Retrobulbar steatitis and meningitis/empyema secondary to right otitis media, right otitis interna and an inflammatory polyp in a cat

Abstract

The purpose was to describe a case of retrobulbar steatitis and meningitis in a cat caused by otitis media, otitis interna and an inflammatory polyp in the middle ear. Investigations included ophthalmic and neurological examinations, haematology and biochemistry, magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis and aerobic, anaerobic bacterial and fungal culture of material from the middle ear. A 6-year-old female neutered domestic-short-haired cat presented with right-sided exophthalmos and resistance to retropulsion. Anisocoria, reduced corneal sensation and oculocephalic movements and low Schirmer tear test (STT1) were found. An MRI revealed the right external ear canal and tympanic bulla to be fluid filled with presence of a thickened contrast-enhancing mucosa. Contrast enhancement extended into the calvarium, as marked thickening and contrast enhancement of the pachymeninges, and further rostrally through the right orbital fissure into the orbit. The retrobulbar tissues were swollen, resulting in mild exophthalmos. Enrichment culture of material from the middle ear revealed Klebsiella pneumonia susceptible to marbofloxacin. The cat underwent a total ear canal ablation with removal of the cartilaginous cuff at the external auditory meatus and local debridement and curettage. A polypoid structure was removed from the middle ear. No bulla osteotomy was performed. Horner’s syndrome was present immediately following surgery. The cat received a course of systemic dexamethasone (1mg/cat SID/3 weeks) tapered off and marbofloxacin (2mg/kg SID/2 weeks). Follow up at 120 days showed no recurrence of the symptoms. The Horner’s syndrome and low STT1 had resolved and returned to normal values respectively. This case highlights the importance of MRI in the investigation of retrobulbar diseases. MRI is a useful tool for the evaluation of the extent of the lesion and the appearance of adjacent structures in which additional potentially life-threatening abnormalities, such as meningitis, can be seen.

Keywords: Exophthalmia, Meningitis, Otitis media/interna, Polyp, Retrobulbar disease