Magnetic resonance imaging of feline hippocampal necrosis.

The clinical, neuropathologic, and magnetic resonance (MR) imaging features in four cats with necrosis of the hippocampus and piriform lobe are described. All cats had acute generalized seizures and behavioral changes including aggression, salivation, polyphagia, and disorientation. Routine hematologic, serum chemistry, and cerebrospinal fluid analyses were normal. MR imaging abnormalities were restricted to the area of the hippocampus and piriform lobe. The lesions were T2-hyperintense, T1-hypointense, and were characterized by various degrees of contrast enhancement. Lesions were consistent with necrotizing encephalitis. Two cats were euthanized and underwent postmortem examination within a week after MR imaging due to the lack of response to antiepileptic drug therapy and progressive encephalopathy [corrected] The remaining two cats lived for about four months and were then euthanized because of persistent behavioral and neurologic signs; only one of these cats underwent postmortem examination with histopathologic examination. Histopathological findings were typical of severe, diffuse, bilateral symmetric necrosis, and degeneration of neurons in the hippocampus and piriform lobe, but an etiologic agent was not apparent. This apparently unique feline syndrome, now reported in Switzerland and Italy, has no known cause at this time.

Echocardiographic changes induced by moderate to marked hypobaric hypoxia in dogs.

Hypobaric (high-altitude) hypoxia is a physiologic cause of pulmonary hypertension, and alters left ventricular (LV) systolic and diastolic function. In the presence of tricuspid regurgitation, systolic pulmonary artery pressure can be measured noninvasively using the peak tricuspid regurgitation velocity and the Bernoulli equation. In the absence of measurable tricuspid regurgitation, severity of pulmonary hypertension may be estimated using two-dimensional, M-mode, and Doppler-derived parameters. To evaluate the usefulness of echocardiographic parameters for detecting mild-to-moderate pulmonary hypertension caused by moderate-to-marked hypoxia and to study the effect of high-altitude hypoxia on systolic and diastolic LV function in dogs, 19 Greenland dogs were examined at moderate altitude (2300 m) and high altitude (3500 m), and 10 Greenland control dogs were examined at 700-900 m. Evaluated parameters were pulmonary flow profile (shape, right ventricular acceleration time (RVAT), ejection time (RVET), RVAT/ET), peak mitral inflow velocities (LVE, LVA, LVE/A-ratio), LV % fractional shortening (FS), systolic time intervals (LVPEP, LVPEP/ET), and stroke volume index (SVI). Notching during deceleration was common in dogs at high altitude and in the control dogs, but not in dogs at moderate altitude. RVAT was shorter in dogs at high altitude compared with moderate altitude, but not compared with control dogs. Peak A-velocity was higher and E/A-ratio was lower in dogs at high altitude compared with moderate altitude and control dogs. FS was increased in dogs at high altitude compared with moderate altitude, and LVPEP and LVPEP/ET were shorter in the dogs at high altitude compared with moderate altitude and control dogs. In conclusion, significant differences in pulmonary flow profiles and systolic and diastolic parameters can be observed echocardiographically in dogs at different degrees of hypobaric hypoxia. However, overlap between the groups compromises their usefulness for diagnosing and estimating the degree of mild-to-moderate pulmonary hypertension in individual dogs.

Fungal rhinitis and sinusitis in three cats.

Localized infection of the nasal or paranasal cavities caused by Aspergillus spp or Penicillium spp was diagnosed in 3 cats. Clinical signs included chronic mucopurulent nasal discharge, epistaxis, and mandibular lymphadenopathy. Rhinoscopic and diagnostic imaging findings were compatible with severe inflammation of the nasal mucosa and destruction of the turbinates. Fungal plaques were observed rhinoscopically in 2 cats, and histologic examination of biopsy specimens revealed fungal colonies with surrounding inflammatory infiltrates in all 3. Results of fungal culture were negative for all 3 cats. Results of serum immunoelectrophoresis for antibodies against Aspergillus spp were positive in 2 cats. Treatment with itraconazole was effective in controlling clinical signs in 1 cat, but hepatotoxicosis developed. A single intranasal infusion of clotrimazole subsequently led to long-term resolution of clinical signs in this cat. Localized aspergillosis-penicilliosis is clinically indistinguishable from other pathologic conditions of the nasal and paranasal cavities in cats and should be considered when examining cats with chronic nasal discharge.