SECTION 7 Urinary System

Section Editor: Cathy E. Langston, DVM, DACVIM (Small Animal)

Acute Kidney Failure

Anemia of Chronic Kidney Disease

Benign Prostatic Hypertrophy in Dogs

Bladder Cancer

Bladder Stones in Cats

Bladder Stones in Dogs

Bladder Trauma

Chronic Kidney Disease in Cats

Chronic Kidney Disease in Dogs

Cystitis in Cats

Cystitis in Dogs

Ectopic Ureter in Dogs

Fanconi Syndrome in Dogs

Kidney Dysplasia in Dogs

Kidney Stones in Cats

Kidney Toxins (Nephrotoxicosis)

Perinephric Pseudocysts in Cats

Polycystic Kidney Disease in Cats

Prostate Cancer in Dogs

Prostatic and Paraprostatic Cysts in Dogs

Prostatitis and Prostatic Abscessation in Dogs

Protein-Losing Nephropathy in Dogs

Pyelonephritis (Kidney Infection)

Renal Neoplasia

Ureteral Obstruction in Cats

Urethral Obstruction in Cats

Urethral Prolapse in Dogs

Urethritis

Urinary Incontinence in Dogs

Acute Kidney Failure

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

TREATMENT AND FOLLOW-UP

Treatment Options

ARF is a serious disease that requires hospitalization in most cases. The mainstay of treatment is intravenous (IV) fluids. Careful monitoring of the patient is necessary, because the volume of urine produced can change dramatically and rapidly, leading to either dehydration or fluid retention. Diuretics, which increase the volume of urine produced, may be tried but are not always effective.

Drugs to control nausea and vomiting are usually needed. Medications may be given IV to correct severe electrolyte imbalances, such as high potassium levels and acidosis of the blood. Some patients with persistent vomiting and lack of appetite may be helped by insertion of a temporary feeding tube. Specific treatments for the underlying cause are also started. (See the handouts on Antifreeze Poisoning, Leptospirosis, and Ureteral Obstruction in Cats.)

If standard medical therapy is ineffective, advanced treatment options may be considered. These include hemodialysis (removal of uremic toxins by passage of the blood through a kidney dialysis machine), continuous renal replacement therapy (CRRT, a form of dialysis), or peritoneal dialysis (administration of fluids into the abdomen that absorb some of the uremic toxins, followed by removal of as much of the fluid as possible). These therapies are generally offered only by specialized hospitals, so your pet may be referred to a veterinary specialist for these treatments.

Follow-up Care

Intensive monitoring is required during hospitalization and often includes measurements of blood pressure, heart and respiratory rates, body temperature and weight, blood electrolytes, kidney function tests, and urine output. After discharge from the hospital, follow-up visits generally involve examinations and laboratory tests. If the ARF completely reverses, long-term monitoring may not be necessary, although yearly blood and urine tests are prudent.

Prognosis

ARF is a serious disease, and only about half of affected animals survive it. Patients with infections, urinary obstruction, or low blood flow as the cause tend to do better than those that developed ARF from a toxin. Of the animals that survive, about half have residual kidney damage.

SPECIAL INSTRUCTIONS:

Anemia of Chronic Kidney Disease

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

Anemia is a low red blood cell (RBC) count. RBCs carry oxygen to the tissues of the body. If RBC numbers are low, body tissues may be deprived of adequate oxygen.

Causes

As RBCs age, they are taken out of circulation and replaced with new, younger RBCs. The kidneys make a hormone, erythropoietin, which stimulates the bone marrow to make these new RBCs. As the kidneys fail, they make less erythropoietin, and fewer RBCs are produced to replace the cells that are removed. This failure to replenish RBC numbers creates a slowly worsening anemia. Another cause of anemia in patients with kidney disease is a bleeding ulcer in the stomach.

Clinical Signs

Anemia often produces signs of tiredness (lethargy), weakness, fast heart rate, rapid breathing, and poor appetite. On physical examination, pale gums, a heart murmur, and weak pulses may be detected.

Diagnostic Tests

Hematocrit and packed cell volume (PCV) are very similar blood tests that measure the percentage of blood composed of RBCs. These values are low with anemia. The reticulocyte count determines the number of new RBCs being produced. This value is also typically low with anemia from chronic kidney disease. In some cases, bone marrow aspiration is recommended to rule out other causes of anemia.

