Papilloedema

Contents

Introduction
Pathophysiology
Aetiology
History
Examination
Imaging/Investigations
Grading
Management

Introduction

Papilloedema is optic disc swelling which is specifically secondary to raised intracranial pressure (ICP). It is nearly always bilateral and can be asymmetrical. [1]

The umbrella terms disc swelling, or oedema include unilateral or bilateral disc involvement with varying causes and not only raised intracranial pressure. [1, 2]

This article will specifically focus on papilloedeoma, its pathophysiology, causes, clinical features, investigations and management.

Pathophysiology

Raised intracranial Pressure is transmitted along the subarachnoid space to the optic nerve which causes venous stasis and impedes axoplasmic flow in the optic nerve leading to optic disc oedema. [2,3]

Figure 1a: Pathophysiology of papilloedema

Aetiology

Causes of raised ICP (and in turn, papilloedema) include:

Idiopathic intracranial hypertension
Obstruction of the ventricular system e.g. due to congenital or acquired lesions
Space occupying intracranial lesions
Reduced CSF absorption due to meningitis, subarachnoid haemorrhage or trauma
Cerebral venous sinus thrombosis (CVST)
Cerebral oedema from blunt head trauma
Severe systemic hypertension
Hypersecretion of CSF by a choroid plexus tumour (rare) [1]

Other causes of optic disc swelling or oedema (unilateral or bilateral):

Pseudopapilloedema / optic disc anomalies e.g. optic disc drusen, tilted disc, crowded disc…
Anterior ischaemic optic neuropathy (AION) – divided into arteritic (A-AION i.e. giant cell arteritis) and non-arteritic (NAION)
Infiltrative optic neuropathy (lymphoma, leukaemia)
Compressive optic neuropathy (optic nerve sheath meningioma)
Diabetic or hypertensive papillopathy
Central retinal vein occlusion
Thyroid ophthalmopathy
Inflammatory e.g. posterior scleritis, uveitis, neuroretinitis
Optic neuritis

A thorough history and examination will aid in diagnosis. [2]

History

Headaches
Typically worse early in the morning and may wake patient from sleep
Worsening intensity with movement, bending, coughing
Progressively worsening, increasing frequency
Nausea
Intermittent
May have associated projectile vomiting

Pulsatile tinnitus
Tinnitus and/or “whooshing” sounds exacerbated by supine position or bending over

In severe cases, the patient can experience drowsiness. Sudden, significant deterioration can indicate involvement of the brainstem and needs urgent attention. [1, 2]

Visual symptoms of raised ICP

Commonly absent in mild/early cases. Vision is generally normal or minimally reduced. A large drop in visual acuity usually occurs in late stages with the onset of optic atrophy and can be associated with corresponding visual field defects.

In established papilloedema, symptoms may include:

Transient visual obscurations – often precipitated by positional changes, coughing, Valsalva manoeuvre
Horizontal diplopia due to 6^th cranial nerve palsy [1,2]

Consider alternative causes of disc swelling when taking a history:

Previous history of space occupying lesions, B symptoms
Co-morbidities including hypertension, systemic autoimmune conditions.
Infections e.g. meningitis
Medications that might cause raised ICP (steroids, tetracyclines, vitamin A analogues, lithium).
Hypercoagulable state (+ve family history, previous VTE, smoking, contraceptive use)
Risk factors for idiopathic intracranial hypertension (IIH) e.g. weight gain/high BMI, thyroid disease, polycystic ovarian syndrome, obstructive sleep apnoea (OSA) etc. [1,2]

Examination

Assessment of optic nerve function:

1. VISUAL ACUITY – using Snellen chart.

2. PUPILS – assess for relative afferent pupillary defect (RAPD).

3. COLOUR VISION – using Ishihara plates. If suspecting optic neuritis (usually unilateral) check for red desaturation.

4. VISUAL FIELD – Humphrey Visual Field 24-2 or confrontational visual field, may find enlarged blind spot. Visual fields tend to be normal unless chronic with optic atrophy or in severe papilloedema. [2]

Neurological exam to identify any neurological deficit.
Blood pressure
Ocular motility examination if patient complaining of diplopia, possible 6^th cranial nerve palsy. [2]

Imaging/Investigations

Optical Coherence Tomography or OCT scans of the disc assessing the retinal nerve fibre layer can be used to identify subtle disc oedema and monitor disc swelling objectively. It can also be used to differentiate pseudopapilloedema from true papilloedema e.g.: pseudopapilloedema due to optic disc drusen. [2]

B-scan ultrasound and fundus autofluorescence scans may also demonstrate the presence of optic disc drusen. [1,2]
Fluorescein Angiography demonstrates leakage at the optic disc in true papilloedema.
Neuro-imaging
CT / CT venogram and MRI / MRV to rule out CVST, stenosis.
Features of IIH include: dilated optic nerve sheath, optic nerve tortuosity, posterior flattening of the globe, empty or partially empty Sella.

Lumbar puncture: only to be done after imaging to ensure no risk of herniation.
Check opening pressure, CSF composition (investigation of neoplastic, infectious or inflammatory causes). [2]

Grading

Papilloedema is graded based on disc margins, vascular and mechanical changes in and around the disc.

Management

The priority is to rule out a space occupying lesion with neuro-imaging.

The aim is to treat the underlying cause, save the vision and provide symptom relief.

Examples of treating the underlying cause:

Malignant hypertension – medical management
Mass / space occupying lesion – neurosurgical review and management
CVST – anticoagulation, subsequent consideration of treatment with acetazolamide
Medication induced – discontinue causative medications e.g. tetracyclines, vitamin A analogues etc.
Management of idiopathic intracranial hypertension – weight reduction, avoid previously mentioned precipitating medications, control risk factors (thyroid disease, OSA). Recurrence is most commonly due to weight gain.
Medications: Acetazolamide, topiramate
Surgical: e.g. VP/LP shunt in appropriate cases
Smoking cessation [2]