Fat malassimilation in three cats

Three cats were thin despite eating well. Steatorrhoea was confirmed in each by 72-hour fat assimilation tests. Fat digestibility in all 3 increased twofold when the diet was supplemented with pancreatic enzymes, suggesting the possibility of exocrine pancreatic insufficiency. However, examination of stained faecal smears gave evidence of both maldigestion and malabsorption of fat, without maldigestion of starch, and only one case had indications of protein maldigestion. In the latter cat, fat digestibility normalised with pancreatic enzyme supplementation and exocrine pancreatic insufficiency was considered likely. However, at post-mortem examination enteropathy and pancreatitis, but not exocrine pancreatic insufficiency, were found. The cause of fat malassimilation in these cats was unknown. The evaluation of malassimilation in cats is difficult because investigative tests used in other species are either unsuitable or have not been evaluated in cats.     

Evaluation of Environmental, Nutritional, and Host Factors in Cats with Hyperthyroidism

The pathologic changes associated with hyperthyroidism (adenomatous hyperplasia, adenoma of the thyroid gland) have been well characterized in cats, but the pathogenesis of these changes remains unclear. In this research, we undertook a case-control study to search for potential risk factors for this disease. Owners of 379 hyperthyroid and 351 control cats were questioned about their cats' exposure to potential risk factors including breed, demographic factors, medical history, indoor environment, chemicals applied to the cat and environment, and diet. The association between these hypothesized risk factors and outcome of disease was evaluated by conditional logistic regression. Two genetically related cat breeds (ie, Siamese and Himalayan) were found to have diminished risk of developing hyperthyroidism. Cats that used litter had higher risk of developing hyperthyroidism than those that did not. Use of topical ectoparasite preparations was associated with increased risk of developing hyperthyroidism. Compared with cats that did not eat canned food, those that ate commercially prepared canned food had an approximate 2-fold increase in risk of disease. When these 4 variables (breed, use of cat litter, consumption of canned cat food, and use of topical ectoparasite preparations) from the univariate analysis were selected for further study as candidate risk factors and analyzed by multivariate conditional logistic regression, a persistent protective effect of breed (ie, Siamese or Himalayan) was found. In addition, results suggested a 2- to 3-fold increase in risk of developing hyperthyroidism among cats eating a diet composed mostly of canned cat food and a 3-fold increase in risk among those using cat litter. In contrast, the use of commercial flea products did not retain a strong association. The results of this study indicate that further research into dietary and other potentially important environmental factors (eg, cat litter) is warranted.     

Transient clinical diabetes mellitus in cats: 10 cases (1989-1991)

Medical records of 10 cats with transient clinical diabetes mellitus were reviewed. At the time diabetes was diagnosed, clinical signs included polyuria and polydipsia (10 cats), weight loss (8 cats), polyphagia (3 cats), lethargy (2 cats), and inappetence (1 cat). Mean (+/- SD) fasting blood glucose concentration was 454 +/- 121 mg/dL, mean blood glucose concentration during an 8-hour period (MBG/8 hours) was 378 +/- 72 mg/dL, and glycosuria and trace ketonuria were identified in 10 and 5 cats, respectively. Baseline serum insulin concentration was undetectable (6 cats) or within the reference range (4 cats) and serum insulin concentration did not increase after i.v. glucagon administration in any cat. Insulin-antagonistic drugs were being administered to 5 cats and concurrent disorders were identified in all cats. Management of diabetes included administration of glipizide (6 cats), insulin (3 cats), or both (1 cat), discontinuation of insulin-antagonistic drugs, and treatment of concurrent disorders. Insulin and glipizide treatment was discontinued 4-16 weeks (mean, 7 weeks) after the initial diagnosis of diabetes was confirmed. At the time treatment for diabetes was discontinued, clinical signs had resolved, mean fasting blood glucose concentration was 102 +/- 48 mg/dL, MBG/ 8 hours was 96 +/- 32 mg/dL, glycosuria and ketonuria were not identified in any cat, and concurrent disorders (except mild renal insufficiency in 1 cat) had resolved. Significant (P < .05) increases occurred in postglucagon serum insulin concentrations, insulin peak response, and total insulin secretion, compared with values obtained when clinical diabetes was diagnosed. Histologic abnormalities were identified in pancreatic islets of 5 cats in which pancreatic biopsies were obtained and included decreased number of islets (4 cats), islet amyloidosis (3 cats), and vacuolar degeneration of islet cells (3 cats). Mean beta cell density was significantly (P < .001) decreased in diabetic cats compared with control cats (1.4 +/- 0.7 versus 2.6 +/- 0.5%, respectively). Cells within islets stained positive for insulin, however, the number of insulin-staining cells per islet and the intensity of insulin staining were decreased in 5 and 2 cats, respectively. Clinical diabetes had not recurred in 1 cat after 6 years, in 4 cats lost to follow-up after 1.5, 1.5, 2.0, and 2.5 years, and in 2 cats that died 6 months and 5.5 years after clinical diabetes resolved. Clinical diabetes recurred in 3 cats after 6 months, 14 months, and 3.4 years, respectively. These findings suggest that cats with transient clinical diabetes have pancreatic islet pathology, including decreased beta cell density, and that treatment of diabetes and concurrent disorders results in improved beta cell function, reestablishment of euglycemia, and a transition from a clinical to subclinical diabetic state.     