TREATMENT AND FOLLOW-UP

Treatment Options

If stomach ulcers are known or suspected to be causing anemia, treatment is usually recommended with antacids, such as famotidine (Pepcid), and the gastric protectant, sucralfate. B vitamin supplements may help the anemia a little.

Blood transfusions immediately increase the PCV and improve signs associated with anemia. In emergency situations, transfusions are the best choice; however, transfused RBCs generally only last few weeks. To sustain an anemic animal long term would require repeated transfusions, and with each transfusion the risk of a transfusion reaction increases, even if blood cross-match tests are performed prior to each transfusion to check for compatibility.

Commercial erythropoietin can be used to replace the natural hormone the kidneys are failing to make. Two forms are available; both are given by injection under the skin (subcutaneous). Erythropoietin (Epogen, Procrit) is initially given three times per week until the PCV is normal, then usually once weekly to maintain the PCV. Darbepoetin (Aranesp) is initially given weekly and can often be decreased to every other week.

Unfortunately, both of these hormones are made for people. Although they work in animals, the immune system of some animals can recognize them as foreign substances and form antibodies against the drugs. If this happens, the immune system inactivates the hormone that has been injected, as well as any natural hormone the kidneys may still be making. This inactivation makes the anemia worse than it was before hormone shots were started. About 20% of patients on erythropoietin and 10% on darbepoetin develop this immune reaction. Some patients can partially recover from it, but many will be dependent on blood transfusions afterward.

Because of this potential reaction, treatment with hormone shots is usually delayed until the signs of anemia are moderate to severe. Other side effects of hormone shots include high blood pressure (hypertension) and seizures. Despite the possibility of adverse effects, most patients feel much better, are more interactive, and eat more while receiving these injections.

Because RBCs contain iron, iron supplements are needed when the animal is receiving hormone shots. Oral iron pills are available, or monthly iron shots may be administered.

Follow-up Care

With hormone treatment, weekly rechecks are often scheduled that include a PCV, blood pressure measurement (if available), and reticulocyte count (ideally) until the anemia has improved. The frequency of rechecks can be gradually decreased if the anemia improves.

Prognosis

Anemia decreases the quality of life of dogs and cats with chronic kidney disease. The combined signs of chronic kidney disease and anemia may cause the animal to feel so poorly that euthanasia is considered. Successful treatment of the anemia often prolongs and improves the quality of the animal’s life.

SPECIAL INSTRUCTIONS:

Benign Prostatic Hypertrophy in Dogs

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

The prostate is a small gland that surrounds the beginning of the urethra. The urethra is the tube that carries urine from the bladder to the outside. The normal prostate has two lobes, one on each side of the urethra, with a small indentation between the lobes. The prostate makes fluid that is secreted into the urethra during ejaculation of semen.

Benign prostatic hypertrophy or hyperplasia (BPH) is a symmetrical enlargement of the prostate that occurs in intact (unneutered), older, male dogs. It is the most common prostatic disease of dogs.

Causes

Testosterone causes certain types of cells in the prostate to grow in number (hyperplasia) and to enlarge in size (hypertrophy). Over time, this effect causes the prostate to become enlarged (prostatomegaly). A large prostate is normal in intact male Scottish terriers and should not be confused with BPH.

Clinical Signs

Most dogs with BPH do not have any clinical signs. Some dogs may strain to defecate, because the enlarged prostate presses on the colon. Rarely, the prostatic enlargement may partially obstruct the urethra, which leads to straining during urination. Other potential signs include a yellow or bloody penile discharge that is not associated with urination and blood in the urine.

In most dog, BPH is discovered during a physical examination. An enlarged prostate can be felt by rectal palpation, but the gland is not painful or irregular.

Diagnostic Tests

An enlarged prostate can be seen on plain x-rays. An abdominal ultrasound may be recommended, because it can confirm that the internal architecture of the prostate is preserved, even though the gland is enlarged. A urinalysis and urine culture may be performed to rule out a urinary tract infection. Rarely, biopsy is needed to distinguish BPH from other causes of prostatic disease, such as prostatic infection or cancer.

