Proptosis

55 Proptosis




INITIAL PRESENTATION


Abnormal appearance – red, swollen



PRESENTING SIGNS


Owners will present patients with proptosis as an emergency. The sudden alteration in appearance will be the most striking abnormality, and most will be aware that the eye has come out of the socket (they frequently state on the telephone that the eye has fallen out). Usually only one eye is affected but occasionally both are involved. Some animals will have other injuries, especially if they have been involved in a road traffic accident or a fight. Brachycephalic breeds are predisposed.



CASE HISTORY


A traumatic incident is usual. This is most commonly a dog fight or a road traffic accident but in some animals, particularly brachycephalic dogs, the trauma can be minimal – restraint for a nail clip for example.



CLINICAL EXAMINATION


On ophthalmic examination the forward displacement of the globe will be obvious. However, the patient should be fully examined and evaluated since other injuries might be present – indeed these might be life threatening. It follows that if a patient has a prolapsed eye following a road accident they have most likely been hit on the head, and skull fractures, concussion and so on might be present. Bite wounds might be severe and in some animals the prolapsed eye can be the least of their problems.


Once the eye is prolapsed the periorbital tissues swell, bruising and haemorrhage ensue and both chemosis and conjunctival haemorrhage occur in response to the injury so these will all be present on ophthalmic examination. The eyelids tightly close around the retrobulbar tissue which impedes venous drainage and further exacerbates the swelling and redness. The eye should be assessed as far as possible in order to provide some prognostic indicators. If the optic nerve and multiple extraocular muscles are severed, then the prognosis is hopeless and enucleation should be performed. If the cornea or sclera is ruptured the same is true, but corneal ulceration does not preclude globe replacement. Pupillary light reflexes should be assessed but are not necessarily reliable. The affected pupil might be miotic (e.g. due to concurrent uveitis) or can be dilated (optic nerve damage). A lack of any light reflex cannot be readily interpreted; however, if a direct and/or consensual constriction is noted, these are favourable signs. Many patients will have hyphaema which can preclude any intraocular examination and indicates severe intraocular trauma. Table 55.1 provides some prognostic indicators for proptosis.


Table 55.1 Prognostic indicators in cases of proptosis







































Factor Positive prognosis Negative prognosis
Breed Brachycephalic Doliocephalic dog, cat
Optic nerve Stretched but intact Ruptured
Extraocular muscles Not visible or swollen Visibly ruptured
Sclera and cornea Intact Ruptured
Ocular tension Normal Soft – suggests posterior scleral rupture
Corneal ulceration Superficial or absent Deep or infected
Intraocular haemorrhage Absent Present
Pupillary light reflex Pupil size unreliable but positive direct and/or consensual reflex are positive signs No direct reflex or consensual response



DIFFERENTIAL DIAGNOSES


The diagnosis is obvious from clinical examination and can easily be differentiated from exophthalmos by the fact that the eyelids are closed behind the protruding globe.

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  4. Limbal melanoma

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Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Proptosis

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