Cats - Liver, Pancreas and Kidney/Urinary Problems

 

Cholangiohepatitis

Cholangitis and cholangiohepatitis are inflammatory and/or infectious diseases affecting the liver and bile ducts. E coli infection can ascend the bile ducts into the liver to cause an infectious cholangiohepatitis, chronic or lymphocytic cholangiohepatitis causes a sterile inflammatory process that  may be caused by an abnormal immune response. Cirrhosis is the end-stage of chronic liver disease, resulting in terminal liver failure. It is the least common form because many cats die before the chronic form progresses to cirrhosis. The clinical signs of these disorders are similar. Jaundice, lethargy, inappetance, and vomiting can occur. Fever is common in the acute form. Cats with the chronic form have recurrent episodes of clinical signs interspersed with weeks or months of being apparently healthy. 

Blood tests to assess liver function are an important aid to diagnosis. Liver biopsy is diagnostic but the procedure does carry a degree of risk. Ultrasound can non-invasively indicate liver abnormalities but is not specific for acute or chronic cholangiohepatitis, and the study may appear normal. Ultrasound is however very useful in determining the presence of biliary obstruction. X-rays may show an enlarged liver, or in cases or cirrhosis and shrunken and fibrous liver.

Therapy with intravenous fluids and nutritional support is important in stabilising these cases. Antibiotics are required in cases of acute infectious hepatitis, corticosteroids such as prednisolone are helpful in acute cases and form the mainstay of treatment for chronic cases. Symptomatic therapy for vomiting with antacids will be used if necessary.

The prognosis varies with the form of the disease. Most cats with the acute form recover clinically in a few days. The chronic form requires continuous therapy in many cats. Those that respond well have a good prognosis, but those that progress to cirrhosis have a poor prognosis.

Chronic Interstitial Nephritis

The most common kidney disease in cats is chronic interstitial nephritis. It may be the end result of any chronic renal disease but in most cases the cause is unknown. Because most affected cats are geriatric, it is likely, in part, to be the result of the normal aging process. The most common clinical signs are weight loss, inappetance, lethargy, excessive thirst and urination. Vomiting may also occur. Cats with this disease become dehydrated and emaciated if not treated.

Older cats that are inappetance, lethargy, and have excessive thirst and urination along with significant weight loss should be suspected of having chronic renal disease. 

Blood tests will indicate kidney failure, urine may be dilute and a mild anaemia can develop. The cat's kidneys are usually smaller than normal and this may be checked using ultrasound or X-rays.

Cats which develop renal failure frequently also have raised blood pressure. Monitoring this is important since it is thought that high blood pressure and kidney failure may aggravate each other. Drugs to reduce blood pressure may be required in some cases.

Treatment centres around correcting the dehydration and restoration of kidney function. This is best achieved by administering intravenous fluids and proper nutritional support. Electrolyte disturbances in the bloodstream can be corrected via supplementation through the intravenous fluids. Vitamin B administration phosphate binding agents can also be of use. Antacids to treat vomiting, low protein diet, and anabolic steroids, may also be employed in the treatment of these cases.

It is not possible to make a prognosis on the outcome of a case of chronic interstitial nephritis at the beginning of therapy. If therapy for 2-3 days fails to achieve significant improvement, a guarded prognosis is likely. If, however, good response to treatment occurs and proper long-term maintenance therapy is provided, many cats will live 1 to 3 years while maintaining a good quality of life.

Diabetes Mellitus

Diabetes is a disease normally resulting from destruction of the insulin producing cells of the pancreas. Secondary diabetes mellitus is due to an underlying condition (often obesity) that causes insulin resistance. Another type develops due to chronic pancreatitis and is probably more common than it is recognized. The clinical signs are increased thirst and urination, excessive appetite, and weight loss. These are brought about by persistently high blood glucose levels. 

Diagnosis can be confirmed by measuring urine and blood glucose levels.

Diabetes can produce a condition called ketoacidosis, which also produces the clinical signs of anorexia, vomiting, dehydration, and lethargy. This situation is an emergency and needs to be treated promptly. It develops as a result of untreated or poorly controlled diabetes. Ketonuria can be caused by starvation or anorexia. Pancreatic disorders can complicate, and sometimes be the cause of diabetes mellitus.

