Evaluation of Iatrogenic Hypocortisolemia Following Trilostane Therapy in 48 Dogs with Pituitary-Dependent Hyperadrenocorticism.

This study aimed to retrospectively describe the clinical progression following diagnosis of iatrogenic hypocortisolemia (iHC) in 48 dogs receiving trilostane for pituitary-dependent hyperadrenocorticism. Cortisol concentrations were ≥1.5 mg/dL within 6 mo following diagnosis of iHC in 76.3% of dogs (95% confidence interval [CI] 59.8-88.6%). At the time of study completion, 25% of dogs (95% CI 13.6-39.6%) were receiving either glucocorticoids or mineralocorticoids or both; 42% of dogs (95% CI 27.6-56.8%) were on no adrenal-related medications; and the remaining 33% of dogs (95% CI 20.4-48.4%) were receiving trilostane. No patient-, clinicopathologic-, or trilostane-associated factors were identified to influence adrenal recovery following diagnosis of iHC, and it remains difficult to predict the clinical progression in this population of dogs.

IMAGING DIAGNOSIS--URINARY BLADDER DUPLICATION IN A CAT.

A female kitten presented for chronic, intermittent, antibiotic-responsive urinary incontinence and chronic kidney disease. Abdominal ultrasound identified bilateral pelvic/ureteral dilation and three closely apposed thin-walled fluid-filled structures in the caudal abdomen, extending toward the pelvic inlet. Excretory urography and negative contrast cystography identified contrast medium accumulation from the dilated ureters into two tubular soft tissue masses of the caudal abdomen, with subsequent gradual filling of a more cranially located urinary bladder. A retrograde vaginocystourethrogram identified a normal uterus, normal vagina, and a single urethra continuous with the cranially located urinary bladder. Antemortem diagnosis was suspicious for bilateral ectopic ureteroceles. Postmortem diagnosis, 35 months following initial presentation, determined the fluid-filled masses to have abundant smooth muscle in the wall, including a muscularis mucosa connected by a common ostium, consistent with urinary bladder duplication. Urinary bladder duplication should be included as a differential diagnosis in cats with these clinical and imaging characteristics. In this case, differentiation of ectopic ureterocele from urinary bladder duplication required histological confirmation.

Effective removal of gadolinium with hemodialysis in a dog with severe acute on chronic kidney injury.

OBJECTIVE: To describe the use of intermittent hemodialysis (IHD) to remove gadolinium (28.1 mg/kg dose) in a dog with severe kidney disease. CASE SUMMARY: A 12-year-old neutered female Yorkshire Terrier presented with severe acute-on-chronic kidney injury and concurrent neurological signs. The dog received extracorporeal therapy as part of management. Uremia improved after hemodialysis, but central nervous system signs persisted; therefore, a contrast-enhanced magnetic resonance imaging was performed, immediately followed by IHD. Two IHD treatments with a low-flux dialyzer were performed 1.5 and 25.75 hours after administration of gadolinium, with almost complete removal of gadolinium. More than 96% of gadolinium was removed with a single treatment. NEW OR UNIQUE INFORMATION PROVIDED: Extracorporeal therapy is effective at removing gadolinium-based chelated contrast agents and could be considered if magnetic resonance imaging is indicated in a patient with substantial kidney impairment. Alternatively, newer contrast agents that have been deemed safer in this patient population could be used.

Age-related trends in urine specific gravity in apparently healthy cats.

OBJECTIVES: Urine specific gravity (USG) is the most common method for the estimation of urine concentration in cats. Utilization of USG as a screening tool is easily accessible and is of low cost to the client if strategically utilized in settings of higher diagnostic value. There is currently minimal population information regarding how USG changes across ages in cats. METHODS: Data were collected from electronic pet medical records from more than 1000 hospitals and screened for cats with an apparently healthy clinical status and complete diagnostic information. USG was compared with age in multiple analyses to examine the relationship between the variables. RESULTS: In the absence of other indicators of disease, renal concentrating ability begins to diminish, on average, starting at approximately 9 years of age. By age group, cats aged 11-15 years (1.044, 95% confidence interval [CI] 1.043-1.044) had statistically significantly lower mean USGs compared with cats aged less than 1 year (1.049, 95% CI 1.048-1.051; P <0.001), 1-6 years (1.049, 95% CI 1.049-1.050; P <0.001) or 7-10 years (1.049, 95% CI 1.048-1.049; P <0.001). Cats aged ⩾15 years (1.038, 95% CI 1.036-1.040) had statistically significantly lower mean USGs compared with cats aged less than 1 year (P <0.001), 1-6 years (P <0.001), 7-10 years (P <0.001) or 11-15 years (P <0.001). CONCLUSIONS AND RELEVANCE: Renal concentrating ability begins to diminish, on average, starting at approximately 9 years of age and is progressive as cat age increases. This study provides important and new information to help improve screening practices for disorders of concentrating ability in cats.

