Table 1

Diagnostic criteria for idiopathic intracranial hypertension (IIH) adapted from Friedman et al1

Diagnosis of IIHDiagnosis of IIH without papilloedema
Diagnosis of IIH is definite if the patient fulfils A–E

  1. Papilloedema.

  2. Normal neurological examination except for sixth cranial nerve abnormalities.

  3. 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; if MRI is unavailable or contraindicated, contrast-enhanced CT may be used.

  4. Normal CSF composition.

  5. Elevated lumbar puncture opening pressure (≥250 mm CSF in adults) in a properly performed lumbar puncture.

In the absence of papilloedema, a diagnosis of IIH can be made if B–E are satisfied, and in addition the patient has unilateral or bilateral abducens nerve palsy.
In the absence of papilloedema or sixth nerve palsy, a diagnosis of IIH can be suggested but not made if B–E are satisfied, and in addition at least 3 of the following are present on neuroimaging:

  1. Empty sella.

  2. Flattening of the posterior aspect of the globe.

  3. Distension of the perioptic subarachnoid space with or without a tortuous optic nerve.

  4. Transverse venous sinus stenosis.

(See figure 2: MRI findings in IIH)

  • The diagnosis of IIH is considered probable if A–D are met, but the cerebrospinal fluid pressure is below 250 mm.