Hyperhomocysteinemia masquerading as pulmonary embolism

We describe a 30-year-old male who presented with acute onset of breathlessness, tachycardia, and palpitations associated with distension of jugular vein and clear lungs on physical examination. The chest X-ray was normal and ECG was showing S1Q3T3 and right ventricular strain pattern. His 2-D echocardiography was showing dilated right atrium, right ventricular dilatation and moderate pulmonary arterial hypertension. He was found to have thrombosis involving left side of deep venous system with normal superficial venous system (Doppler proved). All routine blood investigations for etiology of recurrent DVT were normal except serum homocyteine level, which was significantly raised. Megaloblastic anemia on peripheral smear and hyperhomocysteinemia prompted us to search for its cause, which was subsequently found to be vitamin B12 deficiency. Such an association of megaloblastic anemia due to vitamin B12 deficiency leading to hyperhomocysteinemia and subsequent thrombosis in left venous system presenting as acute pulmonary embolism has not been described earlier in the medical literature.