Ambulatory blood pressure monitoring (ABPM) is a potent tool for detection of arterial hypertension. Cystic kidney diseases such as autosomal recessive polycystic kidney disease (ARPKD), autosomal dominant polycystic kidney disease (ADKPD) and unilateral multicystic dysplastic kidney (MCDK) are often associated with hypertension. In children with these cystic kidney diseases blood pressure (BP) has been studied so far by causal BP measurements only. In the present study authors studied the BP pattern in children with cystic kidney diseases using ABPM. 122 children were investigated - 71 children with ADPKD, 21 with ARPKD, 25 with MCDK and 5 with solitary kidney cysts. Eight children with ARPKD had already antihypertensive treatment. All children with ADPKD had a normal glomerular filtration rate, 50% of children with ARPKD and 8% of children with MCDK were in chronic renal insufficiency. Four children with unilateral MCDK had reflux nephropathy or obstructive uropathy of the contralateral kidney. Hypertension was defined as systolic and/or diastolic daytime and/or nighttime BP mean > 95th percentile for the normal paediatric population according Soergel et al. and/or antihypertensive therapy at the time of the study. Hypertension was detected in 32% children with ADPKD, 86% children with ARPKD, 20% children with MCDK and in none of the patients with solitary cysts. In children with ADPKD the renal volume and number of renal cysts were higher in hypertensive children in comparison to normotensives ones (p < 0.01 for both). Children with ARPKD) had the most severe hypertension, usually requiring double or triple antihypertensive drug therapy. In children with MCDK hypertension was associated mainly with the damage of the contralateral - function solitary kidney. Conclusions: Cystic kidney diseases in children are often associated with hypertension. ABPM should be performed in all children with ARPKD, in children with ADPKD who have increased renal volume or a high number of renal cysts and in children with MCDK who show signs of contralateral kidney damage.

        Key words: ambulatory blood pressure monitoring, children, autosomal dominant and autosomal recessive polycistic kidney disease, multicystic dysplastic kidney, solitary cyst