Renal artery stenosis Flashcards
Define renal artery stenosis
Stenosis of the renal artery
Causes of renal artery stenosis & explanation
older + younger 3 points
ATHEROSCLEROSIS
(older patients)
Widespread aortic disease involving the renal artery ostia
FIBROMUSCULAR DYSPLASIA
(younger patients)
Unknown aetiology
May be associate w/ collagen disorders, neurofibromatosis & Takayasau’s arteritis
May be associated w/ micro aneurysms in mid & distal renal arteries (resemble string of beads on angiography)
Aetiology of renal artery stenosis
3
Renal hypoperfusion stimulates the renin-angiotensin system leading to increased angiotensin II & increased aldosterone
This leads to increased BP
The high BP leads to fibrosis, glomerulosclerosis & renal failure
Epidemiology of renal artery stenosis
prevalence, association, age
Prevalence unknown
Accounts for 1-5% all hypertension
Fibromuscular dysplasia occurs mainly in women w/ hypertension <45 yrs
Presenting symptoms of renal artery stenosis
4
History of hypertension in <50 yrs
Hypertension refractory to treatment
Accelerated hypertension & renal deterioration on starting ACE inhibitors
History of flash pulmonary oedema
Signs of renal artery stenosis on physical examination
3
Hypertension
Signs of renal failure in advanced bilateral disease
Renal artery bruits
Investigations for renal artery stenosis
4
Non invasive
CT angiogram or MR angiography
Digital subtraction angiography
Renal scintigraphy
Investigations for renal artery stenosis - non invasive
2
Duplex US
US measurement of kidney size
Investigations for renal artery stenosis - CT/MR angiography
Risk of contrast nephrotoxicity
Investigations for renal artery stenosis - gold standard?
Digital subtraction angiography
Investigations for renal artery stenosis - renal scintigraphy
(2)
Uses radio-agent that is either excreted by glomerular filtration or by the tubules
Addition of an ACE inhibitor causes delayed clearance by affected kidney
Drug contraindicated by renal artery stenosis
ACE inhibitors
