Continued information gathering

Based on your thinking that medicines are one of the likely causes, you should review whether ramipril or omeprazole are the cause of his symptoms.

Omeprazole does not have any known effect on excessive urination, but an uncommon side-effect of ramipril is increased urine output. You need to establish if causality exists.

You find out that this patient has been hypertensive for four years and has taken ramipril, with no dose changes, since he was diagnosed. So it appears that ramipril is not the cause of his symptoms.

Patients with diabetes often experience one or more of the ‘4P’ symptoms: polyuria, polydipsia, polyphagia and polyneuropathy. In the context of an undiagnosed patient, polyuria and polydipsia are commonly seen, as is the case with our patient. Based on these symptoms, it would seem reasonable to suspect diabetes, given his age, gender and the fact that he is hypertensive.

Problem refinement

You now need to ask further questions to try to confirm this thinking.

Diabetes is also associated tiredness, being overweight (especially central obesity) and a family history.

You find out that there is no diabetes in this patient’s family and general observations show him to be well built but not obviously overweight. You ask about his height and weight to determine his BMI (which is 26).

The patient reports not being overly tired, but does say he can sometimes feel tired, especially after a long day at work.

These additional pieces of information, while not ruling diabetes out, certainly do not provide further convincing evidence that his symptoms are due to diabetes. However, when considering different possible conditions, the lack of other symptoms seems to discount almost all of them.

In renal disease, for instance, other symptoms would include nausea and ankle swelling. In hypokalaemia, there would be muscle weakness.

Hypercalcaemia would cause confusion, constipation and irritability. With hyperthyroidism, there would be weight loss, diarrhoea and palpitations, and hyperparathyroidism would lead to constipation and confusion.

Diabetes insipidus is possible, given that this patient’s two main symptoms are those frequently seen with this condition – so at this stage, it cannot be fully ruled out.