TREATMENT AND FOLLOW-UP

Treatment Options

Castration is an effective treatment for BPH and is the recommended procedure. After termination of testosterone production (by removal of the testicles), the prostate typically shrinks to a normal size within 3-6 weeks. If castration is not performed, the effects of testosterone on the prostate can be blocked with the medication, finasteride (Proscar, Propecia). After finasteride is started, the prostate usually decreases in size by 70% within 10 weeks. If the drug is stopped, the BPH will return within 8 weeks. Finasteride can cause birth defects and should not be handled by pregnant women.

Monitoring alone may be chosen for some dogs with mild BPH and no symptoms. Despite anecdotal reports, Saw palmetto extract is not effective for treating prostate disease in dogs.

Follow-up Care

After castration surgery, the prostate is usually palpated again in 3-4 weeks to ensure that it is shrinking as expected. If the gland is not shrinking, then other diseases (such as prostatic cancer or infection) may be involved, and further testing for those diseases is often recommended. In asymptomatic dogs on no treatment, periodic examinations with rectal palpation are used to assess the prostate.

Prognosis

BPH is a benign disease, but it predisposes the dog to prostatic infections if left untreated. Prognosis is excellent with castration, because the surgery usually cures the condition.

SPECIAL INSTRUCTIONS:

Bladder Cancer

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

Bladder cancer includes all malignant tumors of the bladder and accounts for fewer than 1% of all cancers in dogs and cats. Most tumors of the bladder are malignant. Inflammatory polyps are the most common benign tumors of the bladder.

Causes

The most common type of bladder cancer is transitional cell carcinoma. Breeds predisposed to this tumor include the Scottish terrier, Shetland sheepdog, collie, Airedale terrier, and beagle. Other types of bladder tumors include squamous cell carcinoma, lymphoma, adenocarcinoma, and rhabdomyosarcoma. Although most bladder cancers occur in older pets, rhabdomyosarcoma occurs in young, large-breed dogs. Bladder cancer may be more common in female than in male dogs, and it is rare in cats.

Clinical Signs

The most common signs are blood in the urine, straining to urinate, and urinating small volumes of urine frequently. If the tumor is large, it can sometimes be felt by your veterinarian when palpating the animal’s abdomen. Because these tumors can grow into the urethra (the tube that carries urine from the bladder to the outside), they can sometimes be felt during rectal palpation.

If the tumor blocks the urethra, dogs may strain to urinate without producing any urine. The bladder can become very large because of the retained urine, even if the blockage is not complete. If the tumor blocks one ureter (the tube that carries urine from the kidney to the bladder) as it enters the bladder, clinical signs may not be apparent. If both ureters become blocked, kidney failure occurs.

Diagnostic Tests

Initially, blood and urine tests (urinalysis, culture) are often recommended to investigate the clinical signs. Standard urinalysis is not likely to show cancer cells. A special urine test, called a bladder tumor antigen test, can be used to screen for bladder cancer. Any disease of the bladder, including a simple bladder infection, can cause the test to be positive (false-positive result), but a negative test means that the chance that cancer is present is extremely low. This test can be used to screen older dogs at risk for bladder cancer (especially Scottish terriers) before they develop any signs of bladder disease.

X-rays cannot usually detect bladder tumors, so other tests are needed. An abdominal ultrasound can detect bladder masses but cannot determine whether the mass is benign or malignant. A contrast study may be performed by infusing either carbon dioxide gas (negative contrast) or a liquid dye (positive contrast) into the bladder via a urinary catheter and then taking a series of x-rays. Cystoscopy, which involves passing a small fiberoptic viewing scope into the bladder through the urethra, can be used to identify and biopsy a bladder mass.

The type of cancer present can only be determined with a biopsy. In some cases, the biopsy is obtained at the time of surgery. If cancer is suspected, chest x-rays may be recommended to look for metastasis (spread of tumor).

TREATMENT AND FOLLOW-UP

Treatment Options

Most bladder cancers arise in the region of the bladder where the openings of the ureters and urethra enter the bladder, which makes complete surgical removal difficult. Transplantation of the ureters into other areas of the bladder and diversion of the urethra to the outside of the abdomen may be required.

An experimental technique using laser therapy (with cystoscopy and ultrasound) is being developed to remove portions of bladder tumors. When the tumor regrows, this procedure can be repeated. If the tumor blocks the urethra, a metal tube (stent) can be placed in the urethra to hold it open so that patient can empty the bladder; alternatively, a tube can be placed directly from the bladder to the outside to allow urine drainage. If the tumor blocks the ureters, a stent may also be attempted.

