J. Fraser McConnell

Clinical and topographic magnetic resonance imaging characteristics of suspected thalamic infarcts in 16 dogs

Sixteen dogs with acute-onset, non-progressive signs of brain dysfunction and magnetic resonance imaging (MRI) characteristics compatible with thalamic infarction are described. Topographically the MRI lesions could be grouped in three thalamic regions, namely, paramedian (8/16), extensive dorsal (5/16) and ventrolateral (3/16). Paramedian lesions resulted in signs typical of vestibular dysfunction. Extensive dorsal lesions were associated with vestibular ataxia, circling and contralateral menace response deficits. Ventrolateral lesions resulted in circling and contralateral proprioceptive deficits. In several dogs, regions other than the thalamus were also affected: four extended into the midbrain; six extended to the internal capsule, and two dogs had a second lesion in the cerebellum. Three clinical syndromes were identified in association with thalamic infarction. These signs varied somewhat, most likely because lesions were not confined to specific nuclear boundaries and involved different combinations of thalamic nuclei.

Computed tomographic findings in 15 dogs with eosinophilic bronchopneumopathy

Eosinophilic bronchopneumopathy is a disease characterized by the infiltration of the lung and bronchial mucosa by eosinophils. The aim of the present study was to describe the CT findings in a large series of dogs with confirmed diagnosis of eosinophilic bronchopneumopathy. Computed tomographic scans of 15 dogs with confirmed diagnosis of eosinophilic bronchopneumopathy were evaluated retrospectively by two boarded radiologists who reached a consensus. Abnormalities were identified in 14/15 (93%) dogs, including pulmonary parenchymal abnormalities in 14/15 (93%) dogs, bronchial wall thickening in 13 (87%) dogs, which was considered marked in eight (53%), plugging of the bronchial lumen by mucus/debris in 11 (73%) dogs, and bronchiectasis in nine (60%) dogs. Pulmonary nodules were identified in 5/15 (33%) dogs including one dog with a mass. All dogs with a nodular lung pattern had additional abnormalities. Lymphadenopathy was present in 10 dogs (67%). Lesions associated with eosinophilic bronchopneumopathy are variable and heterogeneous and encompass a wider variety of computed tomographic features than reported previously. Computed tomographic images were abnormal in the majority of affected dogs, hence CT is a useful modality to characterize the nature and distribution of thoracic lesions in dogs with eosinophilic bronchopneumopathy.

COMPARISON BETWEEN SHOULDER COMPUTED TOMOGRAPHY AND CLINICAL FINDINGS IN 89 DOGS PRESENTED FOR THORACIC LIMB LAMENESS

Computed tomography (CT) is an established technique for detecting shoulder lesions in dogs, however the clinical significance of shoulder CT lesions often remains uncertain. The purposes of this retrospective study were to describe the prevalence of CT lesions in both shoulder joints for 89 dogs presenting with thoracic limb lameness and to compare CT lesions with clinical characteristics. For all included dogs, results of a full orthopedic examination, other diagnostic tests, and signalment data were available in medical records. Multilevel, multivariable logistic regression was used to test clinical significance of the most prevalent CT lesions and determine factors associated with their presence. Computed tomographic lesions were detected in one or both shoulder joints for 51/89 dogs (57.3%). Mineralization of one or more surrounding peri-articular soft-tissue structures was identified in 31.5% of dogs, with supraspinatus muscle/tendon mineralization being the most frequently identified (24.7%). The prevalence of humeral head osteochondrosis was 9 and 21.3% of dogs had shoulder osteoarthritis. Border collies (odds ratio [OR] 9.3; 95% CI 1.39-62.1, P = 0.02) and dogs with shoulder pain (OR 4.3; 95% CI 1.08-17.1, P = 0.04) had increased risk of osteochondrosis lesions. Border collies (OR 8.4; 95% CI 1.27-55.6; P = 0.03) and older animals (OR 1.04; 95% CI 1.02-1.1, P < 0.001) had increased risk of osteoarthritis lesions. Female entire dogs had an increased risk of supraspinatus mineralization lesions (OR 6.8; 95% CI 1.55-29.5, P = 0.01). Findings indicated that shoulder CT lesions are common in dogs with thoracic limb lameness, and that some CT lesions are not associated with shoulder pain.

Septic pericarditis and myocardial abscess in an English Springer spaniel.

Septic pericarditis and myocardial abscess are rare conditions in dogs. They are usually caused by foreign bodies, penetrating wounds, systemic infections or extension of local infections such as endocarditis, pleuritis or pulmonary infections to the myocardial tissue. Here we report a septic pericardial effusion and myocardial abscess in a young English Springer spaniel presenting with a long history of pyrexia and lethargy. No cause could clearly be identified although a penetrating injury or dissolving foreign body was highly suspected. The patient was successfully treated with a surgical approach in combination with broad spectrum antibacterials resulting in resolution of clinical signs without recurrence of the infection.

