DIAGNOSTIC EXERCISE: Cerebral Mass in a Puppy With Respiratory Distress and Progressive Neurologic Signs (original) (raw)
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Another case of canine amoebic meningoencephalitis—the challenges of reaching a rapid diagnosis
Parasitology Research, 2011
A case of granulomatous amoebic meningoencephalitis in a previously healthy, mature, apparently immunocompetent dog, with a history of exposure to stagnant water, is reported. The case presented with ataxia and a tendency to fall to the left side. A computed tomography (CT) showed a ring-enhancing lesion within the cerebellum; an examination of cerebrospinal fluid (CSF) revealed nonspecific mixed-cell pleocytosis. Despite antibiotic and anti-inflammatory therapy, clinical signs progressed rapidly to decerebellate rigidity over 4 days, and the dog was euthanased. Significant post-mortem findings were restricted to the brain, with a localised lytic lesion in the deep cerebellar white matter. Histopathological examination of the brain showed focally extensive cavitation of the white matter and communication of the lesion with the fourth ventricle. The affected area contained structures consistent with amoebae and was infiltrated by neutrophils mixed with lower numbers of macrophages, plasma cells and lymphocytes. The amoebae were identified as Balamuthia mandrillaris, based on specific immunofluorescence detection. Amoebic meningeoencephalitis should be considered in dogs with evidence of focal cavitary lesions in the brain, particularly in cases with a history of swimming in stagnant water.
Journal of Veterinary Medical Science, 2003
Canine necrotizing meningoencephalitis (NME) and granulomatous meningoencephalomyelitis (GME) were compared pathologically. Gross observation exhibited lateral ventricular dilation and discoloration, malacia and/or cavitation of the cerebrum in NME. On the contrary, gross changes were milder in GME, except for occasional visible granulomatous mass formation. Histopathologically, the lesions of NME were distributed predominantly in the cerebral cortex and various degrees of inflammatory and necrotic changes were observed according to clinical stages. Besides, microscopic lesions of GME were mainly distributed in the white matter of the c erebrum, cerebellum and brainstem, which are characterized by perivascular cuffing, multiple granulomas and leptomeningeal infiltrates. Although macrophages and lymphocytes were predominant in the inflammatory lesions of both disorders, macrophages in GME transformed into epithelioid cells and exhibited more massive infiltration. Although lectin RCA-1-reactive cells were numerous in both disorders, lysozyme immunoreactive cells in NME were fewer than that in GME. Parenchymal infiltration of MAC387-positive cells was common in GME and limited in NME. The number of CD3-positive lymphocytes in the GME lesions tended to be greater than in NME, though the difference was not statistically significant. Morphological and immunohistochemical differences of the lesions, in particular, the characteristics of infiltrative macrophages may reflect these different pathogeneses of the two disorders.
Clinical and Pathological Findings of Necrotizing Meningoencephalitis in a Maltese Dog
A 2-year-old, intact female Maltese dog was presented to the veterinarian with a history of acute neurological signs. On neurological examination the dog showed deficit of mental status (apathy and depression), seizures, constant howling, head turn and compulsive circling to the right side and falls to the left side. The treatment protocol using prednisolone (for seizures remission) and cyclosporine (initiated in the chronic stage) did not stop the progression of the disease and euthanasia was elected 65 days later. Necropsy revealed mild cerebral asymmetry, and in the frontal (more affected) parietal and occipital lobes of the right hemisphere there were friable, depressed and yellowish areas characterizing malacia. The left contralateral frontal lobe was edematous and slightly yellowish. At histopathology, the lesions were characterized by marked, multifocal to coalescing necrotizing meningoencephalitis, characterized by focally extensive areas of malacia, especially in the cortex of the frontal and right parietal lobes. Extension of lesions to white matter was observed only in the caudal region of the right frontal lobe. Plasma cells and lymphocytes infiltration was observed around vessels, leptomeninges and in the neuroparenchyma. In addition, the non-cavitation areas were also characterized by neuropil vacuolization, neuronal necrosis, neuronophagia, astroglyosis with various gemistocytes, endothelial hyperplasia and hypertrophy. The immunohistochemical analysis showed predominance of CD3 positive T lymphocytes in proportion to CD79 positive cells. Clinical signs, character and distribution of neurological lesions were compatible with necrotizing meningoencephalitis (NME). This condition, initially reported only in Pugs, currently affects other breeds and attention should be given to the differential diagnosis with other neuropathies in dogs.
