Jeanne A. Barsanti

Beneficial effects of chronic administration of dietary ω-3 polyunsaturated fatty acids in dogs with renal insufficiency

Dietary supplementation with polyunsaturated fatty acids (PUFA) alters the course of experimental renal disease in rats. However, chronic renal disease in other laboratory animals and in human beings frequently responds differently to experimental manipulations. We investigated the effects of variations in dietary PUFA composition on the chronic course of induced renal disease in dogs. Two months after 15/16 nephrectomy, dogs were randomly divided into three groups of seven animals each. For the next 20 months, each group of dogs was fed a low-fat basal diet supplemented with one of three sources of lipid to achieve a final concentration of 15% added fat. Fat sources provided omega-3 PUFA (menhaden fish oil, group FO), omega-6 PUFA (safflower oil, group SO), or saturated fatty acids (beef tallow, group BT). Throughout the dietary trial, the magnitude of proteinuria and the plasma concentrations of creatinine, cholesterol, and triglyceride were lower in group FO. The mean overall glomerular filtration rate was 0.89+/-0.18 ml/min per kilogram of body weight in group SO, a value that was significantly less (p < 0.05) than the corresponding values for groups BT and FO (1.21+/-0.18 and 1.43+/-0.20 ml/min/kg, respectively). Renal interstitial fibrosis also was significantly elevated in group SO. The extents of mesangial matrix expansion, glomerulosclerosis, and renal interstitial cellular infiltrate were similar in groups BT and SO, but lower (p < 0.05) in group FO. We conclude that supplementation with omega-6 PUFA enhanced renal injury; supplementation with omega-3 PUFA was renoprotective.

Effects of enalapril versus placebo as a treatment for canine idiopathic glomerulonephritis.

A blinded, multicenter, prospective clinical trial assessed the effects of enalapril (EN) versus standard care in dogs with naturally occurring, idiopathic glomerulonephritis (GN). Twenty-nine adult dogs with membranous (n = 16) and membranoproliferative (n = 13) GN were studied. Dogs were randomly assigned to receive either EN (0.5 mg/kg PO q12-24h; n = 16) or placebo (n = 14) for 6 months (1 dog was treated first with the placebo and then with EN). All dogs were treated with low-dose aspirin (0.5-5 mg/kg PO q12-24h) and fed a commercial diet. At baseline, serum creatinine (SrCr), systolic blood pressure (SBP), and glomerular histologic grade were not different between groups, but the urine protein/creatinine ratio (UP/C) was greater in the EN group compared with the placebo group (8.7 +/- 4.4 versus 4.7 +/- 2.3). After 6 months of treatment, the change in UP/C from baseline was significantly different between groups (EN = -4.2 +/- 1.4 versus 1.9 +/- 0.9 in the placebo group). When data were adjusted for changes in SrCr (SrCr X UP/C) a similar significant reduction was noted ( 2.2 +/- 15.2 versus 8.4 +/- 10.1). The change in SBP after 6 months of treatment also was significantly different between groups (EN = -12.8 +/- 27.3 versus 5.9 +/- 21.5 mm Hg in the placebo group). Response to treatment was categorized as improvement (assigned a value of 2), no progression (assigned a value of 1), and progression (assigned a value of 0). Response was significantly better in the EN group (1.4 +/- 0.8) compared with the placebo group (0.3 +/- 0.5). These results suggest that EN treatment is beneficial in dogs with naturally occurring idiopathic GN.

Canine Prostatic Diseases

Prostatic diseases such as benign hyperplasia, prostatic cysts, acute bacterial prostatitis, chronic bacterial prostatitis, prostatic abscessation, and prostatic neoplasia are discussed. Also discussed are diagnostic techniques such as prostatic palpation and massage, evaluation of semen and urethral discharge, and radiography.

Pathophysiology and management of progressive renaldisease

Recently, the hypothesis that all renal diseases are inherently progressive and self-perpetuating has focused attention on adaptive changes in renal structure and function that occur whenever renal function is reduced. These glomerular adaptations to renal disease include increases in filtration rate, capillary pressure and size, and are referred to as glomerular hyperfiltration, glomerular hypertension and glomerular hypertrophy, respectively. Extrarenal changes, such as dietary phosphate excess, systemic hypertension, hyperlipidaemia, acidosis and hyperparathyroidism occur in animals with renal disease and may be contributors to progression of renal disease. Emphasis in the management of companion animals with renal disease has shifted to identifying, understanding and controlling those processes that play a role in the progression from early to end-stage renal failure. Advances made by veterinary nephrologists in the past 15 years permit resolution of old controversies, formulation of new hypotheses and discussion of unresolved issues about the nature of progressive renal disease in dogs and cats.

Intravesical ureterocele with concurrent renal dysfunction in a dog: a case report and proposed classification system.

