----------------------------------------------------------------------------------------------------------------------------------
Chronic Renal Failure
You can find more about cats here
Introduction
Chronic renal (kidney) failure (CRF) is a common problem in all cat breeds. The digestion of food produces waste products, which are carried by blood to the kidneys to be filtered and excreted in the form of urine. When the kidneys fail, they are no longer able to remove these waste products, and toxins build up in the blood producing clinical signs of kidney disease.
Anatomy of the kidney (from Wikipedia)
Renal capsule: The membranous covering of the kidney.
Cortex: The outer layer over the internal medulla. It contains blood vessels, glomeruli (which are the kidneys' "filters") and urine tubes and is supported by a fibrous matrix.
Hilus: The opening in the middle of the concave medial border for nerves and blood vessels to pass into the renal sinus.
Renal column: The structures which support the cortex. They consist of lines of blood vessels and urinary tubes and a fibrous material.
Renal sinus: The cavity which houses the renal pyramids.
Calyces: The recesses in the internal medulla which hold the pyramids. They are used to subdivide the sections of the kidney. (singular - calyx)
Papillae: The small conical projections along the wall of the renal sinus. They have openings through which urine passes into the calyces. (singular - papilla)
Renal pyramids: The conical segments within the internal medulla. They contain the secreting apparatus and tubules and are also called malpighian pyramids.
Renal artery: Two renal arteries come from the aorta, each connecting to a kidney. The artery divides into five branches, each of which leads to a ball of capillaries. The arteries supply (unfiltered) blood to the kidneys. The left kidney receives about 60% of the renal bloodflow.
Renal vein: The filtered blood returns to circulation through the renal veins which join into the inferior vena cava.
Renal pelvis: Basically just a funnel, the renal pelvis accepts the urine and channels it out of the hilus into the ureter.
Ureter: A narrow tube 40 cm long and 4 mm in diameter. Passing from the renal pelvis out of the hilus and down to the bladder. The ureter carries urine from the kidneys to the bladder by means of peristalsis.
Function of the kidneys
The kidneys have five primary functions:
• Filtering waste products from the body (primarily urea and creatinine).
• Regulating electrolytes (potassium, calcium, phosphorus and sodium).
• The production of erythropoietin, which helps to stimulate the bone marrow to produce red blood cells.
• The production of renin, an enzyme that controls blood pressure.
• Production and concentration of urine
CRF affects all breeds of any age, although older pets are commonly affected, as the prevalence increases with age. The average age of diagnosis in cats is nine years. Breeds thought to be more susceptible include Abyssinians and Persians. CRF affects almost every body system causing many changes throughout the body and usually results in the following:
Abnormal filtration of blood and retention of waste materials
Failure of hormone production (including substances that stimulates the production of red blood cells [erythropoeitin])
Disturbance of fluid, electrolyte and acid-base balance
Causes
CRF can be caused by several different processes. These may include diseases, some of which can be secondary to other disease processes or trauma, that may have caused acute kidney failure such as:
• Toxins
• Poor blood flow and lack of oxygen (ischemia)
• Inflammatory disease
• Infections
• Cancer (neoplasia)
• Immune system abnormalities
Clinical signs
• Increased thirst
• Excessive drinking
• Lethargy
• Vomiting
• Bad breath
• Anorexia
• Weakness
• Lack of coordination when walking
• Depression
• Increased urination (sometimes noted as pet using the litter box more frequently, urinating in abnormal places in the house or increased weight of the litter box)
Diagnosis
Diagnostic tests are needed to recognize CRF and exclude other diseases. These tests may include:
• Complete medical history
• Complete physical examination
• Blood tests
• Urinalysis
• X-rays
• Ultrasound
Treatment
Although there is no cure, early detection can slow the progression of the disease. CRF can be a life threatening condition that requires hospitalization and treatment for stabilization in extremely ill pets. Treatments may include:
• Fluid therapy for dehydrated pets
• Management of blood abnormalities such as hyperkalemia or hypokalemia (abnormal potassium blood levels), metabolic acidosis and hyperphosphatemia
• Dietary therapy with protein a phosphorus restriction
• Free access to water
• Supportive care and careful monitoring of urine output
• Control of vomiting with diet and drug therapy as needed
• Management of anemia if needed
Summary
Chronic renal failure is life-threatening, and if you suspect your pet has this condition, you should see your veterinarian as soon as possible. Follow-up with your veterinarian for examinations, laboratory work and urinalysis. Blood and urine analysis should be repeated within five to seven days after discharge.
Feed your pet the diet recommended by your veterinarian. Provide free access to fresh clean water at all times. Some owners can administer subcutaneous fluid to their pets at home, if necessary. Your veterinarian can provide instructions when indicated.
Administer any prescribed medications as directed by your veterinarian. Drug therapy may include: phosphate binders; potassium supplementation; or drugs for vomiting (such as cimetidine or famotidine); or anabolic steroids for some patients. Epogen may be given for anemia two to three times weekly.
Prevention
There are no specific recommendations for prevention of chronic renal failure. However, general suggestions include:
• Providing frequent attempts to urinate and free access to fresh clean water.
• Avoiding exposure to ethylene glycol and toxic plants (such as Easter lily) that can cause acute kidney damage.