Transitional cell carcinoma does not readily respond to chemotherapy. Piroxicam, a nonsteroidal anti-inflammatory drug, may have some benefit in dogs. Secondary infections are treated with antibiotics.

Follow-up Care

Monthly ultrasounds may be done to monitor tumor progression. Cystocentesis, a method of obtaining urine by inserting a needle into the bladder, should be avoided in dogs with bladder cancer, because it could spread cancer cells along the needle track. Urine cultures (of samples obtained by a catheter or collected at home) are often performed every 2 to 3 months.

Prognosis

Prognosis for transitional cell carcinoma is poor, with average survival times of several months. Causes of euthanasia include obstruction of the urethra, kidney failure, metastasis, and poor quality of life.

SPECIAL INSTRUCTIONS:

Bladder Stones in Cats

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

Bladder stones (cystoliths, cystic calculi) are physical aggregations of minerals and other substances in the bladder. They may rub and irritate the lining of the bladder, increase the risk of bladder infections, or lodge in the urethra (the tube that carries urine from the bladder to outside the body), causing an obstruction.

Causes

The two most common types of bladder stones in cats are calcium oxalate stones and struvite stones. They occur with about equal frequency. Calcium oxalate stones are more likely to develop in acidic urine, whereas struvite stones are more likely to form in alkaline urine. Complex interactions between the animal’s diet and stone formation affect the development of both of these types of stones.

Urate stones are uncommonly encountered in cats and are usually associated with liver disease or vascular shunts. Other types of stones are rare in cats.

Clinical Signs

Signs of bladder irritation include frequent trips to the litter box, voiding of small volumes of urine, blood in the urine, pain on urination, and urinating outside the litter box. Bladder stones may lodge in the urethra, causing a complete urinary obstruction. Urinary obstruction is more common in male cats. Signs of obstruction include straining to urinate without producing any urine and abdominal pain. Urinary obstruction is an emergency situation. (See the handout on Urethral Obstruction in Cats.)

Diagnostic Tests

Diagnostic steps that are often recommended include routine blood and urine tests (urinalysis, culture) and abdominal x-rays. Urinalysis may show microscopic calcium oxalate or struvite crystals. It is important to note that cats can have crystals in their urine without having stones, and they can have stones without having crystals.

Both calcium oxalate stones and struvite stones show up on plain x-rays, making x-rays an excellent test for detecting stones. Some stones are too small to be seen on x-rays, but an abdominal ultrasound can usually detect them.

Analysis of stones is necessary to be sure of their composition, so stones that are physically removed from the bladder are submitted for analysis.

TREATMENT AND FOLLOW-UP

Treatment Options

Struvite stones can often be dissolved by feeding a special, prescription diet (Hill’s S/D). The cat must eat this diet exclusively; no supplemental treats or other foods are allowed. On average, it takes 3-4 weeks to dissolve struvite stones.

Calcium oxalate stones cannot be dissolved with dietary changes or medications. The only effective therapy is physical removal of the stones, which generally means bladder surgery (cystotomy) done through an abdominal incision. In certain cases, particularly in a large female cat with a solitary stone, the stone can be fragmented with a laser during cystoscopy (passage of a small fiberoptic viewing scope into the bladder) and the fragments flushed out. However, few veterinary hospitals have the equipment needed for cystoscopy and laser therapy. Surgery is generally a faster procedure. If the cat is a large female and the stones are small, it may be possible to flush them out with the animal under anesthesia.

With other types of stones, medications may be useful for dissolving them or preventing recurrence. After the stones are removed, preventive measures may include feeding a moist food and certain prescription diets. Prescription diets that are designed to simultaneously prevent struvite and calcium oxalate stones include Hill’s Multicare C/D and Royal Canin’s SO.

Follow-up Care

Following surgery, a recheck visit is usually scheduled at 10-14 days for suture removal. When medical therapy is used to dissolve the stones and also after surgery, urine pH (a measure of acidity) and x-rays are usually repeated at 1, 3, and 6 months to monitor for improvement or recurrence of stones. Longer-term monitoring may also be recommended.

