Consensus recommendations for the diagnostic investigation of dogs with suspected glomerular disease.

BACKGROUND: The International Renal Interest Society (IRIS) offers guidelines for chronic kidney disease and acute kidney injury. As dogs with glomerular disease may present differently and require different treatment than those with whole nephron or tubular disease, the IRIS Canine Glomerulonephritis (GN) Study Group was convened to formulate guidelines for these cases. The Diagnosis Subgroup was asked to make recommendations for diagnostic evaluation of such cases. OBJECTIVE: To seek consensus among renal specialists for the evaluation of dogs with proteinuria because of suspected glomerular disease. METHODS: After reviewing the literature, subgroup members discussed and wrote the draft paper and recommendations, which members of the IRIS Canine GN Study Group voted upon by electronic secret ballot, with comments noted. Consensus was declared if votes showed strong or general agreement from 85% of the respondents. RESULTS: Diagnostic tests were categorized as essential, recommended, or potentially helpful, with prioritization dependent on case characteristics, eg, for cases with uncomplicated proteinuria versus complicated with hypoalbuminemia, azotemia, or both. Consensus was reached with 86-100% agreement on all questions posed. All cases should have basic examinations including blood pressure measurement, blood, and urine testing, and a search for infectious diseases relevant to their environs. The majority ranked imaging (chest radiographs, abdominal ultrasonogram) and renal biopsy procured and interpreted by experienced personnel as essential evaluations in complicated cases, but a few respondents deemed these to be essential in uncomplicated cases as well. CONCLUSIONS AND CLINICAL IMPORTANCE: Strong consensus about recommendations for diagnostic evaluation of dogs with suspected glomerular protein loss was attained. These guidelines help clinicians characterize disease processes for more informed therapeutic decision-making.

Babesiosis caused by a large Babesia species in 7 immunocompromised dogs.

BACKGROUND: A large unnamed Babesia species was detected in a dog with lymphoma. It was unknown if this was an underrecognized pathogen. OBJECTIVE: Report the historical and clinicopathologic findings in 7 dogs with babesiosis caused by a large unnamed Babesia species characterize the 18S ribosomal ribonucleic acid (rRNA) genes. ANIMALS: Seven immunocompromised dogs from which the Babesia was isolated. METHODS: Retrospective case review. Cases were identified by a diagnostic laboratory, the attending clinicians were contacted and the medical records were reviewed. The Babesia sp. 18S rRNA genes were amplified and sequenced. RESULTS: Six of 7 dogs had been splenectomized; the remaining dog was receiving oncolytic drugs. Lethargy, anorexia, fever, and pigmenturia were reported in 6/7, 6/7, 4/7, and 3/7 dogs. Laboratory findings included mild anemia (7/7) and severe thrombocytopenia (6/7). Polymerase chain reaction (PCR) assays used to detect Babesia sensu stricto species were all positive, but specific PCR assays for Babesia canis and Babesia gibsoni were negative in all dogs. The 18S rRNA gene sequences were determined to be identical to a large unnamed Babesia sp. previously isolated. Cross-reactive antibodies against other Babesia spp. were not always detectable. Five dogs were treated with imidocarb dipropionate and 1 dog with atovaquone/azithromycin; some favorable responses were noted. The remaining dog was untreated and remained a clinically stable carrier. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with pigmenturia, anemia, and thrombocytopenia should be tested for Babesia sp. by PCR. Serology is not sufficient for diagnosis of this Babesia sp. Asplenia, chemotherapy, or both might represent risk factors for persistent infection, illness, or both.

Familial protein-losing enteropathy and protein-losing nephropathy in Soft Coated Wheaten Terriers: 222 cases (1983-1997).

