Andrew Barry
Age: 75 years old male
Examiner
Marking Scheme
Data Gathering and Diagnosis
- Elicit why patient had the blood test in the first place.
- Take history from head-to- toe
- Head- have you or anyone noticed you feel muddled or confused? Any drowsiness? any headache, any abnormal jerky movement (Seizures)
- Mouth- Nausea/vomiting, excessive intake of water (primary polydipsia –when people just drink water a lot)
- Chest-Palpitations, chest pain. Also ask for cough (Lung cancer causing SIADH) SOB (hear failure, lung cancer)
- Abdomen- diarrhoea (Gastroenteritis can cause hyponatraemia)
- Urine- reduced urine output (hypovolaemia)
- Ask for weight loss (Cancer)
- Ask about diet (Tea and toast syndrome in elderly patient is a common cause of hyponatraemia in primary care)
- Ask about frequent falls- chronic hyponatraemia causes frequent falls in elderly
- Smoking (Lung cancer risk), alcohol
- Medication uses (Omeprazole, diuretics, SSRI, opioids)
- Give a diagnosis of worsening hyponatraemia likely caused by recent medication
Example of explanation to patient
Mr Barry, thanks for coming in to discuss your blood test results. You’ve recently had a change in your blood pressure medication, and as we often do with new medications like Indapamide, we checked your bloods to make sure your kidneys and salt levels in the blood are okay.
Your results show that your sodium level has dropped further, it’s now at 130, and the normal range is between 135 and 145. While you’re not feeling unwell right now, low sodium like this, especially in someone your age, can lead to symptoms like tiredness, confusion, or even falls. So, it’s important we take this seriously to prevent things from worsening.
Based on this result and the timing, it’s likely that the Indapamide, which we started 2 weeks ago, is contributing to this drop. It’s a known side effect in some people, especially older adults, and that’s why we monitor for it.
So, my plan today is to stop the Indapamide and repeat your blood test in about a week to check if your sodium level starts to return to normal.
You also asked about your low-salt diet. In this case, I’d actually suggest you return to a normal, balanced salt intake, as eating too little salt can sometimes contribute to this issue as well.
In terms of managing your blood pressure going forward, we’ll look at alternative medication options, like bisoprolol or doxazosin, which don’t tend to affect sodium levels.
For now, I’ll arrange your next set of blood tests, and I’d also like you to let us know straight away if you feel unwell at all, especially if you notice symptoms like confusion, headaches, vomiting, or unusual drowsiness, as these could be signs your sodium is dropping further.
We’ll follow up again in about a week’s time to review your bloods, your blood pressure, and how you’re feeling.
Management
- Stop Indapamide, as this is the likely cause of the low sodium (hyponatraemia).
- Repeat blood tests (including sodium) in 1–2 weeks to monitor for improvement.
- Request urine and serum osmolality to assess for the cause of hyponatraemia if sodium remains low in 2 weeks’ time during review. In addition, arrange additional blood tests: Thyroid function tests (TFTs), Full blood count (FBC), Liver function tests (LFTs), BNP – only if there is clinical suspicion of heart failure
- Advise the patient to resume a normal salt diet, as continuing a low-salt diet can worsen hyponatraemia.
- Consider initiating an alternative antihypertensive: Alpha-blocker (e.g., Doxazosin) or Beta-blocker (e.g., Bisoprolol) – depending on individual factors and comorbidities. Repeat Blood pressure in 2 weeks when reviewing his medications.
- Heavily safety-net: advise the patient to seek urgent medical attention if they develop: vomiting, headache, drowsiness, confusion or seizures – all of which may indicate worsening or symptomatic hyponatraemia
- Arrange a follow-up in 1-2 weeks to: repeat bloods, check blood pressure, review symptoms and treatment plan.
Learning point from this station:
Thiazide and thiazide-like diuretics, such as Indapamide, are a well-recognised cause of hyponatraemia, particularly in older adults. This can occur even within the first few weeks of treatment. Routine electrolyte monitoring after initiating such medications is essential to detect early complications.
Patients may be asymptomatic or present with non-specific symptoms such as fatigue, headache, confusion, or in severe cases, seizures. It is crucial to assess contributing factors such as low salt diet, comorbidities, or concurrent medications.
In asymptomatic, mild hyponatraemia, treatment can often be managed in primary care with close follow-up. Moderate to severe hyponatraemia generally warrants hospital admission, regardless of whether the patient has symptoms. Additionally, any symptomatic hyponatraemia, regardless of whether it is mild, moderate, or severe—should also prompt admission for further assessment and management.
This station reinforces that safe prescribing and medication review are crucial in elderly care, and early action can prevent complications like falls or seizures.