Pyelonephritis is an inflammatory disease affecting the kidneys of dogs. Bacterial infections originating in the urinary tract may spread upwards and infect the bladder and the kidneys. The same factors that increase the risk of bacterial cystitis may predispose a dog to developing pyelonephritis as well. Blockages to the normal flow of urine either due to structural abnormalities or kidney stones may lead to the development of pyelonephritis. For example, dogs born with ectopic ureters, when not corrected surgically, usually develop this condition. Others that carry a higher risk are very old dogs, as well as very young ones, and those which are immunocompromised. Some dogs which are unable to regulate the concentration of urine are also prone to developing pyelonephritis. In some instances, the underlying cause of this inflammatory condition cannot be determined.
The usual symptoms of pyelonephritis are fever accompanied by pain in the location of the kidneys, increased thirst as well as urination, loss of appetite and vomiting, and malaise. Kidney failure may occur suddenly in some dogs, while others have long-term pyelonephritis. They may not display any symptoms other than increased thirst and excessive urination. In such cases, pyelonephritis often goes undiagnosed until symptoms of kidney failure begin to appear. The inflammatory condition may be diagnosed from the result of laboratory tests of blood and urine, but ultrasound scans or x-rays with a contrast dye may be needed to confirm it.
Antibiotic therapy to eliminate the underlying infection is the main treatment for pyelonephritis. The drug regimen usually extends from 4 weeks to 6 weeks, and the drugs have to be used in high doses to eliminate the infection completely. In severe cases, the antibiotics and fluid supplementation may be administered intravenously. Even after the treatment period, urine tests may have to be conducted every month to ensure that the infection has resolved completely. Recurrent infections of the urinary system are common in dogs which have developed pyelonephritis once. However, since this inflammatory condition can have potentially fatal outcome, it is very important to avoid recurrence. In some cases, the infected kidney is surgically removed to save the other kidney from the infection, as one healthy kidney is sufficient for the dog to lead a normal life. If kidney failure has occurred in both the kidneys, the prognosis is poor, and only supportive care to keep the dog comfortable is offered.
Some dogs may have only short-term pyelonephritis. Unless severe damage to the kidney has occurred already, dogs with this type of disease usually recover completely.
This is also a type of kidney inflammation usually caused by infections. It may appear suddenly when infectious diseases such as leptospirosis occur in dogs. Leptospirosis is caused by spirochete bacteria such as Leptospira interrogans. The infection is usually acquired from infected rodents and other small mammals. Rats, raccoons and opossums are the usual sources of infection for dogs in rural and suburban areas. The infection can occur in urban areas too. Leptospirosis can be treated with antibiotic therapy, but if the infection has resulted in kidney failure, additional treatments, including fluid supplementation, may necessary. Since this bacterial disease can affect humans too, owners of dogs with leptospirosis should seek medical attention, even though it is rarely transmitted to humans from dogs.
Capillaria plica Infection
A small thread-like worm called Capillaria plica may infect the urinary bladder of dogs, but it is not very common in pet dogs. These worms can affect the kidneys and ureters too, even though it is rarer. The Capillaria plica worms are thin and yellowish in color, measuring 0.5 inches to 2.5 inches in length. The infestation is common in several wild animals, but the usual source of infection in pet dogs is earthworms which may harbor the larvae of the worm. Most dogs acquiring these worms by eating infected earthworms may remain asymptomatic, but in some cases they may have excessive urination. They may lose control over urination, and may begin to void in unusual places. The eggs of the parasite are excreted in the urine of the infected dogs. Their presence in the urine may help the veterinarian diagnose the disease. The infestation is treated with general antiparasitic drugs as any specific treatment against this parasite is not available.