Makindo Medical Notes.com

Related Subjects: |Brain tumour s |Astrocytomas |Brain Metastases |Tuberous sclerosis |Turcot's syndrome |Lhermitte Duclos Disease |Oligodendroglioma |Acute Hydrocephalus |Intracranial Hypertension |Primary CNS Lymphoma (PCNSL)

Requires emergency referral to ophthalmology for assessment and brain imaging as needed which must include assessing veins so needs MRV or CTV to exclude cerebral venous thrombosis. The main mechanism of optic nerve damage is intraneuronal ischaemia secondary to axoplasmic flow stasis and failure to act can result in loss of vision

About

• Venous outflow obstruction or inflammation
• Swelling and oedema of the optic nerve
• Inflammatory / demyelination
• Raised Intracranial pressure

Causes

• Raised ICP
  • Brain tumour : both supra and infratentorial tumour s.
  • Brain abscess, oedema
  • Haemorrhage ICH or SAH , SDH, EDH
  • Encephalitis, Hydrocephalus
  • Cerebral venous thrombosis
  • Sarcoidosis, Guillain Barre syndrome (high CSF protein)
  • Idiopathic intracranial hypertension
• Malignant hypertension
• Retro-orbital lesion (cavernous sinus thrombosis)
• Inflammation (optic uveitis)
• Ischaemia (accelerated HTN)
• CO₂ retention

Pseudopapilloedema

• Optic disc drusen and optic nerve head drusen simulates some features of papilloedema but is secondary to an underlying, usually benign, process.
• Congenital anomalies of the optic disc
• Optic disc infiltration by neoplastic or inflammatory cells
• Down syndrome

The assessment of optic discs can be difficult, even in expert hands, but it is important to make some attempt at examining them. Usually, dilatation is not necessary, but in exceptions topical 0.5% tropicamide can be used (see BNF www.bnf.org) please indicate that a mydriatic has been used in the notes, as this can be a source of confusion if the patient is examined later

Clinical

• Loss of vision is not marked but assess and ensure you document acuity
• Visual acuity is normal until later
• Optic disc may look swollen and oedematous
• Grey vision, blurred or double vision
• Early sign is loss of venous pulsations
• There may be haemorrhages and hyperaemia
• Decreased field of vision or ability to see colours.
• Headache, nausea and vomiting

Differentials

• Pseudopapilloedema

Investigations

• CT+CT venogram or MR+MRV head for a space occupying lesion and venous thrombosis
• Non Mass lesion on imaging then LP to measure opening CSF pressure

Management

• Manage hypertension if present
• Local eye disease refer Ophthalmology
• Mass lesion - refer to on-call neurosurgery
• Non-mass lesion refer to neurology (ie venous sinus thrombosis - anticoagulate and refer to neurology; idiopathic intracranial hypertension - CSF examination and measurement of CSF opening pressure, will need referral to neuro-ophthalmology and assessment of visual fields).

References

• Guidance from David Nicholls

Revisions