Hypertension is defined in childhood as blood pressure >= 95th percentile for age, height and sex. In contrast to adults, hypertension is often a sign of another disease in children.
Secondary hypertension is very likely in children under 6 years of age in whom we should look for an etiology very actively. The whole diagnostic process may be difficult and sometimes is complicated by false positive and negative results of some examinations.
In this article, we present a case report of a three-year-old boy with severe hypertension resistant to combined therapy which was diagnosed by a general pediatrician. The diagnostic approach was complicated by erroneous results of some examinations.