Case Author(s): Samuel Wang, M.D. and Keith Fischer, M.D. , 9/22/96 . Rating: #D3, #Q3

Diagnosis: Renovascular hypertension

Brief history:

56 year old woman with poorly controlled hypertension.

Images:

Baseline posterior static images.

View main image(rs) in a separate image viewer

View second image(rs). Baseline time activity curves.

View third image(rs). ACE inhibited posterior static images.

View fourth image(rs). ACE inhibited time activity curves.

Full history/Diagnosis is available below

Diagnosis: Renovascular hypertension

Full history:

This is a 56-year old patient with hypertension which is poorly controlled with antihypertensive medications. She also has a history of renal failure when placed on angiotensin converting enzyme inhibition.

Radiopharmaceutical:

Tc-99m MAG3 i.v.

Findings:

Baseline renal scintigraphy was performed first. The flow images (not shown) demonstrated mildly decreased perfusion to both kidneys. There is normal uptake bilaterally, though excretion is mildly to moderately reduced. ACE-inhibited renal scintigraphy using enalaprilat i.v. was then performed. This again demonstrates normal uptake bilaterally; however, there is now prolonged retention of activity with markedly delayed excretion bilaterally. These findings are most consistent with renin-dependent renal artery stenosis. Renal angiography demonstrated distal small branch stenoses bilaterally.

Discussion:

Renal artery stenosis causes the renal perfusion pressure to decrease. In an attempt to compensate, the juxtaglomerular apparatus will increase production of renin. Renin converts angiotensinogen produced in the liver to angiotensin I. Angiotensin I is then converted in the lungs to angiotensin II. Angiotensin II causes preferential glomerular efferent arterial constriction, thus maintaining the glomerular filtration rate. Angiotensin II also stimulates release of aldosterone from the adrenal gland with subsequent sodium retention and increased blood volume. ACE inhibitors work by blocking the conversion of angiotensin I to angiotensin II. In a hypertensive population, the prevalence of renovascular hypertension is approximately 0.5%. Approximately 29% of patients with renal vascular hypertension have bilateral stenoses. View followup image(an). Renal arteriogram.

ACR Codes and Keywords:

References and General Discussion of Renal Scintigraphy (Anatomic field:Genitourinary System, Category:Organ specific)

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Case number: rs012

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