Case Description—A 4-year-old sexually intact male mixed-breed dog was evaluated because of clinical signs of acute-onset pelvic limb ataxia, rapidly progressing to paraplegia with severe spinal hyperesthesia.
Clinical Findings—General physical examination revealed pyrexia, tachycardia, and tachypnea. Neurologic examination demonstrated severe spinal hyperesthesia and paraplegia with decreased nociception. Magnetic resonance imaging revealed extradural spinal cord compression at T13-L1 and hyperintense lesions on T1- and T2-weighted images in the epaxial musculature and epidural space.
Treatment and Outcome—Decompressive surgery, consisting of a continuous dorsal laminectomy, with copious lavage of the vertebral canal was performed. Cultures of blood, urine, and surgical site samples were negative. Histologic examination results for samples obtained during surgery demonstrated suppurative myositis and steatitis. These findings confirmed a diagnosis of sterile idiopathic inflammation of the epidural fat and epaxial muscles with spinal cord compression. The dog's neurologic status started to improve 1 week after surgery. After surgery, the dog received supportive care including antimicrobials and NSAIDs. The dog was ambulatory 1 month after surgery and was fully ambulatory despite signs of mild bilateral pelvic limb ataxia 3 years after surgery.
Clinical Relevance—Although idiopathic sterile inflammation of adipose tissue, referred to as panniculitis, more commonly affects subcutaneous tissue, its presence in the vertebral canal is rare. Specific MRI findings described in this report may help in reaching a presumptive diagnosis of this neurologic disorder. A definitive diagnosis and successful long-term outcome in affected patients can be achieved by decompressive surgery and histologic examination of surgical biopsy samples.
CASE DESCRIPTION A 17-year-old FIV-positive cat was evaluated because of weight loss during the preceding few months. The cat had a weight loss of 0.5 kg (1.1 lb) during the last month. Because of its FIV-positive status, the cat was confined indoors.
CLINICAL FINDINGS A large nonpruritic area of alopecia with hyperpigmentation and comedones was present on the right lateral aspect of the neck. The chin had diffuse alopecia and comedones. Mild alopecia was present on the dorsal aspect of the muzzle. Trichography and microscopic examination of acetate tape imprint preparations and skin scrapings revealed a very morphologically heterogeneous population of Demodex mites. Micrometry of adult mites revealed a broad range of body lengths (92.68 to 245.94 μm), which suggested that as many as 3 Demodex spp might be present in the skin lesions of this cat.
TREATMENT AND OUTCOME Owing to its concurrent disease, no treatment was initiated for the demodicosis, and the cat died spontaneously 14 days after the evaluation. Sequence analysis of the 16S rRNA gene of collected mites was performed. Analysis revealed that the 16S rRNA gene sequence of collected mites appeared 100% identical to the Demodex cati 16S rRNA gene sequence deposited in GenBank (JX193759). A similarity of 79.2% and 74.4% was found when the 16S rRNA gene sequence of collected mites was compared with that of Demodex gatoi (JX981921) and Demodex felis (KF052995), respectively.
CLINICAL RELEVANCE Demodicosis in cats is often associated with underlying disease. In cats, FIV infection may lead to an altered immune response and induce species polymorphism of Demodex mites.