A thirty-five-year woman presents with history of trauma to her left hand and a bruise developing the next day. She has a history of recurrent spontaneous abortions. There is also history of delayed separation of umbilical cord beyond one month in infancy.

The most likely cause is:

1. Thrombocytopenia
2. Platelet function defect
3. Factor 8 deficiency
4. Factor 13 deficiency
5. Factor 7 deficiency

Answer: 4

Explanation:
Factor 13 is responsible for cross-linking of fibrin and stabilization of clot, symptoms of delayed hemorrhage are secondary to instability of clot. Delayed bruising, delayed separation of umbilical cord, and recurrent spontaneous abortions are modes of presentation.

Platelet disorders and other clotting factor deficiencies present with immediate bruising. Delayed separation of umbilical cord and recurrent spontaneous abortions are absent in other factor deficiencies.

Q. In the above patient, which of the following test is expected to be abnormal
1. Platelet count
2. PT
3. PTT
4. 5 M urea clot solubility test
5. Euglobulin clot lysis time

Answer:4

Explanation: In Factor 13 deficiency, PT and PTT are normal.

In Factor 13 deficiency, there is increased solubility of clot because of failure of cross-linking. The normal clot remains insoluble in presence of 5 M urea, while it dissolves in Factor 13 deficiency.

Euglobulin clot lysis time is used to  assess a reduction of fibrinolysis.