by rest.

3. The surface of the atherosclerosis may however eventually become

roughened and attract blood clots. These may suddenly detach with

some of the atherosclerosis and flow down the artery to block a

branch completely, so that the part of the heart muscle supplied by

that branch dies. This is a myocardial infarction. Myocardial

infarction normally leads to acute severe central chest pain which is

crushing in character and may radiate to the neck and arm because

of the way in which the nerves to the heart are organised.

4. A myocardial infarction will seriously disrupt the flow of electrical

impulses across the heart that produces the heartbeat, and these

electrical disturbances may be detected with a test known as the

electrocardiogram. The dying cells also release enzymes into the

blood stream which may be detected by a blood test.

5. The objective of immediate management is to prevent more clots

forming (usually by using a drug like aspirin) and to dissolve those

that have formed (usually using a drug like alteplase). In some

circumstances, a stent may be inserted to by-pass the blockage. The

patient will need strong pain relief and oxygen to help to get oxygen

to his damaged heart and the rest of his body. A heart with dying

muscle will not function correctly, and there may be severe

consequences for the circulation.

The above description contains almost everything you need to construct your

concept map, though you may wish to consult a textbook or web-site to

check some information. Remember the concept map does not contain

detailed information itself, just the topics that are relevant. We know you

have not yet studied them, but this does not stop you thinking about what


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they should be from the above description, and in any case you may know

quite a lot already.

Your Concept Map:


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1.6 Self-directed Study

Complete concept map.

Review your understanding of a patient presenting with ‘chest pain’.

Clinical Problem Solving Term 1 Workbook Session Two: Preparing for Assessments

18

2 Session Two: Preparing for Assessments


The aim of this session is that you should understand the format of

examinations across the medical course, and the relationship of that format

to clinical problem solving.


2.2.1 Specific unit learning outcomes addressed by this session

• Explain how concept maps will help you to prepare for assessments

• Describe and explain the educational rationale for the format of

written questions.


By the end of this session you should be able to:

• Describe the pattern of written and OSCE assessments over the

medical course, and in Phase 1 in particular.

• Describe how written questions are constructed

• Describe how written questions are marked

• Describe the ‘standard setting’ process for written questions

• Describe the grading process for written examinations

• Explain the progression rules for progression from year 1 to year 2 of

the course, and from Phase 1 to Phase 2.


1330-1430 Lecture: Assessments in the Medical Course

1430-1530 Group work: understanding outcomes and contexts

1530-1630 Group work: expressing yourself precisely

1630-1700 Self-directed Study: assessing literacy


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2.4 Lecture: Assessments in the Medical Course

This lecture will describe the assessment philosophy and structure for the

medical course at Buckingham. Full details are provided in the ‘Code of

Practice for Assessment’ which may be accessed on Moodle. The Code of

Practice is the definitive statement of rules and in the case of any small

disparities between the explanations in this lecture and the Code of Practice,

the Code of Practice will prevail, as the lecture is inevitably a short summary

of a complex system.

All written assessments in the medical course are in the same format, based

around case scenarios linked to a set of key presentations. The case scenario

introduces a patient, and will often cue the relevant key presentation of

condition. The questions that follow are constructed with reference to

concept maps that staff have in their own heads, by systematic or random

sampling from different parts. The best way to prepare for these

assessments is therefore to emulate the process by which the questions are

set, and prepare your own concept maps for each entry on the list. This will

allow you to prepare for virtually any question which may be asked. You will

not be able to construct all of these maps immediately, but you may begin

with some of the more obvious, and then build the set up over the next few

terms.

The full set of presentations/conditions are defined in the ‘Code of Practice

for Assessment’, and are reproduced below for convenience.

