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Pathology
Third Year, Pharmacy Dept.
College of Pharmacy 2nd Lecture
Dr. Ahmad H. Ibrahim
PhD. University of Science Malaysia USM Malaysia MSc . University of Science Malaysia USM Malaysia
Pathology
• Explain the disease by studying the 4 aspects
of the disease (characteristics of disease) : • Incidence and prevalence (epidemiology) • Aetiology • Pathogenesis • Morphological changes (clinical features).
Objectives
Characteristics of disease:
• There are characteristics of infectious disease
agents which determine whether or not an infectious disease will be transmitted to and
infect a host. • These characteristics also influence the
severity of the disease and even the outcome
of the resulting infection.
Incidence
• The “incidence” or incidence rate of a condition is the number of new cases per
population at risk in a period of time - usually
one year ( see Table 1 ).
Table 1: Incidence (millions) of selected conditions by WHO region, 2004.
a. New cases.
b. Episodes of illness.
c. Incidence of congestive heart failure
due to rheumatic heart disease,
hypertensive heart disease, ischaemic
heart disease or inflammatory heart
diseases.
d. Incidence of injuries severe enough
to require medical attention.
e. An entry of 0.0 in the table refers to
an incidence of less than 0.05 million
(less than 50 000).
Incidence • is the rate of new cases (or newly diagnosed) of the
disease. It is generally reported as the number of new cases occurring within a period of time (e.g., per month, per year). • It is more meaningful when the incidence rate is reported as a fraction of the population at risk of developing the disease (e.g., per 100,000 or per million population).
Incidence • The accuracy of incidence data depends upon the
accuracy of diagnosis and reporting of the disease. • Incidence rates can be further categorized according to
different subsets of the population - e.g., by gender, by racial origin, by age group or by diagnostic category.
Prevalence • is the actual number of cases alive, with the disease
either during a period of time (period prevalence) or at a particular date in time (point prevalence). • Period prevalence provides the better measure of the
disease load since it includes all new cases and all deaths between two dates, whereas point prevalence only counts those alive on a particular date.
Prevalence • The prevalence of an illness or condition is the number
of individuals who have the condition at any moment. Such as epilepsy, individuals will not have symptoms most of the time, but still have the condition.
Prevalence • The effects of the illness and the loss of health
will vary from one individual to another. • The result may be serious impairments and disability or only mild impairments or disability.
Prevalence • "Incidence" means the number of people who
are newly diagnosed with a condition, while
"prevalence" includes newly diagnosed people, plus people who were diagnosed in the past with the condition
Epidemiology
• Incidence and Prevalence are words used in the
field of epidemiology.
• is the study of factors affecting the health and
illness of populations. • means the ways of transmission of a disease inside
community and the leading caused of spread.
Etiology • Why a specific disease occurs?
• Factors that produce predispose toward a
certain disease or disorder. • Cause of disease - primary etiology known, idiopathic unknown. • Help in diagnosis understanding and , treatment of disease.
Etiology • is the study of causes.
• In medical research, etiology can be used to
provide clues into methods of treatment. • In medicine, etiology refers to the many factors coming together to cause an illness. • It is normally the focus of epidemiological studies.
Major etiological factors: • Genetic: age, genes.
• Acquired: infectious, environmental, nutritional etc. • Etiology is followed by pathogenesis
Pathogenesis
-means step by step development of a disease and the chain of events leading to that disease due to a series of changes in the structure and function of a
cell, tissue, and organ being caused by a microbial (inflammation). -Most disease caused by multiple pathogenetical process
together. -The pathogenesis of a disease is the mechanism by
which an etiological factor causes the disease
Infection: This is when an organism enters the body, increases in number and causes damage to the host in the
process.
pathogen: This is an organism that is able to avoid the
various normal defences of the human host to cause
infection.
Stages of Infection
1) The time between the exposure to an agent and the first appearance of clinical symptoms is called the incubation period 2) There may follow a period known as the
prodrome, where non-specific signs and symptoms
such as headache, fever are noted,
It was nothing that you would think was anything’: Qualitative analysis of appraisal and help seeking preceding brain cancer diagnosis
3) Period of signs and symptoms known as acute
stage.
4) Once the acute stage has passed, a period of resolution occurs, where the severity of the
symptoms gradually decreases
5) finally convalescence where the symptoms have
largely gone, but the body is still recovering.
Types of Infection
1/ Acute infection: an acute disease is a disease with either or both of: A/ a rapid onset; B/ a short course (as opposed to a chronic course).
Types of Infection 2/ a chronic disease is a disease that is long-lasting.
The term chronic describes the course of the
disease, or its rate of onset and development.
Hypothetical mechanism of chronic diseases in correlation with COVID-19 infection
Thank you
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