Diseases of the Urinary System
The infectious disease leptospirosis can cause chronic kidney failure, and although vaccination has reduced the incidence of the infection, kidney disease is still a frequent cause of serious illness in adult dogs. Acute kidney failure is equally serious; with prompt treatment the prospects of recovery are reasonably good, but with age chronic disease may occur in damaged kidney tissue. Acute kidney failure is usually characterized by a sudden rise in temperature, accompanied by severe, often continuous vomiting. Thirst is usually increased, with profuse or no urination. The latter symptom is serious and indicates that the kidney has stopped functioning.
Although chronic kidney failure tends to be progressive, a large proportion of the kidney tissue must be out of action before signs of the disease develop. Once kidney function is inadequate, the dog is unable to conserve water by concentrating its urine, and large amounts of very dilute urine are passed. The dog tries to avoid dehydration by drinking more fluid, resulting in a cycle of increased thirst (polydypsia) and increased urination (polyuria).
The kidney is the route whereby the end-products of protein digestion are excreted and with reduced function these accumulate in the circulation and result in a form of self-intoxication known as uremia. Other complications include the loss of protein, minerals, and vitamins via damaged kidney tissue. Once diagnostic tests have established the presence and extent of kidney failure (Chronic Nephritis), treatment is directed towards making the most efficient use of the remaining tissue. Part of this involves protein restriction, feeding only small amounts of those proteins most useful to the dog. Properly compensated cases may live reasonably normal lives for quite long periods.
Some dogs with advanced kidney failure lose so much of essential minerals that their skeletons become seriously demineralized. This is especially apparent in the jaw, where the bones eventually consist of little more than fibrous material and become easily pliable. It is a serious problem needing expert attention.
Retention of urine sometimes occurs in dogs prevented from reasonably frequent opportunities to pass urine. It can also occur in overprotective bitches with newly born litters and may lead to retention cystitis. It may be necessary to remove a puppy from the whelping box so as to coax the bitch out to relieve herself. Complete blockage or severe pain on urination (dysuria) can lead to serious urinary retention. The former occurs chiefly in males with urethral calculi, although bitches can also suffer.
External parasites bring a series of minor problems. Dogs with a heavy infestation scratch for long periods and bite at all accessible parts of their bodies. On short-haired dogs, fleas can often be seen as they scuttle and jump. As fleas live on blood, a heavy infestation can lead to anemia in puppies, though they are usually affected by other signs of ill-health.
Flea droppings are the usual evidence of infestation. Flea dirt, which is really dried blood, looks like specs of soot and is more easily seen in light-coloured dogs. Infestations reach their heights at the end of a hot, humid summer, and a so-called plague of parasites resistant to control measures are merely following their usual pattern. Some dogs are particularly sensitive to the flea droppings and show allergic reaction to the excreta of only a small number.
There is a common belief that dog fleas do not bite humans. Dogs may be infested with dog, cat, human or rabbit fleas, and while dog fleas prefer the company of dogs, they are not averse to humans. Some owners regard flea infestation as some kind of social stigma, more alarming than serious canine diseases. The best pedigree dog attracts fleas, the only crime is with the owner who does nothing to control them.
Flea control is complicated by the fact that fleas lay their eggs off the host animal; larvae can emerge within a few days in warm weather and the whole life cycle may take only a week or two. A further complication is that the flea is needed for an intermediate stage in the development of canine tapeworm, and proper control must include treatment against internal parasites. Fleas can be controlled with flea collars used as directed. and combined with a high standard of grooming and hygiene. One easily forgotten aspect of flea control is keeping the dog’s bedding and all carpets scrupulously clean.