Prognosis

Prognosis for resolution of bladder stones is excellent. For calcium oxalate and struvite stones, dietary management can decrease the risk of recurrence, although some cats develop more stones within 3-5 years.

SPECIAL INSTRUCTIONS:

Bladder Stones in Dogs

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

Bladder stones (cystoliths, cystic calculi) are physical aggregations of minerals and other substances in the bladder. They may rub and irritate the lining of the bladder, increase the risk of bladder infection, or lodge in the urethra (the tube that carries urine from the bladder to outside the body), causing an obstruction.

Causes

Several types of bladder stones occur in dogs. Struvite stones (triple magnesium phosphate), occur in the presence of bladder infections. Female dogs are predisposed to struvite stones. Calcium oxalate stones occur with higher frequency in certain breeds of dogs, such as the miniature schnauzer, shih tzu, bichon frise, Lhasa apso, Yorkshire terrier, and miniature poodle. They may also develop secondary to other diseases, such as hyperadrenocorticism (Cushing’s disease) or hypercalcemia (high blood calcium). Urate stones occur with liver problems, such as portosystemic vascular shunts and other inherited defects of the liver. The Dalmatian and English bulldog breeds are predisposed to urate stones. Other types of stones, such as cystine, calcium phosphate, xanthine, and silica stones, are rarely encountered.

Clinical Signs

Signs of bladder stones include frequent urination and urgency, voiding of only small volumes of urine, and pain on urination. Blood may occur throughout the urine stream or may be worse at the end of urination. Bladder stones may lodge in the urethra, causing blockage. Urinary obstruction from stones is more common in male dogs. Signs include straining to urinate without producing any urine and abdominal pain. Urinary obstruction is an emergency situation.

Diagnostic Tests

Diagnostic steps that are often recommended include routine blood and urine tests (urinalysis, culture) and abdominal x-rays. Urinalysis may show microscopic crystals. It is important to note that dogs can have crystals in their urine without having stones, and they can have stones without having crystals. Urine culture is important, because urinary infections may cause stones, and stones may cause infection.

Struvite and calcium oxalate stones show up on plain x-rays, making x-rays an excellent screening test. Some very small stones and stones of other types may not be apparent on x-rays, but an abdominal ultrasound can usually detect them.

Analysis of stones is necessary to be sure of their composition, so stones that are physically removed from the bladder are submitted for analysis.

TREATMENT AND FOLLOW-UP

Treatment Options

Struvite stones can often be dissolved with a special diet (Hill’s S/D) and control of any underlying infection with antibiotics. The dog must eat this diet exclusively; no supplemental treats or other foods are allowed. On average, it takes 1-3 months to dissolve struvite stones.

Calcium oxalate stones cannot be dissolved with dietary changes or medications. The only effective therapy is physical removal of the stones, which generally means bladder surgery (cystotomy) done through an abdominal incision. In certain cases, particularly in female dogs with a solitary stone, the stone can be fragmented with a laser during cystoscopy (passage of a small fiberoptic viewing scope into the bladder) and the fragments flushed out. However, few veterinary hospitals have the equipment needed for cystoscopy and laser therapy. Surgery is generally a faster procedure. If the dog is a female and the stones are small, it may be possible to flush them out with the animal under anesthesia. After removal, the urine is kept dilute (watery) by feeding moist food, and urine pH is maintained in the alkaline range to help prevent recurrence.

With other types of stones, medications may be useful for dissolving them or preventing recurrence. For urate stones in Dalmatians, a special diet (Hill’s U/D) and the oral drug, allopurinol, may help dissolve stones and prevent recurrences.

Follow-up Care

After removal or dissolution of struvite stones, monitoring for infection with urine cultures is recommended on a monthly basis until three negative cultures in a row are obtained. Because urate stones do not show up on plain x-rays, ultrasounds are needed to monitor for recurrence.

Following surgery to remove calcium oxalate stones, a recheck visit is usually scheduled at 10-14 days for suture removal. Future rechecks consist of urinalyses and x-rays at 1, 3, and 6 months, then every 6 months thereafter. The goal is to detect recurrence of stones while they are small enough to flush out, without the need for surgery.

Prognosis

Bladder stones can be removed surgically, leading to full recovery. Certain types of stones may recur, but appropriate preventive measures may work for years.