Ante mortem diagnosis of pancreatitis in four cats

The ante mortem detection of pancreatitis in four cats is reported. Clinical findings included vomiting, lethargy and constipation in all the cats, diabetes mellitus in two cats and severe jaundice and a vitamin K responsive coagulopathy in one cat. Serum amylase was normal in all the cats and serum lipase was elevated in one azotaemic cat. Ultrasonography revealed predominantly hypoechoic masses in the right cranial quandrant of the abdomen of each cat. The anatomical location of these masses was consistent with the pancreas. Gross examination supported these ultrasonographic observations. The pancreatic lesions were characterised histologically as acute necrotising pancreatitis, acute necrotising pancreatitis with abscessation, chronic active pancreatitis with cystic dilatation of the pancreatic duct causing bile duct obstruction and chronic active pancreatitis with nodular hyperplasia. This report indicates that pancreatitis is a clinically significant disease in cats that may be diagnosed ante mortem.     

Incidence of and risk factors for diabetes mellitus in cats that have undergone renal transplantation: 187 cases (1986-2005)

OBJECTIVE: To compare incidence of diabetes mellitus in cats that had undergone renal transplantation with incidence in cats with chronic renal failure, compare mortality rates in cats that underwent renal transplantation and did or did not develop diabetes mellitus, and identify potential risk factors for development of posttransplantation diabetes mellitus (PTDM) in cats. DESIGN: Retrospective case series. ANIMALS: 187 cats that underwent renal transplantation. PROCEDURES: Medical records were reviewed. RESULTS: 26 of the 187 (13.9%) cats developed PTDM, with the incidence of PTDM being 66 cases/1,000 cat years at risk. By contrast, the incidence of diabetes mellitus among a comparison population of 178 cats with chronic renal failure that did not undergo renal transplantation was 17.9 cases/1,000 cat years at risk, and cats that underwent renal trans-plantation were 5.45 times as likely to develop diabetes mellitus as were control cats with chronic renal failure. The mortality rate among cats with PTDM was 2.38 times the rate among cats that underwent renal transplantation but did not develop PTDM. Age, sex, body weight, and percentage change in body weight were not found to be significantly associated with development of PTDM. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cats that undergo renal transplantation have an increased risk of developing diabetes mellitus, compared with cats with chronic renal failure, and that mortality rate is higher for cats that develop PTDM than for cats that do not.     

