Atypical Histoplasma capsulatum infection in a dog

Disseminated histoplasmosis was diagnosed in a 10-year-old dog suspected of having hepatic carcinoma. Clinical abnormalities included diffuse hepatomegaly, gastrointestinal bleeding, thoracic and abdominal effusion, anemia, leukocytosis, and thrombocytopenia. Histoplasmosis characteristically is a disease of the mononuclear phagocyte system, but in this case was diagnosed by finding Histoplasma capsulatum organisms in neutrophils on the blood smear.     

Experimentally induced Histoplasma capsulatum infection in coyotes and a dog

Captive coyotes (Canis latrans) were inoculated intragastrically (1 coyote), and intratracheally (6 coyotes) with Histoplasma capsulatum to simulate natural routes of exposure. In addition, the infectious organism was inoculated IV into another coyote and into a dog (C familiaris) to simulate hematogenous dissemination of H capsulatum. Isolation of the pathogen from various tissue specimens, using direct plating and mouse inoculation methods, provided mycologic evidence of infection. The presence of anti-Histoplasma serum antibodies also was monitored. Of the 6 coyotes challenged intratracheally, one developed a benign pulmonary form of histoplasmosis. This coyote developed a transient cough, and intracellular yeasts typical of H capsulatum were observed microscopically in pulmonary tissue specimens. The pathogen was isolated from specimens of pulmonary tissue and associated lymph nodes. The coyote that was fed Histoplasma-infected mice (intragastric challenge) did not develop clinical disease. The coyote and the dog inoculated IV developed a multifocal, nonsuppurative infection, without clinical evidence of histoplasmosis. Pathologic findings in the coyote and dog were similar; both animals had splenitis, lymphadenitis, and petechiation of the lungs. The liver and spleen were considered the primary extrapulmonary target organs on the basis of mycologic and histologic findings.     

Dermoid cyst of the spinal cord associated with ataxia in a cat

A young adult Balinese cat developed complete hindlimb paralysis which persisted for six weeks. Clinical findings suggested a lesion compressing the spinal cord and this was confirmed at necropsy. A dermoid cyst was present at the level of the third thoracic vertebra. The cyst was lined by stratified squamous epithelium and contained desquamated keratinised material and hair fragments. Sebaceous glands and hair follicles were present in the connective tissue wall. This is the first report of a dermoid cyst in the spinal cord of a cat. The lesion is considered to be a congenital anomaly.     

Partial lateral corpectomy for ventral extradural thoracic spinal cord compression in a cat

A 7-year-old, female spayed, domestic shorthair cat was presented for ambulatory paraparesis. No trauma history was reported. Myelography and subsequent computed tomography revealed multiple ventrally located extradural spinal cord compressive lesions possibly due to intervertebral disc disease. Compression at the level of Th3-Th4 intervertebral disc space was considered responsible for the paraparesis. The lesion was approached via a right-sided lateral partial corpectomy as described for dogs. Complete spinal decompression was achieved, as documented intraoperatively by visual inspection and palpation of the spinal canal. No surgery related complications were encountered and the cat improved gradually within 8 weeks after the procedure. At 1 year follow-up only a slight proprioceptive deficit in the right hind limb could be noted. This is the first report of partial lateral corpectomy in a cat and should encourage the use of this technique even in small patients.     

Association of spinal cord compression seen on magnetic resonance imaging with clinical outcome in 67 dogs with thoracolumbar intervertebral disc extrusion

OBJECTIVES: To determine whether there is an association between the degree of transverse spinal cord compression detected by magnetic resonance imaging following thoracolumbar Hansen type 1 intervertebral disc disease in dogs and their presenting and postsurgical neurological status. METHODS: Medical records of 67 dogs with surgically confirmed Hansen type 1 intervertebral disc disease (2000 to 2004) were reviewed to obtain the rate of onset of disease, duration of clinical signs and presurgical and postsurgical neurological grade. Percentage of spinal cord compression was determined on transverse T2-weighted magnetic resonance images. Linear regression was used to examine the association between spinal cord compression and each of the above variables. Chi-squared tests were used to examine associations among postsurgical outcome and presurgical variables. RESULTS: Eighty-five per cent (57 of 67) of dogs were chondrodystrophoid. Mean spinal cord compression was 53 per cent (sd=219.7, range 14.3 to 84.9 per cent). There was no association between the degree of spinal cord compression and the neurological grade at presentation, rate of onset of disease, duration of clinical signs or postsurgical outcome, with no difference between chondrodystrophoid and non-chondrodystrophoid dogs. CLINICAL SIGNIFICANCE: The degree of spinal cord compression documented with magnetic resonance imaging in dogs with thoracolumbar Hansen type 1 intervertebral disc disease was not associated with the severity of neurological signs and was not a prognostic indicator in this study.     