SPECIAL INSTRUCTIONS:

Bladder Trauma

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

Traumatic injury to the bladder may cause bruising, bleeding, or rupture of the bladder. The most serious damage is rupture of the bladder, which results in urine leakage into the belly (abdomen).

Causes

Trauma to the bladder may occur from blunt forces (automobile accidents, falls from heights) or penetrating injuries (gunshot, knife, or stick wounds). It can also occur with surgery of the bladder. Occasionally, catheterization, cystocentesis (obtaining urine by needle aspiration of the bladder), or palpation of the bladder results in mild trauma in a diseased bladder. Sometimes the bladder ruptures with no or minimal trauma, especially if it is diseased (such as with cancer) or blocked (obstructed) for a prolonged period.

Clinical Signs

Bloody urine is a very common sign of bladder trauma. Other external signs of trauma may be present, such as bruising, wounds of the abdominal wall, and difficulty walking (fractured pelvis or hips). Inability to urinate may occur if the bladder ruptures, but the ability to pass urine does not exclude bladder rupture. Progressive distension of the belly may indicate urine leakage into the abdomen. The abdomen is also typically very painful, because urine is irritating. Over time, toxins in the urine are absorbed into the bloodstream from the abdomen, leading to signs of kidney failure and potentially widespread infection.

Diagnostic Tests

The history and physical evidence of trauma in the area of the abdomen, along with urinary symptoms, allows a tentative diagnosis of urinary tract trauma. X-rays may show fluid in the belly, but they cannot determine whether the fluid is urine. An abdominal ultrasound helps identify rupture of the bladder or other parts of the urinary tract. A partially filled bladder may be seen on ultrasound (or even felt on palpation of the belly) despite the presence of a partial tear in the bladder. Instillation of contrast material (a liquid dye that shows up white on x-rays) into the bladder through a urinary catheter may reveal leakage into the abdomen, thereby confirming a rupture.

Urine leakage can also be confirmed by testing fluid obtained from the belly by simple needle aspiration (paracentesis). If the creatinine level in belly fluid is higher than the creatinine level in the blood, urine is leaking into the abdomen. Measurement of creatinine is the best test, because substances such as urea may be partially reabsorbed into the bloodstream, making confirmation difficult.

TREATMENT AND FOLLOW-UP

Treatment Options

If the bladder is bruised, no specific treatment is necessary, because the bruising resolves with time. If large blood clots are present in the bladder, they also usually dissolve over time. If the blood clots are causing an obstruction, a urinary catheter may be inserted for a few days to allow urine to drain.

If the bladder has ruptured, a urinary catheter is placed in the bladder to allow urine to drain out of the body instead of into the belly. If the hole in the bladder is small, the hole may seal on its own if the bladder is kept empty with the urinary catheter. It generally takes several days for small holes to seal.

If the hole in the bladder is large or continues to leak, surgery is necessary to repair the tear. If the patient is too unstable for general anesthesia, either because of trauma elsewhere in the body (such as severe lung bruising from an automobile accident) or because of kidney failure caused by the bladder rupture, drainage of urine from the belly may be necessary for several days. A peritoneal catheter can be placed directly into the abdomen to provide drainage. In some cases, peritoneal dialysis (instilling fluid and then draining it to remove toxins) may also be helpful. Surgery is then performed once the patient is stable.

Follow-up Care

After a urinary catheter is removed, urinations are monitored closely. A contrast procedure may also be performed when the catheter is removed to make sure no urine is still leaking. Blood tests for kidney function and electrolytes are often repeated for several days.

Prognosis

With appropriate treatment in the hospital, simple bladder ruptures are likely to heal. Surgical repair of a traumatic bladder rupture is also usually successful. If the bladder ruptured because of severe underlying bladder disease, such as cancer or prolonged blockage, the remaining bladder wall is often unhealthy and there is a substantial risk of urine leakage from the surgery site. Prognosis is poorer in these latter cases.

SPECIAL INSTRUCTIONS:

Chronic Kidney Disease in Cats

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

Chronic kidney disease (CKD), also called chronic renal failure, is long-standing (greater than 3 months) kidney dysfunction that is manifested by dilute urine (urine that is not as concentrated as it should be) and retention of urea (uremia) and other waste products in the body. CKD is a common problem in older cats but can also occur in young and middle-aged cats.

