40 year old lady presented with sudden onset of breathing difficulty. Clinical examination was essentially normal except for tachycardia and tachypnea. She gives history of two episodes of lower limb pain and swelling, first episode was 15 years back during her first pregnancy and second episode 3 months back. What would be the hematological abnormality respoinsible for her condition:

Here the patient is probably suffering from pulmonary embolism as the major symptom of pulmonary embolism is sudden onset of breathlessness. Chest examination will be normal. As the patient gives history of recurrent episodes of lower limb swelling, she must be suffering from reccurrent deep vein thombosis as a result of some thrombophilic condition. FACTS: Heritable causes of venous thrombosis 1. Antithrombin deficiency and factor V leiden mutation 2. Protein C and S deficiency 3. Activated protein C resistance 4. Polycythemia can cause venous thrombosis but in this patient there are no features to suggest polycythema Ref: Harrison, Edition - 18, Page - 987