Renal biopsy in the normal cat: examination of the effects of repeated needle biopsy

Three healthy cats were subjected to percutaneous renal biopsy of the left kidney on three occasions at monthly intervals. Three other cats were subjected to three consecutive biopsy attempts on one occasion using the left kidney. Thereafter the six cats were monitored clinically and by means of laboratory analyses of blood and urine until euthanasia four weeks after the last biopsy. Cautious insertion of the biopsy needle in an attempt to avoid over penetration of the kidney resulted in failure to obtain renal tissue on six occasions but in all 12 specimens which did contain renal tissue, glomeruli were present. Major blood vessels were present in two biopsy specimens. At necropsy, radiographic and histological studies demonstrated renal parenchymal and vascular changes in the biopsied kidneys which were similar to but less severe than those produced by a single biopsy attempt. This confirmed that avoidance of damage to major renal vessels is important and suggested that, with care, repeated biopsies need be no more harmful to the kidney than a single biopsy.     

Feline heart disease: An update

Heart disease is relatively common in cats and our understanding of feline cardiomyopathy has improved considerably over the last two decades, in part as a result of the improved sophistication of non-invasive diagnostic techniques. The incidence of feline dilated cardiomyopathy has declined markedly since the discovery of taurine deficiency as an aetiological factor and subsequent modification of commercial diets. Hypertrophic cardiomyopathy now seems to be the commonest primary form and is characterised by unexplained left ventricular hypertrophy and diastolic dysfunction. Intermediate forms of cardiomyopathy are also recognised. Secondary cardiomyopathies are common; examples of causes include hyperthyroidism, systemic hypertension and acromegaly. Congenital cardiac disease is also well recognised and may lead to clinical signs even late in life.     

RADIOGRAPHIC AND ULTRASONOGRAPHIC FEATURES OF HYPERTROPHIC FELINE MUSCULAR DYSTROPHY IN TWO CATS

Hypertrophic fellne musculer dystrophy has been reported as an X-linked inherited deficiency of a cytoskeletal myofiber protein called dystrophin. This report deserlbes the radiographic and ultrasonographic abnormalities of two male littermate domestic short-hair cats and reviews the previous reported findings assoclated with hypertrophic feline muscular dystrophy. The thoracic radiographic abnormalities included: progressive cardiomegaly, large convex, scalloped irregularities associated with the vetral aspect of the diaphragm, and variable degrees of esophageal dilation (megaesophagus) with associated cranioventral aspiration pneumonia. Echocardiographic features included: concentric left vetricular wall thickening, increased left ventricular and diastolic and systolic dimensions, and an increase in endocardial echogenicity. Abdominal radiographic abnormalities included: hepatosplenomegaly, peritoneal effusion, renomegaly, adrenal gland mineralization, and paralumbar and diaphragmatic musculature enlargement. Abdomlnal ultrasonographic abnormalities included: irregularly thickened muscular portion of the diaphragm; hypoechogenicity of the liver; peritoneal effusion; hepatosplenomegaly; renomegaly with hyperechoic cortex and medulla; and adrenal gland mineralization. The irregular scalloped appearance of the diaphragm (particularly along the ventral/sternal margin) was a consistenl radiographic abnormlity in the two cats with hypertrophic feline muscular dystrophy after the age of 7 months. This finding was confirmed by ultrasound as a thickened irregular, hyperechoic diaphragm. A diagnosis of hypertrophic feline muscular dystrophy should be strongly suspected if this abnormality is identified.     

Development of a teaching laboratory aid for instruction of fine needle aspiration biopsy cytology technique

