A multimodal approach to diagnosis of neuromuscular neosporosis in dogs.

BACKGROUND: Early diagnosis of neosporosis in dogs is challenging. OBJECTIVES: To evaluate the feasibility of a compound multimodal testing approach for diagnosing in dogs neuromuscular and combined forms of neosporosis. ANIMALS: A total of 16 dogs diagnosed with solely neuromuscular neosporosis or with a combination of neuromuscular and central nervous system neosporosis. METHODS: Retrospective review of clinical signs, laboratory findings, treatment, and outcome with focus on the diagnostic utility of different tests. Development of a chromogenic in situ hybridization (ISH) assay for the identification of Neospora caninum in paraffin-embedded muscle samples. RESULTS: 13/16 dogs had only neuromuscular signs of neosporosis, 3/16 had disease signs with concomitant central nervous system (CNS) involvement. Serology was performed in 15/16, with 10/15 showing titers >1 : 160 at admission. PCR on muscle samples detected N. caninum DNA in 11/16. Immunohistochemistry (IHC) detected N. caninum in 9/16 and ISH in 9/16. Histopathology revealed inflammatory myopathy in 10/16, necrotizing myopathy in 5/16, borderline changes in 1/16 and tachyzoites in 9/16. In 4 cases, N. caninum infection was confirmed with all 5 diagnostic methods, 3 cases with 4, 2 with 3, 6 with 2, and 1 animal with 1. CONCLUSIONS AND CLINICAL IMPORTANCE: Diagnosis of N. caninum infection should rely on a multimodal diagnostic approach and negativity of 1 single test should not allow for exclusion. Serology in combination with direct parasite identification via histopathology, DNA via PCR, or both modalities, appears a reliable diagnostic approach.

Comparison of Two Surgical Techniques for the Treatment of Canine Disc Associated-Cervical Spondylomyelopathy.

Objective: To compare prosthetic disc and vertebral distraction stabilization in dogs with disc-associated cervical spondylomyelopathy (DA-CSM). Study Design: A retrospective clinical study. Animals: 25 dogs. Methods: Dogs presenting with clinical signs and MRI findings compatible with DA-CSM underwent surgery. Implantation of the Adamo's prosthetic disc (PD) or vertebral distraction-stabilization (DS) with intervertebral cage, ventral locking plates, and dorsal transarticular screws was performed. All dogs were followed-up and evaluated clinically for a minimum of 1 year and radiographically for at least 3 months. In particular, we focused on the evaluation of subsidence (the degree of vertebral collapse). Results: Twenty-five dogs were enrolled: 12 with PD implantation and 13 with DS implantation. Of these, 24 dogs were followed-up at 1 year. Overall, 12 dogs improved (4 PD and 8 DS), eight were stable (4 PD and 4 DS), and four deteriorated (3 PD and 1 DS). Deterioration was more common in PD cases, especially soon after surgery. In a few PD cases, a second surgery was necessary. The most common complication in dogs with DS was discospondylitis. Subsidence was detected in 11 PD and 7 DS dogs. Subsidence was more severe and occurred sooner after surgery in PD cases compared to DS cases. DS cases were more prone to clinical improvement and less prone to subsidence than PD cases in this study. However, the statistical evidence was weak owing to the small sample size. Conclusion: The preliminary results suggest that prosthetic disc implantation is more prone to clinical and radiographic failures than distraction stabilization. Clinical Relevance: The DS technique is a valuable surgical option for treating dogs with DA-CSM, with favorable short- and long-term clinical and radiographic outcomes.

Occipital cranioplasty using customized titanium prosthesis yields successful outcome in association with foramen magnum decompression in dogs suffering by Chiari-like malformation.

OBJECTIVE: To describe the use of a customized 3-D-printed titanium prosthesis as adjunctive treatment for foramen magnum decompression (FMD) in dogs with Chiari-like malformation (CM) and syringomyelia (SM). ANIMALS: 8 dogs with clinical signs and MRI findings of CM-SM. PROCEDURES: 3-D reconstruction of CT images of the head was used to simulate an occipital craniectomy and design the prosthesis. FMD was performed, and the prosthesis was implanted. Follow-up was performed 1, 6, and 12 months later, and clinical status was scored. Repeated MRI images were compared to identify changes involving the neural structures, particularly the syrinx. RESULTS: All prostheses were easily positioned based on the preoperative 3-D models, with no complications. At 12 months after surgery, 3 dogs were free of previous medications, 4 were still receiving steroid medications but at lower doses, and 1 was occasionally receiving acupuncture. MRI of 5 dogs 6 to 20 months after surgery revealed resolution of SM (n = 1), reduced size of SM (3), or worse SM (1). All dogs showed an increase in size of the caudal cranial fossa. Dogs with a longer presurgical duration of the clinical signs and wider syrinx generally had worse outcomes than other dogs. CLINICAL RELEVANCE: Findings suggested that use of customized 3-D-printed titanium prosthesis and associated FMD can represent an adjunctive option to medically treated dogs with CM-SM. Although the small number of cases precludes definitive conclusions, early surgical treatment, particularly in dogs with a small syrinx, could ensure better long-term outcomes, as previously suggested.