Spinal-evoked potentials in dogs with acute compressive thoracolumbar spinal cord disease

Spinal evoked potentials (SpEP) were recorded on an electromyograph from electrodes placed percutaneously in the ligamentum flava at the lumbosacral junction and between the 10th and 11th thoracic vertebrae following tibial nerve stimulation in 31 anesthetized dogs with acute compressive spinal cord injuries. The neurologic status of each dog was determined by clinical examination before SpEP recordings, and the neurologic status was monitored for 2 months in dogs that had surgical or conservative treatment. Two months after spinal injury, the response to treatment (outcome) of each dog was evaluated and graded as favorable (ambulatory and urinary continent) or unfavorable (nonambulatory, urinary incontinent, or euthanatized with confirmation of myelomalacia). Onset latencies, conduction velocities, amplitudes and durations of the wave forms, and the ratio of conduction velocity to combined durations of the first positive (P1) and first negative (N1) waves (CV/DPN index) were determined and were compared with reference data from clinically normal (control) dogs. Single SpEP recordings were of value in determining the prognosis for recovery. Significant differences were not found in the L7-S1 recordings between the reference (control) and spinal injury groups. Analysis of data from the T10-11 recordings indicated significant differences between the reference and spinal injury groups and between the favorable and unfavorable outcome groups within the spinal injury group. A CV/DPN index was less than 30 in dogs with unfavorable outcomes and greater than 30 in dogs with favorable outcomes. Stepwise discriminant analysis of data from the spinal injury group predicted outcome correctly in all dogs.     

Brain and spinal cord haemorrhages associated with Angiostrongylus vasorum infection in four dogs

Multifocal haemorrhages associated with Angiostrongylus vasorum infection were observed in the central nervous system of four dogs with neurological signs including depression, seizures, spinal pain and paresis. In magnetic resonance images the majority of the lesions were isointense or slightly hyperintense in T1-weighted images, hyperintense in T2-weighted images and hypointense in T2*-weighted (gradient echo) images, compatible with haemorrhages more than seven days old. Lesions were found in the brain of three of the dogs and in the spinal cord of two. The cerebrospinal fluid contained high concentrations of protein and evidence of erythrophagia. All the dogs had coagulopathy and pulmonary haemorrhage of varying severity. A vasorum larvae were detected in the faeces of each of the dogs. Neural A vasorum was confirmed at postmortem examination in two dogs.     

Chronic diarrhea associated with Campylobacter jejuni infection in a cat

Campylobacter jejuni was isolated from a cat with chronic diarrhea. The diarrheic cat and another cat (which previously had diarrhea) in the same household had bactericidal antibody titers to the C jejuni. Clinical response to antibiotic therapy and not recovering Campylobacter sp from normal feces after treatment also supported the diagnosis of Campylobacter-associated diarrhea. Although the owner had a protracted episode of diarrhea, C jejuni was not isolated from the owner's feces, nor was a bactericidal antibody detected in the owner's serum.     

Suppurative rhinitis associated with Haemophilus species infection in a cat

A young cat with signs of chronic rhinitis was evaluated for underlying anatomical, inflammatory, or infectious disease. Initial diagnostics were significant for the isolation of an unusual pathogen, Haemophilus species. Isolation using a human RapID NH system erroneously identified the isolate as H. segnis, a human pathogen. No database of veterinary pathogens (Haemophilus) are included in the system and animal pathogens will either be erroneously identified or yield a unique biocode not listed. Because of the unique nature of the pathogen we explored the possibility of immunosuppression as a contributory factor to infection. A variety of laboratory tests were employed to evaluate immune function. The clinical indications and utility of immune function testing are discussed. No immune dysfunction was identified.     

Cutaneous granulomas associated with Mycobacterium fortuitum infection in a cat

Feline mycobacterial skin infections are reviewed briefly. A case of skin granulomas in a cat associated with the presence of the fast–growing acid–fast bacillus, Mycobacterium fortuitum , is reported. Surgical excision was followed by recurrence, but resolution of the lesions was obtained by tetracycline therapy for 12 weeks interspersed with a 14–day course of choloramphenicol. An attempt at experimental transmission to a kitten was unsuccessful. The characteristics of the fast–growing mycobacteria and the possible sources of infection are discussed.