A unilateral intravesical ureterocele was diagnosed by ultrasonography in a 5-year-old female Pekingese that was referred for evaluation of increased hepatic enzymes. Ureteroceles are cystic dilatations of the submucosal portion of the distal ureter. They are frequently reported in humans but are uncommonly reported in dogs. This report describes surgical resection of the ureterocele and reduction of ipsilateral hydroureter in a dog that also had bilateral renal dysfunction and suffered progressive mild azotemia postoperatively. This report demonstrates that canine ureteroceles can occur concurrently with bilateral renal dysfunction and offers a classification system designed to encourage thorough urinary tract evaluation for determining prognosis.

Interventional nutrition for renal disease

Interventional nutrition plays a central role in the management of renal diseases in veterinary medicine. Most of the clinically observable abnormalities produced by the disruption of renal function are influenced by dietary intake of calories, phosphorus, sodium, potassium, protein, or acid load. Further, the kidney is susceptible to self-perpetuating injury, an inherent property of this organ, and the extent of this injury can be modified by adjustments in dietary intake of phosphorus and polyunsaturated fatty acids. The response of each animal with renal insufficiency to the disease and to nutritional intervention varies dramatically, and individualized therapy is required; the only constant nutritional characteristic of renal insufficiency is inappetance and loss of body weight. Successful interventional nutrition must take all of these principles into account.

Detrusor-sphincter dyssynergia.

Detrusor-sphincter dyssynergia refers to failure of the urethral sphincter to relax during detrusor contraction. The cause is a central nervous system lesion located between the brain stem micturition center and the sacral spinal cord. This is an extremely rare condition in cats. It may be confused with a failure of urethral relaxation due to local urethral causes such as inflammation or edema. This article reviews detrusor-sphincter dyssynergia to allow the reader to distinguish this rare condition from more common conditions that prevent bladder emptying.

Does modifying dietary lipids influence the progression of renal failure

Recent studies have identified important effects of dietary fatty acid composition in animals with chronic renal disease, particularly in dogs. The theoretic basis for these effects provides a rationale for the use of diets enriched with omega-3 (but not omega-6) polyunsaturated fatty acids. A therapeutic trial with a diet enriched with omega-3 polyunsaturated fatty acids should be considered as a maneuver designed to slow the rate of progression of chronic renal disease in dogs.

Laboratory Findings in Urinary Tract Infections

Urinary tract infection should be considered in a differential diagnosis on the basis of history, physical examination, and urinalysis. To definitively diagnose urinary tract infection, significant bacteriuria must be found by quantitative bacterial culture. The absolute definition of significant numbers of bacteria varies with the method of collection because of the possibility of contamination with the normal bacterial flora of the lower genitourinary tract. Numbers of bacteria are also influenced by the manner in which urine samples are handled, by urine concentration, and by frequency of voiding. Quantitative and qualitative urine cultures should also be used to monitor the efficacy of treatment in chronic and recurrent infections. Cultures should be repeated three to five days after the termination of antimicrobial therapy to ensure elimination of infection. If feasible, cultures should also be repeated two to three days after begining therapy to ensure the antimicrobial agent selected is effective. Remission of clinical signs should not be used to judge efficacy of treatment, especially in chronic or recurrent infections, since infections can persist without causing clinical signs, particularly if bacterial numbers are temporarily reduced. Determination of the minimum inhibitory concentration of an antibiotic for a particular bacteria is preferable to Kirby-Bauer antibiotic sensitivity testing in urinary tract infection because of the difference in serum and urine concentrations of most antibiotics. Bacteria are not sensitive or resistant to an antibiotic but rather to a concentration of that antibiotic. If Kirby-Bauer sensitivity testing is used for urinary tract infection, results must be interpreted carefully since drugs reported as ineffective may be effective in vivo.

Lesions in dogs following renal transplantation and immunosuppression.

Renal allografts were transplanted into 20 dogs (12 beagles, eight mongrels) following a prescribed protocol for pre-transplantation blood transfusions and kidney exchange. Immunosuppressive therapy (azathioprine and prednisone) was modified as needed for each dog. Seven of the beagle dogs survived for 1 year and were then euthanized; all other dogs died or were euthanized prior to 1 year post-transplantation. Graft rejection and renal failure were the greatest causes of mortality. Renal lesions which contributed to the death of some animals included renal vein thrombosis, nephrosis, and pyelonephritis. Inflammation of the lower respiratory tract (bronchitis, pneumonia, and pleuritis) was a contributory cause of death in some dogs. Cystitis and ureteritis occurred in almost half of the dogs. Prostatitis was seen in six of the 16 male dogs. Adrenal cortical atrophy, parathyroid gland hyperplasia, and bone marrow hypocellularity were seen in a majority of the dogs which survived 1 year.