Surgery Script 2

7/27/2019 Surgery Script 2

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Liver disorders

This lecture is a continuation of the last lecture subjects, and we are

going to start with liver disorders.

To learn about liver disorders we should remember some of its functions,

to know the complications that might result.

Liver functions:

Liver is important in drug metabolism; many drugs are metabolized bythe liver, so if any problem occurs in the liver impaired drug

detoxification occurs, leading to drug toxicity.

most ofthe drugs are either metabolized in the liver or kidneys Liver is responsible for production of coagulation factors (by means of

vitamin k ) , and so problem in liver might result in bleeding.

Liver cirrhosis is a major disease affecting the liver;

Liver is like a reservoir of viral infections like hepatitis A, B, C and D tolive, which is the leading cause of cirrhosis in eastern countries.

Alcohol consumption (more than 21 units a week for Males, 14 forFemales) is the leading cause of liver disease in western countries. And

here the liver is no longer an active organ; it is just a fibrous tissue.

If any symptom of liver disease mainly jaundice was confirmed by the

patient or if he has one of these diseases or multiple of them combined ,

referral and proper consultation about his situation is needed , we also should

be very cautious in treating the patient i.e. what sort of medication should I

give post operatively, many drugs should be avoided:

Analgesics like paracetamol for example should not be given for liverdisease patients, instead, we give them NSAIDS (because paracetamol

is metabolized in the liver ,while NSAIDs are metabolized in kidneys )

,reduction of drug dose is another option ,but of course always done

under proper consultation from a physician or pharmacist .


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Any local anesthetic especially of the amide group we use like lidocaineand mepivacaine.

Valium (which is a benzodiazepine like lorazepam and diazepam)

Antibiotics like penicillins in generalall these categories of drugs should not be given for a patient

suffering from liver disease; you have to consult his physician.

If a patient comes with an infectious carious tooth for example and he

has got problems in his liver, such patients need comprehensive

treatment, they should do full blood test like bleeding profileINR,PT,PTT, which are usually prolonged in liver disease patients, and

liver function test which are also usually high and accordingly we give

them the proper treatment ,because they have bleeding tendency we

should be ready to deal with them not in our service alone but in the

hospital environment with some specialists who know how to manage

patients with sever bleeding, who tend to use VITAMIN K IV as a

main drug in management of such patients . vitamin K is the

source of too many factors.

More about hepatitis:

2 types, active and chronic hepatitis, active hepatitis is when thepatients have the virus in all body fluids and so they are very

infectious.

Hepatitis B and C are the types we are worried about. As dentists, we all should have the hepatitis vaccination, to maintain

our health and jobs because if any dentist was diagnosed with

hepatitis he/she would be suspended from their career. They found that hepatitis B is the easiest virus to be transmittedby needle stick injury followed by hepatitis C, then HIV.

On the other hand hepatitis B has a vaccine while hepatitis C (fatalityof 50%, others have the risk to develop hepatocellular carcinoma)

and HIV dont, and they are more fatal.


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Endocrine disorders

Diabetes mellitus:

*Persistent elevation of blood glucose level.

*Normal fasting blood glucose is 100 mg/dl, anything above that is not normal

even if it is an elevation of 20 mg/dl.

***Glucose tolerance testis a good test to determine if a patient is diabetic,

we first check the fasting blood glucose, and then we give him glucose and we

recheck blood glucose after two hours, if it is below 11.1 mmol/liter then this

patient is not diabetic, if it is above he is definitely diabetic.Fasting plasma glucose (measured before the OGTT begins) should be below6.1 mmol/L (110 mg/dL). Fasting levels between 6.1 and 7.0 mmol/L (110 and125 mg/dL) are borderline, and fasting levels repeatedly at or above 7.0 mmol/L(126mg/dL) are diagnostic of diabetes reference Wikipedia.

***Diabetes mellitus is a disorder caused by an absolute or relative lack of

insulin: there can be a low output of insulin from the pancreas or the peripheral

tissues may resist insulin.

it is Absolute when the patient has diabetes type 1, they haveautoantibodies against the B- cells of Langerhans, occurs in young

people, they have deficient insulin, they sustain this disease early, it is

insulin dependent from the beginning, no benefit from giving oral

hypoglycemic drugs, they need insulin injection .This type is

genetically determined (doesnt mean it is inherented, because it is

an autoantibody) .