• Acute cough

• Chronic cough

• Acute or chronic chest pain

• Hypertension

• Palpitations

• Abdominal distention

• Abnormal blood glucose

• Abnormal weight

• Acute or chronic blood loss from the GI tract

• Change in bowel habit

• Chronic abdominal pain

• Jaundice

• No energy

• Acute abdominal pain

• Bleeding

• Pre or post-operative patient

• Acute renal failure

• Collapse

• Fits

• Headache

• Loss of consciousness

• Multiple trauma and/or head injury

• Shock

• Sudden or progressive breathlessness

• Swollen or painful leg

• Weakness

• Abnormal movement

• Chronic renal failure

• Confusion

• Falls

• Pallor


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• Problem with impaired voiding or incontinence

• Acute joint pain and/or swelling

• Back pain and/ or sciatica

• Burning pain

• Chronic joint pain and/or swelling

• Fractures/ dislocation

• Soft tissue injury or other trauma

• Addiction

• Affective disorders

• Personality disorders

• Psychosis

• Abnormal palpable lymph nodes

• Breast lump and/or pain

• Dying

• Dysphagia

• Haematuria

• Haemoptysis

• Lump and or problem in the

groin/scrotum/testis/penis

• Neck lump

• Nipple discharge or retraction

• Skin rash/lesion

• Change in hearing

• Earache

• Hoarse voice or stridor

• Mouth problems

• Nasal symptoms

• Numbness

• Painful and/or red eye

• Vertigo/ dizziness

• Visual disturbance

• Genital discharge

• In labour

• Pelvic pain and or mass

• Pregnant

• Problems relating to fertility or contraception

• Prolapse of uterus and/or rectum

• Vaginal bleeding

• Genetic and or congenital disorder

• Developmental delay

• Failure to thrive

• Fever/ infection


21

2.5 Group Work: Outcomes of the Course

The outcomes of the medical course are defined by our regulator – the

General Medical Council, in the ‘Outcomes for Graduates’ 2018.

In the standards for medical education, again prescribed by the General

Medical Council in its document ‘Promoting Excellence – Standards for

Medical Education and Training’ (2015), you are required to achieve each of

these outcomes individually, and we are required both to provide the

opportunities for you to do, and to verify that you have through the

assessments of the course.

The course and the assessments must therefore be mapped (or

‘blueprinted’) to the outcomes, and if you keep focussed on the outcomes

you will have the best chance of succeeding.

You should spend the first hour of this group work familiarising yourselves

with the GMC outcomes and answering the following questions.

The outcomes for graduates are available through Moodle under the ‘GMC’

section of the navigation diagram. You should consult these as you go along.

Questions to test your understanding of concepts:

Discuss the principal differences between “Outcomes for graduates 2018”

Outcome 1 - Professional values and behaviours, Outcome 2 – Professional

skills and Outcome 3 – Professional knowledge


22

CT2.1 Explain precisely what an ‘outcome’ is in this context.

CT2.2 Explain what is meant by the outcome 22(b) – ‘explain the relevant

scientific processes underlying common and important disease

processes.

CT2.3 Discuss what is meant by outcome 24(e) – ‘explain the sociological

aspects of behavioural change and treatment concordance and

compliance, and apply these models to the care of patients as part

of person- centgreendecision making.’

CT2.4 Discuss what is meant by outcome 23(b) – ‘integrate psychological

concepts of health, illness and disease into patient care and apply

theoretical frameworks of psychology to explain the varied

responses of individuals, groups and societies to disease’

CT2.5 Discuss outcome 14(h) – ‘Understand the processes by which

doctors make and test a differential diagnosis and be prepagreento

explain their clinical reasoning to others’. How does this outcome

relate to this unit?

CT2.6 What is the fundamental difference between the Outcomes under

the heading ‘Professional values and behaviours’ and those under

the heading ‘Professional skills’?


23

CT2.7 Discuss what is meant by outcome 6(f) – ‘manage the uncertainty

of diagnosis and treatment success or failure and communicate this

openly and sensitively to patients, their relatives and carers’. How

will you and the medical school know that you have achieved this

outcome?


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2.6 Group Work: Expressing Yourself Concisely

In medical practice you will have to maintain accurate records of your clinical

work, through notes, requests, reports, referral and discharge letters. This

means you must be able to construct concise but accurate prose using

medical language in the correct way. This is a high level skill which takes

time to develop. The assessments early in the course are designed to drive

you to develop the skill of concise expression, as most of the questions are

‘constructed response’ – that is to say you have to write an answer rather

than select one from a list.