Necrotizing Meningoencephalitis in Atypical Dog Breeds: A Case Series and Literature Review
Journal of Veterinary Internal Medicine, 2013
Background: Canine necrotizing meningoencephalitis (NME) is a fatal, noninfectious inflammatory disease of unknown etiology. NME has been reported only in a small number of dog breeds, which has led to the presumption that it is a breed-restricted disorder. Hypothesis/Objectives: Our objective was to describe histopathologically confirmed NME in dog breeds in which the condition has not been reported previously and to provide preliminary evidence that NME affects a wider spectrum of dog breeds than previously reported. Animals: Four dogs with NME. Methods: Archives from 3 institutions and from 1 author's (BS) collection were reviewed to identify histopathologically confirmed cases of NME in breeds in which the disease has not been reported previously. Age, sex, breed, survival from onset of clinical signs, and histopathologic findings were evaluated. Results: Necrotizing meningoencephalitis was identified in 4 small dog breeds (Papillon, Shih Tzu, Coton de Tulear, and Brussels Griffon). Median age at clinical evaluation was 2.5 years. Histopathologic abnormalities included 2 or more of the following: lymphoplasmacytic or histiocytic meningoencephalitis or encephalitis, moderate-to-severe cerebrocortical necrosis, variable involvement of other anatomic locations within the brain (cerebellum, brainstem), and absence of detectable infectious agents. Conclusions and Clinical Importance: Until now, NME has only been described in 5 small dog breeds. We document an additional 4 small breeds previously not shown to develop NME. Our cases further illustrate that NME is not a breedrestricted disorder and should be considered in the differential diagnosis for dogs with signalment and clinical signs consistent with inflammatory brain disease.
Granulomatous meningoencephalomyelitis in dogs: A review
Irish Veterinary Journal, 2005
Granulomatous meningoencephalomyelitis (GME) is an inflammatory disease of the central nervous system in dogs that is characterised by focal or disseminated granulomatous lesions within the brain and/or spinal cord, non-suppurative meningitis and perivascular mononuclear cuffing. The aetiology of the disease remains unknown, although an immune-mediated cause is suspected. This article reviewed the typical history, clinical signs and pathology of the condition along with current opinions on pathogenesis. The potential differential diagnoses for the disease were discussed along with current treatment options.
A novel nonsuppurative meningoencephalitis in young greyhounds in Ireland
2002
Fourteen 4-to 18-month-old vaccinated Greyhounds (10 males, 4 females) from three kennels in southern Ireland presented over a 2-year period with acute or insidious onset neurological signs. Head tilting, ataxia, recumbency, circling, and blindness were commonly observed, and animals were dull, dehydrated, and had lost weight. Hematologic and biochemical parameters reflected dehydration but were otherwise unremarkable. Microscopic examination revealed severe diffuse and focal gliosis and gemistocytosis accompanied by mononuclear cell perivascular cuffing in caudate nucleus and cortical gray matter of the cerebrum and in the periventricular gray matter of the anterior brainstem. Milder lesions were noted in the caudal brainstem, cranial spinal cord, and in the molecular layer of the cerebellum. This was accompanied by a lymphocyte and plasma cell infiltration of the cerebral and cerebellar meninges. Demyelination, neuropil necrosis, neuronophagia, and vasculitis were not observed. No inclusion bodies, fungi, or protozoal cysts were seen. Additional serologic and molecular pathology tests also failed to determine a cause, suggesting that these cases may represent a previously undiagnosed condition in the dog.
Magnetic Resonance Imaging Findings in Histologically Confirmed Pug Dog Encephalitis
Veterinary Radiology & Ultrasound, 2008
The purpose of the study was to describe magnetic resonance (MR) imaging features of histologically confirmed necrotizing encephalitis in four Pugs and to compare those findings with MR imaging characteristics of necrotizing encephalitis in other breeds. All dogs had the following common findings: lesions restricted to the forebrain, both cerebral hemispheres diffusely but asymmetrically affected, lesions affected gray and white matter resulting in loss of distinction between both, most severe lesions in occipital and parietal lobes, lesions were irregularly T2-hyperintense and T1-isointense to slightly T1-hypointense, and no cavitation. There were various degrees of contrast enhancement of brain and leptomeninges. Asymmetry of lateral ventricles and midline shift was seen in one dog each. Two dogs had brain herniation, which may have contributed to the progression of neurologic signs. Hyperintensity on T2-weighted and fluid attenuated inversion recovery images in the hippocampus and piriform lobe was consistent with excitotoxic edema, whereas similar imaging features in other forebrain areas corresponded to areas of inflammation or liquefaction on histopathology. In comparison with necrotizing encephalitis in other canine breeds, Pug dog encephalitis has some unique MR imaging features. Therefore, these characteristics cannot be applied to other breeds, nor should imaging features of necrotizing encephalitis of other canine breeds be used for interpretation of MR images in Pug dogs. Veterinary
Veterinary Radiology & Ultrasound, 2013
Nasal encephaloceles (meningoceles or meningoencephaloceles) are rare and not reported to be infected or coupled with a facial deformity in dogs. This report describes an older dog with acute worsening of seizures due to suppurative meningoencephalitis with coexisting suppurative rhinitis and infection of a meningoencephalocele. Additionally, the dog had a facial deformity for at least 5 years. The results of necropsy, computed tomography, and postmortem magnetic resonance imaging are compared. The development of nasal encephaloceles is discussed, including the potential role of early trauma, and whether separation of neural ectoderm from the surface ectoderm is part of the pathogenesis.