Familial thrombophilia and idiopathic intracranial hypertension

Some cases of raised intracranial pressure, previously diagnosed as idiopathic intracranial hypertension (IIH), are now found to have intracranial venous sinus thrombosis which is linked to a prothrombotic state. This study looked at the prevalence of familial thrombophilia in cases of IIH with normal cerebral sinus imaging. Thirty patients with IIH, fulfilling the modified Dandy criteria, were prospectively enrolled to form the study group. All but two patients were female. All had a full risk-factor history taken and underwent investigation of rheological factors and thrombophilia, including tests for the factor V Leiden mutation, prothrombin G20210A allele, and hyperhomocysteinaemia. Ninety people made up the control group. Twenty-five patients had a normal thrombophilia screen. Two patients were heterozygous for the factor V mutation, two had mild raised levels of antiphospholipid antibodies, one of whom was transient, and one had reduced levels of free protein S. Both males and 28 females (90%) were obese (body mass index >25). Other lifestyle risk factors for thrombosis, such as smoking and the oral contraceptive pill, were not uncommon, and a positive or 1(st)-degree relative family history of deep venous thrombosis was found in three patients. No patient had the prothrombin G20210A variant or raised levels of homocysteine. Despite previous reports of a possible aetiological link between thrombophilia and IIH, the present study does not support this hypothesis.