This is a case of cerebral venous thrombosis secondary to hyperhomocysteinemia caused by vitamin B12 deficiency in a 32-year-old Indo-Aryan man. A detailed coagulation workup led us to find the etiology of cerebral venous thrombosis in this patient who followed a strict vegetarian diet and had vitamin B12 deficiency leading to hyperhomocysteinemia.
A 32-year-old Indo-Aryan man presented to our emergency department with history of frequent vomiting, moderate to severe headache and giddiness for past 5 days. He also developed weakness of the right side of his body along with altered sensorium over last 24 hours prior to presentation. There was also history of one episode of generalized tonic-clonic seizures prior to onset of weakness. His past medical history was not suggestive of any major illness/drug treatment. His family history was non-contributory and he had no addictions. He was afebrile with pulse 86/minute and blood pressure of 126/74 mmHg.
On neurological examination, he was drowsy and was responding poorly to verbal commands. He was having hypertonia and grade III power in his right upper limb and lower limb. Deep tendon reflexes were mildly exaggerated and Babinski sign was positive on right side. His chest, abdomen, and cardiovascular system examination were unremarkable. His preliminary blood examination revealed macrocytic anemia with hemoglobin (Hb) of 11.4 g/dl and mean corpuscular volume (MCV) of 110 fl. Peripheral blood film showed macrocytes and macro-ovalocytes with hypersegmented neutrophils. He had low serum cobalamin levels 68 pg/ml (200–600) with normal folate levels. Test for anti-intrinsic factor antibodies was negative and there was no evidence of gastric atrophy on stomach biopsy. Cerebrospinal fluid (CSF) examination was normal along with negative immunological profile: antinuclear antibodies (ANA), antineutrophil cytoplasmic antibodies (ANCA), lupus anticoagulant and antiphospholipid antibodies.
A detailed thrombophilic workup showed normal prothrombin time 12.8 seconds (11.4–13.7), activated partial thromboplastin time 32.6 seconds (27.8–41.8), protein C 106% (70–140%), protein S 98% (70–140%), and antithrombin III 88% (80–120%). His fibrinogen levels were normal and assays for factor V Leiden and prothrombin gene mutation were negative. The only abnormality was raised fasting total serum homocysteine levels of 36 μmol/l (5.0–13.9). A non-contrast computed tomography (CT) scan of his head was inconclusive. Magnetic resonance imaging (MRI) of his brain showed mixed signal intensity lesion in right posterior parieto-occipital lobe with areas of hypointensity in T2-weighted images. T1-weighted axial images at the same levels showed areas of hyperintensity in the above lesion due to hemorrhage. Magnetic resonance (MR) venography showed no signal in right transverse and sigmoid sinus due to venous thrombosis. A diagnosis of cerebral venous thrombosis due to Hhcy secondary to cobalamin deficiency was made.
He was treated with sodium valproate 20 mg/kg administered intravenously followed by orally administered valproate 20 mg/kg in two divided doses which was gradually escalated on follow-up visits. He was also administered cerebral decongestants, initially mannitol 100 ml 8 hourly for 2 days followed by orally administered glycerol 30 ml 8 hourly for 1 week. In addition, he was administered parenteral cyanocobalamin 1000 μg once daily for 7 days along with low molecular weight heparin. Gradually he regained sensorium, his power improved, and he was discharged on orally administered sodium valproate, warfarin, and methylcobalamin. On subsequent monthly follow-ups, his international normalized ratio (INR) was regularly monitored and maintained between 2.0 and 3.0. He remained seizure free thereafter and was continued on sodium valproate 750 mg twice a day. On neurological examination he showed significant improvement, initially he was walking with support and later he was fully ambulatory on his own. Repeat investigations done at 6 months after stopping anticoagulants showed normal serum cobalamin 364 pg/ml (200–600) and fasting total homocysteine levels 8.4 μmol/l (5.0–13.9). The rest of the thrombophilia profile was within normal limits.