NeurologyTier 1Disease (DEADMAN)

Ophthalmological conditions - papilloedema

Description

Papilloedema = optic disc swelling caused specifically by raised intracranial pressure
- Bilateral (may be asymmetric)
- "Disc swelling" is the sign; "papilloedema" names the cause. Do not use them interchangeably
Mechanism: raised CSF pressure transmitted along the optic nerve sheath -> stasis of axoplasmic flow at the lamina cribrosa -> axonal swelling, disc elevation, venous congestion

Optic disc swelling - the differential

Cause	Laterality	Vision early	Pupil	Pain
Papilloedema (raised ICP)	Bilateral	Preserved (transient obscurations only); enlarged blind spot	No RAPD	Headache, not eye pain
Optic neuritis	Unilateral	Markedly reduced, dyschromatopsia	RAPD	Pain on eye movement
Anterior ischaemic optic neuropathy (AION)	Unilateral	Sudden altitudinal loss	RAPD	Painless (arteritic: jaw claudication, scalp tenderness)
Malignant hypertension	Bilateral	Variable	No RAPD	Headache; BP >=180/120 with retinal haemorrhages, exudates, cotton wool spots
Central retinal vein occlusion	Unilateral	Reduced	+/- RAPD	Painless; "blood and thunder" fundus
Pseudopapilloedema (optic disc drusen, hypermetropic small disc)	Bilateral	Normal	No RAPD	None

*Vision is preserved early in papilloedema and lost early in optic neuritis and AION* - this is the discriminator at the bedside

Frisen grading (0-5)

Grade 1: C-shaped halo, nasal blurring; Grade 2: circumferential halo; Grade 3: obscuration of >=1 major vessel leaving the disc; Grade 4: obscuration of a vessel on the disc; Grade 5: total obscuration

Epidemiology

Frequency follows the underlying cause; idiopathic intracranial hypertension is the commonest cause in young women
- IIH incidence ~1-3/100,000/yr overall, but ~20/100,000/yr in obese women aged 20-44; rising with obesity prevalence
Brain tumour: papilloedema at presentation in ~10-20% of adults (higher in posterior fossa and paediatric tumours)
Malignant hypertension: papilloedema defines grade IV Keith-Wagener-Barker retinopathy
Optic disc drusen (the main pseudopapilloedema) - ~0.3-2% of the population, often familial

Aetiopathogenesis

Causes of raised ICP -> papilloedema

Mass lesion - tumour, abscess, haematoma, large infarct with oedema
Obstructive hydrocephalus - aqueduct stenosis, posterior fossa lesion, colloid cyst
Impaired CSF absorption - post-subarachnoid haemorrhage, post-meningitis, carcinomatous or infectious meningitis
Venous outflow obstruction - cerebral venous sinus thrombosis, jugular obstruction, superior vena cava syndrome, dural AV fistula, right heart failure
Idiopathic intracranial hypertension
Increased CSF production - choroid plexus papilloma (rare)
Craniosynostosis, Chiari malformation
Hypercapnia, chronic type 2 respiratory failure, obstructive sleep apnoea

Optic disc swelling NOT from raised ICP

Optic neuritis - demyelinating (MS), MOGAD, NMOSD, infective, post-infectious
Anterior ischaemic optic neuropathy
- Arteritic (giant cell arteritis) - the emergency; chalky white swollen disc, pallid oedema
- Non-arteritic - "disc at risk" (small crowded disc, small cup), nocturnal hypotension, sleep apnoea, PDE5 inhibitors
Malignant hypertension
Central retinal vein occlusion
Infiltration - leukaemia, lymphoma, sarcoid, carcinoma
Diabetic papillopathy, uveitis/posterior scleritis, Leber hereditary optic neuropathy (pseudo-oedema, telangiectatic vessels), toxic/nutritional optic neuropathy

Pseudopapilloedema

Optic disc drusen - no obscuration of vessels, no hyperaemia, autofluorescence, calcification on B-scan ultrasound or OCT
Small hypermetropic "crowded" disc; myelinated nerve fibres; tilted disc

Diagnosis

History

Headache - worse on waking, lying flat, coughing, straining, Valsalva
Transient visual obscurations - seconds of greying or blackout, often on standing or bending; the hallmark symptom of papilloedema
Pulsatile tinnitus (venous, IIH, dural fistula)
Diplopia - CN VI palsy, a false localising sign
Nausea and vomiting; visual field constriction late
Drug history (see IIH causes): tetracyclines, retinoids, thyroxine, growth hormone, lithium, ciclosporin, steroid withdrawal
Weight gain, sleep apnoea symptoms, anaemia, endocrine disease

Examination

Visual acuity, colour vision, pupils for RAPD, confrontation and formal fields - documented, at every visit
Fundoscopy: blurred disc margins, elevation, hyperaemia, absent spontaneous venous pulsation (absent in ~20% of normals - an unreliable single sign), peripapillary haemorrhages, cotton wool spots, Paton's lines (retinal folds)
Cranial nerves - especially VI
BP in both arms - malignant hypertension
Focal neurological signs, level of consciousness, gait
Temporal arteries, scalp tenderness, jaw claudication if >50

