A man with high blood pressureBMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b1550 (Published 06 May 2009) Cite this as: BMJ 2009;338:b1550
- 1Centre for Population Health Sciences, General Practice Section, University of Edinburgh, Edinburgh EH8 9DR
- 2 Department of Medical Sciences, Western General Hospital, Edinburgh EH42XU
- Correspondence to: B McKinstry
A 29 year old white man presented to general practice after a routine check at work, which was carried out because he felt lightheaded. His work found a blood pressure of 178/104 mm Hg and a pulse rate of 100 beats/min. His cousin, who was a nurse, rechecked his blood pressure and found it to be 138/92 mm Hg. He was not a regular attendee at the surgery and was taking no drugs. He had occasionally felt lightheaded during the past year, but he had never fainted. He had a family history of high blood pressure. He was slim (body mass index of 20), and in the surgery he had a blood pressure of 172/94 mm Hg and a pulse rate of 98 beats/min. Optic fundi, peripheral pulses, heart sounds, and chest examination were all normal. He had no abdominal bruits.
1 What is the most likely diagnosis?
2 What other conditions might you suspect?
3 How would you assess him further?
4 How would you manage and follow up this patient?
1 Primary “essential” hypertension or “white coat hypertension” (high in surgery but normal at home).
2 Secondary hypertension caused by drug misuse, phaeochromocytoma, primary aldosteronism, renal failure, renal artery stenosis, or coarctation of the aorta.
3 Take a history to exclude drug and alcohol misuse as causes. Ask him about symptoms of palpitations or sweating. Measure urea, electrolytes, lipids, and random blood glucose. Carry out a full blood count, liver function tests, urinalysis, ambulatory blood pressure monitoring, and resting electrocardiography. If his high blood pressure is sustained on ambulatory blood pressure monitoring, measure urinary metanephrines and perform renal ultrasonography.
4 The diagnosis was white coat hypertension. His average awake time ambulatory blood pressure was 132/78 mm Hg. He was reassured, but advised to have annual ambulatory blood pressure monitoring.
Even in someone as young as 29 the most likely diagnoses are primary essential hypertension or white coat hypertension. Up to 20% of patients of all ages have white coat hypertension.1 However, guidelines from the British Hypertension Society recommend that a secondary cause of hypertension should be sought in people under 30 years in whom treatment is being considered.2
Although the true prevalence of secondary hypertension is unknown and detailed studies of unselected populations are lacking, it is probably more common in people under 30 years. Some series suggest that hypertension is secondary to other causes in around 10% of people with hypertension.3 4 5 Known causes include misuse of alcohol and drugs, renal failure, renal artery stenosis, phaeochromocytoma, primary aldosteronism, coarctation, Cushing’s syndrome, and acromegaly.
Our patient’s history of a variable blood pressure indicates that he may have white coat hypertension. However, phaeochromocytoma can also be associated with variable blood pressure and dizzy spells.6
In white coat hypertension, blood pressure is high when measured in the surgery or clinic but not when measured at home. In general, people with white coat hypertension have lower morbidity than those with sustained hypertension but higher morbidity than normotensive patients.7 However, trials on the consequences of high blood pressure and the benefits of treatment are largely based on measurement in clinical settings. The withholding of treatment in patients with white coat hypertension is contentious, and such patients need to be followed up.
2 Other causes
Chronic alcohol use and the use of stimulant drugs, such as cocaine and amphetamines, may cause high blood pressure,8 9 as may some prescribed and over the counter drugs, such as non-steroidal anti-inflammatory drugs.10
Phaeochromocytoma is rare (incidence 2-8/1000 000/year worldwide).6 The history of light headedness, tachycardia, and low body mass index suggest phaeochromocytoma as a possible diagnosis in this patient. Other symptoms and signs include sweating, headache, and pallor.
In primary aldosteronism, increased production of aldosterone leads to retention of sodium, excretion of potassium, and high blood pressure. It is one of the more common causes of secondary hypertension and occurs in up to 10% of patients with high blood pressure.5 As well as symptoms associated with high blood pressure, patients may have muscle cramps and muscle weakness. It is diagnosed by measuring renin (which is always low) and aldosterone. A high aldosterone to renin ratio is taken as the marker for further investigation.11 However, antihypertensive drugs, which can confound the test, have to be stopped for up to six weeks for more detailed testing. Most patients with a high aldosterone to renin ratio do not have an adrenal adenoma (Conn’s syndrome) but hyperplastic adrenals and can be treated medically.12
Renal hypoperfusion (renal artery stenosis) leads to hyperactivation of the renin-angiotensin system and hence hypertension. The most common cause of renal artery stenosis is atheroma, although in young people fibromuscular dysplasia is the usual cause. American and European studies have estimated the prevalence of appreciable renal artery fibromuscular dysplasia to be about 0.4%.13 It is more common in women than in men. It should be suspected when creatinine becomes raised after the introduction of an angiotensin converting enzyme inhibitor in bilateral disease, or when the patient has an abdominal bruit. In such situations the optimum sequence of further investigations is unclear, but renal ultrasound should be carried out, followed by magnetic resonance angiography or possibly digital subtraction angiography.14
Coarctation of the aorta is unlikely in this case because the peripheral pulses are normal, but depending on the site this condition can be identified by differential blood pressures in the arms or radio-femoral pulse delay.
3 Further assessment
Ambulatory blood pressure monitoring provides an average of more than 20 readings, and it is a better predictor of ischaemic heart disease and stroke than blood pressure recorded in the surgery.7 It will help establish whether white coat hypertension is present. Patients with phaeochromocytoma may show extreme variability in blood pressure or a reversal of the day-night rhythm (or both).
Evidence of left ventricular hypertrophy on resting electrocardiography might help in borderline decisions about drug management, but the test is insensitive. Echocardiography is more sensitive but also more expensive.
A normal urea test will rule out renal failure. High sodium and low potassium raise the suspicion of primary aldosteronism. Liver function tests may indicate an alcohol problem, as may a raised mean cell volume. Protein or blood in the urine suggest a renal cause or may indicate hypertensive organ damage. The measurement of cholesterol may help with risk stratification, although it is unlikely to influence the decision about whether to treat blood pressure in such a young patient.
Phaeochromocytoma is diagnosed by measuring 24 hour urinary metanephrines. Although most of these tumours are easily diagnosed with this test, the test is fallible. If the clinical suspicion is high, repeated measurement and plasma measurements may be needed. The detection of raised concentrations of metanephrines in plasma shortly after an event (such as sweating, headache, or raised blood pressure) can be helpful.6
A renal ultrasound would detect major differences in renal size or polycystic disease and guide the need for further investigation.
No specific treatment is needed for people with white coat hypertension, but they should be advised to reduce their intake of salt and (where appropriate) alcohol and calories, and to exercise regularly.2 Because some studies have indicated that up to 50% of such patients can develop sustained hypertension over time, they should undergo long term follow-up with annual assessment of blood pressure, by home or ambulatory monitoring.15
Cite this as: BMJ 2009;338:b1550
Competing interests: None declared.
Provenance and peer review: Commissioned; externally peer reviewed.
Patient consent not required (patient anonymised, dead, or hypothetical).