Use of haemodiafiltration in the treatment of massive caffeine intoxication in a dog.

The objective of this case report is to describe the use of extracorporeal therapy, specifically hemodialfiltration, for the treatment of caffeine intoxication. A 12 year old Border Terrier consumed up to 1440 mg/kg of caffeine and rapidly developed clinical signs of tachycardia and tremors. Hemodiafiltration was instituted, using an M60 PrismaFlex cartridge using blood to prime the system due to patient size. Treatment with 11.25 L of therapy fluid (83% dialysate, 17% replacement fluid), or 1.8 L/kg, was provided over 6 h. Pre-treatment serum caffeine concentration of 233 µg/mL was decreased by 89% to 25 µg/nL by the end of treatment. Despite prompt institution of extracorporeal toxin removal therapy, ventricular ectopy developed necessitating sotolol treatment for the following week. Caffeine is efficiently removed via hemodialysis, as predicted by small size, small volume of distribution, and minimal protein binding. A CRRT platform can be used to provide adequate clearance.

Proteinuria in dogs and cats.

Proteinuria is defined as the presence of protein in the urine. Normally, circulating serum proteins are blocked by the glomerulus due to size and/or charge. Any small proteins that pass through a healthy glomerulus are reabsorbed by the renal tubules or broken down by renal tubular epithelial cells. Persistent proteinuria, in the absence of lower urinary tract disease or reproductive tract disease, is usually an indication of renal damage or dysfunction. Less commonly persistent proteinuria can be caused by increased circulating levels of low molecular weight proteins. This article reviews mechanisms of proteinuria in dogs and cats and discusses the importance of screening for and ultimately treating proteinuria.

Effects of IV Fluids in Dogs and Cats With Kidney Failure.

Intravenous fluid therapy has long been the mainstay of treatment of kidney disease, including acute kidney injury and uremic crisis associated with chronic kidney disease. Careful management of fluid dose is critical, as animals with kidney disease may have marked derangements in their ability to regulate fluid homeostasis and acid-base status. Understanding of the physiology of renal fluid handling is necessary, along with repeated attention to parameters of fluid status, electrolytes, and acid-base balance, to achieve optimal hydration status and avoid further damage or decrease in function from dehydration or overhydration.

Acute intrinsic renal failure in cats: 32 cases (1997-2004).

OBJECTIVE: To determine patient demographics, clinicopathologic findings, and outcome associated with naturally acquired acute intrinsic renal failure (ARF) in cats. DESIGN: Retrospective case series. ANIMALS: 32 cats with ARF. PROCEDURES: Cats were considered to have ARF if they had acute onset of clinical signs (< 7 days), serum creatinine concentration > 2.5 mg/dL (reference range, 0.8 to 2.3 mg/dL) and BUN > 35 mg/dL (reference range, 15 to 34 mg/dL) in conjunction with urine specific gravity < 1.025 or with anuria or increasing serum creatinine concentration despite fluid therapy and normal hydration status, and no signs of chronic renal disease. Cases were excluded if cats had renal calculi or renal neoplasia. RESULTS: Causes of ARF included nephrotoxins (n = 18 cats), ischemia (4), and other causes (10). Eighteen cats were oliguric. For each unit (mEq/L) increase in initial potassium concentration, there was a 57% decrease in chance of survival. Low serum albumin or bicarbonate concentration at initial diagnosis was a negative prognostic indicator for survival. Initial concentrations of BUN, serum creatinine, and other variables were not prognostic. Seventeen (53%) cats survived, of which 8 cats had resolution of azotemia and 9 cats were discharged from the hospital with persistent azotemia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that survival rates of cats with ARF were similar to survival rates in dogs and that residual renal damage persisted in approximately half of cats surviving the initial hospitalization.

Managing fluid and electrolyte disorders in renal failure.

