Hypertension
- Affects 10 - 20% of adult population
- Defined as
- Diastolic blood pressure greater than 95 mmHg
- Systolic blood pressure greater than 160 mmHg
- Associated with increased risk of:
- Ischaemic heart disease
- Stroke
- Peripheral vascular disease
- Renal dysfunction
- In 90% cases not cause is found (essential hypertension)
- In 10% cases an underlying abnormality is identified (secondary hypertension)
Causes of secondary hypertension
Renal disease
- Renal artery stenosis
- Glomerulonephritis
- Pyelonephritis
- Interstitial nephritis
- Obstructive nephropathy
- Polycystic disease
- Obstructive uropathy
Adrenal disease
- Primary aldosteronism
- Cushing's syndrome
- Phaeochromocytoma
Drug induced
- Oral contraceptives
- Corticosteroids
- Sympathomimetics
Other causes
- Coarctation of the aorta
- Pre-eclampsia
- Raised intracranial pressure
Renal artery stenosis
- 70% cases are due to atherosclerosis
- 20% cases due to fibromuscular dysplasia
- Accounts for about 2% of all cases of hypertension
- Suspect renovascular cause of hypertension if:
- Severe hypertension (diastolic pressure greater than 125 mmHg)
- Patients with pulmonary oedema
- Patients with generalised atherosclerosis
- The elderly
- The very young
- Diagnosis can be confirmed by:
- Duplex ultrasound
- Digital subtraction angiography
- Increased serum renin levels
- Renal isotope scan
Management
- Initial management should be pharmacological
- If blood pressure is well controlled with drugs no further intervention is required
- In young patient or those with poorly controlled blood pressure consider
- Percutaneous transluminal angioplasty
- Renal stenting
- Renal artery endarterectomy
- Aortorenal bypass graft
- Best results seen in those with fibromuscular dysplasia
Bibliography
Hines G L. Current thoughts on the management of renovascular disease. Heart Dis
2000; 2: 118-123.
Novick A C. Long-term results of surgical revascularisation for renal artery disease. Urol
Clin North Am 2001; 28: 827-831.
Onusko E. Diagnosing secondary hypertension. Am Fam Physician 2003; 67: 67-74
Staessen J A, Wang J, Bianchi G et al. Essential hypertension. Lancet 2003;
361: 1629-1641 |