Specialized training is required to obtain adequate cytology smears by needle aspiration biopsy. An educational method that would provide opportunity for numerous trainees to acquire needle aspiration biopsy and cytodiagnostic skills, and which would not result in the interruption of teaching hospital patient care nor result in the use or sacrifice of animals from laboratory animal resources was sought. An aspiration biopsy cytology teaching aid was developed by placing portions of fresh organ tissue from routine submissions to the necropsy laboratory into a specimen container partially filled with chilled normal saline solution. Specimens were stored immersed in saline at 4 degrees C for up to 48 hours. Prior to the cytopathology teaching laboratory period, the specimen container was removed from storage and covered with a latex diaphragm. Instructors responsible for teaching cytodiagnostic techniques used this ex vivo aspiration biopsy cytology device for instruction of fine needle aspiration biopsy, specimen processing, and microscopy. In the teaching laboratory, puncture of the diaphragm and aspiration of a tissue sample with hypodermic needle and syringe was instructed to, and practiced by, numerous trainees simultaneously using clinical operative technique without the need for live animals. Trainees prepared and stained cytology smears as well as evaluated and interpreted specimens in a single, realistic exercise. Such training experience may improve ability of trainees to procure diagnostic-quality biopsy specimens for cytodiagnosis of lesions from clinic patients.     

Effect of sample quality on the sensitivity of endoscopic biopsy for detecting gastric and duodenal lesions in dogs and cats

Background: The quality of histopathology slides of endoscopic biopsies from different laboratories varies, but the effect of biopsy quality on outcome is unknown.
Hypothesis: The ability to demonstrate a histologic lesion in the stomach or duodenum of a dog or cat is affected by the quality of endoscopic biopsy samples submitted. More endoscopic samples are needed to find a lesion in poor-quality tissue specimens.
Animals: Tissues from 99 dogs and 51 cats were examined as clinical cases at 8 veterinary institutions or practices in 5 countries.
Methods: Histopathology slides from sequential cases that underwent endoscopic biopsy were submitted by participating institutions. Quality of the histologic section of tissue (inadequate, marginal, adequate), type of lesion (lymphangiectasia, crypt lesion, villus blunting, cellular infiltrate), and severity of lesion (normal, mild, moderate, severe) were determined. Sensitivity of different quality tissue samples for finding different lesions was determined.
Results: Fewer samples were required from dogs for diagnosis as the quality of the sample improved from inadequate to marginal to adequate. Duodenal lesions in cats displayed the same trend except for moderate duodenal infiltrates for which quality of tissue sample made no difference. Gastric lesions in dogs and mild gastric lesions in cats had the same trend, whereas the number of tissue samples needed to diagnose moderately severe gastric lesions in cats was not affected by the quality of tissue sample.
Conclusions and Clinical Importance: The quality of endoscopically obtained tissue samples has a profound effect on their sensitivity for identifying certain lesions, and there are differences between biopsies of canine and feline tissues.     

ULTRASOUND-GUIDED TISSUE-CORE BIOPSY OF LIVER, SPLEEN AND KIDNEY IN NORMAL DOGS

Six normal dogs were subjected to ultrasound-guided biopsy of the liver, spleen and kidney to examine the accuracy of the technique (i.e. the presence of targeted tissue) and the histologic quality of the biopsies. Five consecutive tissue-core biopsies of each organ were taken on one or more occasions. The accuracy of the technique was 77% for hepatic, 90% for splenic, 53.5% for left kidney and 40% for right kidney biopsies. The histologic quality of the liver and kidney samples was sufficient, although for some samples the diagnostic value was limited by their size and in renal samples either cortical or medullary tissue was sometimes lacking. In contrast, the quality of the splenic sections was not good. The effect of reused and resterilized needles on the quality of the specimens was evaluated by histologic inspection of the samples and by the amount of biopsies lacking tissue. All tissue samples, including those taken with reused or resterilized needles had sharp-cut edges. Twenty-two of the total number of 120 biopsies (18%) contained no tissue. Absence of tissue in the samples was observed in biopsies taken with all needle types. The animals were observed for possible complications of the repeated needle biopsy. Apart from one case of hematuria, no complications were encountered.     

M-MODE ECHOCARDIOGRAPHY AS A DIAGNOSTIC AID FOR FELINE CARDIOMYOPATHY

Normal cats and cats with congestive cardiomyopathy (CCM) and hypertrophic cardiomyopathy (HCM) were examined using M-mode echocardiography to determine its diagnostic capabilities. Sixteen normal cats were examined to verify previously reported data and to add further echocardiographic inforamtion (left atrial/aortic root ratio, left posterior wall thickness at end systole and end diastole, amplitude of mitral valve excursions, and velocity of valve opening and closure) to aid in differential diagnosis. Significant (p<0.05) changes were detected between the normal cats and those with cardiomyopathy. In each type of cardiomyopathy, alterations in left atrial dimension, left atrial/aortic root ratio, left ventricular dimension, left ventricular wall thickness and percentage of ventricular dimensional change were identified. Altered mitral valve motion was found with HCM. Echocardiography was found to be an accurate technique for definitive diagnosis of feline cardiomyopathy.     

