Adverse drug reactions: a preventable problem
Oedema of the ankles in an elderly patient
Belview nursing home rang, worried about 90-year-old Mrs Glenwils. 'She has oedema of her ankles. Please could you send a script for diuretics?'
Dr Peter Moore discusses.
What further questions should the registrar ask?
Ankle swelling is not a diagnosis and should not be treated until a diagnosis is made. We need to ask the home whether she is unwell. One of the best ways to ask this is: 'If she did not have the ankle swelling would you still be worried about her?' Other important questions:
·Is the oedema on both legs?
·How mobile is she?
·Is the swelling there in the morning after a night's sleep?
·Are the legs painful?
·Is there any shortness of breath especially on exercise or lying down?
·Does she have any other oedema?
It is also worthwhile looking out of the window to see if it is a hot day. If she is sitting still in hot, heavy weather, ankle swelling is more likely.
If she is well with no other problems the registrar may be able to give advice over the phone. However, the nurse must have been worried enough to telephone and may not accept telephone triage, especially if there is no prescription for diuretics. There may also be relatives who have expressed concern. If a visit is not necessary it might be sensible to arrange some blood tests.
What are the likely causes of ankle oedema in the elderly?
Some nurses seem to see ankle swelling as a problem which must be treated. Assuming it is bilateral, for most elderly people a certain amount of postural oedema after sitting all day is normal.
Check the medication. Calcium channel blockers can causes ankle swelling which will not respond to diuretics.
The next possibility is right-sided heart failure. She will need to be examined, especially for signs of left ventricular failure. In the elderly, heart failure can be subtle. There is normally associated fatigue and shortness of breath.
Renal failure with nephrotic syndrome is a possibility but rare in general practice.
She may be suffering from lymphoedema although there will be a long history. Ankle oedema also occurs in severe anaemia and hypothyroidism.
Swelling from thrombosis or venous obstruction from malignancy is usually unilateral.
What examination is necessary?
If a visit is necessary she will need to be examined. This will include the heart and chest to assess if there is any congestive cardiac failure and her abdomen for masses. An assessment of the ankles will give an idea of the scale of the problem.
What basic investigations should be carried out?
Having taken a history it would be sensible to arrange for some basic blood tests. A full blood count, plasma viscosity, urea and electrolytes, liver function tests and thyroid function tests should exclude most causes. A urine test for protein would also be prudent.
Would it do any harm to give diuretics anyway?
Apart from the social inconvenience caused by the diuresis, thiazides and loop diuretics cause hypokalaemia and postural hypotension. Many elderly, especially if poorly nourished, can have low total potassium.
This can lead to lethargy and cardiac arrhythmias. Many also suffer from postural hypotension. By giving diuretics the blood pressure could drop on standing, leading to falls.
If we treat only symptoms then Mrs Glenwils could be given diuretics for her ankle oedema, become giddy from the subsequent postural hypotension and be given prochlorperazine.
This will exacerbate the postural hypotension, leading to further falls and confusion. If the confusion is then treated with a tranquilliser she will become quieter and even more
How should we treat the ankle oedema?
The most important action is to convince the staff and family that postural oedema in the elderly is normal. She does not need diuretics. The best advice is to suggest elevation of the legs when she is sitting down. Support stockings are also helpful.
·Postural oedema in the elderly is common and harmless
·It is important to find out whether elderly people with bilateral ankle swelling are otherwise well
·Most serious differential diagnoses can be excluded with basic blood test and a urine dipstick for protein
·Diuretics should not be used to treat ankle oedema in the absence of other pathology
Peter Moore is a GP in Paignton, Devon