A 10-year old boy presents to the pediatric emergency unit with seizures. Blood pressure in the upper extremity measured as 200/140 mm Hg. Femoral pulses were not palpable. The most likely diagnosis amongst the following is:

Isolated upper extremity hypeension (200/140 mm Hg), with absent/diminished femoral pulses, is characteristic of coarctation of the aoaSeizures may be due to severe hypeension or due to intracranial haemorrhage(from berry aneurysms which are more common in patients with coarctation)The classic sign of coarctation of the aoa is a disparity in pulsations and blood pressures in arms and legsThe femoral, popliteal, posterior tibial and dorsalis pedis pulses are weak (or absent in about 40% of patients) in contrast to bounding pulses in the arms and carotid vesselsBP in the legs is lower than in the arms and 90% of patients have hypeension in upper extremity greater than the 95th percentile for ageAge (yrs)95th percentile (mm Hg)>1 110/601-5115/756-10125/8511-18140/90Takayasu aooaeritis may also present with severe hypeension and absent femoral pulses due to acquired mid-aoic coarctation (but this is an uncommon presentation)Most commonly affects subclan aery and more commonly presents with claudicationCoarctation TakayasuMore commonMore common in boysUpper extremity hypeensionBounding pulses in arms and diminished or absent pulses in lower limbsHypeension is frequentLess commonMore common in girls (8:1 = f:m)Absent or decreased upper limb pulses and blood pressure difference between left and right arms are characteristicHypeension is frequentSystemic symptoms are more common(ref: Harrison's 18/e p1925)