Evaluation of hemorrhage, sample size, and collateral damage for five hepatic biopsy methods in dogs

OBJECTIVES: To compare the volume of hemorrhage, number of lobules, and portal triads available for histologic evaluation, and resultant collateral damage between 5 hepatic biopsy methods: biopsy punch, biopsy needle, ligature method, laparoscopic biopsy forceps, and ultrasonically activated scalpel (UAS). STUDY DESIGN: Experimental, repeated measures, block. ANIMALS: Twelve adult dogs. METHODS: Biopsies were obtained from the periphery and center of the left lateral liver lobe of each dog using each of 5 biopsy techniques. Hemorrhage was quantified and compared between methods and sites. Biopsy samples were evaluated histologically to characterize collateral damage and determine the number of lobules and portal triads sampled. RESULTS: Regardless of technique, liver biopsy resulted in minimal hemorrhage (<2 mL). For peripheral biopsies, UAS was comparable with the ligature method, but caused significantly less hemorrhage than all other methods, whereas for central biopsies, UAS caused significantly less hemorrhage than other methods. Except for the laparoscopic biopsy forceps, UAS caused significantly more collateral damage than other methods. UAS and ligature biopsy methods yielded specimens that had more portal triads per sample than other methods. Eight of 48 biopsy needle samples were inadequate for histologic evaluation, whereas other methods yielded adequate specimens. CONCLUSIONS: All biopsy methods produced minimal hemorrhage and except for needle biopsy yielded adequate tissue samples for histologic evaluation. CLINICAL RELEVANCE: Use of UAS is a reliable, safe alternative technique for liver biopsy and can be used laparoscopically to obtain large tissue samples.     

Congestive heart failure associated with hyperthyroidism in cats

Hyperthyroidism was diagnosed in 4 cats with congestive heart failure. Dyspnea and anorexia were observed in 3 of the 4 cats. In each cat, a holosystolic left and/or right apical heart murmur was auscultated. In 3 cats, a prominent extra heart sound (gallop rhythm) was auscultated. All cats had a palpably large thyroid lobe(s) and weight loss. The laboratory and ECG changes were similar to those reported for feline hyperthyroidism. Moderate-to-severe pleural effusion and cardiomegaly were detected via radiography in all cats. Some cats had radiographic signs of pulmonary venous engorgement and pulmonary edema. Echocardiography revealed cardiac dilatation and low left ventricular shortening fraction (wall motion) in all cats. Three cats responded initially to cardiac drugs and propylthiouracil or thyroidectomy. One of these died later, presumably from an adverse reaction to propylthiouracil, and the others died from recurrent congestive heart failure (1) or postoperative cardiac arrest (1). One cat did not respond to treatment, and died 2 days after diagnosis.     

CARDIAC AND PULMONARY ARTERY MENSURATION IN FELINE HEARTWORM DISEASE

A retrospective study was undertaken to quantify thoracic radiographic changes in cats with heartworm diseases, ( Dirofilaria immitis ). Using a blinded study format, the cardiac silhouette, thoracic cavity and pulmonary arteries were measured from thoracic radiographs of 21 cats with feline heartworm disease and 30 cats without known cardiac or pulmonary vessel pathology. Measured data were normalized to the thoracic cavity or bony structures within the radiographic field of view. The measurements were compared between the two groups of cats using an unpaired, two-tailed Student's t -test, with a p value of < 0.05 being considered significant. Cats with feline heartworm disease had enlargement of the craniocaudal aspect of the cardiac silhouette and normalized cardiac:thoracic ratio (p < 0.05) on the lateral view. Also, there was significant enlargement of the central and peripheral caudal lobar pulmonary arteries and their normalized ratios (p < 0.05) in the heartworm infected cats as visualized on the ventrodorsal projection. Tortuosity of the pulmonary arteries was seen in three of the 21 infected cats. Eleven of the 21 cats with feline heartworm disease had pulmonary parenchymal changes. Based on the present study, central and peripheral pulmonary artery enlargement as viewed on the ventrodorsal radiograph was the single best radiographic indicator of feline heartworm disease.     

