Excess Acidity in the Blood in Cats

There are two types of RTA. Type 1, or distal, RTA, affects the ability of the distal nephrons to release hydrogen ions. It is this secretion of hydrogen that when at normal levels, prevents a buildup of acid in the urine. With Type 2, or proximal, RTA, the proximal nephrons are unable to properly reabsorb bicarbonate. Instead, the protective bicarbonate ions are flushed out of the body. 

The kidneys are among most important organs in cats. Made up of literally thousand of tiny funnel-like tubes called nephrons, they constantly filter and reabsorb fluid and filter waste. Kidneys also have the role of regulating sodium, which maintains an even blood pressure. Unfortunately, many cats, especially particular breeds, are afflicted by what is generally known as kidney disease. As kidney disease progresses, these nephrons in the kidneys progressively die off. With less functioning nephrons available to act as a filter, toxic waste products accumulate in the bloodstream, eventually affecting other organs. 

Due to the malfunctioning of the nephrons, the cat becomes increasingly unable to excrete acid, and this backlog of acid builds up in the urine, in turn making the blood highly acidic. As the blood's acidity rises, the body’s pH becomes too low. Excess acidity in the blood, also called metabolic acidosis or renal tubular acidosis (RTA) is one of the more common types of chronic kidney diseases that cats suffer from. 

Cats with chronic kidney disease often show no signs at first. Eventually, as a result of the elevated levels of acid, the cat might exhibit symptoms such as:

• Vomiting
• Fever
• Panting
• Lethargy
• Dehydration
• Weight loss
• Anorexia
• A bony spine
• Mouth ulcers
• Excessive thirst
• Excessive urination
• Difficulty urinating
• Muscle weakness

There are many causes of excess acidity in the blood, both primary and secondary in nature. Distal RTA is very rare in cats. Some of the possible causes are:

• Pyelonephritis (a kidney infection)
• Immunodeficiencies
• Common causes of proximal RTA are:
• Congenital abnormalities such as Fanconi syndrome
• Exposure to toxins such as antifreeze, pesticides, plants and cleaning fluids
• Hypoparathyroidism
• Multiple myeloma
• Uremia
• Infection of the kidney and ureter
• Liver disease 

A urinalysis is critical in providing information about the cat's current level of kidney functioning. It measures the concentration of the cat's urine and detects the levels of acid and proteins. A veterinarian will also perform a full blood panel on the cat to detect the levels of various compounds in the blood, such as creatinine and symmetric dimethylarginine (SDMA), that build up because of poor filtering. 

A vet might perform further tests including X-ray, ultrasound, urine culture and kidney tissue biopsy, and arterial blood gas analysis. 

If a cat is experiencing acute kidney failure, it will be hospitalized for more aggressive treatment. Treatment of the underlying diseases causing metabolic acidosis will ultimately help resolve the disorder. However, a variety of additional therapies will speed the recovery process along. There is a range of options to consider including: 

• IV fluid therapy to correct electrolyte and fluid imbalances. This procedure is very common and may be administered from time to time.
• Bicarbonate therapy to replenish the lost bicarbonate in the cat's body. Sodium bicarbonate is widely available and can be dissolved in water and administered with a syringe in the mouth of the cat, or given as a gelcap. Your veterinarian will advise. 
• A vet will include a systematized plan of acid base and electrolyte monitoring.
• Potassium citrate can be a good option for some cats because it makes the urine less acidic and prevents development of kidney stones.
• Potassium supplementation
• Renal transplantation is an option in extreme cases as a last option.
• Dialysis is offered at some veterinary centers for extreme cases.

The partnership between caregiver and veterinarian, as well as careful monitoring, are absolutely essential in the recovery and management of excess acidity in the feline's blood. Together you will find a management plan that will both prevent further buildup of waste products in the blood and maintain a good quality of life for the cat. 

Dietary changes are often extremely helpful. With the help of the vet, a suitable therapeutic kidney diet can be found which usually contains low amounts of high quality protein, and low amounts of sodium and phosphorus, B vitamins, vitamin D, and omega-3 fatty acids.

Fluid therapy can be administered periodically in the hospital, and cat owners can easily learn to give subcutaneous fluids at home in the scruff of the neck between the shoulder blades. 

Make plenty of fresh water available to the cat and make the cat's environment as stress-free as possible.