Papilledema Overview and Causes

Overview

This lecture covers papilledema—its definition, causes, pathogenesis, clinical features, stages, investigations, and management—with a focus on its association with raised intracranial pressure (ICP).

Definition & Pathogenesis

• Papilledema is edema of the optic disc due to raised intracranial pressure (ICP).
• The optic nerve is surrounded by meninges and subarachnoid space, allowing ICP changes to affect the nerve head.
• Pathogenesis theories: compression of the central retinal vein and blockade of axoplasmic transport in optic nerve fibers.
• Papilledema is a non-inflammatory, hydrostatic swelling.

Causes of Papilledema

• Decreased skull size (craniosynostosis), increasing ICP due to limited space.
• Space-occupying lesions (tumors, abscesses, aneurysms) increase brain volume and ICP.
• Obstruction to CSF flow (hydrocephalus, colloid cyst, papilloma of choroid plexus).
• Increased CSF production or reduced absorption (meningitis, venous thrombosis).
• Pseudotumor cerebri (benign intracranial hypertension), common in obese females.
• Malignant hypertension can contribute to raised ICP.

Clinical Features

• Early papilledema has minimal symptoms; central vision remains normal for long.
• Transient visual blurring and blackouts, precipitated by postural change (often bilateral).
• Visual field shows an enlarged blind spot initially.
• Other symptoms: headache, morning nausea/vomiting, pulsatile tinnitus (“whooshing”), and sixth nerve palsy (double vision/esotropia).

Fundus Findings & Stages

• Mechanical/vascular signs: blurred disc margins (initially superior, inferior, nasal), hyperemia, disc edema, cup obliteration, dilated/tortuous vessels, absence of spontaneous venous pulsation.
• Acute papilledema: disc hemorrhages, exudates (yellowish), cotton wool spots, incomplete macular star formation.
• Chronic papilledema: disc pallor, watermarks, optociliary shunts, gliosis (secondary optic atrophy), amyloid deposits.
• Graded by Frisén scale: 0 (normal) to 5 (severe: blurred vessels, loss of margins).

Special Cases & Syndromes

• Foster-Kennedy syndrome: optic atrophy in one eye, papilledema in the other, usually from a frontal lobe/olfactory groove tumor.
• Papilledema can be asymmetrical or bilateral.

Diagnostic Investigations

• Diagnosis via fundus examination.
• Rule out malignant hypertension by checking BP.
• Ophthalmic tests: Spectral Domain OCT (RNFL/macular scan), stereo disc images, automated perimetry, fluorescein angiography to distinguish true vs. pseudo-papilledema.
• Neuroimaging: CT/MRI to rule out space-occupying lesions, venography for venous thrombosis, and assessment for tonsillar ectopia (must be ruled out before lumbar puncture).
• Lumbar puncture (after imaging): checks CSF pressure and composition.

Management

• Treat underlying cause: control hypertension, remove mass, treat thrombosis, stop causative drugs, promote weight loss.
• Ophthalmic interventions for vision-threatening cases: optic nerve sheath fenestration, CSF diversion procedures (ventriculoperitoneal/lumboperitoneal shunts).
• Visual field monitoring is important for timely intervention.

Key Terms & Definitions

• Papilledema — swelling of the optic disc due to raised intracranial pressure.
• Axoplasmic transport — movement of substances within axons, blocked in papilledema.
• Pseudotumor cerebri — increased ICP without mass lesion, mainly in obese women.
• Frisén scale — grading system for papilledema severity.
• Optociliary shunt — vessel connecting ciliary and retinal circulations, seen in chronic cases.
• Macular star — radial exudate pattern at the macula due to severe disc edema.
• Foster-Kennedy syndrome — unilateral optic atrophy with contralateral papilledema.

Action Items / Next Steps

• Review Frisén grading images.
• Read about spectral domain OCT and its role in optic neuropathies.
• Study clinical fundus photos illustrating each papilledema stage.