A blood test for fructosamine can be used to assess the average glucose level for  the last 2 weeks. 

Treatment involves administering regular insulin injections and monitoring of blood and/or urine glucose levels. For animals that develop ketoacidosis intravenous fluid and electrolyte supplementation is required. High fibre diets will also help.

Treating a diabetic animal requires a major commitment from the owner.

The prognosis for cats with diabetic ketoacidosis is guarded until they have responded to treatment. However, once the cat is stabilized or if the cat is diagnosed as having uncomplicated diabetes, the prognosis is good. The likelihood of achieving good control varies with the commitment of the owner and several undefined variables with the cat. It is not unusual for owners to elect euthanasia when recurrent regulation problems occur.

Exocrine Pancreatic Insufficiency

Destruction of pancreatic cells usually occurs secondary to chronic pancreatitis. Another cause of exocrine pancreatic insufficiency may be pancreatic cancer. This disorder produces abnormal intestinal function and impaired absorption of sugars, proteins, and fatty acids. Affected cats typically have soft, pale, voluminous stools with weight loss. Greasy material may collect on the haircoat, especially in the region of the perineum. In cases with pancreatic damage diabetes mellitus may occur concurrently.

The diagnosis is most accurately achieved by the feline trypsin-like immunoreactivity test. We can also measure the fecal proteolytic activity which will identify most affected cats. However, it will give false positive or equivocal results in some cats with small intestinal disease. 

Hyperthyroidism and inflammatory bowel disease cause clinical signs similar to EPI. These conditions are much more common, so they should be ruled out before testing for EPI. 

Treatment involves administering enzyme replacers with each meal. High protein, low fat diets are ideal. Antibiotics may be required to help restore normal bacterial flora in the intestine.

The prognosis generally is good.

Feline Lower Urinary Tract Disease

The term "feline lower urinary tract disease" is used to describe a disorder presenting with difficulty passing urine and blood in the urine that is not caused by bacterial infection, crystals, or bladder tumours. Affected cats often urinate frequently in small amounts and frequently in inappropriate locations, blood is usually present in the urine. Male cats frequently lick the penis. Crystals may be present in the urine. If a large amount of mucoid material combines with this crystalline material, a plug forms that may lodge in the tapering distal urethra, resulting in urethral obstruction. Obstructed cats will die if urine flow is not reestablished quickly. This disease does not appear to be contagious and affects male and female cats, although female cats are extremely unlikely to experience a urethral obstruction. 

This disorder causes most cats to empty their bladders when only a small amount of urine is present. Upon presentation, most cats have an empty bladder. Cats with an obstructed urinary tract present with pain in the abdomen and a large, firm urinary bladder. These cats become dehydrated and very depressed with increasing duration.

Treatment involves ensuring there is a patent urinary tract, if obstruction is present then catheterisation and bladder irrigation will be required. If any secondary kidney damage has occurred then intravenous fluids may be necessary. For non obstructed cases anti-spasmodics and anti-inflammatories such as prednisolone, megestrol acetate and amitriptyline are useful to help re-establish urine flow. If concurrent cystitis is suspected then antibiotics should be given. Obesity can contribute to this disease so weight loss is recommended in overweight animals.

Analysis of the urine is important to check for bacterial infection and crystals. If crystals are presents the diet may have to be altered to eliminate their excretion in the urine.

Inappropriate urination is the most common behavior problem of cats and it can be confused with the loss of litterbox training. 

If this problem does not respond to treatment then further investigation should be carried out to rule out other urinary problems. Additional tests include X-rays and ultrasound and bacterial culture of the urine.

Prognosis depends on the underlying cause, the prognosis for cats without urinary obstruction is good, although the problem may be recurrent. Those cases that have urethral obstruction and have a more guarded prognosis. Recovery is likely if urine flow occurs normally and kidney function is unimpaired.

