I got this from a practice exam and am a little confused.

62yo F w/ HTN comes for follow up. BP was well controlled until 1 yr back. Ranged from 160/100-180/120mmHg over last year. Pt is already taking max doses of an ACE, B blocker, and diuretic w/ no control. 2 year history of increasing leg pain with walking that improves with rest; otherwise asymptomatic. LMP 7 years back. 40-80 pack year smoking hx but quit 1 yr back. Exercise capacity has IMPROVED during last year. BMI 21kg/m2.
Pulse 85/min, BP 160/100 mmHg R arm, 145/105 in L arm, and 155/90mmHg in R leg. Cardiac exam shows non displaced PMI; S4 but no other added sounds. Normal abdominal exam. Pulses 2+ in upper limbs, but femoral and dorsalis pedis 1+. Serum studies show K+ 4.5 mEq/L, BUN 20mg/dl, and creatinine 1.2 mg/dL. What is the cause of this patients HTN?

A) atherosclerotic renal artery stenosis
B) coarctation of aorta
C) fibromuscular dysplasia
D) polycystic Kidney disease
E) primary hyperaldosteronism

I put coarctation of aorta but this was considered incorrect.

The only other possibility is atherosclerotic renal artery stenosis cause she has signs of atherosclerosis (S4 and claudication)but would that not cause a hyperaldosterone type state and --> lower K+ levels? Also why else would there be BP difference of 15/5mmHg between arms

This is a NBME q

it culd not be renal artery stenosis bcz pt is taking max doses of ACE inhibitors. and ACE inhibitors are contraindicated in renal artery stenosis so fibromuscular dysplasia and atherosclerotic renal artery become wrong.

'A' option is the ans by excluding other choices though it s also not compatible.

u are saying true about ace inhibitors but also remember they are contra only in bilateral renal artery stenosis not in unilateral stenosis. So this patient may have unilateral renal a. stenosis though bruit is not there but everything else is there. So its the right option. Regarding fibromuscular dysplasia , it s present in adolescents and a congenital condition. Hope u get this ! Thanks......................