Primary ciliary dyskinesia with situs inversus totalis, hydrocephalus internus and cardiac malformations in a dog

A nine-month-old golden retriever bitch was presented with exercise intolerance and recurrent nasal discharge. Based on clinical, radiographic and ultrasonographic examination, a diagnosis of rhinitis, situs inversus totalis and tricuspid valve insufficiency was established. The results of video- and electron microscopy studies of the respiratory epithelium were compatible with primary ciliary dyskinesia (PCD). However, no evidence of a primary ultrastructural defect of the cilia was found. The dog was euthanased because of the poor prognosis. At necropsy, a hydrocephalus internus and a subaortic stenosis were additionally diagnosed. PCD, in combination with situs inversus, has been previously reported in golden retrievers, but without a concomitant hydrocephalus internus. Furthermore, concomitant occurrence of internal cardiac malformation and PCD has not previously been reported in the dog.     

Polymicrogyria in Standard Poodles

Background: Polymicrogyria is a disorder of cerebrocortical migration resulting in increased numbers of small, disorganized gyri. This disorder occurs in Standard Poodles and in cattle.
Objectives: To describe the clinical, electroencephalographic, imaging, and histopathologic features in poodles with polymicrogyria.
Animals: Five Standard Poodles with histologically confirmed polymicrogyria.
Methods: Retrospective case series. Cases were obtained by personal communication with 1 of 2 authors (TJVW, DPO).
Results: All dogs had cortical blindness and other neurologic abnormalities including gait and behavioral changes. Magnetic resonance imaging of 3 dogs showed multiple disorganized gyri, which were especially apparent on T2-weighted dorsal plane images. Electroencephalogram (EEG) of 1 dog revealed epileptiform discharges, including both spike and spike and wave discharges with voltage maximum potentials over the parietal/occipital region. The EEG supported that the repetitive behavior displayed by the dog was a complex partial motor seizure. One dog had concurrent hydrocephalus. All dogs had occipital lobe involvement and 2 dogs had involvement of other lobes.
Clinical Importance: The cases presented here demonstrate a larger age range (7 weeks to 5 years) and a decreased frequency of associated hydrocephalus when compared with the previous report.     

Ventricular ependymoma in a German Shepherd dog

Using magnetic resonance imaging (MRI) together with clinical, pathomorphological and immunohistological methods, a ependymoma is described in a 9-year-old German Shepherd dog, which presented with behavioural and oculocephalic responses and generalised ataxia. The ependymoma, 9 x 6 x 5mm in size, was localised intra-axially in the right interventricular foramen and hydrocephalus was observed by MRI. Microscopically, the tumour was composed of pseudorosettes, and immunohistochemical examination revealed vimentin and glial fibrillary acidic protein immunoreactivity in the neoplastic cells.     

Application of ventriculoperitoneal shunt as a treatment for hydrocephalus in a dog with syringomyelia and Chiari I malformation

A twenty-month-old Chihuahua male dog was presented to us suffering with ataxia. Based on the physical examination, X-ray and magnetic resonance imaging (MRI) examinations, we diagnosed the dog with hydrocephalus, Chiari I malformation and syringomyelia. Treatment consisted of internal medical treatment and the placement of a ventriculoperitoneal (VP) shunt. The ventricular dilatation was relieved and the dog improved neurologically; however, the Chiari I malformation and syringomyelia remained after surgically positioning the VP shunt.     

INTRACRANIAL EPIDERMOID CYST AND SYRINGOHYDROMYELIA IN A DOG

A 5-year-old female Cocker Spaniel dog had a sudden onset of vestibular disease that localized to the caudal fossa. Upon computed tomography of the brain, a large, hypoattenuating mass with a slight peripheral ring enhancement pattern was detected ventral to the cerebellum. A hypoattenuating region was also identified in the center of the C2 spinal cord segment, consistent with syringohydromyelia. Postmortem examination of the brain revealed a fluid filled, cystic mass located dorsal to medulla oblongata that caused severe compression of the overlying cerebellum. The histopathologic diagnosis was an epidermoid cyst. Extensive syringohydromyelia and obstructive hydrocephalus were identified, both thought to be secondary to overcrowding of the caudal fossa.     

