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Biomedical subjects

D J Polzin

Publications and source records attributed to D J Polzin.

At least 19 recordsLinked to original sources

Dietary management of feline chronic renal failure: where are we now? In what direction are we headed?

Dietary modification is of primary importance in managing cats with chronic renal failure. Diets designed for cats with chronic renal failure are typically formulated to be pH neutral and contain reduced quantities of protein, phosphorus and sodium and an increased quantity of potassium. These changes in diet formulation are designed to ameliorate clinical signs of renal failure by adapting dietary intakes to meet the limited ability of failing kidneys to adapt to the normal range of dietary intakes. Important recent clinical trials support the therapeutic value of dietary therapy in cats with chronic renal failure.

Acidosis↗

Analysis of 77,000 canine uroliths. Perspectives from the Minnesota Urolith Center.

Of the hundreds of minerals that are found in the earth, most canine uroliths are comprised of only six types: (1) magnesium ammonium phosphate, (2) calcium oxalate, (3) calcium phosphates, (4) ammonium urate and other salts or uric acid, (5) cystine, or (6) silica. Each type has characteristics that allow its identification. During the past two decades, the prevalence of calcium oxalate canine uroliths has dramatically increased, while struvite has decreased. The most effective treatment and prevention protocols are based on knowledge of the primary mineral type comprising the urolith.

Age Distribution↗

Medical dissolution and prevention of canine struvite urolithiasis. Twenty years of experience.

Two types of canine struvite uroliths have been recognized: infection-induced struvite is the most common type; sterile struvite is uncommonly recognized. Infection-induced struvite is most commonly associated with urease-producing staphylococcal UTI. For dogs that qualify, medical dissolution is an effective method of treatment. Medical dissolution protocols encompass: (1) eradication or control of UTI; (2) use of calculolytic diets; and (3) administration of urease inhibitors to patients with persistent UTI caused by urease-producing microbes.

Animals↗

Canine and feline nephrolithiasis. Epidemiology, detection, and management.

Calcium oxalate (39%) and struvite (33%) were the predominant mineral types in canine nephroliths submitted to the Minnesota Urolith Center. Urate salts (12%) and calcium phosphate (2%) occurred less frequently. Provided they are not causing obstruction, struvite nephroliths may be dissolved with medical protocols. Although there are no dissolution protocols for nephroliths containing calcium, risk-benefit ratios should be considered before proceeding with surgery.

Animals↗

Canine retrograde urohydropropulsion. Lessons from 25 years of experience.

Uroliths are commonly voided into the urethra where they often lodge adjacent to the os penis in male dogs. Urethral patency can, with few exceptions, be restored by flushing uroliths back into the bladder lumen by retrograde urohydropropulsion. To be consistently successful, one must be familiar with the concepts of the procedure and each step of the technique.

Animals↗

Clinical disorders of potassium homeostasis. Hyperkalemia and hypokalemia.

Potassium plays an important role in cell metabolism and membrane excitability. Disorders of potassium balance can have profound clinical effects, particularly on the cardiovascular and neuromuscular systems. Chronic hyperkalemia invariably results from impaired renal potassium excretion. Hyperkalemia can be a potentially life-threatening disturbance requiring emergency intervention. Treatment is usually directed at correcting the defect in potassium excretion. Hypokalemia has become closely linked with in cats. Clinical signs include muscle weakness and renal dysfunction, which usually respond well to oral potassium supplementation.

Animals↗

Effects of sample handling on total carbon dioxide concentrations in canine and feline serum and blood.

OBJECTIVE: To determine whether underfilling blood collection tubes leads to in vitro reduction in serum measured total CO2 concentration ([TCO2]m) in canine and feline blood samples sufficient to create the impression of metabolic acidosis (pseudometabolic acidosis) or high anion gap. SAMPLE POPULATION: Blood samples from healthy client-owned animals (16 dogs, 17 cats). PROCEDURE: Venous blood samples were collected in random order for determination of serum [TCO2] and blood gas tensions. Blood gas analysis was performed on iced, capped blood samples. In dogs, serum [TCO2] was measured in 1-, 3-, and 10-ml samples in 10-ml type-B tubes and in a 3-ml sample in 3-ml type-A tubes. In cats, serum [TCO2] was determined in 1-, 2-, and 3-ml samples in 3-ml type-A tubes and in a 3-ml sample in 10-ml type-B tubes. RESULTS: For dogs, serum [TCO2] in full-tube, 10-ml samples was a mean +/- SD, 2.0 +/- 1.1 mmol/L greater than that in 3-ml samples and 3.7 +/- 1.3 mmol/L greater than the value in 1-ml samples; both differences were significant at P < 0.0001. The serum [TCO2] in full 3-ml samples was lower by 0.4 +/- 0.6 mmol/L than the value in full-tube 10-ml samples (P = 0.019). For cats, serum [TCO2] in full-tube, 3-ml samples was 0.5 +/- 0.6 mmol/L greater than that in 2-ml samples (P = 0.004) and was 1.5 +/- 0.8 mmol/L greater than the value in 1-ml samples (P < 0.0001). Serum [TCO2] in 3-ml samples of feline blood in 10-ml tubes was 0.8 +/- 0.8 mmol/L lower than that in samples from full 3-ml tubes (P = 0.0007). In dogs and cats, [TCO2] in fully filled collection tubes was approximately 6 mmol/L higher when calculated from blood gas analysis data than when chemically determined in serum. CONCLUSIONS AND CLINICAL RELEVANCE: Underfilling blood collection tubes results in a false decrease in serum [TCO2], which can contribute in part to descrepancies between blood gas and chemical analyses as estimates of plasma bicarbonate concentration. This, and other in vitro effects of sample handling and collection, may result in a false assessment of metabolic acidosis in dogs and cats.