Investigation - the order matters

1. Urgent neuroimaging first - CT if immediately available, but MRI brain + MR venography is the correct study

MRV is mandatory: cerebral venous sinus thrombosis is the great mimic of IIH
MRI signs of raised ICP: empty sella, flattened posterior globe, distended perioptic subarachnoid space, transverse sinus stenosis

2. Then lumbar puncture with opening pressure - only after imaging excludes a mass lesion or hydrocephalus

Measure in the lateral decubitus position with legs extended and the patient relaxed
Send cell count, protein, glucose, cytology, culture, and for opening pressure

3. Bloods: FBE (anaemia, leukaemia), UEC, TFT, cortisol, ESR/CRP, vitamin A if suspected

Ophthalmic monitoring

Automated perimetry (Humphrey 24-2 or 30-2) is the key outcome measure - not acuity
- Earliest defects: enlarged blind spot, then inferonasal loss, then generalised constriction
- Central acuity is preserved until very late - relying on it will cost the patient their vision
OCT retinal nerve fibre layer - quantifies swelling and tracks resolution or progression to atrophy
Fundus photography at each visit

Management

A. Treat the cause - always the priority

Mass lesion -> neurosurgery, dexamethasone for vasogenic oedema
Hydrocephalus -> external ventricular drain or shunt
CVST -> anticoagulation (see that note)
Malignant hypertension -> controlled BP reduction; do not drop BP precipitously (aim ~25% reduction in the first hours)
Meningitis -> antimicrobials
Suspected giant cell arteritis -> immediate high-dose corticosteroid, before biopsy
IIH -> weight loss, stop the culprit drug, acetazolamide

B. Protect vision - the parallel job

Serial visual fields and OCT determine escalation, not symptoms
Acetazolamide - the mainstay medical therapy for IIH-related papilloedema; titrate as tolerated
- Paraesthesia, dysgeusia (fizzy drinks taste odd), fatigue, renal stones, metabolic acidosis
- Contraindicated in sulfonamide allergy and severe renal impairment
Topiramate - alternative (also promotes weight loss)
Furosemide as an adjunct
*Corticosteroids are not used for chronic papilloedema* - rebound on withdrawal, weight gain worsens IIH; reserve for fulminant visual loss as a bridge to surgery
Therapeutic LP - temporary relief only

C. Surgical - for progressive visual loss

Optic nerve sheath fenestration - protects vision; less effective for headache
CSF diversion (VP or LP shunt) - treats both pressure and headache; high revision rate
Venous sinus stenting - where a significant pressure gradient across a transverse sinus stenosis is demonstrated
Fulminant IIH (rapid severe visual loss over days) is a surgical emergency - do not temporise with acetazolamide alone

D. Ongoing

Weight management for IIH: ~5-10% total body weight loss frequently produces remission; bariatric surgery outperforms dietary programmes in trials
Treat obstructive sleep apnoea
Headache management (avoid medication overuse)
Regular ophthalmology follow-up until the disc swelling resolves, then interval review
Contraception counselling - pregnancy does not contraindicate management but alters drug choice (acetazolamide avoided in the first trimester)

Associations

Obesity and recent weight gain (IIH); obstructive sleep apnoea
Female sex, reproductive age (IIH)
Drugs: tetracyclines (doxycycline, minocycline), retinoids/excess vitamin A, thyroxine, growth hormone, lithium, ciclosporin, nitrofurantoin, corticosteroid withdrawal
Endocrine: Addison disease, Cushing syndrome, hypoparathyroidism, thyroid disease
Anaemia (iron deficiency), polycythaemia, chronic kidney disease
Cerebral venous sinus thrombosis and prothrombotic states
Down syndrome, Turner syndrome, SLE, Sjogren
Malignant hypertension, phaeochromocytoma, renal artery stenosis
Craniosynostosis, Chiari malformation
Giant cell arteritis (as a cause of pallid disc swelling, not papilloedema)

Natural history & complications

Papilloedema resolves once ICP normalises - but chronic papilloedema produces irreversible optic atrophy
- Sequence: hyperaemic swelling -> chronic "champagne cork" disc -> secondary optic atrophy (pale disc, no swelling)
- *A patient whose disc swelling has "improved" but whose fields are worse is going blind, not getting better*
Visual outcome depends on how long pressure stayed high and how early monitoring began
IIH: most stabilise; severe permanent visual loss in ~5-10%, higher in fulminant disease, men, black patients and those with anaemia or rapid weight gain

Complications

Permanent visual field loss and blindness - the reason this is a medical emergency
Secondary optic atrophy
Chronic daily headache and analgesic overuse
Diplopia from VI nerve palsy
Shunt complications - obstruction, infection, low-pressure headache, multiple revisions
Acetazolamide adverse effects - paraesthesia, stones, acidosis, aplastic anaemia (rare)
Missed underlying cause: tumour, CVST, meningitis

Every patient with papilloedema needs neuroimaging with venography before lumbar puncture, and formal perimetry before discharge from clinic

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