Sustained severe hypertension in children is most commonly suggestive of –
Hypertension in children

Hypertension is defined as the arterial blood pressure above 95th percentile with reference to age and sex.
Between the 90th and 95" percentile it is called borderline high blood pressure. 
	Causes of hypertension in children
Essential hypertension is relatively uncommon (10%) in children in contrast to aged persons.
The four most common causes of hypertension in children are : -

i)   Chronic glomerulonephritis (most common) —>           25 %
ii) Chronic pyelonephritis                                       —>           10 %
iii) Renal artery stenosis                                           -->           10 %
iv) Essential hypertension                                       —>           10 %
Remember

MC cause of hypertension in children chronic glomerulonephritis.
MC cause renovascular hypertension in children —› renal artery stenosis.
Coarctation of aorta
Pheochromocytoma
Renal parenchymatous disease
Drug induced