Causes

In many cases, the underlying cause of CKD is never discovered. Identifiable causes include kidney infections and stones, obstruction of the ureter (the tube that carries urine from the kidney to the bladder), incomplete recovery from previous damage to the kidney (such as acute renal failure), polycystic kidney disease (an inherited condition common in long-haired cats), and certain tumors (such as lymphoma). In young cats, congenital kidney disease (such as kidney dysplasia) may be the cause. Kidney stones are common in middle-aged cats.

Clinical Signs

CKD may be detected on routine screening of blood and urine prior to the onset of signs. Diagnosis at this stage allows treatments to be started that may slow the progression of CKD. Early clinical signs may include increased water intake and urine production, decreased appetite, and nausea. In later stages, vomiting, lethargy, and dehydration may be apparent. Physical examination findings may include dehydration, weight loss or muscle loss, poor hair coat, small or irregular kidneys, and a uremic odor to the breath.

Diagnostic Tests

Initially, a biochemistry panel, complete blood test, and urinalysis are usually recommended. With CKD, kidney function tests, such as blood urea nitrogen (BUN) and creatinine, are elevated. Levels of blood electrolytes (potassium) and certain chemicals (phosphorus, calcium) may also be abnormal. Urinalysis is crucial to determine the ability of the kidneys to concentrate the urine and to look for protein in the urine.

Additional diagnostic tests may include a urine culture to screen for infection, blood pressure measurement (especially if there is protein in the urine) to check for high blood pressure (hypertension), and a complete blood count to look for anemia. Abdominal x-rays and an ultrasound are often done to look for kidney stones, evidence of infection, or other changes. In some cases, a kidney biopsy may be recommended, along with laboratory tests to rule out other diseases that can cause similar signs.

TREATMENT AND FOLLOW-UP

Treatment Options

Currently, no treatments are available that will reverse CKD. The goals of treatment are to slow progression of CKD and treat the clinical signs. Feeding a special kidney diet, which contains less protein and phosphorus, is the most effective method of slowing progression of CKD. Cats eating a kidney diet can live twice as long as those eating a regular maintenance diet. These diets can be started even before signs occur. Control of blood phosphorus levels is also necessary. If dietary changes alone do not accomplish this, drugs to bind the phosphorus in the food can be given with each meal.

If chronic dehydration is present, injections of fluid under the skin (subcutaneous fluids) may be helpful. The frequency varies from daily to twice weekly, and the injections can be given at home. If hypertension is present, a variety of drugs can be used to control it. Hypertension is more common in early stages of CKD in cats. Excess protein in the urine is rare in cats and can be treated with angiotensin-converting enzyme (ACE) inhibitor drugs.

Potassium supplements may be needed in some cats, as well as drugs to treat excess acid in the blood. Severe, advanced anemia can be treated with hormone injections to stimulate the production of red blood cells, but some cats develop side effects from the hormone the longer it is used. Antacids, such as famotidine, are frequently prescribed for vomiting, and appetite stimulants may be given.

Follow-up Care

Follow-up visits often involve examinations, laboratory tests, and blood pressure measurements (when available). Frequency of visits depends on the severity of CKD, with monthly visits recommended in advanced cases. Cats with early, stable disease may only need to be checked every 3-6 months.

Prognosis

CKD is a progressive disease that slowly worsens, but the rate of progression is highly variable. Cats diagnosed with early disease have an average survival time of 3 years. Those with moderate disease live an average of 2 years. Those with advanced disease generally succumb to CKD within months. Despite these general rates, the survival time of any individual cat is impossible to predict.

SPECIAL INSTRUCTIONS:

Chronic Kidney Disease in Dogs

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

Chronic kidney disease (CKD), also called chronic renal failure, is long-standing (greater than 3 months) kidney dysfunction that is manifested by dilute urine (urine that is not as concentrated as it should be) and retention of urea (uremia) and other waste products in the body. CKD is a common problem in older dogs but can also occur in young and middle-aged dogs.

Causes

In many cases, the underlying cause of CKD is never discovered. Identifiable causes include kidney infections and stones, incomplete recovery from previous damage (such as acute kidney failure), and diseases of the glomerulus (filtering structure) in the kidney (such as protein-losing nephropathy or glomerulonephritis). In young dogs, congenital kidney disease (such as kidney dysplasia) may be the cause. CKD may also arise as the kidneys deteriorate with age in older dogs.