Type 2 which is non insulin dependent (there is enough insulin in theirbodies), but they have resistance to the receptors of insulin (they wontlet glucose get in) and it is inherent.

Gestational diabetes: happens in pregnant females usually in theirthird trimester, they usually recover after delivery but such females are

very susceptible to have diabetes in the future.


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P.S infants of diabetic mothers are born overweight because there is too

much sugar in blood and sugar can cross the placenta without

hormones, so the baby will get bigger .Because glucose travels across the placenta, in untreated gestationaldiabetes the fetus is exposed to consistently higher glucose levels. Thisleads to increased fetal levels of insulin (insulin itself cannot cross the

placenta). The growth-stimulating effects of insulin can lead to excessivegrowth and a large body (macrosomia). After birth, the high glucoseenvironment disappears, leaving these newborns with ongoing high insulin

production and susceptibility to low blood glucose levels (hypoglycemia)wikipwdia

Oral manifestation of diabetes mellitus

high level of alveolar bone resorption xerostomia delayed or defective wound healing gingivitis pulpitis in non carious teeth impaired sensation in tongue Acetone smell (ketoacidosis): hyperglycemia-body will degrade fat

(triglycerides) and supply the organs with some other nutrient--->

waste products of such process are ketone bodies. Patients who reach

this level are very poorly controlled.

Of course this happens in non controlled diabetic patients, controlled diabetic

patients can be treated as normal people.

Dental management:

*diabetic patients are given early morning appointments, we want them to

come after theyve had their breakfast and medicine, and most importantly

not to miss a meal, if they do, hypoglycemia is the result. SO (they have their

breakfast, come to clinic, get treated, after a couple of hrs they can resume

their diet),, they are advised to have small meals with low carbohydrates.

*Regarding premedication some would advise certain antibiotics as

prophylaxis if the patient come as an emergency.

*Make sure appointments are short (about 30 min).
http://en.wikipedia.org/wiki/Insulinhttp://en.wikipedia.org/wiki/Insulinhttp://en.wikipedia.org/wiki/Hypoglycemiahttp://en.wikipedia.org/wiki/Hypoglycemiahttp://en.wikipedia.org/wiki/Hypoglycemiahttp://en.wikipedia.org/wiki/Hypoglycemiahttp://en.wikipedia.org/wiki/Insulin


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RENAL FAILURE

renal patients are Immunocompromised , so they need antibioticprophylaxis .

If they are having hemodialysis, then they are taking anticoagulants, andthis will limit and might prevent you from treating them, so the best

day to treat such patients is the day after hemodialysis because the

blood will be in its best performance it is fresh and new, and the blood is

free of heparin (the blood lost its bleeding tendency).

Antibiotics before and after treatment is required for these patients. They are prone to have anemia, because they have deficient

erythropoietin which is normally produced from the kidneys. And so

only minimal bleeding is allowed.

We should check if those patients have any sort of viral diseases,, asthey are prone to catch a disease from the hemodialysis machines if they

were not very well sterilized .

End of part one of the lecture, now we start with another topic which is

bleeding disorders.

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Bleeding disorders

Hemostasis consists of three phases; primary, secondary and tertiary.

Primary: what vessels do to stop bleeding (vasoconstriction) alongwith the platelets which aggregate on injured collagen only and they

release ADP, thromboxane A2 which will increase the number of blood

cells (chemotaxis to start a cascade and initiate the secondary phase).

Secondary: the most important phase, which is the coagulationcascade (intrinsic, extrinsic and common pathways). Until it forms thefibrin mesh which will stop the bleeding.

Tertiary: fibrinolysis to get the vessel back to its normal state bymelting away the fibrin mesh, otherwise thrombosis would result,

which actually happens if they have problem in this phase and they

develop thrombotic accidents all over the body.


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.

It is very important to take a comprehensive history from the patient,

esp. about any previous or current diseases e.g.: liver or kidney diseases. Any

medications e.g: heparin, warfarin or aspirin. Family history

It is very helpful to ask the pt. about previous tooth extractions ortonsillectomy, and if any complications happened at the time. We would

expect that the pt has no diseases like hemophilia A and von willebrand

disease.

