Choked disc. Neuro-retinitis. Papillo-retinitis. Nerve swelling blocks
veins. Causes: lead, tumors in brain bilateral, in orbit unilateral,
influenza, petechial fever. Symptoms: redness of optic disc, retinal
arteries contracted, veins gorged, papilla swollen (woolly), vitreous
opacity. Treatment.
This is also known as _choked disc_ from the obstruction of the return
of blood by the veins of the retina which pass out at the cribriform
lamina. The swelling of the nerve ending and papilla compress the veins,
causing stagnation and venous congestion in the retina. When the retina
is thus involved the term neuro-retinitis or papillo-retinitis is often
applied.
_Causes._ The condition has been traced to lead poisoning, brain or
orbital tumors, and various infectious diseases. Except in orbital tumor
the disease is usually bilateral. In horses Schindelka has seen the
condition in influenza and Peters in petechial fever, heart failure and
dyspnœa. In a necropsy on a horse the writer found complete cataract,
atrophy of the bulb to less than two-thirds the size of its fellow,
thickening and furrowing of the sclera, the presence of an extensive old
blood clot in the seat of the vitreous, cupping of the disc,
retro-ocular neuritis with exudate inside the sheath, and a considerable
reddish brown tumor of the choroid plexus on the same side. The trouble
was attributed to the blow of a rope on the eye a considerable time
before. The blood in the vitreous retained its dark hue and showed no
evidence of microbian invasion.
_Symptoms._ To the phenomena of retinitis there is added violent
injection of the capillary plexus of the papilla. The arteries of the
retina are contracted while the veins are dilated and tortuous. The
papilla is swollen and is said to have a woolly appearance. The vitreous
may be opaque by reason of exudation or blood extravasation into its
substance. Retro-ocular neuritis is usually present, and brain tumor in
certain cases. Möller calls attention to the fact that with atrophy of
the bulb the elliptical outline of the papilla gradually lessens and it
becomes more nearly round. In dogs, too, the form of the papilla is also
changed and the same author has found it distinctly triangular. The
pupil may be at first strongly contracted and later freely dilated.
_Treatment_ is usually of little avail and does not differ materially
from that adopted in retinitis. In tumor of the orbit pressing on the
optic nerve it may sometimes be reached through the temporal fossa, but
usually in all such cases enucleation of the eyeball is demanded.