Clinical features of muscle cramp in 14 dogs.

BACKGROUND: Muscle cramps (MCs) are prolonged, involuntary, painful muscle contractions characterized by an acute onset and short duration, caused by peripheral nerve hyperactivity. OBJECTIVES: To provide a detailed description of the clinical features and diagnostic findings in dogs affected by MCs. ANIMALS: Fourteen dogs. METHODS: Multicenter retrospective case series. Cases were recruited by a call to veterinary neurologists working in referral practices. Medical records and videotapes were searched for dogs showing MCs. The follow-up was obtained by telephone communication with the owner and the referring veterinarian. RESULTS: Three patterns of presentation were identified depending on the number of affected limbs and presence/absence of migration of MCs to other limbs. In 9/14 (64%) of dogs, MCs were triggered by prompting the dogs to move. 8/14 (58%) dogs were overtly painful with 6/14 (42%) showing mild discomfort. The cause of MCs was hypocalcemia in 11/14 (79%) dogs: 9 dogs were affected by primary hypoparathyrodism, 1 dog by intestinal lymphoma and 1 dog by protein losing enteropathy. In 3/14 cases (21%) the cause was not identified, and all 3 dogs were German Shepherds. CONCLUSIONS AND CLINICAL IMPORTANCE: Muscle cramps can manifest in 1 of 3 clinical patterns. Muscle cramps are elicited when dogs are encouraged to move and do not always appear as painful events, showing in some cases only discomfort. The main cause of MCs in this study was hypocalcemia consequent to primary hypoparathyroidism. In dogs having MCs of unknown etiology, idiopathic disease or paroxysmal dyskinesia could not be ruled out.

Canine Cerebral Intravascular Lymphoma: Neuropathological and Immunohistochemical Findings.

Intravascular lymphoma (IVL) is a rare angiotropic large-cell lymphoma in which neoplastic lymphocytes proliferate within the lumina of small blood vessels in the absence of a primary extravascular mass or leukemia. This study included 10 cases of canine IVL restricted to the CNS. Dogs had an average age of 8 years and neurological signs mainly referred to brain involvement such as depression, seizures, and ambulatory deficits. Gross examination at necropsy showed focal extensive or multiple hemorrhagic areas mainly distributed in the telencephalon and diencephalon. Histopathologically, numerous veins and capillaries were filled with neoplastic lymphoid cells, accompanied by edema, hemorrhage, and thrombosis. Immunohistochemistry (IHC) for CD3, CD20, and PAX5 was performed to phenotype the neoplastic lymphocytes. IHC for CD44 and CD29 were used to investigate the pathogenetic mechanism leading to the intravascular aggregation of the neoplastic lymphocytes. The same IHC panel was applied to 8 cases of primary and metastatic canine CNS lymphoma in order to compare IVL immunoreactivity. Three IVLs were typified as T-cell, 3 as B-cell, and 4 as non-T non-B. Neoplastic lymphocytes showed marked expression of CD44 in all IVL cases, and CD29-immunolabeled cells were observed in 4 IVLs. CD44 immunoreactivity was consistent with the findings reported in human IVL, suggesting a predisposition to the formation of lymphocyte aggregates. CD29 was inconsistently immunonegative in canine IVL, confirming only partially the pathogenetic mechanism suggested for the human counterpart.

Neuroaxonal Dystrophy and Cavitating Leukoencephalopathy of Chihuahua Dogs.

A novel form of neuroaxonal dystrophy is described in 3 Chihuahua pups, 2 of which were from the same litter. It was characterized not only by accumulation of numerous and widely distributed axonal swellings (spheroids) but also by a severe cavitating leukoencephalopathy. The dogs presented with progressive neurological signs, including gait abnormalities and postural reaction deficits. Magnetic resonance images and gross examination at necropsy revealed dilation of lateral ventricles and cerebral atrophy, accompanied by cavitation of the subcortical white matter. Histopathologically, severe axonal degeneration with formation of large spheroids was found in the cerebral and cerebellar white matter, thalamus, and brainstem nuclei. Small-caliber spheroids were observed in the cerebral and cerebellar gray matter. The telencephalic white matter had severe myelin loss and cavitation with relative sparing of the U-fibers. Different from previously reported cases of canine neuroaxonal dystrophy, in these Chihuahuas the spheroid distribution predominantly involved the white matter with secondary severe leukoencephalopathy.

Canine acute cervical myelopathy: Hydrated nucleus pulposus extrusion or intraspinal discal cysts?

