Progressive headache may indicate CVT

Isolated headache is sometimes the only neurological sign of cerebral venous thrombosis (CVT), according to French investigators. In such cases, CVT most often involves a lateral sinus.The investigators studied patients with CVT presenting with isolated headache, normal brain computed tomography (CT) and normal cerebrospinal fluid (CSF) examination. From a prospective study of 123 consecutive patients with CVT, headache was the only sign in 17 patients. Onset of headache was progressive in 11 patients, acute in 3 patients, and thunderclap in 3 patients. Once established, the headache was continuous is almost all (n = 15) patients and usually unilateral (n = 13).The authors point out that the patient characteristics are biased in favour of CVT and headache due to their centre treating a large number of CVT patients and also running an emergency headache centre. Eight of the 17 patients were recruited through the emergency headache centre and nine were admitted directly to the neurology unit.There were a number of predisposing factors or causes of CVT among the patients, including current oral contraceptive use (n = 9) and pre-existing conditions. The lateral sinus was most frequently involved (n = 15), either alone (n = 8), with jugular vein thrombosis (n = 4) or with other sinuses (n = 3). The "unusually high" frequency of lateral sinus involvement was in contrast to the low frequency of superior sagittal sinus involvement (n = 4), probably because the latter is usually associated with other neurological signs, say the authors.The headache mechanism in the absence of intracranial hypertension, subarachnoid haemorrhage, meningitis, or intracranial lesion is unknown, the authors say. They suggest, "Stretching or irritation of nerve fires in the walls of the occluded sinus is a possibility. It is also possible that a local inflammatory reaction occurs with dilatation of vessels in the sinus walls?" They conclude that their results indicate a need for MRI in all patients with recent severe, persisting, unilateral and throbbing headache (progressive or thunderclap) with normal CT scan and CSF examination.Reference...