Records and pedigrees of Soft Coated Wheaten Terriers (SCWT) with protein-losing enteropathy (PLE) or protein-losing nephropathy (PLN) were studied retrospectively. Criteria for inclusion were defined based on analysis of blood (panhypoproteinemia for PLE, hypoalbuminemia for PLN) and urine (proteinuria for PLN) and histopathologic examination of tissue. Two hundred twenty-two affected dogs (female:male ratio = 1.6, P < .001) were clinically identified. Dogs were diagnosed with PLE earlier (P < .005; mean +/- SD age: 4.7+/-2.6 years, n = 76) than with PLN (6.3+/-2.0 years, n = 84) or with both diseases (5.9+/-2.2 years, n = 62). Clinical signs included vomiting, diarrhea, weight loss, pleural and peritoneal effusions, and less commonly thromboembolic disease. Dogs with PLE generally had panhypoproteinemia and hypocholesterolemia; intestinal lesions included inflammatory bowel disease, dilated lymphatics, and lipogranulomatous lymphangitis. Dogs with PLN generally had hypoalbuminemia, proteinuria, hypercholesterolemia, and azotemia; renal lesions typically showed chronic glomerulonephritis/glomerulosclerosis, and less commonly endstage renal disease. Dogs with combined PLE/PLN had intermediate mean values (P < .001) for serum total protein, albumin, globulin, and cholesterol but had a higher mean urine protein:creatinine ratio than did PLN dogs (P < .05); intestinal and renal lesions in these dogs were similar to those in the other groups. Two dogs had incidental mild renal dysplasia. Pedigree analysis from 188 dogs demonstrated a common male ancestor, although the mode of inheritance is unknown. Both PLE and PLN are common diseases in this small breed population. The prognosis is poor. Compared with previously reported intestinal and renal diseases in dogs, a new, distinctive familial predisposition for both PLE and PLN has been recognized in the SCWT breed.

Spontaneous systemic hypertension in 24 cats.

Twenty-four cats with spontaneous systemic hypertension were retrospectively studied. Blood pressure (BP) was measured indirectly by the Doppler technique in 17 cats (mean systolic 219.4 +/- 43.2 mm Hg) and directly by femoral arterial puncture in 15 cats (mean systolic/diastolic 233.2 +/- 40.9/148.1 +/- 28.7 mm Hg). All cats had bilateral retinal hemorrhages and/or detachments. Twenty cats presented because of blindness. Other presenting signs included polyuria/polydipsia, weight loss, neurological signs, and/or epistaxis. Diagnostic tests were performed to determine the presence and the cause of any secondary organ damage. Common findings included retinal hemorrhages/detachments, low-grade systolic murmurs, cardiomegaly with left ventricular hypertrophy (LVH), small kidneys, mild azotemia, and urine specific gravity < or = 1.020. Only 3 cats had hyperthyroidism. One cat was transiently diabetic. Necropsies on 2 cats with neurological signs showed nephrosclerosis, arteriosclerosis, and multifocal cerebral hemorrhages. Twenty cats were treated with diuretics, beta-adrenergic antagonists, and/or an angiotensin converting enzyme (ACE) inhibitor. One cat was treated with methimazole only, and 1 was treated with insulin transiently. The median survival of the 24 cats was 18 months. Response to therapy did not appear to have an impact on survival time.

Macrohematuria and life-threatening anemia attributable to subepithelial vascular ectasia of the urinary bladder in a dog.

Hematuria leading to life-threatening anemia was evaluated in a 9-year-old male dog. At surgery, an abnormal vessel resembling an ulcerated varicose vein was found on the surface of the bladder mucosa. After removal of the lesion, hematuria ceased and had not recurred 22 months later.

Essential hypertension in a dog.

Severe hypertension was diagnosed in a dog that initially was referred for evaluation of visual deficits and retinal hemorrhage and eventually was donated for medical treatment of hypertension. Initial blood pressure measured by direct methods was markedly high (systolic, 275 mm of Hg; diastolic, 170 mm of Hg). Measures of renal function were within normal limits, with the exception of hypotonic urine. A test protocol was designed to exclude possible secondary causes of hypertension; negative results of such tests allowed the diagnosis of essential hypertension. The consistency of the hypertension and its response to medical control were studied for 5 years. Blood pressure while the dog was untreated during those years was 240 +/- 24 mm of Hg (systolic) and 146 +/- 14 mm of Hg (diastolic). Plasma renin activity was within normal limits, and the response of the renin-angiotensin system to varied salt intake was normal. The most effective medications used to lower blood pressure were propranolol and captopril, both of which were more effective than salt restriction alone. Five years after the diagnosis of hypertension, the dog was euthanatized because of chronic renal failure secondary to pyelonephritis. Hypertension was less severe as the condition progressed into chronic renal failure. Complete necropsy did not reveal an obvious cause of the hypertension, and histopathologic changes were limited to the cardiovascular system, eyes, and kidneys.