Use of pulmonary hydrogen gas excretion to detect carbohydrate malabsorption in dogs

Pulmonary H2 excretion was measured in 10 healthy dogs, in 6 dogs with pancreatic exocrine insufficiency, and in 6 dogs with chronic small intestinal disease. Concentration of expired H2 in fasted healthy dogs was 0.9 +/- 0.1 ppm (mean +/- SEM) and peak H2 concentration of 1.4 +/- 0.2 ppm was detected up to 8 hours after feeding. Dogs with pancreatic exocrine insufficiency had fasting expired H2 concentrations of 3.3 +/- 0.9 ppm, which increased to a mean peak H2 concentration of 28.8 +/- 2.0 ppm 6.5 hours after feeding. Following xylose administration, expired H2 concentrations increased from fasting concentrations of 3.6 +/- 0.9 ppm to peak at 19.0 +/- 2.0 ppm in 1.5 hours. Blood xylose concentrations were diagnostic for carbohydrate malabsorption in 4 of 6 dogs with pancreatic exocrine insufficiency. Plasma p-aminobenzoic acid concentration identified bentiromide maldigestion in all dogs with pancreatic exocrine insufficiency. In 3 pancreatic exocrine insufficient dogs tested, pancreatic enzyme replacement therapy partially corrected carbohydrate malabsorption. Fasting expired H2 concentration was 5.3 +/- 1.3 ppm in dogs with chronic small intestinal disease and increased to a peak H2 of 72.2 +/- 18.0 ppm 7 hours after feeding. Following administration of xylose to dogs with chronic small intestinal disease, fasting expired H2 concentration increased from 3.0 +/- 1.0 ppm to a peak of 35.5 +/- 7.2 ppm at 2 hours. Blood xylose concentration was abnormal in only 2 of 6 dogs with chronic small intestinal disease. Results of these studies indicate that expired H2 analysis can identify carbohydrate malabsorption in dogs with pancreatic exocrine insufficiency or chronic small intestinal disease, and that pulmonary H2 testing is more sensitive than xylose absorption testing for the identification of carbohydrate malabsorption.     

A case of feline paraneoplastic alopecia with secondary Malossezia-associated dermatitis

A 13-year-old neutered female domestic shorthaired cat had progressive ventral abdominal alopecia attributed initially to hyperthyroidism. Corrective treatment by unilateral thyroidectomy did not, however, resolve the dermatosis and the alopecia progressed to involve the whole ventral trunk, the lower limbs and the head. Pruritus of the lower limbs was a prominent feature and was associated with the finding of Malassezia on cytology; Malassezia -associated dermatitis was diagnosed. Resolution of pruritus was seen after treatment with oral ketoconazole and a cleansing shampoo to eliminate the yeast, but severe polyphagia, small intestinal diarrhoea and polydipsia developed subsequently and the cat was euthanased. Necropsy revealed an exocrine pancreatic adenocarcinoma with hepatic metastases. The pancreatic, hepatic and dermatologlcal lesions were found to be typical of feline paraneoplastic alopecia (FPA). Malassezia -associated dermatitis can be associated with pruritus in cats with FPA.     

Urinary tract infections in cats with hyperthyroidism, diabetes mellitus and chronic kidney disease

The prevalence of urinary tract infections (UTIs) in cats with hyperthyroidism (n=90), diabetes mellitus (DM) (n=57) and chronic kidney disease (CKD) (n=77) was evaluated retrospectively. It was found to be 12% in cats with hyperthyroidism and DM, respectively, and 22% in cats with CKD. Associations between UTIs and clinical signs, biochemical markers in serum and urinalyses were investigated. Many of the cats with UTIs had no clinical signs of lower urinary tract disease or changes in their laboratory values indicative of infection. Therefore, a urinalysis alone should not be used to exclude UTIs in these cats. UTIs are relatively common in cats with hyperthyroidism, DM and CKD, and urine cultures are recommended as part of the basic diagnostic plan for cats suspected of suffering from these conditions.     