Doing well in these assessments depends on being able to express yourself

concisely and accurately, and it is common for students to lose marks

through poor expression even if their underlying knowledge is reasonably

sound. That said, however, the better you understand something the easier

it is to express it concisely, so the matter is not just one of language.

Try the following tasks in your group and see if you can work out collectively

how best to express yourselves. You are then asked to take an individual test

of literacy that will enable you to establish how much more work you need to

do, and whether you need additional support to do it. Please contact the

unit lead, if you feel that you need additional support.

Questions to test your understanding of concepts

CT2.8 What is the difference between the meaning of the words ‘principle’

and ‘principal’?

CT2.9 What is the difference between the words ‘practice’ and ‘practise’?

Which word will you use when in a sentence?

CT2.10 Describe in the simplest way you can all the possible moves that you

might make with a knight on a chessboard

CT2.11 Find someone in your group who is keen on football. Get her or him

to explain the offside rule to the group, then write a description of it

using the fewest possible words.


25

CT2.12 Describe in as few words as possible, but with complete accuracy,

the differences between your right and left hands

CT2.13 Explain precisely, in as few words as possible, the differences

between your coccyx and your elbow.

CT2.14 Explain precisely, in no more than 10 words, the fundamental

biological difference between men and women

CT2.15 Explain precisely, in as few words as possible, the difference

between substances that are hydrophilic and those that are

hydrophobic?

CT2.16 Explain precisely, in as few words as possible, the difference

between a prokaryotic and a eukaryotic cell.


26

2.7 Self-directed Study: Literacy

Writing concisely and accurately is a key skill for medicine, but is also

requigreento do well in the assessments of this course, as you will have to

write a lot of ‘short answers’. Experience has shown that not all new

students have this skill naturally, so the purpose of this group session is to

help you establish exactly how good you are at writing properly, and whether

you need to seek any further training to improve. Such services are available

to you. You should undertake this part of the session on your own.

If you have difficulty with these exercises, please speak to, or email the unit

lead.

Punctuation

CT2.17 Punctuate the following so that it makes full grammatical sense.

Other than changing lower case letters to upper case letters, you

should only insert punctuation. You should not delete, insert or

move letters or words.

1. my fiance abhik is a bit useless and doesnt seem to be able to cope

without me as I said to him yesterday a woman without her man is

nothing

CT2.18 Literacy

2. dear john i want a man who knows what love is all about you are

generous kind thoughtful people who are not like you admit to being

useless and inferior you have ruined me for other men i yearn for you i

have no feelings whatsoever when were apart i can be forever happy

will you let me be yours jane

Jane would like to end her relationship with John. Please punctuate this

statement.


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Tautological Repetition

The following quote is attributed to William of Ockham, a fourteenth century

Franciscan theologian, “Entia non sunt multiplicanda praeter necessitatem.”

It means, ‘Entities should not be multiplied beyond necessity’. Ockham was

referring to philosophy but you would be well advised to follow his

exhortation (which could be interpreted, ‘words should not be used

unnecessarily’) in all your future medical writing, including your ‘Narrative

Medicine’ dissertation. One way to avoid using too many words is to avoid

tautology. Tautology is the use of words which merely repeat something

already stated, as in ‘reverse back’.

CT2.19 Cross out redundant words, as you rewrite the following sentences,

so that meaning and grammatical correctness are maintained.

1. The Fire and Police services in the Milton Keynes area both share the

same aim, which still continues, to minimise down the number of lives

lost in vehicular traffic accidents.

2. Up until the present, all past records about victims of the previous

accident show that live survivors had been quickly transported, with

haste, to safe havens comprising of emergency tents and school

buildings.

3. Future prospects for new initiatives depended on the resulting outcome

of planned talks which have been cancelled.

4. Results and findings from research work which tested out methods of

raising up new antibodies further enhance and increase our knowledge

and understanding of illness and disease.