Drugs are also important because there are some medications especiallyfor older people which can lead to bleeding, or the patient will have a

tendency for bleeding because of them.

Renal diseases, hepatic diseases, infections, hepatitis B and C will causea problem in the liver in general which will cause bleeding tendency.


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Examination, pts have wide spread purpura or hemarthrosis, it is sign ofbleeding problem.

Laboratory investigations, of course in the end if you have any suspicionby history if he was taking any medication or if he has any disease or

illness or by examination if it revealed some suspicious findings, always

the definitive diagnosis would be LABORATORY.

Test for homeostasis platelets, now the normal count for platelets is150-400*10^9/Liter, less than 150*10^9/L then the patient has problems in

his platelets, but the range differs sometimes because some people say

its from

100-400* 10^9,and its not something constant, for example you mightgo check your platelet count and find that its 200,then in the next month

you might find it 250 so again it is not a constant number all the time

but the important thing is that it stays within the normal range. The

platelet type is affected by the platelets count and the function in the

blood vessels.

Now were going to talk about the platelet tests:

Bleeding time, the normal bleeding time is from 2-9 minutes, its avery long span, and if the patients bleeding time is more than 9

minutes, either he has thrombocytopenia (low platelet count) or his

platelets arent functioning , there might be a 3rd reason which is a

problem in the blood vessels which we will talk about later.

Hess test, it is not a reliable test but to perform the test, pressure isapplied to the forearm with a blood pressure cuff inflated to between

systolic and diastolicblood pressurefor 10 minutes. After removing the

cuff, the number ofpetechiaein a 5 cm diameter circle of the areaunder pressure is counted. Normally less than 15 petechiae are

seen, 15 or more petechiae indicate capillary fragility,which occurs due

to poorplateletfunction,bleeding diathesisorthrombocytopenia.

Now as for coagulation tests:
http://en.wikipedia.org/wiki/Blood_pressurehttp://en.wikipedia.org/wiki/Blood_pressurehttp://en.wikipedia.org/wiki/Blood_pressurehttp://en.wikipedia.org/wiki/Petechiaehttp://en.wikipedia.org/wiki/Petechiaehttp://en.wikipedia.org/wiki/Petechiaehttp://en.wikipedia.org/wiki/Platelethttp://en.wikipedia.org/wiki/Platelethttp://en.wikipedia.org/wiki/Platelethttp://en.wikipedia.org/wiki/Bleeding_diathesishttp://en.wikipedia.org/wiki/Bleeding_diathesishttp://en.wikipedia.org/wiki/Bleeding_diathesishttp://en.wikipedia.org/wiki/Thrombocytopeniahttp://en.wikipedia.org/wiki/Thrombocytopeniahttp://en.wikipedia.org/wiki/Thrombocytopeniahttp://en.wikipedia.org/wiki/Thrombocytopeniahttp://en.wikipedia.org/wiki/Bleeding_diathesishttp://en.wikipedia.org/wiki/Platelethttp://en.wikipedia.org/wiki/Petechiaehttp://en.wikipedia.org/wiki/Blood_pressure


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Activated Partial Thromboplastin Time (aPPT): is a performanceindicator measuring the efficacy of both the "intrinsic" and the common

coagulation pathways. Apart from detecting abnormalities in blood

clotting, it is also used to monitor the treatment effects withheparin, a

majoranticoagulant.It is used in conjunction with theprothrombin time(PT) which

measures the extrinsic pathway.

The normal time for PPT is 25 seconds, now if a patient came to

the clinic to do an extraction and he is on heparin we a PPT test, if its

high then that means that the blood is very thin so we cannot perform

the procedure because he will keep bleeding.

Prothrombin Time : it works on the extrinsic pathways, the normaltime is 12 seconds

INR (International normalized ratio):its the same as the PT but it isthe PT compared to a control, which means the PT of the patient dividedby the PT of a normal person multiplied by 100%, but If that patient

takes warfarin which works on PT (fights the extrinsic pathway

factors) we expect that the PT will be high so as a result the INR will be

high as well.

