Complications associated with cerebrospinal fluid collection in dogs.

BACKGROUND: This study aimed to identify complications associated with cerebrospinal fluid (CSF) collection in dogs. METHODS: This was a prospective, observational multicentre study using data collected from 102 dogs undergoing CSF collection for the investigation of neurological disease. CSF was collected from the cerebellomedullary cistern (CMC), lumbar subarachnoid space (LSAS) or both sites. Pre-, intra- and postprocedural data were collected. Descriptive statistics were performed to outline complications associated with CSF collection. RESULTS: CSF sampling was attempted on 108 occasions, and CSF was acquired on 100 occasions (92.6%). Collection from the CMC was more likely to be successful than that from the LSAS. No dogs exhibited neurologic deterioration following CSF collection. There was no significant difference between pre- and post-CSF collection short-form Glasgow composite measure pain scores in ambulatory dogs (p = 0.13). LIMITATIONS: The scarcity of complications limited the ability to quantify the incidence of some potential complications reported elsewhere. CONCLUSIONS: Our results may be used to inform clinicians and owners that CSF sampling is associated with a low frequency of complications when performed by trained personnel.

Bruxism in awake dogs as a clinical sign of forebrain disease: 4 cases.

BACKGROUND: Bruxism is a repetitive masticatory muscle activity characterized by clenching or grinding of the teeth, or by bracing or thrusting of the mandible, or both. OBJECTIVES: To investigate whether bruxism in awake dogs could be associated with brain lesions. ANIMALS: Four dogs with episodic bruxism in the awake state. METHODS: Observational retrospective single-center case series. Inclusion criteria were dogs examined between 2010 and 2021 with episodic bruxism as a presenting complaint or observed during the examination or hospitalization, complete medical records and magnetic resonance imaging or computed tomography of the brain. Bruxism during epileptic seizures as oroalimentary automatism was an exclusion criterion. RESULTS: Four dogs met the inclusion criteria. Two dogs had bruxism while awake as a presenting complaint, whereas in the remaining 2 it was a clinical finding. All dogs had neuroanatomical localization consistent with a forebrain lesion, with diencephalic involvement in 3/4. The diagnostic evaluation was consistent with neoplasia (n = 2) and meningoencephalitis of unknown origin (n = 2), in 1 case accompanied by corpus callosum abnormality affecting the forebrain, in 3 dogs advanced imaging findings were suggestive of increased intracranial pressure. All dogs were euthanized. CONCLUSIONS AND CLINICAL IMPORTANCE: Our results suggest that the presence of bruxism in the awake state associated with other neurological deficits might indicate a forebrain lesion.

Utility of a flexed neck sagittal magentic resonance imaging sequence for the assessment of cerebellomedullary cistern in dogs.

Cerebrospinal fluid (CSF) collection from the cerebellomedullary cistern (CM) of dogs with congenital or acquired cerebellar herniation could lead to serious complications. It is anecdotally more challenging in large brachycephalic breeds possibly due to the increased distance between the skin and CM. The first objective of this study was to assess whether flexed-neck sagittal magnetic resonance imaging (MRI) sequences would assist in the decision-making process of collecting CSF from the CM. The second objective was to examine the dimensions of the CM measured in extended and flexed views, and whether cranial index (CI), skull height and body weight correlated with the distance of the CM from the skin surface. Forty-one dogs of various breeds were included in the study. Measurements were performed on T2-weighted sagittal sequences acquired in extended and flexed-neck positions, and transverse sequences acquired in an extended-neck position. Mild cerebellar herniation was detected in 23/41 (56%) of the flexed-neck views versus none in the extended views. The CM area was significantly larger in flexed-neck views than in extended views (p < 0.05). In 29% of the cases (12/41), the trajectory of the needle intersected the cerebellar vermis. There was a positive correlation between the distance of the CM from the skin and body weight (p < 0.05) and skull height (p < 0.05), but not with the CI (p = 0.23). These findings suggest that a flexed-neck sagittal MRI sequence helps with assessment of the size of the CM and degree of cerebellar herniation, and that skull height and body weight, but not cranial index, affect the distance of the CM from the skin surface.

What Is Your Diagnosis?

In collaboration with the American College of Veterinary Radiology.

Clinical features, diagnosis, and survival analysis of dogs with glioma.

