F. J. Barr

Prevalence of polycystic kidney disease in Persian cats in the United Kingdom

The prevalence of polycystic kidney disease was assessed in 132 Persian cats, 46 of them referred for the investigation and treatment of medical or surgical conditions, and 86 apparently healthy cats referred specifically to be screened for the disease. Cats referred for the investigation of renomegaly or renal failure were excluded, and cats under 10 months old were only included if they had been examined postmortem. One hundred and twenty-six of the cats were examined ultrasonographically with a 7.5 MHz sector scanner, and the other six cats were examined postmortem. Forty-nine of the 86 cats referred specifically for screening (57.0 per cent) and 16 of the 46 cats referred for other clinical reasons (34.8 per cent) were affected by the disease, giving an overall prevalence of 49.2 per cent.

Targeted lymph node immunization can protect cats from a mucosal challenge with feline immunodeficiency virus.

With the rapid spread of human immunodeficiency virus (HIV) infection worldwide it is clear that effective strategies for mucosal vaccination against lentiviruses are urgently required. The aim of the present study is to determine whether protective immune responses against a mucosal challenge by feline immunodeficiency virus (FIV) can be elicited by targeting the immunization to the medial iliac lymph nodes--the principal site of migration of cells from the genital and rectal mucosa. Cats were challenged with homologous FIV via the rectal route. Targeted lymph node immunization was found to be an effective route of immunization eliciting both humoral and proliferative responses to peptide-based and fixed cell vaccines. Vaccination with fixed virus infected cells elicited protection against a cell-free mucosal FIV challenge. In addition, some cats vaccinated with fixed uninfected cells also remained uninfected following a cell-associated FIV challenge.

A retrospective study of the MRI findings in 18 dogs with stifle injuries.

OBJECTIVES To make an objective assessment of the usefulness of magnetic resonance imaging in the diagnosis of meniscal damage and cranial cruciate ligament disease in the canine stifle by comparing magnetic resonance imaging findings with surgical findings. METHODS Magnetic resonance images of 18 stifles from 18 dogs which had undergone magnetic resonance imaging for the investigation of stifle disease were reviewed. For every stifle, the menisci and cranial cruciate ligaments were assessed according to predetermined criteria. The magnetic resonance imaging findings were compared with the reported surgical findings and the sensitivity, specificity, positive and negative predictive values (PPV and NPV) were calculated using the surgical findings as the gold standard. Kappa analysis was used as an objective measure of agreement between surgical and magnetic resonance imaging findings. For 11 stifles, meniscal evaluation by three different observers was used to measure interobserver agreement using Kappa analysis. RESULTS Magnetic resonance imaging was demonstrated to be an accurate technique in the detection of meniscal injury (k=0.86), with excellent interobserver agreement (k=0.89 to 1.0). Disruption of cranial cruciate ligament continuity and an increase in ligament intensity were found to be useful criteria in the diagnosis of cranial cruciate ligament rupture. CLINICAL SIGNIFICANCE Magnetic resonance imaging offers a non-invasive alternative to exploratory surgery in the evaluation of cranial cruciate ligament and meniscal disease.

Treatment and long-term follow-up of extrahepatic biliary obstruction with bilirubin cholelithiasis in a Somali cat with pyruvate kinase deficiency.

A 2-year-old female neutered Somali cat was presented with vomiting and acute onset jaundice 1 year after diagnosis of pyruvate kinase (PK) deficiency. Diagnostic investigations revealed a moderate regenerative haemolytic anaemia, severe hyperbilirubinaemia and elevated liver enzymes. Ultrasonography revealed marked distension of the gall bladder and common bile duct (CBD), consistent with extrahepatic biliary obstruction (EHBO). At cholecystotomy, the gall bladder contained purulent material, and two obstructive choleliths were removed from the CBD by choledochotomy. The cat recovered from surgery uneventfully, and serum liver enzymes and bilirubin normalised within 10 days. Postoperative treatment consisted of cephalexin, metronidazole and ursodeoxycholic acid (UDCA). Bacterial culture of the gall bladder contents yielded a pure growth of an Actinomyces species. Cholelith analysis revealed that they consisted of 100% bilirubin. Antibiotic treatment was stopped 4 weeks after surgery but UDCA was continued indefinitely. The cat remains clinically well with no recurrence of cholelithiasis 20 months after initial presentation. This is the first report of successful treatment and long-term follow-up of a cat with EHBO due to bilirubin cholelithiasis in association with PK deficiency-induced chronic haemolysis.