Glomerulonephritis

Glomerulonephritis is an immune-mediated kidney disease. The clinically significant causes of this are diseases due to the feline leukemia virus, the feline immunodeficiency virus, or the feline infectious peritonitis virus; chronic progressive polyarthritis; lupus; pancreatitis; and incompatible insulin (usually of human origin). Affected cats, which are usually young adult males, have two clinical forms of the disease. The first is the nephrotic syndrome. These cats often develop extensive subcutaneous fluid build up and abdominal swelling but are otherwise reasonably healthy. They often have mild weight loss and a depressed appetite. The second form is renal failure. These cats have more pronounced weight loss and appetite depression, increased thirst and urination, and they may be vomiting. Cats with both forms of glomerulonephritis have small, firm kidneys. The nephrotic syndrome is thought to represent an early stage of the disease, and the renal-failure form is believed to be the latter stage. 

Signs of the nephrotic syndrome are typical of the first form of this disease. Signs of renal failure occur in the second form but do not differ from renal failure due to other causes. 

Blood tests are required to assess renal damage. These cats should be tested for the FeLV, FIV, and feline coronavirus.

Treatment for renal failure can be started and in some cases diuretics and corticosteroids may be of use.

The prognosis depends on the form of the glomerulonephritis, the stage of diagnosis, and the underlying disease. Non-azotaemic cats with the nephrotic syndrome diagnosed early can often be managed for months or years, especially if an underlying disease can be cured.. Cats in end stage renal failure have a poor prognosis.

Hepatic Lipidosis

Hepatic lipidosis, or fatty liver syndrome is a relatively common liver disorder of cats. It is associated with a build up of fat within the liver tissue and a prolonged period of inappetance. Cats that are obese are especially prone to this disorder. It can develop as a result of another disease process such as cholangiohepatitis, liver tumours and obstruction or inflammation of the bile ducts. The normal clinical presentation involves inappetance, weight loss, jaundice and vomiting.

In order to diagnose this problem your vet will wish to carry out blood tests to check the liver enzyme levels and the blood cell types (there may be a degree of anaemia). Definitive diagnosis is achieved through liver biopsy and histopathology but this procedure does carry some degree of risk. X-rays will reveal any change in the size of the liver and ultrasound is useful in assessing liver architecture.

Treatment involves rehydration and maintenance with intravenous fluids, nutritional support by feeding with a nasogastric tube if necessary, and antibiotics due to the likelihood of infection underlying the disease process. Initial stabilisation can take several days. Over the following weeks the goal is to provide adequate nutritional support and control of vomiting until the cat returns to normal eating habits.

Survival rates vary from 50-90% and the majority of fatalities occur during the first week of illness. Recurrence is possible if a prolonged interruption of food intake occurs.

Pancreatitis

Pancreatitis in the cat  can present concurrently with cholangiohepatitis or inflammatory bowel disease. Causes also include trauma and infection.

The signs of pancreatitis are non specific, affected cats can be fevered, lethargic and inappetant. Some may have high blood glucose levels (interference with insulin production) and jaundice. The clinical signs are indistinguishable from many liver or gastrointestinal disorders. In order to achieve a diagnosis abdominal X-rays, ultrasound scanning, blood biochemistry and the feline TLI test may all be required. Occasionally the diagnosis is only made when surgical exploration of the abdomen is undertaken.

Supportive nutrition and maintenance of hydration are important, nasogastric tube feeding and intravenous fluid therapy should be undertaken. If abdominal pain is present then painkillers may be administered and drugs to control vomiting can be used if this is a problem. Those cases with raised blood glucose levels will benefit from insulin supplementation and antibiotics should be used if infection is though to be the cause of the disease process.

When the animal resumes feeding small meals should be offered at frequent intervals.

This disease, especially if complicated by hepatic lipidosis, can be difficult to manage, some acute cases can become fatal.

Polycystic Kidney

This disorder is more common in the long haired breeds of cat, particularly Persians. The kidney tissue contains multiple fluid filled cysts of varying size, one or both kidneys can be affected. 

The onset of clinical disease does not tend to occur until the cat is a few years old but severely affected kittens with little normal kidney tissue will die at a young age. The clinical signs of disease are increased thirst and urination, vomiting, weight loss, lethargy, and inappetance.