BACKGROUND: Gliomas in dogs remain poorly understood. OBJECTIVES: To characterize the clinicopathologic findings, diagnostic imaging features and survival of a large sample of dogs with glioma using the Comparative Brain Tumor Consortium diagnostic classification. ANIMALS: Ninety-one dogs with histopathological diagnosis of glioma. METHODS: Multicentric retrospective case series. Signalment, clinicopathologic findings, diagnostic imaging characteristics, treatment, and outcome were used. Tumors were reclassified according to the new canine glioma diagnostic scheme. RESULTS: No associations were found between clinicopathologic findings or survival and tumor type or grade. However, definitive treatments provided significantly (P = .03) improved median survival time (84 days; 95% confidence interval [CI], 45-190) compared to palliative treatment (26 days; 95% CI, 11-54). On magnetic resonance imaging (MRI), oligodendrogliomas were associated with smooth margins and T1-weighted hypointensity compared to astrocytomas (odds ratio [OR], 42.5; 95% CI, 2.42-744.97; P = .04; OR, 45.5; 95% CI, 5.78-333.33; P < .001, respectively) and undefined gliomas (OR, 84; 95% CI, 3.43-999.99; P = .02; OR, 32.3; 95% CI, 2.51-500.00; P = .008, respectively) and were more commonly in contact with the ventricles than astrocytomas (OR, 7.47; 95% CI, 1.03-53.95; P = .049). Tumor spread to neighboring brain structures was associated with high-grade glioma (OR, 6.02; 95% CI, 1.06-34.48; P = .04). CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with gliomas have poor outcomes, but risk factors identified in survival analysis inform prognosis and the newly identified MRI characteristics could refine diagnosis of tumor type and grade.

Cytological and microbiological characteristics of middle ear effusions in brachycephalic dogs.

BACKGROUND: Middle ear effusion is common in brachycephalic dogs with similarities to otitis media with effusion in children. Association with the cranial and eustachian tube morphology and bacterial infection is suspected in both species. HYPOTHESIS/OBJECTIVES: To determine cytological and bacteriological features of middle ear effusions in dogs, provide information on histological features, and further assess the dog as a model of the human disease. ANIMALS: Sixteen live dogs, 3 postmortem cases of middle ear effusion, and 2 postmortem controls. METHODS: Prospective; clinical investigation using computed tomography, magnetic resonance imaging, video-otoscopy, myringotomy; cytological assessment of 30 and bacteriology of 28 effusions; histology and immunohistochemistry (CD3 for T-lymphocytes, Pax5 for B lymphocytes and MAC387 for macrophages) of 10 middle ear sections. RESULTS: Effusions were associated with neurological deficits in 6/16 (38%) and concurrent atopic dermatitis and otitis externa in 9/16 (56%) of live cases. Neutrophils and macrophages predominated on cytology (median 60 [range 2%-95.5%] and 27 [2%-96.5%]) whether culture of effusions was positive or not. In histology sections, the mucosa was thickened in affected dogs but submucosal gland dilatation occurred in affected and unaffected dogs. There was no bacterial growth from 22/28 (79%) of effusions. Bacteria isolated from the other 6 (21%) were predominantly Staphylococcus pseudintermedius (4/6, 67%). CONCLUSIONS AND CLINICAL IMPORTANCE: Clinical, morphological, and cytological findings in middle ear effusions of dogs and people suggest similar pathogeneses. Middle ear effusion of dogs could be a useful model of human otitis media with effusion. Such comparisons can improve understanding and management across species.

Pathogenic variants in COL6A3 cause Ullrich-like congenital muscular dystrophy in young Labrador Retriever dogs.

The collagen VI-related muscular dystrophies in people include a broad spectrum of diseases ranging from the severe Ullrich congenital muscular dystrophy to the mild Bethlem myopathy. Clinical features are attributable to both muscle and connective tissue and include progressive muscle weakness and respiratory failure, hyperlaxity of distal joints, and progressive contracture of large joints. Here we describe two different COL6A3 pathogenic variants in Labrador Retriever dogs that result in autosomal recessive or autosomal dominant congenital myopathies with hyperlaxity of distal joints and joint contracture, similar to the condition in people.

Botulinum toxin type A for the treatment of muscle contractures secondary to acute spinal cord injury in a young cat.