5. Doctors are exiting out of the association and forming an utterly unique

forum at this moment in time in order to free up personnel to make

future plans.


28

Writing correctly

CT2.20 A student tells her personal tutor about the incident below. Retell

the following incident using formal, grammatically correct prose.

1. “We’re on the ward round and Dave’s Give me my stethoscope back and

the patient’s like No go away and he’s like please Mr Brown I really need

it and Tracey’s walking round the bed to get it from his other hand when

this consultant? comes up and he’s looking for his patient? and Trace

trips over the drip stand and it’s falling over and pulls? the cannula out

and the patient’s like screaming? and the consultant’s face is white as

his shirt”


Complete group work and literacy assessment. If you have difficulties with

this assessment, contact the unit lead. There is help available for those who

need it.

Clinical Problem Solving Term 1 Workbook Session Three: Cystic Fibrosis

29

3 Session Three: Cystic Fibrosis


The aim of this session is that you should continue to develop your

understanding of the development of expertise in clinical problem solving

through consideration of a genetic disease with a clear link between a

fundamental pathological process and its presentation.



• Describe in general terms the process of clinical problem solving

• Apply the information on your ‘concept map’ to identify important

questions that may be asked in assessments relating to any clinical

presentation or condition, and how you will prepare to answer them



• Explain the concept of ‘expertise’ and define ‘deliberate practice’

• Explain the concepts of ‘Type 1’ and ‘Type 2’ thinking and the role of

encapsulation in moving between them

• Construct a concept map defining and linking topics that enable you

to understand the presentation and prognosis of a patient with an

identifiable genetic disease

• Construct a concept map for the condition Cystic Fibrosis


1330-1430 Lecture: Cystic Fibrosis

1430-1500 Group work: Quiz

1500-1545 Group work: Concept map and presentation

1545-1615 Group work: Role play

1615-1700 Group work: Questions


30

3.4 Lecture: Cystic Fibrosis

The overall aim of the medical course is that you should develop expertise in

the diagnosis and management of illness in your patients. The characteristics

of expertise have been well studied, and it is known that experts think

differently to novices when solving problems. When you are first learning

how to be a doctor, and are presented with a patient problem, you have to

think very deliberately and logically about that problem in order to solve it.

This is often called ‘type 2 thinking’, and when you are using it you will have

consciously to identify all material relevant to a problem, and then work

through it systematically in order to reach a solution. Type 2 thinking is slow

and deliberate, and does not always reach the correct solution even though

you will have to collect of lot of information from your patient and spend a

lot of time processing it.

As you develop expertise you will gradually move to ‘type 1 thinking’, where

most of the mental steps that you have to engage in consciously in type 2

thinking happen automatically without you really being aware of them. Your

problem solving will become both much more rapid and much more accurate

through this process known as ‘encapsulation’.

Developing expertise requires a long period of what is known as ‘deliberate

practice’. Deliberate practice involves frequent repetition of problem solving

tasks, so that underpinning ideas and knowledge are constantly re-visited in

many different contexts. It is vital to realise that deliberate practice is not

going over things again and again in exactly the same context (like revising

by going repeatedly through a set of notes), it involves continually revisiting

ideas by using them in different contexts.

Developing expertise takes a significant amount of time, and it takes a long

time to reach a high level of expertise. Your expertise will develop

throughout the medical course, and beyond – so the earlier you start the

quicker you will get there. In this session we will practise deliberately using

the example of the condition Cystic Fibrosis.

Cystic fibrosis is a genetic disease. It is an autosomal recessive condition,

which means that people with one copy of the defective gene may act as

carriers, and only those with two copies are affected. Around 1 in 25 people

are carriers, and about 1 in 2,500 is affected. The defective gene codes for a

membrane protein in epithelial cells which is involved in the transport of

chloride ions. The channel is crucial for normal movement of ions into and

out of epithelial cells. As a result secretions from epithelial cells become

more viscous (greatly thickened), which affects the function of many organs

as epithelial cells are found on all surfaces of the body that are outside or

lining tubes which open to the outside.

