Snake Bullous Spectaculopathy
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Introduction
A bullous spectaculopathy is an accumulation of clear fluid in the subspectacular space that presents as a bulging of the spectacle. It is a common problem caused by the blockage of the nasolacrimal duct, which is often secondary to infectious stomatitis. In newborn snakes it may be caused by a congenital agenesis of the lacrimal duct.
- For more information on the eye, see Snake Eye.
Examination
Bulging spectacles are a common presenting complaint in snakes. The cause may either be a subspectacular infection or impaired tear drainage. On physical examination, the subspectacular fluid tends to be clear when there is impaired drainage. If the fluid is not clear, an infectious process should be suspected. Vascularity is not usually evident in the normal spectacle; when there is distension of the spectacle the vessels may become engorged and easily visualised with an ophthalmoscope.
Diagnosis
A bulging spectacle can be investigated by the insertion of a small gauge needle through the lateral canthus into the subspectacular space. Paracentesis of some fluid is followed by the injection of a small amount of fluorescein dye. The mouth is then examined with the aid of an ultraviolet light. In cases of bullous spectaculopathies there will be no fluorescence in the mouth. The tear sample can be submitted for microscopy, culture and sensitivity.
Therapy
Several treatments have been advised for bullous spectaculopathies. Paracentesis gives a temporary solution and the condition sometimes resolves with treatment of any infectious stomatitis. The spectacular distension usually returns though. Most cases will resolve with the excision of a 30° wedge of the ventral spectacle, which allows drainage, in combination with treatment of the inciting stomatitis. A surgical fistula between the subspectacular space and the mouth (conjunctivoralostomy) has also been recommended as a treatment. The prognosis for complete resolution of individual cases can be difficult to assess and the loss of vision due to an opaque spectacle is a common sequelae.
Therapy - Conjunctivoralostomy
This procedure involves incising the spectacle and passing an 18g needle from the subspectacular space into the mouth. Fine silastic tubing is then threaded through the needle. This is left in position for drainage for one month. Any oral lesions are vigorously treated.
Prevention
Bullous spectaculopathies are often secondary to upper alimentary tract disease. This is usually associated with poor husbandry such as unhygienic conditions and keeping snakes outside their POTZ. Prevention therefore comes from good husbandry practices.