choked disc

choked disc.

See papilledema.

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papilloedema 

A non-inflammatory oedema of the optic nerve head produced by raised intracranial pressure, and due most commonly to a cerebral tumour. It can also result from cerebral abscesses, meningitis, encephalitis, subarachnoid haemorrhages, head injury, hydrocephalus, etc. The optic disc appears raised above the level of the retina and its margins are blurred, the central vessels on the surface of the disc are displaced forward, the retinal veins are dilated and there is nearly always a loss of induced venous pulsation. The swollen disc displaces the retina and this causes an enlargement of the blind spot on visual field measurement. In the early stages visual acuity is not affected (unlike in papillitis), although if the condition persists there will be some loss. In advanced stages, there may be haemorrhages around the disc, secondary optic atrophy, exudates, as well as headaches and vomiting. The condition is usually bilateral. Note: also spelt papilledema. Syn. choked disc. See optic atrophy; optic neuritis; pseudopapilloedema; Foster Kennedy syndrome.

Table P1 Differential diagnosis between papilloedema and papillitis
		papilloedema		papillitis
signs
disc elevation		raised		slightly raised
disc hyperaemia		present		present
disc margins		blurred		blurred
retinal veins		congested		congested
haemorrhages		near disc		some in late stage
pupil light reflex		normal		impaired
venous pulsation		absent		present
secondary optic atrophy		present in late stage		may appear in late stage
symptoms
visual acuity		normal, except in late stage		reduced
visual field		enlarged blind spot		central scotoma
diplopia		present		absent
colour vision		normal		impaired
pain		absent		present on moving the eyes
headache		present		absent