OBJECTIVE: To differentiate between hydrated nucleus pulposus extrusion and ventral intraspinal discal cysts in dogs. STUDY DESIGN: Prospective case series. ANIMALS: Twenty dogs with acute onset of cervical myelopathy due to hydrated nucleus pulposus extrusion or ventral intraspinal discal cysts. METHODS: Clinical and magnetic resonance (MR) imaging findings, outcome after surgical treatment, cytologic and histologic findings of compressive material were taken into account. Comparisons and considerations were done between findings reported herein and what was previously described as suspected hydrated nucleus pulposus extrusion and intraspinal cysts. RESULTS: All dogs were presented with acute onset of cervical myelopathy. MR imaging showed compressive cervical myelopathy at C2-C3 (n = 1), C3-C4 (n = 6), C4-C5 (n = 8), and C5-C6 (n = 5) intervertebral disc spaces, due to extradural material suggestive of either partially hydrated nucleus pulposus extrusion or intraspinal discal cyst, with T2 hyperintense and T1 iso-hypointense signal and variable contrast enhancement after gadolinium injection. All dogs were treated surgically by ventral slot (n = 15) or dorsolateral hemilaminectomy (n = 5). All dogs had a favorable outcome and regained a normal gait. The extradural material collected at surgery varied from liquid to more obvious gelatinous material. Cytologic or histologic examination of the material revealed similar findings for all dogs, compatible with partially degenerated nucleus pulposus. CONCLUSIONS: Dogs with acute onset of compressive cervical myelopathy due to extradural material resembling human intraspinal cysts on MR images are most likely to have extrusion of partially degenerated nucleus pulposus and should be treated accordingly.

Dorsal midbrain syndrome associated with persistent neck extension: Clinical and diagnostic imaging findings in 2 dogs.

Two young dogs were evaluated for an acute onset of abnormal head posture and eye movement. Neurological examination was characterized mostly by permanent neck extension, abnormalities of pupils, and eye movement. A mesencephalic mass lesion was detected on magnetic resonance imaging in both cases. Neurophysiological pathways likely responsible for this peculiar clinical presentation are discussed.

Syndrome du mésencéphale dorsal associé à une extension du cou persistante : résultats de l'évaluation clinique et de l'imagerie diagnostique chez 2 chiens. Deux jeunes chiens ont été évalués suite à l'apparition soudaine d'une posture de tête et d'un mouvement des yeux anormaux. Un examen neurologique a été caractérisé surtout par une extension permanente du cou, des anomalies des pupilles et un mouvement des yeux. Une masse mésencéphalique a été détectée à l'imagerie par résonance magnétique dans les deux cas. Les voies neurophysiologiques, qui étaient probablement responsables de cette présentation clinique, sont discutées.(Traduit par Isabelle Vallières).

Blindness and behavioural changes in the cat: common neurological causes.

PRACTICAL RELEVANCE: Blindness and behavioural changes occur relatively commonly in cats, either separately or in combination, causing devastating consequences for the cat and owner. Blindness can be caused by primary ophthalmic, metabolic or intracranial disease. Similarly behavioural changes may be the primary result of intracranial or systemic disease, but also occur secondarily to visual deficits or changes in interaction with the external environment (ie, non-medical problems). The anatomical pathways involved in vision are very close to those involved in behavioural regulation. It is, therefore, likely that a brain lesion (especially a forebrain lesion) that causes blindness will also cause behavioural abnormalities. CLINICAL CHALLENGES: In cases of partial or unilateral blindness, obvious visual deficits may not be apparent to the owner or clinician. Rather, the visual impairment may manifest more subtly as changes in behaviour, reluctance to jump or unwillingness to go outside. Similarly, behavioural problems may be episodic and, hence, a cat presenting with behavioural disturbances may appear clinically normal on evaluation. Behavioural changes are unlikely to be noticed unless marked and associated with bilateral blindness or advanced systemic illness. AUDIENCE: This article discusses these two major disorders separately, with the aim of highlighting for the clinician some of the important aspects of the general clinical and neurological examination that can be performed to identify these challenging cases.

Contrast-enhanced fluid-attenuated inversion recovery vs. contrast-enhanced spin echo T1-weighted brain imaging.

In humans, contrast-enhanced fluid-attenuated inversion recovery (FLAIR) imaging plays an important role in detecting brain disease. The aim of this study was to define the clinical utility of contrast-enhanced FLAIR imaging by comparing the results with those with contrast-enhanced spin echo T1-weighted images (SE T1WI) in animals with different brain disorders. Forty-one dogs and five cats with a clinical suspicion of brain disease and 30 normal animals (25 dogs and five cats) were evaluated using a 0.2 T permanent magnet. Before contrast medium injection, spin echo T1-weighted, SE T1WI, and FLAIR sequences were acquired in three planes. SE T1WI and FLAIR images were also acquired after gadolinium injection. Sensitivity in detecting the number, location, margin, and enhancement pattern and rate were evaluated. No lesions were found in a normal animal. In affected animals, 48 lesions in 34 patients were detected in contrast-enhanced SE T1WI whereas 81 lesions in 44 patients were detected in contrast-enhanced FLAIR images. There was no difference in the characteristics of the margins or enhancement pattern of the detected lesions. The objective enhancement rate, the mean value between lesion-to-white matter ratio and lesion-to-gray matter ratio, although representing an overlap of T1 and T2 effects and not pure contrast medium shortening of T1 relaxation, was better in contrast-enhanced FLAIR images. These results suggest a superiority of contrast-enhanced FLAIR images as compared with contrast-enhanced SE T1WI in detecting enhancing brain lesions.