CASE SUMMARY: A 4-month-old male entire domestic shorthair cat presented for sudden onset of right thoracic monoparesis following a fall; within 18 h, the clinical signs progressed to non-ambulatory right hemiplegia with absent sensation in the distal right thoracic limb and left hemiparesis. MRI revealed changes consistent with a C6-C7 acute non-compressive nucleus pulposus extrusion with suspected secondary C5-C7 spinal cord haemorrhage. Rehabilitation exercises were started immediately after the diagnosis of acute spinal cord trauma. Sensation in the right thoracic limb improved and, with the help of a splint applied to that limb, the cat was ambulatory on all four limbs. Unfortunately, clinical signs started to progress over the course of 10 days. The cat developed progressive discomfort on manipulation of the right elbow and carpus, and a hyperflexion of the right carpus. Radiographs revealed no skeletal abnormalities. Muscle contractures were suspected. Under general anaesthesia the triceps and flexor muscles of the carpus and digits were injected with a total of 100 U of botulinum toxin type A (BTX-A). No complications were associated with the procedure and 24 h after the injection the carpal hyperflexion resolved. RELEVANCE AND NOVEL INFORMATION: The use of BTX-A to treat muscle contractures in human medicine is an established and increasingly used technique. For example, in subacute stroke patients with a non-functional arm, BTX-A forearm injection appears to prevent disabling finger stiffness, likely by minimising the development of contractures. Here, we demonstrate that intramuscular BTX-A is an effective treatment for acquired muscle contractures in a cat.

Network analysis of canine brain morphometry links tumour risk to oestrogen deficiency and accelerated brain ageing.

Structural 'brain age' is a valuable but complex biomarker for several brain disorders. The dog is an unrivalled comparator for neurological disease modeling, however canine brain morphometric diversity creates computational and statistical challenges. Using a data-driven approach, we explored complex interactions between patient metadata, brain morphometry, and neurological disease. Twenty-four morphometric parameters measured from 286 canine brain magnetic resonance imaging scans were combined with clinical parameters to generate 9,438 data points. Network analysis was used to cluster patients according to their brain morphometry profiles. An 'aged-brain' profile, defined by a small brain width and volume combined with ventriculomegaly, was revealed in the Boxer breed. Key features of this profile were paralleled in neutered female dogs which, relative to un-neutered females, had an 11-fold greater risk of developing brain tumours. Boxer dog and geriatric dog groups were both enriched for brain tumour diagnoses, despite a lack of geriatric Boxers within the cohort. Our findings suggest that advanced brain ageing enhances brain tumour risk in dogs and may be influenced by oestrogen deficiency-a risk factor for dementia and brain tumours in humans. Morphometric features of brain ageing in dogs, like humans, might better predict neurological disease risk than patient chronological age.

Feline meningioma with extensive nasal involvement.

CASE SUMMARY: A 9-year-old male neutered domestic longhair cat was presented with a 3 week history of lethargy and pain of unknown origin. A large extra-axial mass was demonstrated on MRI of the head, with cribriform plate destruction, extensive nasal invasion and intracranial expansion, producing a severe mass effect. The mass was isointense on T1-weighted imaging, predominantly hypointense with some hyperintense areas on T2-weighted imaging and fluid attenuation inversion recovery, markedly contrast enhancing, and caused transtentorial and cerebellar herniation. Histopathological evaluation confirmed a transitional (mixed) meningioma. RELEVANCE AND NOVEL INFORMATION: To our knowledge this is the first report of a meningioma with extensive nasal involvement in a cat. Based on this case, meningioma should be considered as a differential diagnosis for tumours involving the nasal cavity and frontal lobe with cribriform plate destruction.

Feline hyperaesthesia syndrome with self-trauma to the tail: retrospective study of seven cases and proposal for an integrated multidisciplinary diagnostic approach.

