Profile of Continuous ambulatory blood pressure monitoring in children and adolescents with nephrotic syndrome

Nephrotic syndrome is the most frequent pediatric glomerular disease, affecting from 1.15 to 16.9 per 100,000 children per year globally, characterized by alterations of perm-selectivity at the glomerular capillary wall, resulting in its inability to restrict the urinary loss of protein and manifested as edema, hypoalbuminemia and hyperlipidemia. Almost 80 percent of the children with nephrotic syndrome (NS) have steroid sensitive disease and show minimal changes on renal histology and respond to steroid therapy. Most patients both with steroid sensitivity or steroid resistant nephrotic syndrome receive oral prednisolone for prolonged periods. Besides, hypercholesterolemia is a ubiquitous finding in nephrotic syndrome, the magnitude of dyslipidemia directly correlates with the severity of proteinuria. Children with nephrotic syndrome have been shown to be at a higher risk of hypertension due to the underlying condition, use of corticosteroids for prolonged periods and use of medications like calcineurin inhibitors. Ambulatory hypertension, abnormalities in blood pressure (BP) circadian rhythm, and measures of BP variability are prevalent in patients with NS. Left ventricle hypertrophy (LH) is strongly associated with hypertension in children, especially with masked hypertension. Hence, casual blood pressure monitoring alone is insufficient for detection of hypertension induced LVH. Continuous ambulatory blood monitoring (CABPM) measures blood pressure for 24 hours during normal physical activity rather than a single instant, thus allowing assessment of 24 hour blood pressure profile of a patient and nocturnal dipping which is often lost early prior to the onset of overt hypertension in children and adults. For methodology of the study, an informed consent and or assent will be taken from patient and caregivers before enrolling for the study. A study Performa shall be filled that will include baseline information (age, diagnosis, duration of NS, treatment details) of the patient. A detailed examination and anthropometry will be done and recorded Anthropometry values (weight, height, BMI) will be categorized using India Academy of Pediatrics charts. Biochemical investigations including hemogram, kidney function tests, serum albumin, lipid profile, HbA1c will be done at baseline for all patients by drawing a 2ml blood sample. Casual BP will be measured and patient will be admitted for 24 hours for Continuous ambulatory blood pressure monitoring using CABPM device AND TM2441 which will record BP readings every 30 minutes during daytime and every 1 hour at night for a 24 hours period using an optimum Pediatric size cuff placed on the non-dominant arm of the patient. An echocardiography for detection of left ventricular hypertrophy will be done for all patients and the indices that will be measured are- interventricular septal thickness, LV posterior wall thickness and LV mass index. BP loads will be calculated from the data-(percentage of readings above the ambulatory 95th percentile for both SBP and DBP during the entire 24-hour awake and sleep periods). The cut off for CABPM values will be taken from the references provided by the German Collaboration Group (Aged 6 yr or > 120cm height). Based on these results the patients would be categorized into different categories of hypertension.