IMAGING DIAGNOSIS-CHRONIC CANINE DISTEMPER MENINGOENCEPHALITIS

Histopathological Features of Spinal Cord Lesions in Dogs with Distemper-Associated Demyelinating Leucoencephalomyelitis

Demyelinating leucoencephalomyelitis (DLEM) is one of the pathological presentations of canine distemper, but its histological characteristics and topographical distribution of spinal cord injuries have been poorly explored. Seventeen dogs submitted for necropsy to a veterinary pathology service (2006-2008) and diagnosed with distemper-associated DLEM were investigated. Seventy-two of 231 spinal cord sections from these animals had histological lesions, which consistently affected the white matter. The lumbosacral region was mostly affected (13/17), followed by the thoracolumbar (11/17), cervical (9/17) and cervicothoracic (9/17) regions. Among the 72 affected cord sections, lesions in the lateral (42/72) and dorsal funiculi (31/72) were the most common. Demyelination (17/17), astrocytosis (17/17), microgliosis (17/17), gemistocytes (11/17) and non-suppurative inflammation (10/17) were frequently seen in the white matter. Grey matter changes were less common, and included gliosis (8/17), non-suppurative inflammation (7/17) and malacia (5/17). Acute lesions were most prevalent (13/17) but it was common (10/17) for the same dog to have lesions at different stages of evolution in distinct spinal cord regions. Pathological changes in several spinal cords did not correlate with the reported clinical signs and some dogs did not present with spinal cord-related clinical signs. Our results highlight important aspects of the distribution and morphology of spinal cord lesions in dogs with distemper-associated DLEM, and may assist clinicians and pathologists in the diagnosis of spontaneous cases of this important infectious disease and contribute to further studies concerning distemper pathogenesis.

Magnetic resonance imaging findings and clinical management of suspected intracranial hypovolemia after transfrontal craniotomy in a dog

OBJECTIVE

To report the diagnosis and clinical management of a case of suspected intracranial hypovolemia (IH) in a dog after resection of a large fronto-olfactory chordoid meningioma.

STUDY DESIGN

Clinical case report.

ANIMAL

One 8-year-old border collie with forebrain neurological signs caused by a fronto-olfactory extra-axial mass diagnosed by using MRI.

METHODS

The dog underwent bilateral transfrontal craniotomy for excision of the mass by using ultrasonic aspiration. Immediate postsurgical MRI revealed complete gross resection with no evidence of early-onset complications such as edema, hemorrhage, mass effect, or pneumoencephalus. However, diffuse symmetric meningeal thickening and contrast enhancement were noted. No complications were noted during surgery or while under anesthesia.

RESULTS

Neurological deterioration was observed postoperatively. No abnormalities were detected systemically. Thus, early MRI-confirmed findings and neurological deterioration were suspected to be caused by IH. Conservative treatment consisting of bed rest, gabapentin, and intravenous theophylline was then initiated in addition to steroids, antiepileptic drugs, and antibiotics. A gradual neurological improvement was observed, and the dog was discharged completely ambulatory with moderate proprioceptive ataxia 15 days after surgery.

CONCLUSION

The clinical and MRI-confirmed findings reported here are consistent with IH, a well-described syndrome in man. This is the first report of a dog with MRI-confirmed findings consistent with IH describing subsequent response to medical management.

CLINICAL SIGNIFICANCE

Intracranial hypovolemia after craniotomy should be considered when there is neurological deterioration and characteristic MRI-confirmed findings.

Bilateral Telencephalic Gliomatosis Cerebri in a Dog

An 8-year-old intact male Lagotto Romagnolo was presented with forebrain signs. Neuroanatomic localization was diffuse prosencephalon. MRI revealed diffuse, bilateral, and symmetric T2 and FLAIR hyperintensities in the parieto-occipital white matter and corpus callosum. No mass effect or contrast enhancement was noted. Analysis of cerebrospinal fluid revealed normal protein content and mild mononuclear pleocytosis. Atypical cells were not identified. 15 days later because of the worsening of clinical condition the patient was euthanized upon owner’s request. Neuropathological investigations were consistent with gliomatosis cerebri (GC). Such an unusual imaging pattern appeared similar to some cases of human GC and to a previous reported case in a dog, suggesting a possible repeatable imaging findings for this rare brain neoplasm. GC should be included in the MRI differentials for diffuse bilateral white matter signal changes and specific MRI findings described in this report may help in reaching a presumptive diagnosis of this tumor.

The Use of Botulinum Toxin for the Treatment of Generalized Myoclonus in a DogS

A 13 mo old spayed female mixed-breed dog presented in a nonambulatory state that was attributed to severe myoclonus secondary to distemper. The authors hypothesized that mitigating the myoclonus would help the dog become ambulatory and expedite convalescence. They injected the severely affected muscles with botulinum toxin on two separate occasions over a period of 18 days. Those injections reduced the myoclonus, helping the dog become ambulatory and attaining a comfortable, functional state.

Magnetic Resonance Imaging Lesions in the Central Nervous System of a Dog with Canine Monocytic Ehrlichiosis

A ten-year-old neutered male dog was examined for tetraparesis, vestibular dysfunction, ataxia, and vertebral column hyperesthesia of 10 days duration. On magnetic resonance imaging (MRI), there were multifocal, punctate, T2-hyperintense lesions in the brain and cervical spinal cord and intracranial leptomeningeal contrast enhancement. Cerebrospinal fluid (CSF) analysis revealed a predominantly mononuclear pleocytosis and mildly elevated protein.Ehrlichia caniswas diagnosed by serum immunofluorescent antibody (IFA) testing. The dog improved with administration of doxycycline. This report describes MRI central nervous system findings in a dog with ehrlichiosis.