From the Guidelines
Idiopathic intracranial hypertension (IIH) is characterized by symptoms such as headache, pulsatile tinnitus, transient visual obscurations, and diplopia, with papilledema being the hallmark finding on examination. Patients with IIH often experience headaches that are worse when lying down or in the morning, along with other symptoms like back pain, dizziness, neck pain, visual blurring, cognitive disturbances, radicular pain, and typically horizontal diplopia 1. The diagnostic criteria for IIH include elevated opening pressure (>25 cmH2O in adults, >28 cmH2O in children) on lumbar puncture with normal CSF composition, normal neuroimaging without hydrocephalus or mass lesion, and no other identified cause of intracranial hypertension.
Some key findings in IIH include:
- Headache is the principal morbidity in these patients
- Visual phenomenon such as photopsia, diplopia (from sixth nerve palsy) and functional visual field loss are common
- Papilledema is the hallmark finding, visible on fundoscopic examination as optic disc swelling
- Sixth nerve palsies may occur, causing lateral gaze weakness
- Neuroimaging may show empty sella, flattening of the posterior globe, distension of the optic nerve sheath, and transverse venous sinus stenosis
The management of IIH should focus on weight management and headache treatment, with surgical management only considered in exceptional cases. According to the consensus guidelines on management, all patients with IIH should be managed as typical IIH and counselled about weight management, and management of headache should be the same as typical IIH 1. Surgical management to control elevated intracranial pressures in IIH should not routinely be considered unless advised by experienced clinicians within the multidisciplinary team setting.
It is essential to note that the role of neurovascular stenting in IIH is not yet established, and long-term antithrombotic therapy is required for longer than 6 months following neurovascular stenting treatment 1. The investigation of papilloedema should include CT or MR venography to exclude cerebral sinus thrombosis within 24 hours, and lumbar puncture to check opening pressure and ensure contents are normal 1.
From the Research
Idiopathic Intracranial Hypertension Findings
- Idiopathic intracranial hypertension (IIH) is a neurological disorder characterized by increased intracranial pressure, often affecting obese women of childbearing age 2.
- The condition can lead to symptoms such as headache, pulsatile tinnitus, transient visual obscurations, and diplopia, with the potential for vision loss being a significant concern 3, 4.
- Diagnostic criteria for IIH include increased intracranial pressure, normal cerebrospinal fluid composition, and the absence of an alternative cause for the increased pressure 2.
Ophthalmological Findings
- Papilledema is a common finding in IIH, with a significant reduction in papilledema degree observed after a single lumbar puncture (LP) in some patients 5.
- Optical coherence tomography (OCT) can be used to assess peripapillary retinal nerve fibre layer (pRNFL) thickness and ganglion cell layer (GCL) volume, with changes in these parameters observed after LP 5.
- Arachnoid optic nerve sheath diameter (AONSD) can also be measured using transbulbar sonography, with a decrease in AONSD observed after LP 5.
Treatment and Management
- Lumbar puncture (LP) may have a therapeutic effect on ophthalmological outcomes in IIH, but its usefulness as a therapeutic measure remains controversial 5.
- Weight loss, acetazolamide, and topiramate are established treatment options for IIH, with surgical interventions such as optic nerve sheath fenestration (ONSF) and ventriculoperitoneal shunting considered in more severe cases 2, 6.
- Deferring LP may be acceptable in patients with suspected IIH who are systemically well, have mild optic disc edema, and preserved visual function, but this decision should be made with caution and under the care of an experienced neuro-ophthalmologist 4.