Table 1 Diagnostic criteria for idiopathic intracranial hypertension syndrome (IIH) (adapted from Friedman DI, et al., 2013) [8]

Diagnostic criteria for IIH: A-E required

a. Papilloedema

b. Normal neurologic examination, except for cranial nerve abnormalities

c. Neuroimaging: normal brain parenchyma without evidence of hydrocephalus, mass, or structural lesion and no abnormal meningeal enhancement on MRI, with and without gadolinium, for typical patients (female and obese), and MRI, with and without gadolinium, and magnetic resonance venography for others; contrast-enhanced CT may be used if MRI is contraindicated or unavailable*

d. Normal CSF composition

e. Elevated LP opening pressure (> 25 cmH2O in adults; > 28 cmH2O in children; > 25 cmH2O CSF if the child is not sedated and not obese)

Diagnostic Criteria for IIH without Papilledema

a. B-E from above PLUS unilateral or bilateral VI nerve palsy

b. Diagnosis may be suggested, but not made in absence of VI nerve palsy nor papilloedema if B-E criteria from above satisfied AND at least 3 of the following neuroimaging criteria are satisfied:

1. Empty sella

2. Flattening of the posterior aspect of the globe

3. Distention of the perioptic subarachnoid space

4. Transverse venous sinus stenosis

A diagnosis of IIH syndrome is definite if the patient fulfills criteria A-E.

The diagnosis is considered probable if criteria A-D are met, but the measured CSF pressure is lower than specified for a definite diagnosis.

* Signs of elevated intracranial pressure frequently found on MRI: perioptic subarachnoid space distension and empty sella.