A study of hyperhomocysteinemia in cerebral venous sinus thrombosis

Background & objectives: Vegetarianism may result in low vitamin B12 and acquired hyperhomocysteinemia leading to thrombotic conditions such as cerebral venous sinus thrombosis (CVST). The clinico-radiological presentation and outcome of patients with hyperhomocysteinemia may be different from those without, but there is a paucity of information. This study was undertaken to find out the relationship of homocysteine (Hcy) with vitamin B12, folic acid and methyltetrahydrofolate reductase (MTHFR) mutation in the patients with CVST, and compare clinico-radiological severity and outcome of patients with and without hyperhomocysteinemia. Methods: Ninety-six CVST patients in whom Hcy level was measured, were included, and their risk factors and neurological, magnetic resonance (MR) imaging and MR venography findings were noted. They were evaluated for prothrombotic conditions including Hcy, vitamin B12, folic acid and MTHFR 677C -> T mutation. Three month outcome was categorized as death, poor and good. Results: Seventy three per cent patients had risk factors; hyperhomocysteinemia in 52.1 per cent, protein S deficiency in 47.8 per cent, protein C deficiency in 19.4 per cent, MTHFR 677C -> T mutation in 30.7 per cent, antinuclear antibody 11 per cent, and Factor V Leiden mutation in two per cent each. Thirty two per cent patients with hyperhomocysteinemia had no other thrombotic cause, and 22 per cent of them had either vitamin B12 and or folic acid deficiency only. The patients with hyperhomocysteinemia more frequently had vitamin B12 deficiency (70 vs. 13%), MTHFR 677C -> T mutation (47.5 vs. 9.1%) and superior sagittal sinus thrombosis (78 vs. 56.5%) than normal Hcy group. The clinico-radiological severity and outcome were similar. Interpretation & conclusions: Hyperhomocysteinemia was an important correctable risk factor of CVST in patients from northern India, and majority of them had either low vitamin B12 level or MTHFR mutation.