X-rays and ultrasound may show irregular enlarged kidneys with fluid filled cysts. If one cat is diagnosed with this problem then related cats should also be checked because the disease has a genetic basis.

Treatment for chronic renal failure may extend then lifespan of affected cats but the long term prognosis for those individuals in renal failure is poor.

Affected animals should not be used for breeding.

Portosystemic shunts

Portosystemic shunts are abnormal blood vessels that allow blood from the intestine to bypass the liver. The consequence of this is that the blood is not detoxified by the liver. The most common form of this disorder is congenital therefore many cats with this disorder develop illness at a relatively young age, although it has been recorded at ages of 4-5 years.

The common signs produced by this disorder include excess salivation, vomiting, diarrhoea, increased thirst and urination, nervous signs such as tremors or seizures can also develop.

Blood tests can reveal various abnormalities, specifically the bile acid stimulation test is extremely useful in diagnosing this condition. Further work is then required to determine whether or not the condition can be corrected surgically.

The treatment of choice for suitable cases is surgical correction to ligate or occlude the abnormal blood vessels. Not all cases can be considered for surgery and those that cannot will require medical management. In these cases a high quality low protein diet along with lactulose, neomycin and metronidazole will temporarily improve the situation.

Cats which successfully undergo surgery have a good prognosis, medical management normally only provides temporary respite and the prognosis remains guarded.

Pyelonephritis

Pyelonephritis is the inflammation of the kidney, usually created by bacterial infection. When the infection is active the cat may be fevered, inappetant and lethargic. Some cats will maintain chronic infection within the kidney for a long period of time and eventually develop renal failure as a result.

If the cat is presented with an episode of acute bacterial infection it usually has painful kidneys and blood, protein, or pus detectable within the urine. Culture of the urine to identify the bacterial infection is important. Cases of chronic infection may present in renal failure with specific abnormalities to be found on blood tests. Ultrasound of the kidney is useful.

Treatment depends on the severity of the problem, mild cases may only require lengthy courses of antibiotics, cats in renal failure may require intravenous fluids, electrolyte supplementation, B vitamins, and anabolic steroids. Some acute cases will not have functioning kidneys and may fail to properly produce urine, re-establishing urine flow in these cases is a priority and may require diuretics and intravenous fluids.

Once apparent recovery has been achieved and the antibiotic course is finished the urine should be sent for bacterial culture to ensure the infection is eliminated. Some cats are left with permanent kidney damage which can lead to chronic renal failure later in life.

Urolithiasis

Urolithiasis is the formation of stones and crystals within the kidneys and bladder. There are four mains types of urolith which vary in their mineral composition. The most common are struvite uroliths, the others are calcium oxalate, calcium phosphate, and urate.

Formation of uroliths can be induced by chronic bacterial infection within the bladder but more commonly it is dietary related. When the kidneys excrete to much of a certain type of mineral it crystallises in the urine. Uroliths present a problem because they irritate the bladder, provide a focus for persistent infection and, more seriously, can obstruct urine flow. The typical signs include blood in the urine and difficulty or inability to pass urine. Diagnosis of the problem will require urine testing for crystals and possibly X-rays for bladder stones.

If the bladder is blocked the animal should be seen promptly as an emergency case. Cats with blocked bladders are extremely uncomfortable, frequently attempting to urinate, in considerable discomfort and very vocal. Male cats are much more likely to suffer bladder obstruction than females.

Treatment of cases with complete obstruction involves catheterisation of the bladder to re-establish urine flow and surgical removal of any uroliths from the bladder. The prognosis depends on how quickly urine flow can be re-established and whether any renal damage has been suffered, if minimal then the prognosis is good. Cases which are left are likely to result in a ruptured bladder with grave prognosis.

All cats should have their diet modified to reduce the urinary excretion of the offending minerals. Most will require antibiotics to clear bacterial infection. Recurrence of this condition is a problem so strict adherence to a prescribed diet so be ensured. Frequent testing of urine for crystals should be undertaken to monitor the condition.