Clinical Signs

CKD may be detected on routine screening of blood and urine prior to the onset of signs. Diagnosis at this stage allows treatments to be started that may slow the progression of CKD. Early clinical signs may include increased water intake and urine production, decreased appetite, and nausea. In later stages, vomiting, lethargy, and dehydration may be apparent. Physical examination findings may include dehydration, weight loss or muscle loss, small or irregular kidneys, and a uremic odor to the breath.

Diagnostic Tests

Initially, a biochemistry panel, complete blood test, and urinalysis are usually recommended. With CKD, kidney function tests, such as blood urea nitrogen (BUN) and creatinine, are elevated. Levels of certain blood chemicals (especially phosphorus) may also be abnormal. Urinalysis is crucial to determine the ability of the kidneys to concentrate the urine and to look for protein in the urine.

TREATMENT AND FOLLOW-UP

Treatment Options

Currently, no treatments are available that will reverse CKD. The goals of treatment are to slow progression of CKD and treat the clinical signs. Feeding a special kidney diet, which contains less protein and phosphorus, is the most effective method of slowing progression of CKD. Dogs eating a kidney diet can live twice as long as those eating a regular maintenance diet. These diets can be started even before signs occur.

Control of the blood phosphorus levels is also necessary. If diet alone does not accomplish this, drugs to bind the phosphorus in the food can be given with each meal. Administering a form of vitamin D (calcitriol) may also help delay an increase in phosphorus. If chronic dehydration is present, injections of fluid under the skin (subcutaneous fluids) may be helpful. The frequency varies from daily to twice weekly, and the injections can be given at home.

Excess protein in the urine can be treated with angiotensin-converting enzyme (ACE) inhibitor drugs. If hypertension is present, a variety of drugs can be used to control it. Dogs rarely develop low blood potassium levels from CKD, but potassium supplements may be needed in some cases. Severe, advanced anemia can be treated with hormone injections to stimulate production of red blood cells, but some dogs develop side effects from the hormone the longer it is used. If vomiting is present, antacids (such as famotidine or omeprazole) or antiemetics (such as metoclopramide, ondansetron, or dolasetron) may be prescribed.

Follow-up Care

Follow-up visits often involve examinations, laboratory tests, and blood pressure measurements (when available). Frequency of visits depends on the severity of CKD, with monthly visits recommended in advanced cases. Dogs with early, stable disease may only need to be rechecked every 3-6 months.

Prognosis

CKD is a progressive disease that slowly worsens, but the rate of progression is highly variable. Some dogs may worsen over months, and others over 2-3 years, before reaching a point where quality of life deteriorates to an unacceptable level.

SPECIAL INSTRUCTIONS:

Cystitis in Cats

Cathy E. Langston, DVM, DACVIM (Small Animal)

BASIC INFORMATION

Description

Bladder inflammation (cystitis) is common in young adult to middle-aged cats. The term feline lower urinary tract disease (FLUTD) refers to any condition that causes inflammation of the bladder of cats. It is not a specific disease. When cats show signs of bladder disease, testing is necessary to determine the underlying cause, so that specific therapy, if available, can be started.

Causes

Bladder stones account for about 15% of cystitis cases in cats. Bladder infections are not common in cats and account for fewer than 2% of cystitis cases. Structural abnormalities, such as bladder cancer, inflammatory polyps, and ectopic ureters, account for fewer than 10% of the cases. Behavioral problems also account for fewer than 10%.

In more than half of cats with signs of cystitis, no underlying cause can be found. If appropriate tests to exclude all other causes of cystitis are performed and are found to be negative, the term feline idiopathic cystitis (cystitis of unknown cause) is used.

Clinical Signs

Common signs of cystitis in cats include difficulty urinating or straining to urinate, pain on urination, urinating small volumes frequently, frequent trips to the litter box, urinating outside the litter box, and blood in the urine. Cystitis can progress to obstruction of urine outflow in male cats. (See also the handout on Urethral Obstruction in Cats.)

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Tags: Small Animal Practice Client Handouts

Sep 11, 2016 | Posted by admin in SMALL ANIMAL | Comments Off

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