IMAGING DIAGNOSIS—VENTRICULO‐PERITONEAL SHUNT ASSOCIATED INFECTION IN A DOG

Ventriculo-peritoneal shunting is a surgical treatment for hydrocephalus. Complications of this procedure are not well described in dogs. The most common complication in humans is infection, which can be fatal if not diagnosed and treated quickly. We describe the magnetic resonance (MR) imaging characteristics of a shunt-associated cerebral infection in a dog. The MR features of the infection included hyperintensity of the lining of the ventricular system visible on a T2-weighted FLAIR sequence and marked linear contrast enhancement of the ependymal layer on T1-weighted sequences, similar to that described in people.

Clinical and clinicopathologic abnormalities in young dogs with acquired and congenital portosystemic shunts: 93 cases (2003-2008)

OBJECTIVE To determine whether clinical and clinicopathologic data could assist differentiation of congenital portosystemic shunts (CPSSs) from acquired portosystemic shunts (APSSs) in young dogs. DESIGN Retrospective case series. ANIMALS Dogs < 30 months of age with CPSSs (n = 62) or APSSs (31). PROCEDURES Medical records from 3 referral centers identified 31 dogs with APSSs and 62 dogs with CPSSs diagnosed from July 2003 to July 2008. Signalment, clinical signs, physical examination, and clinicopathological data were recorded, and statistical analyses were performed to determine differences between groups. RESULTS Univariable analysis showed APSS patients were older, heavier, and in poorer body condition, compared with CPSS patients. In CPSS patients, diarrhea was less prevalent, and neurologic signs were more prevalent. Ascites was more prevalent in APSS (Fisher exact test; OR, 50.2; 95% confidence interval [CI], 6.2 to 409.7), with no significant difference in albumin concentration between groups. The logistic regression model used to assess clinicopathological parameters showed lower Hct (OR, 1.42 × 10(-12); 95% CI, 1.42 × 10(-17) to 4.0 × 10(-6)), higher mean corpuscular volume (OR, 1.27; 95% CI, 1.08 to 1.50), and higher alanine aminotransferase concentrations (OR, 1.005; 95% CI, 1.001 to 1.009) were more likely in APSS patients. CONCLUSIONS AND CLINICAL RELEVANCE Several clinicopathologic differences between dogs with congenital and acquired shunts were identified; however, assessed alone, these would be unlikely to enable differentiation between the 2 conditions. Awareness of the rarity of ascites in CPSS cases should prompt recognition of a likely diagnosis of APSS, allowing the veterinarian to target further diagnostics and counsel the owner appropriately.

Arrhythmias and transient changes in cardiac function after topical administration of one drop of phenylephrine 10% in an adult cat undergoing conjunctival graft

HISTORY A 2-year-old, entire female, Somali cat weighing 3.8 kg was admitted for a conjunctival graft on the right eye, for treatment of an acute descemetocele. Medetomidine 4.2 μg kg(-1) and methadone 0.2 mg kg(-1) were administered by intramuscular injection as preanaesthetic medication. Anaesthesia was induced using diazepam 0.26 mg kg(-1) and propofol 4 mg kg(-1) administered by intravenous (i.v.) injection. Following endotracheal intubation, anaesthesia was maintained with isoflurane delivered in oxygen (1 L minute(-1)) and nitrous oxide (2 L minute(-1)) via a non-rebreathing system. Twenty minutes after induction of anaesthesia, one drop of a 10% phenylephrine hydrochloride solution was administered topically to the right eye. PHYSICAL EXAMINATION After phenylephrine administration, a decrease in heart rate (from 95 to 80 beats minute(-1)) and an increase in arterial blood pressure occurred. The pulse then became difficult to palpate manually and multifocal ventricular premature contractions were observed on the electrocardiogram. MANAGEMENT Nitrous oxide was discontinued and the isoflurane vaporizer setting was decreased from 1.5% to 0.5%. Lidocaine 1 mg kg(-1) i.v. was administered, this resulted in ventricular bigeminy. The quality of the femoral pulse improved and was regular in rhythm and character. Surgery was completed as fast as possible. The bigeminy progressively disappeared and before disconnecting the cat from the breathing system, there was a normal sinus rhythm with a heart rate of 85 beats minute(-1). FOLLOW-UP Echocardiography was performed during recovery and showed mitral and aortic valve insufficiency and dilation of the left ventricle, suggesting a reduction in systolic function. Echocardiography was repeated the following day and was normal. CONCLUSIONS In order to diminish the potential for cardiovascular sequelae associated with systemic absorption of ocular phenylephrine, less concentrated solutions, smaller drop size or different instillation techniques should be considered for topical use in small patients.