The lungs are particularly affected, and become very prone to infections

because of the abnormal accumulation of secretions. Recurrent infections

progressively damage the airways in the lungs, which in the past often led to

an early death. Many other organs are affected, including sweat glands in

the skin which secrete sweat with exceptionally high sodium content, the

cells lining the intestines, cells in the pancreas and cells lining the

reproductive tract, especially in men.

In the UK, all newborn babies are screened for cystic fibrosis as part of the

blood spot test (heel prick test), which is carried out soon after they are

born. If the screening test is positive, then they will need additional tests to

confirm that they have the condition: Sweat test – measures salt (sodium) in

sweat and genetic test (blood or saliva) to identify the faulty gene. These

tests can also be used in adults and children who didn’t have the newborn

test.

When genetic tests indicate that both parents are carriers, a child has a 1 in 4

chance of being affected and a 1 in 2 chance of being a carrier. There is some


31

hope that the defective gene might be replaced in individuals using modern

molecular biology techniques.

Management of cystic fibrosis involves reducing the risk of respiratory

infection and managing the adverse effect of the condition upon other organ

systems, such as the intestines, pancreas and reproductive tract.

Sophisticated antimicrobial therapy combined with physiotherapy and other

treatment is essential to preserve lung function as long as possible.

To understand and explain this condition you must draw together

information about genetics, molecular biology, the cell biology of membrane

transport processes, the structure of affected organs, such as lungs,

intestine, pancreas and male reproductive tract, how the function of these

organs may be affected, how the lungs may become infected and with what,

how the antimicrobial drugs used to manage the condition work against

which organisms, how the lives and wellbeing of individuals are affected by

the disease, and the public health and health service implications of such a

common condition.


32

Your Concept Map


33

3.5 Group Work: Cystic fibrosis Questions

After creating the first draft of your concept map above, consider the

following questions by locating the area of your concept map that addresses

each question and then answering the question based on what you have

written in your concept map.

Now ask yourself whether you are satisfied with your answer based on your

concept map. If not, why not? How could you improve your concept map?

If you are satisfied, are there further questions which could be raised?

Remember, you are not limited in where you obtain information that you

feel is necessary. So, it should be possible for you to create a concept map

that addresses all possible questions by linking different concepts. It is not

about writing down everything in detail but about being able to infer

answers from concepts.

Cystic fibrosis is characterised by repeated chest infections due to thick

mucus that the person finds difficult to clear.

CT3.1 What type of epithelium lines the upper respiratory tract?

CT3.2 Name the unicellular glands within this epithelium which secrete

mucus.

A neighbour who has cystic fibrosis seems to be unwell frequently.

CT3.3 What non-pharmacological treatments are commonly used for

patients with cystic fibrosis?

CT3.4 What pharmacological agents are commonly used to combat lung

infections in cystic fibrosis?

You notice that your neighbour’s fingernails look “sort of swollen”.

CT3.5 What is the medical term for this appearance of the fingernails?

A patient with cystic fibrosis has to take pills to help him with his diet.

CT3.6 What are these pills likely to be?


34

CT3.7 How does cystic fibrosis affect the fertility of males?

CT3.8 Generally, how would you ascertain whether a disease, such as

cystic fibrosis, is due to genetic or environmental factors?

CT3.9 What tests can be used to detect cystic fibrosis in the newborn?

CT3.10 Why is the mucus excessively thick in a patient with cystic fibrosis?

CT3.11 How is the transfer of water linked to sodium ion transport across

the cell membrane?

CT3.12 How is sodium ion transport linked to chloride ion transport?

CT3.13 What are the common pathogens causing respiratory infections in

patients with cystic fibrosis?

CT3.14 How does DNAase contribute to the chest symptoms in cystic

fibrosis?

CT3.15 What other conditions or diseases are associated with clubbing of

the fingernails?


35

CT3.16 Which key enzyme is not secreted into the lumen of his small

intestine?