Renal dysfunction in dogs with pyometra.

Renal function and pathologic changes in 27 dogs with pyometra were studied. Evaluation included CBC; serum biochemical evaluation; urinalysis; urine and uterine bacteriologic culture; uterine morphologic features; and light, electron, and immunofluorescent microscopic evaluation of renal tissues. Measurements of 24-hour creatinine clearance, protein excretion, Na excretion, and urine volume were made in 12 dogs without azotemia. Of 27 dogs, 26% were azotemic and 89% had a urine sp gr less than 1.035. Glomerular filtration rate was reduced in 75% of 12 dogs without azotemia. None of these 12 dogs was proteinuric. Examination of renal biopsy specimens revealed a high prevalence of mild tubulointerstitial nephritis, but few specific glomerular lesions. Minimal immunofluorescence was detected within the mesangium in 18% of the dogs. Immunofluorescence was not associated with the interstitium or tubules. Urinary tract infection was detected in 22% of the dogs. Escherichia coli and Klebsiella were recovered from the uterus in 59 and 15% of the dogs, respectively. Low urine specific gravity values were obtained from dogs without azotemia and from dogs with uterine cultures considered negative for E coli and other gram-negative bacteria. The reduction in glomerular filtration rate was a functional abnormality not correlated with structural damage in the glomerulus.

Spontaneous systemic hypertension in dogs: five cases (1981-1983).

Spontaneous (not experimentally induced) systemic hypertension was detected in 5 male dogs that were examined because of apparent blindness caused by intraocular hemorrhage and/or retinal detachment. Secondary causes of hypertension, including renal, adrenal, and thyroid disease, were investigated. Four of the dogs had glomerulonephropathy, renal insufficiency, and proteinuria. Four dogs had compensatory cardiac hypertrophy. Hypertension in 4 of 5 dogs was associated with glomerulosclerosis with chronic renal insufficiency, bilateral adrenocortical hyperplasia, adrenocortical adenoma with renal amyloidosis, and immune-mediated glomerulonephritis with chronic renal insufficiency, respectively. The fifth dog was determined to have essential hypertension. The dogs were treated for their primary diseases. Sodium restriction alone was inadequate to reduce blood pressure; 4 of the dogs also required antihypertensive medications.

Systemic paecilomycosis in a dog.

Disseminated paecilomycosis was diagnosed in an adult dog without underlying immunosuppressive disease. During the 3-month illness (before euthanasia), the dog had ulcerative granulomatous inguinal lymphadenitis, fever, anorexia, dyspnea, generalized lymphadenopathy, retinochoroiditis, and seizures. Fungal organisms isolated from inguinal and prescapular lymph nodes before the dog was euthanatized were identified histologically. Paecilomyces variotii was isolated from the prescapular lymph node specimen. Paecilomyces variotii may be more pathogenic (once it has gained bodily entry) than previously thought.

Hypertension and renal function.

The presence of hypertension in domestic animals is poorly described. Values for hypertension were established in dogs using a direct blood pressure measurement. A protocol was devised to recognize and characterize primary (essential) and secondary hypertension. Essential hypertension was associated with marked elevations in blood pressure and can be shown to be a hereditary disease in dogs. Secondary hypertension is more common and most frequently associated with Cushing's disease and renal failure. Treatment to reduce blood pressure in both groups can be achieved using pharmacologic agents which are more effective than sodium restriction alone. Hypertension appears to be an underdiagnosed disease in dogs. The significance of chronic hypertension in dogs in terms of vascular pathology is not yet clear.

Essential hereditary hypertension in dogs: a new animal model.

The objective of this project is to characterize a genetically determined model of essential hypertension in dogs. A pair of unrelated dogs with essential hypertension were identified. Breeding of these dogs and back-cross matings have resulted in 24 offspring, approximately half of which have essential hypertension (systolic blood pressure 170 mmHg, diastolic 105 mmHg). Other offspring are either borderline hypertensive or normal. Blood pressure is measured in the trained, unanaesthetized state by direct arterial puncture. Offspring have normal plasma chemistries, electrolytes, glomerular filtration rate, plasma renin activity, aldosterone and catecholamines. These dogs appear to salt-sensitive compared with normal dogs. Further breeding studies will characterize this new model of hereditary essential hypertension.