Ocular lesions associated with systemic hypertension in cats: 69 cases (1985-1998)

OBJECTIVE: To characterize clinical and clinicopathologic findings, response to treatment, and causes of systemic hypertension in cats with hypertensive retinopathy. DESIGN: Retrospective study. ANIMALS: 69 cats with hypertensive retinopathy. PROCEDURE: Medical records from cats with systemic hypertension and hypertensive retinopathy were reviewed. RESULTS: Most cats (68.1%) were referred because of vision loss; retinal detachment, hemorrhage, edema, and degeneration were common findings. Cardiac abnormalities were detected in 37 cats, and neurologic signs were detected in 20 cats. Hypertension was diagnosed concurrently with chronic renal failure (n = 22), hyperthyroidism (5), diabetes mellitus (2), and hyperaldosteronism (1). A clearly identifiable cause for hypertension was not detected in 38 cats; 26 of these cats had mild azotemia, and 12 did not have renal abnormalities. Amlodipine decreased blood pressure in 31 of 32 cats and improved ocular signs in 18 of 26 cats. CONCLUSIONS AND CLINICAL RELEVANCE: Retinal lesions, caused predominantly by choroidal injury, are common in cats with hypertension. Primary hypertension in cats may be more common than currently recognized. Hypertension should be considered in older cats with acute onset of blindness; retinal edema, hemorrhage, or detachment; cardiac disease; or neurologic abnormalities. Cats with hypertension-induced ocular disease should be evaluated for renal failure, hyperthyroidism, diabetes mellitus, and cardiac abnormalities. Blood pressure measurements and funduscopic evaluations should be performed routinely in cats at risk for hypertension (preexisting renal disease, hyperthyroidism, and age > 10 years). Amlodipine is an effective antihypertensive agent in cats.     

Serum fructosamine concentration in cats with overt hyperthyroidism.

OBJECTIVE: To determine the effect of hyperthyroidism on serum fructosamine concentration in cats. DESIGN: Cohort study. ANIMALS: 22 cats with overt hyperthyroidism. PROCEDURE: Hyperthyroidism was diagnosed on the basis of clinical signs, detection of a palpable thyroid gland, and high total serum thyroxine (T4) concentrations. Hyperthyroid cats with abnormal serum albumin, total protein, and glucose concentrations were excluded from the study. Samples for determination of serum fructosamine concentration were obtained prior to initiating treatment. Results were compared with fructosamine concentrations in healthy cats, cats in which diabetes had recently been diagnosed, and cats with hypoproteinemia. In 6 cats, follow-up measurements were obtained 2 and 6 weeks after initiating treatment with carbimazole. RESULTS: Serum fructosamine concentrations ranged from 154 to 267 mumol/L (median, 198 mumol/L) and were significantly lower than values in healthy cats. Eleven (50%) of the hyperthyroid cats had serum fructosamine concentrations less than the reference range. Serum fructosamine concentrations in hyperthyroid, normoproteinemic cats did not differ from values in hypoproteinemic cats. During treatment, an increase in serum fructosamine concentration was detected. CONCLUSIONS AND CLINICAL RELEVANCE: In hyperthyroid cats, concentration of serum fructosamine may be low because of accelerated protein turnover, independent of blood glucose concentration. Serum fructosamine concentrations should not be evaluated in cats with overt hyperthyroidism and diabetes mellitus. Additionally, concentration of serum fructosamine in hyperthyroid cats should not be used to differentiate between diabetes mellitus and transitory stress-related hyperglycemia.     

Systolic blood pressure in cats with diabetes mellitus

OBJECTIVE: To determine the prevalence of systemic hypertension in cats with diabetes mellitus and establish ranges for echocardiographic variables in diabetic cats. DESIGN: Prospective study. ANIMALS: 14 cats with diabetes mellitus and 19 healthy control cats. PROCEDURE: Systolic blood pressure was measured indirectly with a noninvasive Doppler technique. Ophthalmic and echocardiographic examinations were performed, and urine protein concentration was measured. Cats were considered to have hypertension if they had systolic blood pressure > 180 mm Hg and at least 1 other clinical abnormality typically associated with hypertension (eg, hypertensive retinopathy, left ventricular hypertrophy, or proteinuria). RESULTS: None of the diabetic or control cats had systolic blood pressure > 180 mm Hg. One diabetic cat had left ventricular hypertrophy, but systolic blood pressure was 174 mm Hg. None of the cats had evidence of hypertensive retinopathy or proteinuria. Mean values for echocardiographic variables for the diabetic cats were not significantly different from published values for healthy cats. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that hypertension does not occur or occurs in only a small percentage of cats with diabetes mellitus.     

