Renal artery stenosis
Where a narrowing of the renal artery causes problems.
It can be down to fibromuscular dysplasia in young females - if so it will cause a "beaded" appearance of the renal artery on angiography.
Classically, they are generally asymptomatic, with a patient just suffering from secondary hypertension, that isn't easily controlled with medication.
Angiography can often show a narrowing of the blood vessel, or the beaded appearance of fibromuscular dysplasia.
As said before, it can be hard to treat clinically. Often, patients will be started on an ACE inhibitor since the doctor assumes its essential hypertension. This can cause a deterioration in renal function, so ACE inhibitors should not be given with renal artery stenosis.
If renal function deteriorates, blood pressure can't be controlled, or the cause is fibromuscular dysplasia, the treatment is angioplasty (surgical vessel widening), with or without stenting.