CT3.17 What is not being absorbed correctly in his small intestine?

CT3.18 Why is the pancreas compromised?

CT3.19 What is the similarity between what is happening in his pancreas,

and what is happening in his chest?

CT3.20 What is the inheritance pattern for cystic fibrosis?

CT3.21 How common is the carrier status?

CT3.22 What types of people are unlikely to be a carrier?

CT3.23 How common is the disease in the population?

CT3.24 Cystic fibrosis patients have a key protein defect. What is the effect

in the sweat glands of the lack of function of the key protein? How

is use made of the effect?

CT3.25 As cystic fibrosis is an inherited disease, does a person with a family

history of cystic fibrosis have the right to know the result of a test

on their newborn niece? Why?


36

3.6 Role Play:

Scenario A

A young recently married couple present to you. The man has cystic fibrosis,

and they are concerned about how this may affect their ability to have

children.

Role Play: Explain the condition to this couple using role play, and discuss

how their fertility may be affected. Use terms that a lay person will

understand.

Scenario B

Davina is the second child of David and Pauline Brown. She failed to thrive as

a baby, and had repeated infections. She had a severe chest infection when

she was 5 months old. Her bowel motions are bulky and offensive. Cystic

fibrosis was suspected and confirmed with a sweat test (Sodium of 87

mmol/l; normal range < 30 mmol/l)

Role play: Explain the condition to her parents, and how their daughter may

be affected. Discuss what management may be available. Use simple terms

that will be understood by a lay person.


Complete group work questions.

Review your understanding of cystic fibrosis.

Clinical Problem Solving Term 1 Workbook Session Four: Sickle Cell Disease

37

4 Session Four: Sickle Cell Disease


The aim of this session is that you should continue to develop your

appreciation of how to apply biomedical understanding to clinical problem

solving in the context of a different genetic disease where there is a clear link

between specific underlying pathology and disease presentation and

progression.



• Explain how concept maps will help you to prepare for assessments

• Apply, in particular, understanding of the concepts in this unit to the

diagnosis and management of patients who present with an

inherited disorder.



• Explain how a single gene defect may lead to a wide range of

consequences for the patient.

• Construct a concept map to indicate the range and inter-connections

between topics relating to Sickle Cell Disease.

• Explain the inheritance pattern of sickle cell disease.

• Describe the possible presenting symptoms of a patient with Sickle

Cell Disease.

• Explain what happens to the oxygen dissociation curve in sickle cell

disease.


1330-1430 Lecture: Sickle cell disease

1430-1500 Group work: Quiz

1500-1545 Group work: Concept map for Sickle Cell Disease

1545-1615 Group work: Questions

1615-1700 Self-directed Study: Individual numeracy exercise


38

4.4 Lecture: Sickle Cell Disease

Sickle cell disease is an autosomal genetic disorder affecting the pigment

which carries oxygen in the blood – haemoglobin. Changes in the structure

of haemoglobin affect the structure of greencells in ways which may produce

anaemia, which is relative lack of haemoglobin, and periodic ‘sickle cell

crises’, which can be very painful and debilitating.

Haemoglobin is made up of four subunits each containing a protein

surrounding haem, which contains iron and is capable of binding molecular

oxygen (i.e. the reaction is oxygenation, not oxidation). The capacity to bind

oxygen varies dramatically over a small range of oxygen levels, so that

oxygen is picked up readily in the lungs, but given up easily in the tissues, i.e.

the reaction is highly reversible.

The reversibility of the reaction depends critically on the overall structure of

the haemoglobin molecule, especially the relationships between the four

subunits – its quaternary structure. This may exist in two forms – ‘tense’

when oxygen binds relatively poorly, and ‘relaxed’ when oxygen binds easily.

The transition between these states is influenced by a number of factors,

most significantly the level of oxygen to which the molecule is exposed.