CASE SERIES SUMMARY: This was a retrospective study on the clinical features and response to treatment in seven cats with feline hyperaesthesia syndrome (FHS) and tail mutilation. FHS is a poorly understood disorder characterised by skin rippling over the dorsal lumbar area, episodes of jumping and running, excessive vocalisation, and tail chasing and self-trauma. The majority of the cats were young, with a median age of 1 year at the onset of clinical signs, male (n = 6) and with access to the outdoors (n = 5). Multiple daily episodes of tail chasing and self-trauma were reported in five cats, with tail mutilation in four cats. Vocalisation during the episodes (n = 5) and rippling of lumbar skin (n = 5) were also reported. Haematology, serum biochemistry, Toxoplasma gondii and feline immunodeficiency virus/feline leukaemia virus serology, MRI scans of brain, spinal cord and cauda equina, cerebrospinal fluid analysis and electrodiagnostic tests did not reveal any clinically significant abnormalities. A definitive final diagnosis was not reached in any of the cats, but hypersensitivity dermatitis was suspected in two cases. A variety of medications was used alone or in combination, including gabapentin (n = 6), meloxicam (n = 4), antibiotics (n = 4), phenobarbital (n = 2), prednisolone (n = 2) and topiramate (n = 2); ciclosporin, clomipramine, fluoxetine, amitriptyline and tramadol were used in one cat each. Clinical improvement was achieved in six cases; in five cats complete remission of clinical signs was achieved with gabapentin alone (n = 2), a combination of gabapentin/ciclosporin/amitriptyline (n = 1), gabapentin/prednisolone/phenobarbital (n = 1) or gabapentin/topiramate/meloxicam (n = 1). RELEVANCE AND NOVEL INFORMATION: This is the first retrospective study on a series of cats with FHS. The diagnostic work-up did not reveal any significant abnormalities of the central or peripheral nervous system; dermatological and behavioural problems could not be ruled out. We propose an integrated multidisciplinary diagnostic pathway to be used for the management of clinical cases and for future prospective studies.

Expression of microRNAs in cerebrospinal fluid of dogs with central nervous system disease.

In this pilot study we investigated the expression of 14 microRNAs in the cerebrospinal fluid (CSF) of dogs with neoplastic, inflammatory and degenerative disorders affecting the central nervous system (CNS). CSF microRNA (miRNA) expression profiles were compared to those from dogs with neurological signs but no evidence of structural or inflammatory CNS disease. Seven miRNAs were easily detected in all samples: miR-10b-5p, miR-19b, miR-21-5p, miR-30b-5p, miR-103a-3p, miR-124, and miR-128-3p. Expression of miR-10b-5p was significantly higher in the neoplastic group compared to other groups. There was no relation between miRNA expression and either CSF nucleated cell count or CSF protein content. Higher expression of miR-10b-5p in the neoplastic group is consistent with previous reports in human medicine where aberrant expression of miR-10b is associated with various neoplastic diseases of the CNS.

Restored vision in a young dog following corticosteroid treatment of presumptive hypophysitis.

BACKGROUND: Hypophysitis is an umbrella term for a group of disorders involving inflammation of the pituitary gland. A rare occurrence in humans, hypophysitis can produce a range of clinical signs including (but not limited to) visual deficits and diabetes insipidus. Only five cases of canine hypophysitis exist in the literature, all presenting in mature dogs with no visual deficits and a grave outcome. This case report describes the clinical and advanced imaging features of blindness-inducing presumptive hypophysitis in a dog, which rapidly resolved with medical management. CASE PRESENTATION: A 1-year-and-seven-month-old neutered male Standard Poodle presented with subacute blindness, ataxia, and polyuria/polydipsia (PUPD). Magnetic resonance imaging (MRI) detected a contrast-enhancing pituitary mass with perilesional oedema compromising the optic chiasm. Suspecting neoplasia, anti-inflammatory corticosteroid was commenced prior to radiation therapy planning. Complete resolution of neurological and visual deficits occurred within 12 days of starting steroid treatment. Repeated advanced imaging indicated macroscopic resolution of the lesion. An extended thyroid panel with insulin-like growth factor-1 analysis supported a diagnosis of hypophysitis. Resolution of PUPD was achieved with tapering courses of prednisolone and desmopressin; the dog has since been clinically normal for 14 months and treatment-free for 11 months. CONCLUSIONS: To the authors' knowledge, this is the first instance in which a canine pituitary mass has demonstrated long-term resolution with palliative medical treatment alone, alongside reversal of associated blindness and presumptive diabetes insipidus. We suspect this lesion to be a form of hypophysitis, which should be included among differential diagnoses for pituitary masses, and for subacute blindness in dogs. Where possible, we advocate biopsy-confirmation of hypophysitis prior to timely intervention with anti-inflammatory treatment.

Idiopathic sclerosing orbital inflammation mimicking a malignant spindle cell tumor in a dog.

A dog presented with a retrobulbar mass, diagnosed histopathologically as malignant spindle cell neoplasia. Emergence of analogous findings in the contralateral orbit prompted extended immunohistochemistry of the original mass and reassignment to idiopathic sclerosing orbital inflammation. Early incisional biopsy with extended immunohistochemical analysis should be considered for canine orbital tumors.