Now warfarin is a widely used medication for anyone with heart

problems and has a tendency to develop a thrombosis, so to make it

easier between all the medical professionals instead of asking about the

PT of the patient which could be for example 15, it is easily

comprehended to use the INR values which can be 1,2,3 etc

The other tests youre not really concerned to about,

Fibrinogen degradation product (FDP)> the D dimer is important fordeep venous thrombosis, they found that Its very sensitive but not

specific which means it could be in many people including the ones who

have DVT, for example if we suspect that a certain patient has DVT we

do a D dimer test, if its high then there is a very high probability that

this patient actually has DVT.

Specific factor assays. Now these factors, protein C and protein S andhereditary resistance to activated protein C they are for the coagulation,

if someone has a problem in these factors he will develop or tend to

have a thrombosis.

Tests of physiological inhibitors
http://en.wikipedia.org/wiki/Heparinhttp://en.wikipedia.org/wiki/Heparinhttp://en.wikipedia.org/wiki/Heparinhttp://en.wikipedia.org/wiki/Anticoagulanthttp://en.wikipedia.org/wiki/Anticoagulanthttp://en.wikipedia.org/wiki/Anticoagulanthttp://en.wikipedia.org/wiki/Prothrombin_timehttp://en.wikipedia.org/wiki/Prothrombin_timehttp://en.wikipedia.org/wiki/Prothrombin_timehttp://en.wikipedia.org/wiki/Prothrombin_timehttp://en.wikipedia.org/wiki/Anticoagulanthttp://en.wikipedia.org/wiki/Heparin


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Vascular Defects

In addition to increased bleeding time and defective platelets we also have

defects in the blood vessels like patients with Hereditary Hemorrhagic

Telangiectasia, its an autosomal dominant hereditary disease, patients who have this disease, their skin is very thin to the point that

you clearly see the vessels in their faces,

they can easily have a nose bleed Its a constant problem for them because even their vessels are very

thin. So they develop recurrent bleeding from fragile vessels, iron

deficiency anemia

They can develop cardiac failure because as we said in the previouslecture patients with severe iron deficiency anemia will develop cardiac

failure.

Treatment involves cryosurgery orAr (argon) laser where they burnthe area from inside the nose to prevent recurrent bleeding.

Dental aspects>

they can bleed from any minor trauma, regional anesthesia should be avoided. We mean by regional the ID

blocks, and it should be avoided because the needle goes through many

layers which can cause bleeding. Problems with GA, because when we insert the tube to give general

anesthesia we either put it through the nose or the mouth and that can

cause bleeding because of the very fragile vessels.

Bleeding disorders

They can be divided into two parts,

either there is a problem in the production (thrombocytopenia), or there is high destruction which means that the body is producing auto-antibodies which destroy the

platelets

Or the patient is taking medications like aspirin (anti plateletmedication which if the patient took one tablet of, it will

destroy the platelets for 8 days) which also leads to the


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destruction of the platelets and having them below normal

limits.

We talked about bleeding time; its a test for patients on aspirin. Hess test we said it is not that reliable or specific.

Thrombocytopenia is when the platelet count is less than100*10^9/L.

clinical features include> petechiae, ecchymoses and post operative

bleeding.

Now we talked about the causes of platelet destruction, which are medications

and the other is auto anti-bodies which is like idiopathic thrombocytopenic

purpura (ITP)

idiopathic thrombocytopenic purpura (ITP)this is a strange disease, it can develop at anytime, for example a patient

comes to you and tells you that all of a sudden he woke up with red

spots all over his bodyor he has had these red spots for a week so you

check his oral cavity and find that there are red spots in his mouth as

well, he has inflamed gum with high tendency to bleed, now these

patients have developed all of a sudden an autoimmune disease which

is called ITP, where theirplatelets count can drop really low (


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Other patients develop splenomegaly because all of the destructed platelets go

to the spleen, and in the end they will have to do a splenectomy.

Coagulation defects

Haemophilia A (the most common coagulation disorder)It is not a bleeding problem, Its a coagulation problem, which means its

related to the factors, to the secondary part of the haemostasis process. Its an

x-linked disease, which means that males are infected whereas females

might be infected or carriers of the disease. If the female was a carrier then

she can transmit the disease to her offspring but she is not a symptomaticpatient.