Retrospective Study: Surgical intervention in the management of severe acute pancreatitis in cats: 8 cases (2003–2007)

Objective – To evaluate clinical characteristics and outcomes of cats undergoing surgical intervention in the course of treatment for severe acute pancreatitis. Design – Retrospective observational study from 2003 to 2007 with a median follow‐up period of 2.2 years (range 11 d–5.4 y) postoperatively. Setting – Private referral veterinary center. Animals – Eight cats. Interventions – None. Measurements and Main Results – Quantitative data included preoperative physical and clinicopathologic values. Qualitative parameters included preoperative ultrasonographic interpretation, perioperative and intraoperative feeding tube placement, presence of free abdominal fluid, intraoperative closed suction abdominal drain placement, postoperative complications, microbiological culture, and histopathology. Common presenting clinical signs included lethargy, anorexia, and vomiting. Leukocytosis and hyponatremia were present in 5 of 8 cats. Hypokalemia, increased total bilirubin, and hyperglycemia were present in 6 of 8 cats. Elevated alanine aminotransferase and aspartate transferase were present in all cats. Surgery for extrahepatic biliary obstruction was performed in 6 cats, pancreatic abscess in 3 cats, and pancreatic necrosis in 1 cat. Six of the 8 cats survived. Five of the 6 cats that underwent surgery for extrahepatic biliary obstruction and 1 cat that underwent pancreatic necrosectomy survived. All 5 of the cats with extrahepatic biliary obstruction secondary to pancreatitis survived. The 2 nonsurvivors included a cat with a pancreatic abscess and a cat with severe pancreatitis and extrahepatic biliary obstruction secondary to a mass at the gastroduodenal junction. Postoperative complications included progression of diabetes mellitus, septic peritonitis, local gastrostomy tube stoma inflammation, local gastrostomy tube stoma infection, and mild dermal suture reaction. Conclusion – Cats with severe acute pancreatitis and concomitant extrahepatic biliary obstruction, pancreatic necrosis, or pancreatic abscesses may benefit from surgical intervention. Cats with extrahepatic biliary obstruction secondary to severe acute pancreatitis may have a good prognosis.     

Multiple endocrine neoplasia type-I-like syndrome in two cats

Multiple endocrine neoplasia (MEN) embodies a group of diseases in human patients and domestic animals that are characterized by hyperplasia or neoplasia, or both, of two or more endocrine tissues. The MEN-1 syndrome is associated with menin gene mutations that induce various combinations of parathyroid, pituitary, and pancreatic endocrine tumors in humans. Two male, Domestic Shorthair cats developed symmetric alopecia, insulin-resistant diabetes mellitus, and pituitary-dependent hyperadrenocorticism at 12 and 13 years of age. Examination of skin biopsy specimens revealed atrophic dermatosis associated with hyperadrenocorticism. In one cat, cutaneous lesions consistent with paraneoplastic alopecia associated with pancreatic adenocarcinoma also were evident. Multiple invasive pancreatic beta cell carcinomas, pituitary corticotroph adenomas, and thyroid C-cell and parathyroid chief cell hyperplasia were diagnosed on the basis of results of gross, histologic, and immunohistochemical findings in both cats. Pancreatic exocrine adenocarcinoma was diagnosed in both cats. One cat also had hepatocellular carcinoma. Exons 1-8 of the feline menin gene were sequenced and were found to bear 93% homology with the human gene sequence, and the corresponding amino acid sequences shared 98% homology. Purification of total RNA and amplification of cDNA from lesional tissues to document mutations in the feline menin gene sequence were unsuccessful. The combination of lesions observed was consistent with the diagnosis of MEN-1-like syndrome in both cats.     

