Taurine Deficiency (Feline)

Feline taurine deficiency refers to the deficiency of an amino acid (precursor of protein) called taurine in the feline diet.

Common name:Taurine deficiency
Scientific name: Feline taurine deficiency

Diagnosis

Signalment
Cats eating an improperly balanced home-cooked diet or a vegetarian diet are susceptible. Other less common causes are loss of taurine via the intestinal tract, insufficient production of taurine, or decreased protein digestion.

Incidence/prevalence
There is no sex, age or breed predisposition.

Geographic distribution
There is no known geographic predilection for this disease.

Clinical signs (primary,most to least frequent, scientific term, synonyms)
Decreased vision or blindness (secondary to central retinal degeneration), slow growth, signs of heart failure (difficulty breathing, decreased activity, loss of appetite).

Clinical signs (secondary,most to least frequent, scientific term, synonyms)
Reproductive failure.

Cause (scientific, common term)
Deficiency of the amino acid taurine in the diet.

Organ system affected >(most to least affected)
Heart (dilated cardiomyopathy), eye (central retinal degeneration).

Diagnostic tests
Plasma and whole blood taurine measurements; because plasma taurine concentrations can decrease rapidly with fasting, careful interpretation must be done. Echocardiography (an ultrasound of the heart) is the best test for dilated cardiomyopathy, ophthalmologic examination for central retinal degeneration.

Differential Diagnosis
Blindness of other causes (high blood pressure, glaucoma, uveitis to list a few), heart failure of other causes (hypertrophic cardiomyopathy, dilated cardiomyopathy).

Overview

Feline taurine deficiency is a syndrome most commonly caused by inadequate intake of taurine in the diet. Taurine is an amino acid that is required for many cellular functions. Years ago, this was caused by low levels of taurine in the diet. Cats can synthesize (manufacture) taurine in their bodies; however the rate of synthesis is much lower than in dogs, therefore it is readily used up. The most common cause for deficiency is an improperly balanced diet – most commercial diets are supplemented with taurine. Cats eating an improperly balanced home-cooked diet or vegetarian diet are at increased risk. Taurine deficiency most commonly results in dilated cardiomyopathy, an enlarged, weakened heart. This condition is usually reversible with taurine supplementation. Deficiency can also cause central retinal degeneration, degeneration of the functional part of the eye (the retina) which can lead to partial or complete blindness.

Treatment

Home Care
Long-term treatment involves switching the cat to a satisfactory diet, and supplementing the diet with oral taurine twice daily for 12 to 16 weeks, or until the changes in the heart return to normal. If dilated cardiomyopathy is present, regular follow up with a veterinary cardiologist will be required.

Professional Care
The diagnosis is based on low plasma or whole blood taurine concentrations, and clinical suspicion (presence of dilated cardiomyopathy or central retinal degeneration). If the cat is in heart failure, supportive treatment for heart failure should be instituted (including hospitalization, intravenous diuretics, oxygen therapy).

Action
If the cat is eating a vegetarian or home-cooked diet, a consultation and dietary formulation with a veterinary nutritionist is recommended.

Outcome
Dilated cardiomyopathy secondary to taurine deficiency is reversible with taurine supplementation if recognized and treated early. The prognosis worsens if there is extensive permanent change in the myocardium (heart muscle). If the cat is in advanced heart failure, then the prognosis also worsens.

References/Additional Readings

Buffington, C. A. Tony; Meurs, Kathryn M. Taurine Deficiency. In: Cote, Etienne, ed. Clinical Veterinary Advisor – Dogs and Cats. St. Louis: Elsevier, 2007;1066-1067.

Kittleson, Mark D.; Pion, Paul; Rishniw, Mark. Measuring Taurine in Plasma and Whole Blood – Medical FAQs. In: Veterinary Information Network, 2007. Accessed at: http://www.vin.com/Members/Proceedings/Proceedings.plx?CID=medfaq&PID=pr...

Michel, Kathryn E. Nutritional Assessment. In: Ettinger, Stephen J.; Feldman, Edward C, eds. Textbook of Veterinary Internal Medicine, 6th edition. St. Louis: Elsevier, 2005; 559-560.

Freeman, Lisa M.; Rush, John E. Nutritional Modulation of Heart Disease. In: Ettinger, Stephen J.; Feldman, Edward C, eds. Textbook of Veterinary Internal Medicine, 6th edition. St. Louis: Elsevier, 2005; 580.

Author
Sarah Alward, DVM

Editor
Sharon M. Gwaltney-Brant, DVM, PhD, DABVT, DABT