Condition- Renal Artery Stenosis Flashcards
What is renal artery stenosis?
Narrowing of the renal artery
What is the main cause of renal artery stenosis?
Atherosclerosis (85%)
Which cells in the kidney release renin? Which cells stimulate the release of renin?
Macula Densa- monitors blooks K+ and Na+
Stimulate Juxtaglomerular cells to release renin
What is the main cause of renal artery stenosis in younger patients?
Fibromuscular dysplasia (10%)
= abnormal growth of wall of artery
Describe how renal artery stenosis may lead to renal failure
- Renal artery stenosis
- Renal hypoperfusion
- stimulates RAS=> increase AngII and Aldosterone
- Hypertension
- = fibrosis, glomerulosclerosis and renal failure
What features in a patient’s history might suggest the presence of renal artery stenosis?
- Hypertension onset <50yrs
- Hypertension resistent to Tx
- History/ signs of unexplained kidyney dysfunction
- History of atherosclerotic disease
- PVD
- Coronary artery disease
- Sudden pulmonary oedema
State some signs of renal artery stenosis on physical examination
Resistant hypertension, renal bruits, may hear bruits in carotids + femoral, weak leg pulses (PVD)
Which medication is contraindicated in renal artery stenosis?
ACEi
Leads to accelerated hypertension and renal deterioration- exacerbates renal hypoperfusion => AKI
What might you look for in he bloods of someone with Renal Artery Stenosis?
- Creatinine= look at GFR (normal or high)
- Potassium= low (due to high aldosterone)
- aldosterone to renin ratio= low (exclude primary hyperaldosternism as a cause of hypertension and hypokalaemia)
List some investigations which could be used to confirm + measure th reduction in diameter of the renal arteries in RAS
- Duplex US
- CT Angiogram/ MR angiogram
- Digital Subtraction renal angiography- invasive + side effects