Laryngeal disease in cats: A retrospective study of 35 cases

The aim of this retrospective study was to review the medical records of cats referred to the University of Bristol for investigation of laryngeal disease (n=35). Cases were categorised into one of four groups: cats with laryngeal paralysis (LP, n=14), laryngeal neoplasia (n=10), laryngeal inflammation (n=6), or miscellaneous laryngeal diseases (n=5). Laryngoscopy and echolaryngography were useful diagnostic techniques but histology was required for diagnosis of diseases other than LP. Two cats with lymphoma received chemotherapy achieving survival times of 60 and 1440 days. Four cats with LP were treated surgically, with a median survival time of 300 days (range 10–360 days) and six were treated conservatively with a median survival time of 780 days (range 300–2520 days). Three cats with inflammatory disease were treated medically and one by excision of the lesion. Two cats achieved survival times of 120 and 2800 days. Cats with LP, laryngeal lymphoma or laryngitis had excellent long-term survival following appropriate treatment.

Ultrasonography of the medial palmar intercarpal ligament in the Thoroughbred: technique and normal appearance

REASONS FOR PERFORMING STUDY Tearing of the medial palmar intercarpal ligament (MPICL) has been recognised as a cause of lameness in the Thoroughbred, but diagnosis is difficult due to the nonspecific clinical signs, and can be achieved only by performing arthroscopy on the mid carpal joint (MCJ). It would be beneficial to be able to image the MPICL using ultrasonography to determine whether pathology is present in the ligament in order to aid diagnosis and prognosis. OBJECTIVES To determine whether the MPICL could be imaged using ultrasound from the dorsal aspect of the MCJ, and to describe the technique and normal ultrasonographic appearance of the ligament. METHODS A pilot study was performed using 2 cadaver carpi. Each carpus in turn had the MPICL imaged simultaneously using arthroscopy and ultrasound, with a metallic probe positioned on the dorsal aspect of the ligament to highlight the position of the MPICL. Six further pairs of carpi had the MPICL imaged ultrasonographically followed by dissection of the carpus to evaluate the ligament and relate its anatomy to the ultrasound images. Finally, 15 Thoroughbreds with no history of lameness isolated to the carpus had their MPICLs assessed and measured ultrasonographically. RESULTS The MPICL could be imaged via the dorsal aspect of the MCJ using standard ultrasound equipment. The body and division into medial and lateral branches could be seen as a distinct, moderately dense granular echogenic structure in the palmar aspect of the joint, with clearly defined margins. CONCLUSIONS The normal MPICL can be imaged reliably using ultrasound in the Thoroughbred from the dorsal aspect of the MCJ. There is a wide range in the normal width of the lateral aspect of the MPICL, but there is good symmetry between contralateral limbs. POTENTIAL RELEVANCE This report of the normal ultrasonographic appearance of the ligament will be beneficial in acting as a reference for the detection of pathology using ultrasound.

Liver size, bodyweight, and tolerance to acute complete occlusion of congenital extrahepatic portosystemic shunts in dogs