Insulin therapy in cats with diabetes mellitus

Thirteen cats with diabetes mellitus were evaluated. Clinical signs included polydipsia, polyuria, polyphagia, lethargy, and weight loss. Results of physical examination included obesity, hepatomegaly, mild seborrhea sicca, muscle wasting, and dehydration. One cat walked plantigrade and was suspected of having a diabetic neuropathy. Persistent hyperglycemia, glucosuria, high liver enzyme activities, hypercholesterolemia, hyperproteinemia, and low electrolyte concentrations were the common laboratory findings. In 3 cats diabetes mellitus developed after megestrol acetate therapy; 2 of these cats required only temporary insulin treatment. In a 3rd cat, which had no history of receiving diabetogenic drug therapy, remission of diabetes mellitus also was observed. Serum insulin and plasma glucose concentrations were determined in 6 cats after administration of an intermediate-acting insulin (isophane insulin) and in 3 cats after administration of a long-acting insulin (protamine zinc insulin). The insulin concentration peaked 2 to 6 hours after the injection of intermediate-acting insulin and 6 to 12 hours after the injection of long-acting insulin. The lowest glucose concentration was recorded 4 to 8 hours after injection of intermediate-acting insulin, and 6 to 12 hours after injection of long-acting insulin. It was concluded that, although insulin therapy must be adjusted to the individual, the diabetic cat usually requires twice-daily administration of isophane insulin; however, the protamine zinc insulin can be given once daily for satisfactory control.     

Stress hyperglycemia in cats

It may be difficult to differentiate the possible causes of hyperglycemia in the cat. The following investigation was on transient hyperglycemia in 320 cats. The frequency and degree of stress-hyperglycemia and its relation to different types of primary diseases was proven. Animals with overt diabetes mellitus or pancreatic diseases were not included in this study. Plasma glucose was analyzed with the o-Toluidine- or with the glucose oxidase-method. Plasma immune-reactive insulin (IRI) was estimated by RIA. A glucose concentration of greater than or equal to 140 mg/dl (7.77 mmol/l) in the fasted animal was defined as hyperglycemia. The results of the retrospective investigation show in cats transient hyperglycemia occurs more often (3.2%) than permanent hyperglycemia (0.57%). Contrary to overt diabetes mellitus there is no sex- or age-related predisposition. Glucose values above 300 mg/dl (16.65 mmol/l) with maximal values up to 620 mg/dl (34.42 mmol/l) were estimated in 12% of the animals. In 12 from 19 hyperglycemic animals the basal IRI values were between 4 and 14 microU/ml, 11 animals had a lowered I/G ratio. In the following order of frequency the primary diseases found in combination with transient hyperglycemia were: dys- and stranguria, viral and bacterial infections, gastrointestinal diseases, neoplasia, renal insufficiency, cardiopathies etc. With improvement of the underlying disturbance the stress-related hyperglycemia normalized without insulin therapy within a few days. In conclusion, it is necessary to initially identify basic diseases that may trigger the onset of stress-hyperglycemia in the cat. Neither the extent of the glucose level nor a single plasma-insulin-value are valid indicators of confirming the diagnosis of diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transsphenoidal hypophysectomy for treatment of pituitary-dependent hyperadrenocorticism in 7 cats

