Kidney Infection (Pyelonephritis)

Condition Overview

Pyelonephritis is a bacterial infection of the kidney, including the renal pelvis and ureter.

Symptoms

Acute pyelonephritis begins with fever, loss of appetite, vomiting, and pain in the lower back. A stiff-legged gait and hunched-up posture are characteristic. Some dogs exhibit signs of painful urination.

Chronic pyelonephritis is an insidious disease that may or may not be preceded by an acute pyelonephritis. Signs are loss of appetite, weight loss, and excessive urination and thirst. This disease smolders for months or years, eventually culminating in kidney failure. Early treatment of acute pyelonephritis may prevent this.

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Causes

Most cases are caused by an ascending bladder infection. There may be a predisposing blockage or congenital malformation of the urinary tract. Occasionally, the infection is blood-borne.

Diagnosis

Acute pyelonephritis: on microscopic examination, the urine contains white blood cells casts, which are plugs of cells expelled from kidney tubules. An IVP or renal ultrasound may show an enlarged kidney or dilated renal pelvis.

Treatment

Kidney infection is difficult to eliminate and relapse is common. Any underlying predisposing causes should be dealt with. Pyelonephritis is treated with antibiotics selected on the basis of bacterial sensitivity tests Antibiotics should be continued for 6 - 8 weeks. The urine should be re-cultured during treatment to be sure the antibiotic selected is still effective against the bacteria in question.

After treatment, it is important to re-culture the urine on 3 separate occasions at 6 - 8 week intervals before concluding that the dog is cured.

Prevention

Treatment at the earliest possible time after symptoms become apparent returns the best results for preventing the disease from progressing.

Support

Please contact your veterinarian with questions regarding this condition.