These patients have deficiency in factor VIII and deep bleeding intomuscles and joints (haemarthroses) due to the constant pressure on

the joints because of movement so it will eventually cause bleeding in

these joints.

Bleeding from extraction may continue for days or weeks and that isvery serious.

now in platelet problems the patient takes aspirin and it stops the function ofthe platelets for almost a 8 days as we said, but this doesnt mean that we tell

the patient if you want to do an extraction you should stop the aspirin and

come after 8 days so we could to the extraction; because they did a

comparison between the importance of aspirin for the patient and the

importance of stopping aspirin to do an extraction, and they found that it is

much more important for the patient to stay on aspirin because the bleeding

will be very minor and can be controlled.

Now in haemophilia A, its a coagulation problem so its the opposite, also in

patients on warfarin; the bleeding is very serious to the degree they can diefrom a simple extraction because they lack factor VIII.

Now the severity of the bleeding depends on the severity of the trauma,

which means if a patient came with haemophilia, haemophilia has types, mild,

moderate and severe, if that patient had moderate haemophilia and you did a

major surgery for him (extraction of a very deep wisdom tooth), the


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possibility that he will develop bleeding is high but if it was a minor surgery

he might not have any problem and you wont even notice the bleeding.

Level of factor VIII deficiency; now lets say that the normal level of

factor VIII is 100%, until 25% a patient with haemophilia can live his life

normally without any problems. Patients with 5-25% of factor VIII will have mild haemophilia, patients with 1-5% will have moderate haemophilia, and less than 1% will have severe haemophilia.

Diagnosis of haemophilia A comes mainly when taking the history of the

patient, and the clinical picture as well because he might have haemarthroses,

hell have history of bleeding and elevated aPTT but normal PT and bleeding

time.

Management of haemophilia A patients:

replacement of factor VIII either by Cryoprecipitate, which is a group of factors including factor VIII Human factor concentrate which is given in a less quantity than

cryoprecipitate

or we could give him human freeze dried factor VIII.The important thing is to replace factor VIII despite of the method.

Dental aspects

We have to make sure that haemophilia A patients apply preventivedental care, because if they needed extractions it will be a very difficult

procedure because they have to take factors and after a while these

factors may develop auto antibodies so youll have to give him

something else (factor x for example), so its a very complicated

procedure. So preventive dentistry is very important for such patients.

Always regional anesthesia is never used with patients with coagulationproblems unless factor VIII is higher than 30%, and as for the simple

extractions factor VIII should be 50-75%.

All surgical procedures should be done in one visit following factor VIIIreplacement. for example if a haemophilia patient came and we gave

him a factor replacement, we have to use the time from the minute we

gave him the replacement so we perform every surgery needed and that
http://en.wikipedia.org/wiki/Cryoprecipitatehttp://en.wikipedia.org/wiki/Cryoprecipitatehttp://en.wikipedia.org/wiki/Cryoprecipitate


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is to take advantage of the high factor VIII present in the blood at that

time.

Now after we do the extractions we give him a mouthwash called

tranexamic acid, which is either a mouth wash or given as pills, both

cases its local, it works to decrease fibrinolysis (which is the 3rd step of

hemostasis) because in these patients we try to delay this process to

make sure that the fibrin mesh is well established, so we give them

something which prevents fibrinolysis (tranexamic acid) and we give

him antibiotics of course.

Haemophila BIt is just the same as haemophilia A in terms of management but the only

difference that the deficiency is in factor IX.

Von willebrand diseaseIts the most common bleeding disorder, and it is one of the most common

diseases in our region, the problem here is in von willebrands factor, this

factor is a link, as we said before the platelets and the blood forms then the

mesh so this factor is the link between them. So it is not really known if this

disease is related to the primary hemostasis or the bleeding tendencies like

telangiectasia for example, or the coagulation process, but its more close to a

bleeding disorder.

It is also autosomal dominant so it affects both males and females the patient will develop bruising all over his body and will have

prolonged blood oozing from the sockets after extraction,

his bleeding time will be prolonged in all types, but the PTT could behigh or normal, thats why this disease is closer to the primary type.

Warfarin is medication which works against factor VIII,,,,well talk about it in

the next lecture

The End


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Done byRuby Daoud & Narmeen Ghannam

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Surgery Script 2