De prevalentie van primair hyperaldosteronisme bij katten met chronisch nierlijden

Abstract

Primary hyperaldosteronism is seen in middle-aged and older cats. The zona glomerulosa of the adrenal gland produces the mineralocorticoïd aldosterone. An excess of production of aldosterone in primary hyperaldosteronism originates from tumorous or non-tumorous adrenal tissue. Increase of retention of sodium and excretion of potassium in the kidney can result in systemic arterial hypertension which can cause loss of vision due to retinal detachment and intraocular hemorrhage. Development of hypokalemia may lead to decreased neuromuscular function which shows in episodes of muscle weakness and paresis with typical ventroflexion of the neck. Through thrombosis and fibrosis primary hyperaldosteronism in the cat may progress renal failure. In this study the prevalence of primary hyperaldosteronism was determined amongst a group of eleven cats with chronic kidney disease. Based on plasma creatinine levels of >164 μmol/L cats were selected. Systolic blood pressure was measured with Doppler technique, and eye examination was performed through ophthalmoscopy. Urine and bloodsamples were analyzed. Plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were measured and the PAC to PRA ratio (ARR) was calculated. Primary hyperaldosteronism was diagnosed in one of eleven cats based on ARR (9%). A significant correlation was found between ARR and plasma creatinin. In four cats the systolic bloodpressure was ≥ 185 mmHg, one cat had leasions of the fundus. Hypokalemia was found in three cats, one of them had signs of muscle weakness. To diagnose primary hyperaldosteronism with a higher reliability repeated and complementary measurements are needed. Nevertheless, the disease seems to play an important role in cats with chronic kidney disease. Only a small number of cats were evaluated. More research is required to obtain more data and reliable results concerning the prevalence of primary hyperaldosteronism in cats.