From the Guidelines
The most appropriate diagnostic test to perform next is renal artery CT angiography (option C). This patient presents with new-onset hypertension at a young age (27 years) with a significant physical exam finding of a systolic-diastolic abdominal bruit in the right lower quadrant. This bruit strongly suggests renal artery stenosis, which is a potentially curable cause of secondary hypertension, as indicated by the guidelines 1. CT angiography would provide detailed imaging of the renal arteries to confirm or rule out stenosis. The patient's normal electrolytes, including potassium and bicarbonate, along with normal renal function and absence of proteinuria, make primary aldosteronism (option A) less likely. There are no symptoms suggesting pheochromocytoma that would warrant plasma metanephrines testing (option B). While urine albumin-creatinine ratio (option D) is important for assessing end-organ damage in hypertension, it would not address the underlying cause suggested by the abdominal bruit. Identifying and treating renal artery stenosis could potentially cure this patient's hypertension, making renal artery imaging the priority diagnostic step.
Some key points to consider in this case include:
- The presence of a systolic-diastolic abdominal bruit, which is a classic sign of renal artery stenosis, as noted in the guidelines 1.
- The patient's age and lack of family history of hypertension, which makes primary hypertension less likely and secondary causes more likely to be considered.
- The normal laboratory results, which do not suggest other common causes of secondary hypertension such as primary aldosteronism or pheochromocytoma.
- The importance of identifying and treating renal artery stenosis, which can potentially cure the patient's hypertension and improve their quality of life, as emphasized by the guidelines 1.
From the Research
Diagnostic Approach
The patient presents with newly diagnosed hypertension and a systolic-diastolic abdominal bruit over the right lower quadrant, suggesting possible renal artery stenosis. The most appropriate diagnostic test to perform next would be one that can accurately diagnose renal artery stenosis.
Considerations for Diagnostic Tests
- Non-invasive tests such as ultrasound, CT angiography, and magnetic resonance angiography are preferred for initial diagnosis 2, 3.
- CT angiography has been shown to be effective in detecting renal artery stenosis with high sensitivity and specificity, especially at the main renal artery level 4, 5.
- Digital subtraction angiography (DSA) remains the gold standard but is typically reserved for cases where non-invasive tests are inconclusive or when intervention is planned.
Most Appropriate Diagnostic Test
Given the patient's presentation and the need for a non-invasive initial test, Renal artery CT angiography is the most appropriate diagnostic test to perform next. This test can help confirm the presence of renal artery stenosis, which is suggested by the abdominal bruit and the patient's new onset of hypertension.
Rationale for Choice
- CT angiography is a non-invasive test that can provide detailed images of the renal arteries.
- It has been shown to have high sensitivity and specificity for detecting renal artery stenosis 4, 5.
- The test is less invasive than DSA and can be used as a screening tool before considering more invasive procedures.
The correct answer is: C Renal artery CT angiography 6, 2, 4, 3, 5