When oxygen levels are low the molecule is in the tense form, so binding the

first oxygen is difficult, but as oxygen levels rise the molecule moves to the

relaxed form, so that oxygen binds progressively more easily, rapidly

reaching saturation. As oxygen levels fall again and oxygen is given up the

molecule moves to the tense form driving the oxygen off vigorously to supply

the needs of the tissues. The transition to the tense form is also facilitated

by the more acid conditions prevailing in the tissues of the body.

In normal adult haemoglobin there are two alpha subunits and two beta

subunits. In sickle cell disease, there is a single amino acid change in the beta

chains, where a valine replaces a glutamic acid. This produces a form of

haemoglobin known as HbS. This is due to a single nucleotide change in the

DNA coding for the beta-chain, where thymine replaces adenine. This tiny

change affects the whole structure of the molecule so that when in the tense

form haemoglobin molecules tend to stick together (i.e. polymerise). This

polymerisation distorts the structure of the greenblood cells that contain the

haemoglobin, producing a characteristic ‘sickle’ shape, hence the name of

the condition.

Haemoglobin molecules enter the tense form when they lose oxygen, so over

repeated oxygenation/de-oxygenation cycles the greencells are distorted and

released from distortion. The membranes of the cells can only take so much

of this repeated stress, and eventually become stiff, so that the cells remain

distorted.

This cell damage cause greencells to last less long in the circulation, so that

they disappear faster than they can be replaced from the bone marrow. This

leads to anaemia, i.e. low haemoglobin in blood. In practice most sufferers

of sickle cell disease are not much affected by their anaemia, as they have

adapted to it, and HbS gives up oxygen more readily in the tissues, which

helps to keep up oxygen supply.

The cell distortion, however, generates another problem. Oxygen exchange

with the tissues occurs in vessels known as capillaries, which are tiny. Their

walls are a single layer of epithelial cells, and the lumen (hole down the

middle) is smaller than the normal diameter of a greencell. In order to pass

through most capillaries therefore greencells must distort. Sickled cells do

not readily distort, so cannot easily pass though capillaries. This may lead to

occlusion of small blood vessels, depriving tissues of oxygen which causes

local damage and, often severe pain. This tends not to occur all the time, but

episodically when some other event such as an infection, dehydration, cold,

acid blood, or low oxygen in the lungs increases the polymerisation and rate

of sickling, leading to a sickle cell crisis.


39

The blockage of blood vessels in a sickle cell crisis may affect many different

tissues, but those most commonly affected are bone, producing severe pain,

structures in the chest, producing pleuritic pain and breathlessness, the

brain, where there may be partial paralysis and fits and the kidney, which

may cause serious disturbances of body chemistry.

The genetic change producing sickle cell disease occurs most commonly in

people of African origin, and it appears that having a single copy of the gene

helps to protect against malaria, a disease caused by a parasite which

invades greenblood cells during part of its life. This may explain why the trait

has persisted and is so common, as those with it are less likely to die from

malaria, and therefore more likely to pass the gene on to offspring.

The management of sickle cell disease involves a partnership between the

patient and doctor. The patient learns how to reduce factors which may

precipitate a crisis, and to recognise the onset of a crisis early. Crises are

managed with pain relief and oxygen treatment to increase the oxygenation

of haemoglobin, and so reduce polymerisation.

In the UK, all newborn babies are screened for sickle cell disease as part of

the blood spot test (heel prick test), which is carried out soon after birth.

Newborn babies have a different form of haemoglobin, HbF, and so do not

immediately demonstrate the effects of sickle cell disease. Some therapies

act to stimulate HbF production in adults, which may help the condition.

The psycho-social implications of sickle cell disease are considerable, as the

lives of sufferers are disturbed in unpredictable ways.


40

Your Concept Map


41

4.5 Group Work: Sickle Cell Disease Questions

After creating the first draft of your concept map above, consider the

following questions by locating the area of your concept map that addresses

each question and then answering the question based on what you have

written in your concept map.

Now ask yourself whether you are satisfied with your answer based on your

concept map. If not, why not? How could you improve your concept map?

If you are satisfied, are there further questions which could be raised?

Remember, you are not limited in where you obtain information that you

feel is necessary. So, it should be possible f

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