Allergic inhalant dermatitis attributable to marijuana exposure in a dog

Exposure to marijuana was believed to be responsible for clinical signs consistent with allergic inhalant dermatitis in a dog. The dog had facial and pedal pruritus associated with bilateral ocular discharge. Clinical signs resolved when the dog was kenneled, but returned when the dog was returned to its home. The results of intradermal skin testing, using a standard tray of 51 inhalant extracts, did not adequately account for the dog's clinical signs. Later, the owners indicated that previous residents of the owners' home had cultivated marijuana intensively inside and outside of the home. Intradermal skin testing with a source of marijuana pollen extract was performed, yielding a positive reaction in the dog and a negative reaction in another dog without clinical or historical evidence of allergic inhalant dermatitis. The affected dog was treated successfully and exclusively by hyposensitization with marijuana pollen extract.     

Severe brain damage after punitive training technique with a choke chain collar in a German shepherd dog

The features of severe ischemic brain damage after strangulation by the owner of a 1-year-old German shepherd dog are described. The dog was disciplined by the owner during training by holding the dog off the ground by his choke chain collar. At first, the dog behaved normally, but he became increasingly ataxic and started circling to the left and showed reduced consciousness. The neurological examination revealed severe disorientation, left lateral pleurothotonus, and circling. The neurological findings were consistent with a multifocal brain lesion. A magnetic resonance imaging scan was performed and showed changes in the T2- and diffusion-weighted images, consistent with severe cerebral edema resulting from ischemia. Because of the severity of the clinical features, the dog was later euthanized. To the author's knowledge, this is the first report of a severe brain ischemia after strangulation in a dog.     

Thrombocytosis associated with a myeloproliferative disorder in a dog

A dog with a myeloproliferative disorder and thrombocytosis had clinical signs that were consistent with a diagnosis of essential thrombocythemia. The dog was treated with aspirin, radioactive phosphorus, and melphalan. Eighteen months after referral, the disorder progressed to chronic granulocytic leukemia, and treatment was switched to hydroxyurea. Fourteen months later, the dog was euthanatized because of uncontrollable atrial fibrillation.     

Severe hydrocephalus in a raccoon dog (Nyctereutes procyonoides)

Hydrocephalus is one of the most common central nervous system malformations in domestic dogs, yet they are poorly documented and studied in wild carnivoran mammals. A pup of raccoon dog (Nyctereutes procyonoides) was rescued and brought to Wildlife Center. The pup showed generalized ataxia, a domed skull, and an open bregmatic fontanelle. Ultrasound and MRI showed severe enlargement of the lateral ventricle with the loss of septum pellucidum resulting in a single large ventricle and cervical syringohydromyelia. Although treatment was attempted, the animal was euthanized due to poor prognosis. At necropsy, macroscopic findings were identical to the diagnostic imaging, where marked enlargement of the calvarium, and attenuated gyri and sulci were observed. Finally, hydrocephalus was confirmed. Here, we describe a case of hydrocephalus in a raccoon dog (Nyctereutes procyonoides).     

PREVALENCE OF EAR DISEASE IN DOGS UNDERGOING MULTIDETECTOR THIN‐SLICE COMPUTED TOMOGRAPHY OF THE HEAD

Previous reports describing the prevalence of ear diseases in dogs have primarily been based on dogs presenting with clinical signs of disease. The prevalence of subclinical ear disease remains unknown. The purpose of this cross‐sectional retrospective study was to describe the prevalence of lesions consistent with middle and external ear disease in dogs presented for multidetector computed tomography (CT) of the head and/or cranial cervical spine at our hospital during the period of July 2011 and August 2013. For each included dog, data recorded were signalment, CT findings, diagnosis, and treatment. A total of 199 dogs met inclusion criteria. Nineteen dogs (9.5%) were referred for evaluation of suspected ear disease and 27 dogs (13.5%) had histories or physical examination findings consistent with otitis externa. A total of 163 dogs (81.9%) had CT lesions consistent with external ear disease (i.e. ear canal mineralization, external canal thickening, and/or narrowing of the external canal). Thirty‐nine dogs (19.5%) had CT lesions consistent with middle ear disease (i.e. soft tissue attenuating/fluid material in the tympanic bullae, bulla wall thickening or lysis, and/or periosteal proliferation of the temporal bone). Findings from this study indicated that the prevalence of external and middle ear disease in dogs could be higher than that previously reported.     

