Idiopathic intracranial hypertension: need to rule out cerebral venous sinus thrombosis

I thank Drs. Micieli and Micieli for their report on fulminant idiopathic intracranial hypertension, which highlighted the importance of promptly considering interventions like optic nerve sheath fenestration or shunting in the setting of vision loss, rather than just standard medical therapy with acetazolamide.1 However, a key caveat in the diagnostic process for idiopathic intracranial hypertension that is worth noting is the need to rule out secondary causes of intracranial hypertension, the most important one being cerebral venous sinus thrombosis, which can exactly mimic the clinical symptoms and examination findings of idiopathic intracranial hypertension. There are critical implications for management, as patients with cerebral venous sinus thrombosis require anticoagulation.

Consequently, the diagnostic criteria for idiopathic intracranial hypertension require a normal neuroimaging result, including venography with no evidence of abnormal meningeal enhancement or venous thrombosis.2 This can be accomplished using computed tomography or magnetic resonance imaging with venography, but the latter has the added advantage of also potentially showing supportive features of idiopathic intracranial hypertension such as flattening of the posterior globes, tortuous optic nerves, enlargement of the pre-optic optic subarachnoid space, empty sella turcica, or narrowing of the transverse venous sinuses.

The presence of 3 or more of these findings is required to make the diagnosis of suspected idiopathic intracranial hypertension in the absence of papilledema or sixth nerve palsy, although idiopathic intracranial hypertension without papilledema is a controversial entity.3