OBJECTIVE To investigate the relationship between preoperative liver size, bodyweight, and tolerance to shunt occlusion in dogs with congenital extrahepatic portosystemic shunt(s) (CPSS). STUDY DESIGN Longitudinal cohort study. ANIMALS Dogs with CPSS (n=35). METHODS Ultrasonography was used to measure preoperative maximum transverse dimension of the liver (TS) of each dog. Intraoperative portal pressures were measured, before and after CPSS occlusion, via a jejunal vein catheter. Tolerance to shunt occlusion was judged on gross visceral observations, and on changes in portal pressure, central venous and mean arterial pressures. RESULTS TS was significantly related to bodyweight (P<.05). Mean ratios for TS/bodyweight were calculated for dogs tolerant and intolerant of acute complete shunt occlusion. Dogs tolerant to occlusion had significantly higher TS/bodyweight ratios than dogs intolerant to occlusion (P=.025). Dogs with a TS/bodyweight ratio of >7 were more likely to tolerate CPSS occlusion than dogs with a TS/bodyweight ratio of <5 (P=.036). A model was generated to predict portal pressure rise after shunt occlusion, based on liver dimensions and bodyweight (R=0.668). Intestinal oxygenation did not correlate significantly with tolerance to CPSS occlusion (P=.29). CONCLUSION In dogs with CPSS, liver size (relative to bodyweight) is significantly greater (P=.025) in dogs that are tolerant of full ligation than intolerant of occlusion. CLINICAL RELEVANCE Preoperative measurement of bodyweight and liver size help indicate the likelihood of tolerance to acute complete occlusion of CPSS in dogs.

MRI Findings of a Middle Ear Cholesteatoma in a Dog

This article describes the MRI features of a middle ear cholesteatoma in an 8 yr old flat-coated retriever. Physical examination revealed pain on opening the jaw, and otoscopic examination showed tympanic membrane rupture associated with hyperplastic tissue at the entrance of the middle ear. Standard MRI sequences allowed for the identification of a severely expanded bulla containing material that was isointense to brain tissue on T1-weighted images and of mixed intensity on T2-weighted and fluid-attenuated inversion recovery sequences. No postcontrast enhancement of the content was present, but the lining of the bulla was partially enhanced. The images allowed evaluation of the surgical margins and the secondary changes due to the expansion of the mass. Surgery was performed and histopathology confirmed the presumptive diagnosis of cholesteatoma. In the present case, MRI appeared to serve as a good alternative to computed tomography for the diagnosis of cholesteatoma.

Evaluation of the repeatability of ultrasound scanning for detection of feline polycystic kidney disease.

Polycystic kidney disease (PKD) is the most prevalent inherited genetic disease in cats with Persian and Persian-related breeds predominantly affected. Diagnosis of PKD relied on ultrasound scanning until the recent development of the PKD gene test. However, gene testing has limitations as it will only identify the autosomal dominant form of PKD and not other forms of cystic kidney disease. Ultrasound scanning also has the advantage of being able to assess the severity and progression of disease in PKD affected cats. The aim of this study was to demonstrate the repeatability of ultrasound scanning in the detection of PKD and to assess progression of the disease over time. This study demonstrated 100% repeatability of ultrasound scanning in the detection of PKD and has also demonstrated progression of disease in 75% of PKD positive cats assessed over a 1-year period.

Lumbosacral transitional vertebrae in cats and their effects on morphology of adjacent joints

The present study aimed to describe the radiographic appearance of lumbosacral transitional vertebrae in the cat and compare prevalence of hip dysplasia and lumbosacral spondylosis with a population of cats without transitional vertebrae. Pelvic radiographs of cats were reviewed retrospectively, providing a population of 100 cats without transitional vertebrae and 14 examples of lumbosacral transitional vertebrae. All cats were assessed for hip dysplasia and lumbosacral spondylosis; the lumbosacral transitional vertebrae identified were also assessed for asymmetry or rotation of sacro-iliac (SI) attachment. The transitional vertebrae demonstrated a wide variety of morphology; six cats had asymmetry or rotation of SI attachment in a dorsal plane; four of those six cats had lumbosacral spondylosis and two of these had hip dysplasia. No further examples of degenerative changes were identified in the remaining eight cats with lumbosacral transitional vertebrae. The frequency of lumbosacral spondylosis was higher in the population with lumbosacral transitional vertebrae, but this was not statistically significant. There was a marked trend towards lumbosacral spondylosis in cats with pelvic rotation or asymmetry. The frequency of hip dysplasia in cats with lumbosacral transitional vertebrae was very similar to those without.