For each case of disordered haemostasis A–E, select the most appropriate option from the following list of findings.
1. Capillary abnormality.
2. Deficiency of factor VIII.
3. Increased fibrinogen level.
4. Deficiency of prothrombin.
5. Deficiency of vitamin K.
6. Excessive heparin activity.
7. Massive blood transfusion.
8. Platelet count 90 109 per litre.
9. Platelet count 20 109 per litre
- A 15-year-old child is admitted to hospital with recent onset of widespread purpura (pin-head areas of haemorrhage into the skin). Laboratory investigations reveal an abnormality which accounts for the bleeding tendency
- A 50-year-old man is receiving anticoagulant therapy (warfarin, a vitamin K antagonist) after heart valve replacement. He is admitted to hospital with haematuria (blood in the urine) and his INR (international normalized ratio, a measure of the prothrombi
- A 90-year-old women has blotchy purple areas about 5 cm diameter on her hands and arms. They are not uncomfortable and she has no health complaints.
- A 70-year-old man is operated on for aneurysm (swelling) of his aorta. Severe bleeding requires infusion of forty units of blood. His recovery is complicated by a bleeding tendency and he is found to have a very low level of fibrinogen. His treatment incl
- A 10-year-old child with no known medical problems has been admitted to hospital for persistent bleeding after tooth extraction. Haemostasis had been achieved initially after the extraction but subsequently prolonged oozing from the tooth socket began
Medicine
A. Option 9 Platelet count 20 109 per litre. Widespread purpura is due to failure of platelet plugging of capillaries and may be due to a low platelet count or to capillary abnormality. An abnormal laboratory test to account for this would be a low platelet count. Although both those given are below normal, only values below 20–40 109 per litre account for serious bleeding.
B. Option 4 Deficiency of prothrombin. The action of warfarin, a vitamin K antagonist, is to impair formation of several coagulation factors, notably prothrombin. There are a number of cardiological indications for the use of warfarin, including heart valve replacement. The value quoted is above the usual recommended range and the prolonged prothrombin time due to a low level of prothrombin would account for the bleeding.
C. Option 1 Capillary abnormality. With advancing age, capillaries like tissues generally become less resilient in the face of stress such as a relatively high internal pressure. This leads randomly to patchy areas of bleeding such as those described. Apart from their appearance they cause no problems.
D. Option 7 Massive blood transfusion. Massive blood transfusion may lead to widespread activation of the coagulation mechanism – diffuse intravascular coagulopathy. This in turn causes so much deposition of fibrin that the circulating fibrinogen level falls to levels which result in a bleeding tendency. Paradoxically heparin, by preventing the abnormal coagulation, allows the fibrinogen level to rise and can relieve the condition.
E. Option 2 Deficiency of factor VIII. This condition (haemophilia) does not interfere with initial haemostasis due to vascular closure, so the bleeding time is normal as in this case. However, when the vascular spasm wears off, failure to clot is revealed as a persistent ooze of blood. Treatment is by supplying the missing factor VIII.
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