Because of the role of the kidneys in maintaining homeostasis in the body, kidney failure leads to derangements of fluid, electrolyte, and acid-base balance. The most effective therapy of a uremic crisis is careful management of fluid balance, which involves thoughtful assessment of hydration, a fluid treatment plan personalized for the specific patient, repeated and frequent reassessment of fluid and electrolyte balance, and appropriate changes in the treatment plan in response to the rapidly changing clinical situation of the patient that has renal failure. Disorders of sodium, chloride, potassium, calcium, and phosphorus are commonly encountered in renal failure and may be life threatening. Treatment of metabolic acidosis and nutritional support are frequently needed.

Hemodialysis in a dog with acute renal failure from currant toxicity.

A 3 1/2-year-old Labrador retriever being presented for acute onset vomiting and lethargy was diagnosed with acute renal failure (ARF). The dog had ingested dried currants, a type of raisin. Hemodialysis was successfully performed to treat the ARE Raisin toxicity can cause ARF and warrants early recognition and aggressive treatment.

Hemodialysis catheter-associated fibrin sheath in a dog.

OBJECTIVE: To describe an intravascular fibrin sheath associated with a hemodialysis catheter in a dog. CASE SUMMARY: A 4-year-old dog presented for hemodialysis to treat acute kidney injury. Hemodialysis catheter dysfunction during the course of treatment was temporarily alleviated using a tissue plasminogen activator. A thrombus composed of fibrin and granulation tissue creating a sheath around the catheter and focally adherent to the vessel wall was identified on postmortem evaluation. NEW OR UNIQUE INFORMATION PROVIDED: Fibrin sheath formation is a commonly recognized problem of central venous catheters used for hemodialysis in people and is likely a common problem in veterinary patients undergoing dialysis as well. This report provides a description of the clinical features of the catheter dysfunction, response to treatment, postmortem radiographic and direct imaging, and histology of the fibrin sheath, and also provides a brief review of potential management techniques that have been described in people.

Managing Fluid and Electrolyte Disorders in Kidney Disease.

Because of the role of the kidneys in maintaining homeostasis in the body, kidney disease leads to derangements of fluid, electrolyte, and acid-base balance. The most effective therapy of a uremic crisis is careful management of fluid balance, which involves thoughtful assessment of hydration, a fluid treatment plan personalized for the specific patient, and repeated and frequent reassessment of fluid and electrolyte balance. Disorders of sodium, chloride, potassium, calcium, and phosphorus are commonly encountered in kidney disease and some may be life-threatening. Treatment of metabolic acidosis and nutritional support is frequently needed.

Hyperthyroidism and the kidney.

Hyperthyroidism and chronic renal failure (CRF) are both common diseases of older cats. Hyperthyroidism increases GFR by a variety of physiologic effects. Chronic renal failure can suppress total T4 concentrations in cats with concurrent hyperthyroidism, and free T4 is not a useful distinguishing test. Medical therapy (ie, methimazole) is recommended in cats with pre-existing CRF. Overt renal failure occurs in approximately 30% of cats treated for hyperthyroidism. It usually occurs within one month of treatment and tends to remain mild and stable over time. There is no practical way to predict which cats will develop CRF after treatment of hyperthyroidism, although GFR measurement does seem useful.

Evaluation of the relationship between clinical variables and thromboelastographic findings in dogs with protein-losing nephropathy.

OBJECTIVE: To determine whether hypercoagulability in proteinuric dogs, defined by thromboelastography (TEG), is related to the degree of proteinuria, presence of systemic arterial hypertension, presence of hypoalbuminemia, or reduced antithrombin activity. DESIGN: Prospective study of client-owned dogs. Data collected from each patient included signalment, body weight, urine protein-to-creatinine ratio (UPC), serum albumin concentration, TEG values, noninvasive arterial blood pressure, and AT activity. Hypercoagulability was diagnosed by TEG and odds ratios for other measurements were assessed by univariate logistic regression. SETTING: Urban referral center and teaching hospital. ANIMALS: Seventy-six dogs with protein-losing nephropathy (PLN) based on UPC, diagnosed between Oct 2009 and Oct 2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The prevalence of hypercoagulability was 89%. No statistically significant associations were detected between hypercoagulability and UPC, serum albumin, noninvasive blood pressure, or AT activity (all P > 0.05). The prevalence of thromboembolism was 6.6%. CONCLUSIONS: Hypercoagulability was prevalent in dogs with PLN but could not be predicted based upon the presence or degree of proteinuria, systemic arterial hypertension, hypoalbuminemia, or low AT activity. The prevalance of thromboembolism was low in this population with PLN.