Magnetic resonance imaging of syringomyelia in five dogs

This report describes the use of magnetic resonance imaging (MRI) in five dogs to diagnose spontaneous syringomyelia. Four of the dogs had cervical syringomyelia associated with hydrocephalus, and one of these cases was analogous to the Dandy-Walker syndrome in humans. The fifth dog had thoracic syringomyelia without hydrocephalus. It was possible to diagnose the condition antemortem in all of the dogs by MRI. It is suggested that MRI is a straightforward and effective tool for the antemortem diagnosis of syringomyelia in dogs.     

Magnetic resonance imaging in the diagnosis and surgical management of sacral osteochondrosis in a mastiff dog

The clinical, radiographic, magnetic resonance imaging (MRI), surgical and pathological findings related to an osteochondral lesion of the sacrum in a mastiff dog are described. The dog showed chronic signs of pain in its pelvic limbs. Radiography revealed a triangular mineralised opacity at the craniodorsal aspect of the sacrum consistent with sacral osteochondrosis. A T2-weighted spin-echo MRI revealed dorsal and lateral compression of the cauda equina. The osteochondral fragment was removed via a dorsal laminectomy, and the clinical signs resolved. Histological abnormalities in the fragment were consistent with a diagnosis of osteochondrosis.     

Congenital external hydrocephalus in a dog

A 4-year-old female Chihuahua was presented with progressive seizures, blindness and lethargy. Neurolocalisation was consistent with a diffuse brain lesion affecting the forebrain and cerebellum. MRI demonstrated dilation of the subarachnoid space dorsolaterally surrounding the cerebrum, filled with cerebrospinal fluid (CSF). Ventricular system size was normal, but mild cerebral atrophy was suspected. There was pachymeningeal contrast enhancement, but CSF analysis was unremarkable. This lesion was interpreted to be an external hydrocephalus of suspected congenital origin.     

MAGNETIC RESONANCE IMAGING FINDINGS ASSOCIATED WITH LATERAL CEREBRAL VENTRICULOMEGALY IN ENGLISH BULLDOGS

Multiple congenital or developmental anomalies associated with the central nervous system have been reported in English Bulldogs. The purpose of this retrospective study was to identify and describe the prevalence and MRI characteristics of these anomalies and their association with presence and degree of cerebral ventriculomegaly. Magnetic resonance imaging studies of 50 English Bulldogs were evaluated. Forty‐eight dogs had some degree of cerebral ventriculomegaly, 27 of which had an otherwise normal brain. Presence of lateral ventriculomegaly was not significantly associated with presence of another intracranial lesion. Appearance of the septum pellucidum was variable, ranging from intact to incomplete or completely absent. The corpus callosum was subjectively thinned in all but three dogs, two of which had normal lateral ventricles. Fusion of the rostral colliculi was not found in any dog. A persistent craniopharyngeal canal was identified in one dog. Aqueductal stenosis caused by fusion of the rostral colliculi was not identified in any dog. Findings indicated that cerebral ventriculomegaly is a common finding in English Bulldogs with or without other intracranial lesions, aqueductal stenosis caused by fusion of the rostral colliculi is unlikely to be a common etiology leading to obstructive hydrocephalus, and a large craniopharyngeal canal is a rare finding that has unknown clinical significance at this time.     

Peliosis hepatis and hemoperitoneum in a dog with diphacinone intoxication

Objective: To describe the clinical course of a dog presented with peliosis hepatis and hemoperitoneum in concert with anticoagulant rodenticide intoxication.
Case summary: A 7.75-year-old spayed female Shetland Sheepdog presented with clinical signs consistent with hypovolemia, hemoperitoneum, and a history of bright green stool 3 days before the onset of clinical signs. Initial packed cell volume/total solids were consistent with acute hemorrhage. A coagulation profile showed prolongation in activated clotting time and prolongation of both prothrombin and activated partial thromboplastin time, suggesting abnormal coagulation. Abdominal hemorrhage persisted in the face of normalization of the hemodynamic status and coagulation profile, and treatment with Vitamin K₁. Abdominal ultrasound revealed multiple patchy hypoechoic areas throughout the caudate liver lobe. An exploratory laparotomy was performed 24 hours after presentation and revealed the caudate liver lobe as the source of the hemorrhage. Histopathologic examination of a specimen of the liver was consistent with peliosis hepatis. Toxicologic testing identified diphacinone levels in the blood consistent with anticoagulant rodenticide intoxication. Postoperative recovery was uneventful, and within 48 hours the dog was discharged. The dog returned to full function and a hepatic ultrasound performed 15 months postoperatively showed no significant abnormalities.
New or unique information provided: Exposure to anticoagulant rodenticides may be associated with the development of peliosis hepatis in dogs.     

