100 QUESTIONS IN CARDIOLOGY

3 Who should be screened for a cause of

secondary hypertension? How do I screen?

Kieran Bhagat

The clinical context and the outcome of investigations that should

be carried out on all hypertensive patients will determine who

should be investigated for secondary causes of hypertension.

Routine tests that should be performed

• Urinalysis. Proteinuria is suggestive of underlying renal damage

or a causative lesion within the kidney.

• Routine biochemistry. This may suggest the presence of renal

dysfunction (urea, creatinine, uric acid) or underlying endocrine

disease (Conn’s, Cushing’s, hyperparathyroidism).

• Electrocardiography. This may show the effects of long standing

or poorly controlled hypertension (left ventricular hyper-

trophy, left axis deviation).

Further testing

If routine testing reveals abnormalities or the patient has been

referred for “resistant hypertension” then further investigations

are justified. These should be determined by clinical suspicion

(for example, symptoms or signs of phaeochromocytoma,

Cushingoid appearance etc.) and the outcome of routine investi-

gations (for example proteinuria, haematuria, hypokalaemia etc.).

• Urinalysis. 24 hour quantification of protein, electrolytes, and

creatinine clearance.

• Radiological. Initially, ultrasound examination of the abdomen

screens renal size, anatomy and pelvicalyceal disease.

Computerised tomography of the abdomen scan has greater

sensitivity for adrenal tumours and phaeochromocytomas.

MIBG scanning will help identify extra-adrenal phaeo-

chromocytoma. Renal angiography will identify renal artery

stenosis.

• Renal biopsyshould be performed if microscopy or plasma

immunological screening is suggestive of systemic

inflammatory or renovascular disease.