ULTRASOUND LOCALIZATION AND GUIDANCE FOR RENAL BIOPSY IN THE HORSE

Real-time ultrasonography was used to assist percutaneous renal biopsies in seven normal horses. Ultrasound (US) guidance and blind biopsy following US localization were compared. Ten biopsies (seven right kidney and three left kidney) were performed. A transverse approach to the lateral border of the right kidney through the 17th intercostal space was favored, with the needle angle being approximately perpendicular to the body wall. Both biopsy techniques were effective, but blind biopsy following US localization was favored as it was easily performed by one operator without the need for specialized biopsy equipment. The spleen had a variable location and its penetration with the biopsy needle was necessary to obtain two left kidney biopsies. Macroscopic and microscopic hematuria was observed postbiopsy in one and four horses, respectively, out of six horses examined. Perirenal hemorrhage was a prominent finding on necropsy in five of six horses euthanized.     

ULTRASONOGRAPHY OF ALIMENTARY LYMPHOSARCOMA IN THE CAT

Clinical, radiological and ultrasonographic findings from 22 cats with gastrointestinal lymphosarcoma were reviewed. The most common clinical findings were anorexia, weight loss, vomiting, lethargy, depression, fever, anemia and a palpable abdominal mass. Abdominal radiographs of 12 cats revealed a mass associated with the gastrointestinal tract and/or mesentery, and decreased serosal detail, suggestive of peritoneal effusion. The most common ultrasonographic finding was transmural gastric or intestinal thickening associated with loss of normal wall layering, reduced wall echogenicity and localized hypomotility. As is noted in people, other patterns such as transmural-segmental, transmural-nodular, transmural-bulky and mucosal infiltration were represented. In 3 cats, mesenteric lymph-adenopathy was responsible for most of the mass-effect. Fine-needle aspiration biopsy, automated microcore biopsy, endoscopic biopsy or necropsy confirmed the diagnosis of lymphosarcoma in all cats. Chemotherapy was instituted in 19 cats. Only 6 cats had a complete response to treatment. The results of this study indicate that ultrasonography is a valuable tool for the diagnosis of feline alimentary lymphosarcoma and that biopsies can be obtained under ultrasonographic guidance.     

Laryngeal, laryngotracheal, and tracheal masses in cats: 27 cases (1998-2003)

Medical records of 27 cats with masses of the larynx and trachea were examined. Six cats had inflammatory masses, and 21 cats had neoplastic lesions. A definitive diagnosis was reached in 22 cats with a single biopsy. The median age of the cats was 12.0 years (range 6 to 20 years). Dyspnea was the most common clinical sign. Accurate diagnoses were best obtained through direct laryngeal or tracheal examination combined with histological examination of tissue biopsies. Kaplan-Meier survival data for all inflammatory and neoplastic lesions showed a median survival of 5 days, with 7.4% of cats alive at 1 year.     

Congestive heart failure associated with a large transverse left ventricular moderator band in a cat

Cardiomyopathy associated with abnormal trabecular bands of tissue traversing one or both ventricles is reported rarely in cats. The case of a 9-year-old cat which presented in congestive heart failure is reported. Multiple cardiac abnormalities were found, including a large trabecular tissue bridge which bisected the left ventricle. Other findings included arrhythmia, thrombocytopaenia and raised serum creatine kinase. The cat was euthanased due to clinical deterioration. Necropsy findings included increased cardiac weight, the division of the left ventricle by a large trabecular band composed of connective tissue and cardiac myofibres consistent with a moderator band, nodular thickening of the mitral valve, left atrial dilation, and fibroplasia/fibrosis of the left ventricular myocardium associated with widespread myofibre necrosis due to infarction. Pathological findings in this case differ from previous reports of ventricular transverse bridging tissue in cats with cardiac disease.     