Acidosis↗

Medical management of feline urethral obstruction.

A step-by-step priority of procedures is recommended when attempting to restore urethral patency in an obstructed male cat. In order of priority they are: (1) massage of the distal urethra, (2) attempts to induce voiding by gentle palpation of the urinary bladder, (3) cystocentesis, (4) retrograde urethral flushing, (5) combinations of 1 through 4, (6) diagnostic radiology to determine if the cause of urethral obstruction is intraluminal, mural or extramural, and if absolutely necessary, (7) surgical procedures.

Animals↗

Management of postrenal azotemia.

Postrenal azotemia is a potentially life-threatening consequence of urinary obstruction Its most serious consequences include fluid volume deficits, hyperkalemia, and metabolic acidosis. Immediate therapy should be directed at restoring urine flow, correcting extracellular fluid volume deficits, minimizing the cardiac toxicity of hyperkalemia, and ameliorating the cardiovascular effects of metabolic acidosis. Most patients respond quickly and completely to such therapeutic intervention.

Acidosis↗

Feline perineal urethrostomy: a potential cause of feline lower urinary tract disease.

Perineal urethrostomies are associated with complications that may mimic primary causes of feline lower urinary tract disorders. Though postoperative urethral strictures may be minimized by proficiency with an effective surgical technique, removal of the distal urethra may result in bacterial urinary tract infections in 25% to 30% of patients after surgery. Urinary tract infections caused by urease-producing microbes may induce struvite urolith formation. Thus the prophylactic benefits of minimizing recurrent urethral obstruction by urethrostomy must be weighed against a long-term predisposition to recurrent bacterial urinary tract infection and urolith formation.

Animals↗

Medical management of iatrogenic rents in the wall of the feline urinary bladder.

Surgical closure may not be necessary to successfully manage all patients with ruptured urinary bladders. If the margins of the walls of tears in the bladder wall are not devitalized, and if they remain in close apposition via maintenance of the bladder lumen in a nondistended state for an appropriate period, these conditions may simulate those created by use of surgical sutures. This is not advocating an all-or-none choice. Because the clinical status of patients with ruptured urinary bladders can range from that characterized by only hematuria and dysuria to life-threatening postrenal uremia, a range of surgical and medical options should be considered.

Animals↗

What role does dietary protein restriction play in the management of chronic renal failure in dogs?

Dietary protein restriction has been the mainstay of conservative medical management of canine renal failure for many years. Although dietary protein restriction minimizes many signs of uremia, its potential benefits to the progression of renal failure are now being questioned. Two case scenarios of different degrees of renal failure are described; guidelines for dietary protein restriction are based on currently available scientific knowledge.

Animals↗

Diet therapy guidelines for cats with chronic renal failure.

Dietary modification is an important component of conservative medical management of renal failure in cats. Dietary factors have been implicated or hypothesized to promote clinical signs of uremia and progressive renal injury. This article presents guidelines for selecting and formulating diets for cats with chronic renal failure.

Acid-Base Equilibrium↗

Hypertension and renal disease.

Systemic hypertension is commonly associated with chronic renal failure in dogs and cats. Consequences of systemic hypertension are manifested by pathologic changes involving the eyes, heart, central nervous system, and/or kidneys. These changes may be prevented or reversed by diagnosing and treating systemic hypertension. Therefore, blood pressure determination and ophthalmic examination should be performed routinely in animals with chronic renal failure. Therapy for systemic hypertension associated with chronic renal failure should be initiated cautiously with the goal being to lower arterial pressure below values considered to be hypertensive. Therapy may involve nonpharmacologic strategies and/or hypertensive drugs. This article discusses pathophysiologic mechanisms, consequences, diagnosis, and treatment of systemic hypertension associated with chronic renal failure in dogs and cats.

Animals↗

Diagnosis and long-term management of protein-losing glomerulonephropathy. A 5-year case-based approach.

Protein-losing glomerulonephropathy can be a challenging disease for veterinarians to manage. This case-based article illustrates long-term management of protein-losing glomerulonephritis in a dog. Prolonged survival of this patient was attributed to early diagnosis and carefully planned therapeutic intervention consisting of dietary protein reduction and modulation of blood pressure with angiotensin converting enzyme inhibition.

Animals↗

Percutaneous needle biopsy of the kidney. Indications, applications, technique, and complications.

During the past three decades, percutaneous renal biopsy has evolved as a valuable method of clinical evaluation of patients with various forms of glomerular proteinuria and primary renal failure. The advent of automated core biopsy needles and ultrasound guidance has substantially improved the safety of needle biopsy techniques and almost eliminated the need for surgical wedge biopsy.

Animals↗