GPs Dr Kathryn Griffith and Dr Ivan Benett use a case history to outline how to manage raised blood pressure in the under-40s
A 28-year-old woman has been referred to you by the practice nurse. She had her first child a year ago and wants to restart the combined oral contraceptive pill. Her blood pressure is 170/95mmHg.
What should you do next?
It is important to confirm she has a persistently raised blood pressure before diagnosing her with hypertension.
Check previous readings and particularly any recordings you have from her pregnancy. Pre-eclampsia may be a precursor to the development of sustained hypertension. Loaning her an automated sphygmomanometer is a good way of assessing BP fluctuations, and more convenient than bringing her back to the surgery for repeated measurements. It is important to explain the recommended protocol for measurement and that the device has been accredited by the British Hypertension Society (see the BHS website).
Use the following protocol:
• the patient should be relaxed and seated for at least five minutes before the reading, and should not be speaking
• her arm should be supported at the level of the heart with no constricting clothing
• use the right sized cuff so it is comfortable, with the cuff bladder encircling at least 80% of the arm but not 100% – a standard cuff is appropriate for an arm 23-32cm in circumference
• have the device regularly serviced if it is to be used long term.
Take a focused history
She returns to see you with two weeks of readings. They are about 150/85 on average. This corresponds with surgery readings of 160/90 and confirms persistently raised blood pressure. In people under 30, essential hypertension is still much more likely than hypertension resulting from an underlying renal or endocrine cause. However, in this age group, an underlying cause should be sought, particularly if there is resistance to standard therapy.1 Other prompts include a labile BP, abnormal U&Es, urine protein or blood, a family history of polycystic kidneys, or signs of end-organ damage.2 The box below lists causes to be considered.
Important questions to ask in the history
• Are there other systemic symptoms, such as flushing, palpitations or weight loss, that indicate an underlying cause such as phaeochromocytoma or hyperthyroidism?
• Does she or anyone else in her family have a history of kidney problems? In particular did she have recurrent infections as a child to suggest renal scaring from chronic pyelonephritis, or does anyone in her family have polycystic kidney disease with an autosomal dominant inheritance?
• Is she on any other medication? Consider over-the-counter drugs, particularly NSAIDs, or sympathomimetics in cold remedies. Excessive liquorice consumption or recreational stimulants may also affect BP.
• Smoking will affect cardiovascular risk, and alcohol consumption can affect stroke risk.
• Is there a family history of hypertension, stroke or CVD?
What would you do about the combined pill?
She should not start the combined pill – consider an alternative.
What do you need to check for on physical examination?
It is important to confirm BP is the same in both arms and that there is no evidence of radio-femoral delay. If present, this would raise the suspicion of coarctation of the aorta. Palpate the abdomen for enlarged kidneys that suggest polycystic kidney disease or hydronephrosis, and listen for renal bruits in case she has renal artery stenosis. Check the optic fundi for evidence of hypertensive retinopathy, if the BP has been consistently over 160/90.
It is also important to identify markers of increased cardiovascular risk such as obesity and hyperlipidaemia.
Endocrine conditions associated with hypertension such as Cushing's disease and hyperthyroidism have classical clinical findings, which may be apparent.
Which tests do you need?
Check the urine for blood and protein. Urine should be sent to the laboratory for albumin-creatinine ratio if the urine is stick-test negative for protein.
Blood tests should include creatinine and eGFR, sodium and potassium for Cushing's or Conns' syndrome. However only a third of patients subsequently confirmed with primary hyperaldosteronism have hypo-kalaemia. The remainder have potassium levels at the lower end of the normal range and sodium levels at the upper end.3 Blood should also be taken for fasting-lipid profile and glucose to enable an accurate cardiovascular risk assessment score.
An ECG should be arranged at this stage. High left ventricular voltages may indicate left ventricular hypertrophy (LVH). These patients should have an echocardiogram to confirm LVH as they are at a high risk of cardiovascular events.
