Metabolic acidosis in people can exacerbate azotemia and promote further protein catabolism, muscle wasting, and hypokalemia.27 Alkalization therapy (usually oral potassium citrate or sodium bicarbonate) is indicated if acidosis is severe; commercial
renal diets are formulated with alkalizers.
Hypokalemia (reported in 20% to 30% of cats with chronic kidney disease) may exacerbate kidney disease and can cause weakness
and muscle wasting.28 Provide supplementation with oral potassium gluconate or potassium citrate in these cats.
Table 1 Initial Diagnostic Evaluation of Feline Kidney Transplant Candidates
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Hyperphosphatemia develops secondary to a decreased glomerular filtration rate. Oral phosphate-binding agents are indicated
in cats that cannot maintain normal serum phosphorus concentrations with dietary phosphorus restriction alone.
Calcitriol production may also be impaired in chronic kidney disease, disrupting calcium homeostasis and contributing to the
development of renal secondary hyperparathyroidism.29 Calcitriol supplementation is now advocated in dogs with normal phosphorus and increased serum parathyroid hormone (PTH)
concentrations.30 Monitor serum phosphorus and PTH concentrations to document control and prevent adverse effects of toxicosis.
DIAGNOSTIC EVALUATION
Recipient cats
Table 2 Conditions That May Preclude Kidney Transplantation in Cats
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Perform a thorough screening of a potential transplant recipient to identify abnormalities and concurrent diseases before
transplant referral. A typical required preoperative diagnostic protocol as well as conditions that preclude transplantation
are listed in Table 1 and Table 2, respectively.
Obtain a minimum database including a complete blood count, serum chemistry profile, urinalysis, urine culture, and serum
total thyroxine concentration. Any cat with a negative urine culture result but with a history of urinary tract infection
should undergo a two- to three-week cyclosporine challenge followed by a second urine culture. If a positive culture result
is obtained, institute treatment for presumptive chronic pyelonephritis and obtain a second culture after treatment. A second
positive culture result eliminates the cat as a potential transplant recipient.
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) infections are contraindications to transplantation because
of the theoretically increased risk of secondary infections once immunosuppression is initiated.
A serum titer against Toxoplasma gondii antibodies does not signify active infection, but candidates should be considered at higher risk of developing clinical toxoplasmosis
after immunosuppression.31 The best course of action to prevent possible recrudescence of infection in antibody-positive recipient cats is unclear;
recommendations vary among institutions, with treatment with clindamycin varying from a two-week course before transplantation
to lifelong therapy.31,32
Perform blood typing, and identify multiple compatible donors before surgery. Crossmatching typically occurs after patient
transfer to the transplant center.
Hyperthyroidism is a common concurrent disease in cats with chronic kidney disease. Affected cats are excluded unless definitive
treatment is completed before transplantation because hyperthyroidism treatment can further decrease the glomerular filtration
rate and exacerbate chronic kidney disease.33
Perform a complete cardiac evaluation to detect underlying cardiomyopathy. Severe cardiac disease is a relative contraindication
because of heightened anesthetic risk and anticipated shortened life span.
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