De associatieve factor van hyperaldosteronisme bij progressief chronisch nierfalen bij de kat

Abstract

Primary hyperaldosteronism (PHA) was first described in 1983 in cats and was reported in literature as a rare diagnosis. In spite of the classic and well-known hemodynamic action of (an oversecretion of) aldosterone, the hormone also accounts for non-hemodynamic actions. Studies indicate that aldosteron is a contributable factor of chronic renal disease by inducing aldosteron-mediated changes as inflammation and oxidative stress, fibrosis, hypertrophy, endothelial dysfunction, podocyte injury, apoptosis and thrombosis. In view of the fact that the common feline disease chronic kidney failure is regularly compatible with hypertension and an inexplicable hypokalemia, it is important to investigate the incidence of primairy hyperaldosteronism in cats suffering from chronic renal disease. Since systemic arterial hypertension and hypokalemia is a usual hallmark of primairy hyperaldosteronism and the excessive secretion of aldosterone has deteriorating effects associated with the progression of renal failure, PHA is conceivable a more commonly condition in cats suffering from progressive chronic kidney failure. To obtain the percentage of PHA in cats with progressive chronic renal disease, this study included fourteen house cats of different breeds with an iterative plasma concentration of creatinine above the upper limit of the reference range of 164 µmol/L. All cases underwent a systolic arterial blood pressure measurements by using the Doppler ultrasonograpy, ophthalmic examination of the fundus by the use of an indirect ophthalmoscopy, a haematology and biochemistry profile also including measurement of plasma concentration of aldosterone and renin activity in the plasma and an urinalysis. The diagnosis of feline hyperaldosteronism is based on the measurements of the plasma concentration of aldosteron (PAC) and the activity of renin in the plasma (PRA), and the estimation of the PAC to PRA ratio (ARR). Two cats (14%) in this research were considered as hypertensive patients, and one of them had an ocular abnormality in form of pupillary light reflex deficits. Three cats (21%) exhibit hypokalemia, of whom two of these cats displayed hypokalemic polymyopathy. In none of the cases the ARR of the fourteen cats exceeded the upper limit of the reference range. Neither the plasma aldosterone concentration exceeded its upper reference range, nor the plasma renin activity surpassed its lower reference range. Despite of the fact that primairy hyperaldosteronism in none of these fourteen cats had been diagnosed, a closer analyze of the incidence of PHA in cats with chronic renal disease is recommendable considering the existing publications.