Key Facts

Papilloedema refers to bilateral swelling of the optic disc caused by raised intracranial pressure. It must be distinguished from other causes of disc swelling such as optic neuritis, ischaemic optic neuropathy, and disc drusen. Papilloedema is always a medical emergency until a serious underlying cause is excluded.

Epidemiology

• Incidence depends on underlying cause
• IIH incidence: 1-2 per 100,000 overall; 12-20 per 100,000 in obese women of childbearing age
• Space-occupying lesions, hydrocephalus, and venous sinus thrombosis are other common causes
• Can occur at any age

Aetiology

• Space-occupying lesion: primary or metastatic brain tumour, abscess
• Idiopathic intracranial hypertension (IIH): most common cause in young obese women
• Cerebral venous sinus thrombosis: particularly in prothrombotic states, OCP use
• Meningitis/encephalitis: infective or inflammatory
• Hydrocephalus: obstructive or communicating
• Malignant hypertension: BP >180/120 mmHg with end-organ damage
• Drugs: tetracyclines, vitamin A (retinoids), lithium, corticosteroid withdrawal

Pathophysiology

• Raised ICP is transmitted along the subarachnoid space surrounding the optic nerve
• Increased pressure impairs axoplasmic flow at the lamina cribrosa
• Axonal swelling causes disc elevation and blurring of disc margins
• Venous congestion leads to haemorrhages and cotton-wool spots
• Chronic papilloedema leads to axonal loss, optic atrophy, and permanent visual loss
• In IIH, impaired CSF absorption at arachnoid granulations is the proposed mechanism

Symptoms

• Headache: often worse on waking, exacerbated by bending, straining, coughing (Valsalva)
• Transient visual obscurations: brief (seconds) episodes of greying or blacking out of vision, often positional
• Diplopia: from abducens (VI) nerve palsy (false localising sign due to long intracranial course)
• Pulsatile tinnitus: synchronous with heartbeat
• Nausea and vomiting if ICP severely raised

Examination Findings

• Bilateral optic disc swelling with blurred disc margins
• Venous engorgement, loss of spontaneous venous pulsation
• Peripapillary flame haemorrhages and cotton-wool spots
• Enlarged blind spot on visual field testing
• Reduced visual acuity in advanced cases
• VI nerve palsy (unilateral or bilateral)

Red Flags

• Sudden severe headache with papilloedema (exclude SAH, venous sinus thrombosis)
• Rapidly declining visual acuity (fulminant IIH, urgent surgical intervention needed)
• Focal neurological signs (suggest space-occupying lesion)
• Papilloedema in a child (higher suspicion for posterior fossa tumour)
• New papilloedema during pregnancy

Bedside

• Visual acuity (Snellen chart)
• Pupil examination (RAPD in asymmetric cases)
• Colour vision (Ishihara plates)
• Visual field testing: enlarged blind spot is earliest finding; progressive field constriction
• Fundoscopy: bilateral disc swelling, haemorrhages, exudates
• Blood pressure measurement (exclude malignant hypertension)

Bloods

• FBC, U&Es, LFTs, coagulation screen
• ESR, CRP
• Thrombophilia screen if venous sinus thrombosis suspected

Imaging

• MRI brain with gadolinium: essential first-line to exclude SOL, hydrocephalus
• MR venography (MRV): to exclude cerebral venous sinus thrombosis
• CT head: if MRI not immediately available or contraindicated
• Do NOT perform LP before neuroimaging (risk of tonsillar herniation with SOL)

Special Tests

• Lumbar puncture (after imaging excludes SOL):
  • Opening pressure >25 cmH2O (adult, lateral decubitus) confirms raised ICP
  • CSF analysis: protein, glucose, cell count, cytology, culture
• OCT: retinal nerve fibre layer (RNFL) thickness to monitor and grade papilloedema
• Formal perimetry (Humphrey visual fields): serial monitoring of visual fields

Non-pharmacological

• Weight loss: target 5-10% body weight reduction in IIH (shown to reduce ICP and improve papilloedema)
• Treat underlying cause (tumour surgery, antibiotics for infection, anticoagulation for CVST)
• Serial visual field and OCT monitoring

Pharmacological

• Acetazolamide 250mg BD-QDS, titrate up to 2g/day (IIH Treatment Trial — IIHTT)
  • Carbonic anhydrase inhibitor reducing CSF production
  • Monitor U&Es (hypokalaemia), paraesthesiae, metabolic acidosis
• Topiramate 25-50mg BD: alternative or adjunct (also aids weight loss)
• Treat underlying cause: dexamethasone for SOL, anticoagulation for CVST
• Therapeutic LP can provide temporary relief of ICP

Surgical

• Optic nerve sheath fenestration: for progressive visual loss unresponsive to medical therapy
• CSF shunting (ventriculoperitoneal or lumboperitoneal): for refractory IIH with headache predominance
• Venous sinus stenting: emerging treatment for IIH with venous sinus stenosis

Referral Criteria

• Urgent ophthalmology and neurology referral for all cases of papilloedema
• Emergency neurosurgical referral if SOL or acute hydrocephalus
• Neuro-ophthalmology follow-up for monitoring visual function
• Bariatric surgery referral if BMI >40 and refractory IIH

• Prognosis depends on underlying cause and duration of papilloedema
• IIH: 25% experience permanent visual field loss; 5-10% develop significant visual impairment
• Fulminant IIH (rapid visual decline over days) carries high risk of blindness without urgent intervention
• Visual loss in chronic papilloedema is often insidious and irreversible once optic atrophy develops
• With appropriate treatment (weight loss, acetazolamide), >80% of IIH patients achieve resolution
• Recurrence of IIH: 10-40%, particularly with weight regain
• SOL-related papilloedema prognosis depends on tumour type and treatability

Frisén Grading of Papilloedema

Modified Dandy Criteria for IIH

IIH Treatment Trial (IIHTT) Key Results