Refer for a renal ultrasound if there is a family history of polycystic kidney disease even if you cannot palpate the kidneys, or if there is a rapid decline in renal function after starting an ACE inhibitor even if you don't hear a renal bruit. Phaeochromocytoma occurs in less than 0.2% of people with hypertension – that is less than once in a clinical lifetime. It has classical symptoms of headache, sweating and palpitations that are intermittent. Without these symptoms it is most unlikely that a 24-hour urine vanillylmandelic acid, a measure of serum catecholamines, will yield a positive result, so in the absence of symptoms the test is unnecessary. Cushing's or Conn's syndrome, also rare, may be suspected if pre-treatment potassium is reduced and there is resistance to treatment. If either is seriously suspected then an endocrinologist should be consulted for more specific tests.
What are the best treatments?
Lifestyle advice remains the cornerstone of initial and ongoing management.4 The principles of and evidence for lifestyle management are covered in Professor Caulfield's Key Questions article. Buying into lifestyle changes and taking medication is important. Explanation and targeted education is the key to optimising concordance with both. People must understand why they need to make these changes, and their ideas, concerns and expectations must to be addressed.
Before starting medication it is important to consider overall cardiovascular risk. The patient will be at low absolute 10-year risk (unless she has malignant hypertension). On the other hand she will have hypertension for a long time, so many would intervene with drugs if lifestyle alone does not bring her BP under control.
If she has evidence of target organ damage, CKD, diabetes or a risk score of 20% or more, then she should be started on and ACE inhibitor – or an ARB if ACE intolerant – as she is under 50. People of African origin or over 50 years should start on a calcium-channel blocker or thiazide diuretic. As a young woman it is important to check if she plans to have more children since these drugs are contraindicated in pregnancy. Also consider fibromuscular dysplasia in young women, which – although rare – causes renal artery stenosis. So start medication at a low dose, repeating renal function two weeks after starting an ACE inhibitor or ARB.
Who should be referred?
The BHS Guidelines recommend that, where there is any clue in the history or examination of an underlying cause, then the patient should be considered for specialist referral.1 This can be to secondary care or a GPSI.
In particular consider referral if there is:
• hypokalaemia with increased or high normal plasma sodium to suggest Cushing's or Conn's syndrome3
• an abnormal creatinine result, proteinuria or haematuria
• sudden-onset or worsening of hypertension
• resistance to standard treatment, usually more than three drugs
• raised BP in anyone under 20 and BP raised enough to warrant treatment in under-30s
• any sign of accelerated or malignant hypertension such as retinal haemorrhages or deteriorating renal function.
Plan of action with this patient
The patient has a BMI of 35 and until recently smoked 20 cigarettes per day. All her investigations have been normal. She worked very hard with the practice nurse and managed to stop smoking although progress with weight loss has been slow. With the money she has saved from cigarettes she has now joined a gym. She has decided on a copper IUCD, wishing to avoid all hormones. Her BP is currently 148/92, measured with a large arm cuff. She has been put on the hypertension register to ensure follow-up but is not currently taking any medication. She has not been referred to a specialist. As she appears to have uncomplicated hypertension she should be treated to a target of 140/90.5
Why does this matter?
People with grade 1 hypertension 140-159/90-99 are more likely to proceed to higher grades of hypertension and thus be at increased risk of cardiovascular events.6 In addition, a study of BP-related cognitive decline, over an average of 20 years' follow-up, demonstrated that higher levels of systolic and diastolic BP were associated with a similar decline in cognitive abilities in both younger adults (mean age 35 at the start) and a group whose mean age was 58. Persistent hypertension may therefore be associated with risk even where calculated CVD risk is low.7
Dr Ivan Benett is a GPSI in cardiology for NHS Manchester
Dr Kathryn Griffith is a GP in York and hospital specialist at York Hospital Foundation Trust
Competing interests None declaredCAUSES Young overweight woman having her BP taken Hypertension in younger people