Subdural accumulation of fluid in a dog after the insertion of a ventriculoperitoneal shunt

A dog with hydrocephalus as a result of aqueduct stenosis and cerebellar herniation underwent ventriculoperitoneal shunting. Magnetic resonance images and computed tomography scans taken after the surgery revealed subdural accumulations of haemorrhagic fluid and cereberocortical collapse caused by overshunting and leakage of cerebrospinal fluid from the site of insertion of the shunt. However, the degree of cerebellar herniation was reduced after the shunt was inserted, and the dog did not develop any neurological signs and made good progress.     

A case of T-cell chronic lymphocytic leukemia progressing to Richter syndrome with central nervous system involvement in a dog

An 8-year-old neutered Beagle dog was presented with polyuria and polydipsia. Routine clinicopathologic testing showed a significant lymphocytosis and proteinuria. Lymphocytes were of small to intermediate in size with a mature morphology. Infectious disease screening was negative. PCR for antigen receptor gene rearrangements showed a clonal T-cell receptor (TCR) rearrangement consistent with T-cell chronic lymphocytic leukemia (CLL). Bone marrow cytology showed <30% lymphocytes, while the proportion in splenic fine-needle aspirate cytology was considered increased. The dog was initially monitored but started on prednisolone and chlorambucil therapy 2 months later due to worsening clinical signs and progressive lymphocytosis. After an additional 2 weeks, the dog developed multifocal spinal pain and single-node lymphadenomegaly. Cytology of the lymph node showed a monomorphic population of large lymphoblasts consistent with lymphoma. Cytology of a cerebrospinal fluid sample also showed large lymphoblasts. PCR for antigen receptor gene rearrangement at both sites showed a clonal TCR rearrangement of the same molecular size as in the initial leukemic cells. The dog was diagnosed with a transformation of the CLL to Richter syndrome (RS) with involvement of the central nervous system (CNS). Therapy was started with L-asparaginase and an increased dose of prednisolone; however, the dog was euthanized due to progressive clinical signs. To our knowledge, this is the first report of canine RS with direct involvement of the CNS.     

Dermatitis and lymphadenitis resembling juvenile cellulitis in a four-year-old dog

A four-year-old, entire male toy poodle was presented with a two-and-a-half-week history of ocular discharge progressing to periorbital alopecia, depigmentation, alopecia and ulceration around the muzzle. There was also a haemorrhagic discharge from the ears, pyrexia, lethargy and generalised lymphadenopathy. The clinical, cytological, bacteriological and histopathological findings were consistent with a diagnosis of dermatitis resembling juvenile cellulitis in an adult dog. Glucocorticoid therapy led to rapid resolution of the clinical signs and the dog has remained in remission for two years after cessation of treatment.     

MAGNETIC RESONANCE IMAGING OF A MEDULLARY DERMOID CYST WITH SECONDARY HYDROCEPHALUS IN A DOG

Magnetic resonance images were acquired of the brain of a 7-year-old male Golden Retriever with hydrocephalus secondary to a medullary lesion. Images were acquired prior to and 4 weeks following surgical treatment for the hydrocephalus, and the dog was euthanased following the second imaging session. The MR images demonstrated a medullary lesion with patchy but predominantly hyperintense signal with both T1- and T2-weighting, within which small areas of low signal were scattered. There was little edema associated with this lesion and no enhancement with gadolinium. Postmortem examination revealed the medullary mass to be a dermoid cyst. Several small nodular lesions were identified within the central nervous system on the magnetic resonance images whose origin was uncertain on postmortem examination.