Is Progressive Chronic Kidney Disease a Slow Acute Kidney Injury?

International Renal Interest Society chronic kidney disease Stage 1 and acute kidney injury Grade I categorizations of kidney disease are often confused or ignored because patients are nonazotemic and generally asymptomatic. Recent evidence suggests these seemingly disparate conditions may be mechanistically linked and interrelated. Active kidney injury biomarkers have the potential to establish a new understanding for traditional views of chronic kidney disease, including its early identification and possible mediators of its progression, which, if validated, would establish a new and sophisticated paradigm for the understanding and approach to the diagnostic evaluation, and treatment of urinary disease in dogs and cats.

Urinalysis interpretation: how to squeeze out the maximum information from a small sample.

The urinalysis is an essential part of the diagnostic evaluation for all urinary and many metabolic diseases. Its assessment includes evaluation of physical characteristics (color, clarity, and volume), biochemical parameters (urine pH, blood, glucose, ketones, bilirubin, urobilinogen, and protein) and microscopic sediment evaluation (RBC, WBC, organisms, epithelial cells, crystals, and casts). Many of these parameters are influenced by collection method and therefore, it is essential to interpret accordingly. Knowledge of factors that can interfere with the accuracy of some test results can decrease improper interpretation. When all of these parameters are evaluated in combination with clinical signs, physical examination, thorough history and other laboratory tests, a diagnosis will often be attained.

Acute renal failure caused by lily ingestion in six cats.

Acute renal failure was diagnosed in 6 cats that had ingested Easter lily or tiger lily plants. All 6 were treated medically; 2 underwent hemodialysis. Three cats survived the acute episode, and although they had chronic renal failure, they survived for more than 1.5 years. Two cats died despite aggressive medical management, including hemodialysis. One cat was euthanatized shortly after the diagnosis was made. Three of the cats were oliguric or anuric at the time of initial examination, and all 3 died. None of the 3 cats that survived had oliguria or anuria. Various members of the lily family (Liliaceae) can cause nephrotoxicosis in cats, but the toxic principle is not known. Although the prognosis for full recovery of cats with lily toxicosis is poor, long-term survival is possible with supportive care. The prognosis appears to be better for cats with nonoliguric renal failure.

Cryptococcal pyelonephritis in a dog.

A 5-year-old castrated male Golden Retriever was evaluated for polyuria, polydipsia, and progressive regurgitation thought to be a result of bacterial pyelonephritis and megaesophagus. Bacteriologic culture of urine failed to yield clinically relevant growth, and results of a urine sediment examination were normal. With time, intention tremors and progressive neurologic dysfunction were also observed. At necropsy, a diagnosis of cryptococcal disease was confirmed histologically and immunohistochemically. Findings in the dog of this report were indicative of nephrogenic diabetes insipidus with polyuria and polydipsia caused by cryptococcal pyelonephritis. Neurologic manifestations of systemic cryptococcus infection included megaesophagus, esophageal hypomotility, and regurgitation attributed to localization of cryptococcal organisms in the brain stem in the region of the dorsal motor nucleus of the vagus nerve. To the authors' knowledge, this is the first report of polyuria secondary to cryptococcal pyelonephritis.

Leptospirosis. A re-emerging zoonotic disease.

Leptospirosis is a re-emerging infectious disease that occurs in dogs in urban and rural environments. It is caused by a filamentous spiral bacterium that has a predilection for renal tubules. Acute renal failure, hepatic dysfunction, and hemorrhagic diathesis are the most common clinical signs. Treatment with antibiotics and supportive care can manage a high percentage of cases successfully. Newer vaccines developed in response to the change in frequency of certain serovars may decrease the incidence of clinical disease. Leptospirosis affects a wide variety of species and is zoonotic.

The use of erythropoietin.

EPO is a hematopoietic growth factor produced in the kidney that stimulates erythropoiesis. It effectively treats hypoproliferative anemia associated with CRF, improving quality of life in these patients. Other uses that are poorly characterized in veterinary medicine include treatment of cancer patients on chemotherapy, hematologic disorders, and anemic FeLV-infected cats as well as preoperative conditioning for elective surgeries that may involve significant blood loss. Careful monitoring of therapy is necessary for optimal results. Several complications are associated with rHuEPO therapy. The production of anti-rHuEPO antibodies is the most significant and can be a life-threatening event. Alternatives to human EPO are being sought to provide beneficial effects while avoiding antibody formation.