OBJECTIVE: Evaluation of microsurgical transsphenoidal hypophysectomy for the treatment of pituitary-dependent hyperadrenocorticism (PDH) in cats. STUDY DESIGN: Prospective clinical study. ANIMALS OR SAMPLE POPULATION: Seven cats with PDH. METHODS: Urinary cortisol/creatinine ratios, pituitary-adrenocortical function tests, and computed tomography (CT) were performed on 7 cats that presented with a provisional diagnosis of hyperadrenocorticism. All cats underwent microsurgical transsphenoidal hypophysectomy with histologic examination of the excised specimen. Follow-up consisted of clinical evaluation, repeat adrenocortical function testing, and CT. RESULTS: Four cats had concurrent diabetes mellitus. In all cats, the urinary cortisol/creatinine (C/C) ratios were elevated. The dexamethasone screening test showed that 2 cats did not meet the criterion for hyperadrenocorticism. The response of the cats' plasma concentrations of cortisol and adrenocorticotrophic hormone to a high dose of dexamethasone varied from very sensitive to completely dexamethasone resistant. Basal plasma alpha-melanocyte-stimulating hormone concentrations were elevated in 2 cats with a pars intermedia adenoma and in 3 cats with an adenoma that originated from the anterior lobe. Preoperative CT enabled accurate assessment of pituitary size (5 nonenlarged pituitaries with a height <4 mm and 2 enlarged pituitaries with a height >5 mm) and localization relative to intraoperative anatomic landmarks. Two cats died within 4 weeks after surgery of a nonrelated disease. In the remaining 5 cats, the hyperadrenocorticism went into both clinical and biochemical remission. Hyperadrenocorticism recurred in 1 cat after 19 months, but no other therapy was given and the cat died at home 28 months after surgery. CT evaluation of this cat had identified pituitary remnants 6 weeks after surgery. The main postoperative complications were oronasal fistula (1 cat), complete dehiscence of the soft palate (1 cat), and transient reduction of tear production (1 cat). One cat died at 6 months (undefined anemia), and another cat at 8 months (recurrent nose and middle ear infection secondary to soft palate dehiscence) after surgery. In the surviving 2 cats, the remission periods at the time of writing were 46 and 15 months. In the 2 cats with sufficient follow-up time, the concurrent diabetes mellitus disappeared, ie, insulin treatment could be discontinued at 4 weeks and 5 months after hypophysectomy. In all 7 cats, the histologic diagnosis was pituitary adenoma. CONCLUSIONS: Microsurgical transsphenoidal hypophysectomy is an effective method of treatment for feline PDH in specialized veterinary institutions having access to advanced pituitary imaging techniques. Concurrent diabetes mellitus is usually reversible after hypophysectomy. Thorough presurgical screening for coexisting diseases is imperative. CLINICAL RELEVANCE: PDH in cats can be effectively treated by hypophysectomy. The neurosurgeon performing hypophysectomy must master a learning curve and must be familiar with the most frequent complications of the operation to treat them immediately and effectively. Urinary C/C ratios are sensitive indicators for the assessment of remission and recurrence of hyperadrenocorticism.     

Evaluation of dietary and environmental risk factors for hyperthyroidism in cats

OBJECTIVE: To identify dietary and environmental risk factors for hyperthyroidism in cats. DESIGN: Case-control study. ANIMALS: 100 cats with hyperthyroidism and 163 control cats. PROCEDURE: Medical records were examined, and owners completed a mailed questionnaire. Data collected included information regarding demographic variables, environmental exposures, and diet, including preferred flavors of canned cat food. RESULTS: Case cats were significantly less likely to have been born recently than control cats. Housing; exposure to fertilizers, herbicides, or plant pesticides; regular use of flea products; and presence of a smoker in the home were not significantly associated with an increased risk of disease, but cats that preferred fish or liver and giblets flavors of canned cat food had an increased risk. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cats that prefer to eat certain flavors of canned cat food may have a significantly increased risk of hyperthyroidism.     

Treatment of feline diabetes mellitus using an alpha-glucosidase inhibitor and a low-carbohydrate diet

