Introduction
- Gradual, progressive loss of renal tissue → inability of kidney to perform normal functions of waste excretion, fluid/electrolyte/acid-base homeostasis and endocrine function.
- Cause : in younger animals, most likely either congenital or familial.
- In older animals usually acquired.
- Signs : initially polyuria/polydipsia → uremia (vomiting, anorexia, oral ulceration) if >75% of renal tissue not functioning.
- Treatment : IV fluid therapy, H-2 blockers, nutritional support, +/- phosphate binding agents, +/- erythropoeitin.
- Prognosis : early detection of chronic renal failure and management of the disease will ameliorate the signs of uremia and may, in some cases, slow down the progression of disease.
Diagnosis
Clinical signs
- Weight loss.
- Dehydration.
- Oral ulceration (especially buccal mucosae adjacent to teeth) and stomatitis.
- Small kidneys on abdominal palpation.
- Pale mucous membranes.
- Hypertension (ophthalmologic fundoscopic examination).
- Hyperemic mucous membranes (sign of uremia).
- Tongue-tip necrosis.
- Osteodystrophy/rubber jaw. 'Rubber jaw' is mainly seen in young dogs with familial renal disease.
- Muffled heart sounds.
Diagnosis
Differential diagnosis
Acute renal failure (ARF)
- ARF
: normal to large kidneys, no history of polyuria/polydipsia.
- Prerenal uremia (caused by diseases that reduce perfusion of the kidneys and reduce GFR).
- Post-renal uremia (urinary tract obstruction, urinary tract rupture).
Sequelae
Prognosis
- Poor:
- If renal disease is far advanced and underlying disease cannot be treated.
- If symptoms persist and animal remains severely uremic, despite adequate rehydration (intensive therapy for 3-7 days).
- Guarded:
- If detected at a very early stage and appropriate therapy is started.
- If level of uremia and symptoms decrease after appropriate fluid therapy.
- If underlying renal disease can be treated, although some permanent damage has already been done, the disease may progress slowly.
- Some animals may remain compensated for a long period on maintenance therapy.
Expected response to treatment
- Improvement in clinical signs.
- Decreased uremia.
- Decreased anemia.
- Decreased serum inorganic phosphate level.
Reasons for treatment failure
- Renal failure is too severe.
- Underlying disease process progresses despite therapy, which is typical.
Sources
Publications
Refereed papers
- Finco D R et al(1999) Progression of chronic renal disease in the dog. JVIM 13 (6), 516.
- Brown S A, Finco D R & Brown C A (1998) Is there a role for dietary polyunsaturated fatty acid supplementation in canine renal disease? J Nutr 128 (12 Suppl), 2765S-2767S.
- Devaux C, Polzin D J & Osbourne C A (1996) What role does dietary protein restriction play in the management of chronic renal failure in dogs? Vet Clin North Am 26 (6), 1247-1267.
- Macdougall D F, Cook T, Steward A P & Cattell V (1986) Canine chronic renal disease - prevalence and types of glomerulonephritis in the dog. Kidney Int 29 (6), 1144-1151.