COMPARISON OF GLOMERULAR NUMBER AND SPECIMEN LENGTH OBTAINED FROM 100 DOGS VIA PERCUTANEOUS ECHO-ASSISTED RENAL BIOPSY USING TWO DIFFERENT NEEDLES

Our objective was to evaluate possible differences in the number of glomeruli and length of renal biopsies collected in canine subjects by two different types of biopsy needles: a semiautomatic 18-gauge Trucut and an automated 18-gauge Jamshidi modified (Biopince). One hundred biopsy samples obtained from dogs of different ages and gender affected by different nephropathies were evaluated retrospectively. All animals were biopsied using one of the two different needles. Biopsies were performed under ultrasound guidance and evaluated by a single pathologist. Statistical analysis was performed to evaluate possible differences in the number of glomeruli and length of renal biopsies collected comparisons were determined between subgroups of dogs with or without the identification of renal interstitial infiltrates and/or fibrosis. Neither the mean difference of the number of glomeruli nor the length of tissue sample collected with the different needles was significantly different. Likewise, the average biopsy length did not differ in dogs with or without renal interstitial infiltrate in animals biopsied with either biopsy needle. Both the Biopince and the Trucut devices provide diagnostically adequate biopsy renal specimens using ultrasound-guidance.     

Effects of serial ultrasound-guided renal biopsies on kidneys of healthy adolescent dogs

Ten healthy mixed-breed dogs were used to evaluate the functional and structural effects of serial ultrasound-guided renal biopsies obtained with an automated biopsy needle. In each dog, one lateral renal cortex was biopsied at 2, 4, and 6 months of age; the other kidney was the control. Five dogs had two tissue cores and five dogs had four tissue cores taken on each biopsy occasion, and one core was examined microscopically. One week before each biopsy and a month after the final biopsy, the glomerular filtration rate (GFR) was determined by renal scintigraphy. Dogs were then euthanized for evaluation of gross and microscopic lesions attributable to the biopsies. There was no difference between GFR values for biopsied kidneys and those of control kidneys ( P >0.05). Microscopic lesions were not identified in biopsies taken at 2 and 4 months, but focal lesions were found in three of 10 specimens taken at 6 months of age. At necropsy, six of 10 biopsied kidneys had small visible capsular scars, and linear tracts <2 mm wide were observed on cut surfaces in six of 10 biopsied kidneys cut transversely into slices 5 mm thick. Discrete light microscopic lesions were observed in 25 of 452 (5.5%) of randomly selected 6-mm-diameter sections of renal cortex from biopsied kidneys. We conclude that serial renal cortical biopsies can be obtained by our method from healthy adolescent dogs with minimal risk of inducing changes that might be confused with those of a progressive renal disease.     

Renal biopsy in the normal cat: development of a modified disposable biopsy needle

A disposable biopsy needle was modified to reduce the length of the obturator tip and specimen notch. The modified needle was then used to take renal biopsy specimens at four sites from each kidney in four cats. Twenty-nine samples of renal tissue were obtained and the average numbers of glomeruli per specimen length compared favourably with similar studies using the standard needle.     

A comparison between the cytological and histological characteristics in thirteen canine and feline thymomas

Cytological smears and histological sections collected from histologically diagnosed cases of thymoma in nine dogs and four cats were reviewed. Most of the histological features were apparent in the cytological specimens with two notable differences. The epithelial component was underestimated and Hassal's corpuscles were not observed using Wright's-stained cytological preparations. Features of thymoma were recognized in seven of the nine cases in which fine needle aspiration biopsy was done. Therefore, cytology, and specifically fine needle aspiration biopsy, has the potential to be a useful aid in the rapid diagnosis of canine and feline thymomas.     

Natural history of hypertrophic cardiomyopathy and aortic thromboembolism in a family of domestic shorthair cats

A feline domestic shorthair queen and her 3 offspring were all diagnosed with asymptomatic hypertrophic cardiomyopathy (HCM). The family has been followed for 13 years, and 3 cats have died of aortic thromboembolism (ATE). This communication documents the long-term progression of HCM in these cats that presented with mild left ventricular hypertrophy and hyperdynamic systolic ventricular function, developed progressive left atrial enlargement, and eventually resulted in hypodynamic left ventricular systolic function with relative left ventricular chamber dilation at the time of ATE.