The purpose of this study was to determine the effect of an alpha-glucosidase inhibitor (acarbose), combined with a low-carbohydrate diet on the treatment of naturally occurring diabetes mellitus in cats. Eighteen client-owned cats with naturally occurring diabetes mellitus were entered into the study. Dual-energy X-ray absorptiometry (DEXA) was performed prior to and 4 months after feeding the diet to determine total body composition, including lean body mass (LBM) and percent body fat. Each cat was fed a commercially available low-carbohydrate canned feline diet and received 12.5mg/cat acarbose orally every 12h with meals. All cats received subcutaneous insulin therapy except one cat in the study group that received glipizide (5mg BID PO). Monthly serum glucose and fructosamine concentrations were obtained, and were used to adjust insulin doses based on individual cat's requirements. Patients were later classified as responders (insulin was discontinued, n=11) and non-responders (continued to require insulin or glipizide, n=7). Responders were initially obese (>28% body fat) and non-responders had significantly less body fat than responders (<28% body fat). Serum fructosamine and glucose concentrations decreased significantly in both responder and non-responder groups over the course of 4 months of therapy. Better results were observed in responder cats, for which exogenous insulin therapy was discontinued, glycemic parameters improved, and body fat decreased. In non-responders, median insulin requirements decreased and glycemic parameters improved significantly, despite continued insulin dependence. The use of a low-carbohydrate diet with acarbose was an effective means of decreasing exogenous insulin dependence and improving glycemic control in a series of client-owned cats with naturally occurring diabetes mellitus.     

Evaluation of the low-dose dexamethasone suppression test and ultrasonographic measurements of the adrenal glands in cats with diabetes mellitus

The objectives of the study were to evaluate the low-dose dexamethasone suppression (LDDS) test and the size of the adrenal glands via ultrasonography in cats with diabetes mellitus. Twenty-two cats were enrolled in the study. In 19 cats, suppression of cortisol concentrations below 5.5 nmol/litre occurred four and eight hours after intravenous administration of dexamethasone (0.1 mg/kg). In one other cat, the cortisol concentration was also below 5.5 nmol/litre at eight hours but was 11.0 nmol/litre at four hours. The results were in agreement with those of healthy cats in a previous study. The cortisol concentrations four and eight hours after administration of dexamethasone did not differ between cats with good glycemic control (n = 8) and those with moderate to poor control (n = 12). The adrenal glands of the diabetic cats were not enlarged compared with those of healthy cats. In two diabetic cats, the LDDS test results were abnormal. One cat had a pituitary adenoma and adrenal glands of normal size as determined by ultrasonography. The size of the adrenal glands of the other cat clearly differed; histological examination of the larger adrenal gland revealed an adrenocortical adenoma. Based on our findings, the results of the LDDS test using 0.1 mg/kg of dexamethasone are normal in cats with diabetes mellitus independent of the quality of glycemic control. In addition, diabetes mellitus does not lead to a measurable increase in the size of the adrenal glands in cats. Further studies are needed to evaluate if the dexamethasone dosage used in this study is useful to diagnose mild form of hypercortisolism.     

Basal glucosuria in cats

Objective of this study was to demonstrate the ubiquitous presence of glucose in urine of euglycemic cats by a highly sensitive glucose assay. The local electronic database was searched for results of quantitative urine glucose measurements in cats. A total of 325 feline urine glucose measurements were identified, of which 303 (93%) had been submitted by one of the co‐authors working in a near‐by small animal practice. After the exclusion of patients with kidney disease (n = 60), hyperthyroidism (n = 15), diabetes mellitus (n = 11), multiple diseases (n = 9) or steroid treatment (n = 3), as well as serial measurements (n = 87) and outliers (n = 8), the final study population consisted of 132 cats. Urine creatinine concentration was unavailable in five patients. Whereas all but one cat had glucose concentrations above the detection limit of the assay (0.11 mmol/L, Gluco‐quant Enzyme Kit/Roche Diagnostics), no positive glucose dipstick test result (Combur 9‐Test, Roche Diagnostics) was observed. The median (range) of urinary glucose concentration and the glucose‐to‐creatinine ratio (UGCR) was 0.389 (<0.11–1.665) mmol/L and 0.0258 (0.007–0.517) respectively. The UGCR was not affected by age, gender, breed or leukocyturia, whereas cats with hematuria had slightly higher values. Data show that so‐called “basal glucosuria” is present in the majority of cats and by no means diagnostic for diabetes mellitus or renal glucosuria. This has to be considered when using bio‐analytical methods with a low limit of quantification.