Case history

An 80 year old woman presented to her general practitioner in July 2006 with a 2 month history of diarrhoea. She complained that she passed loose stools approximately four times a day and had to get up at night to open her bowels. Her appetite had been poor and, as a consequence, she thought that she had lost approximately 6 kg in weight. The patient had noticed that the diarrhoea began shortly after one of her regular medications, dosulepin hydrochloride, had been stopped. Her only medical history was hypertension, angina, and a benign breast lump. She was a non-smoker and did not drink any alcohol. Her regular medications were as follows: aspirin 75 mg once daily, atenolol 50 mg twice daily, bendroflumethiazide 2.5 mg once daily, doxazosin 6 mg once daily, and simvastatin 40 mg once daily.

The patient was referred to a gastroenterologist and an outpatient computed tomography colonography was arranged. The results of this investigation were normal.

Routine blood tests were requested at the initial consultation and the results were as follows (normal ranges shown in brackets):

• Haemoglobin 131 g/l (130-180)

• Platelet count 150×10⁹/l (150-450)

• White blood cell count 5.4×10⁹/l (4-11)

• Sodium concentration 139 mmol/l (135-145)

• Potassium concentration 3.8 mmol/l (3.4-5.0)

• Urea concentration 6.9 mmol/l (3.1-7.9)

• Creatinine concentration 105 000 μmol/l (70 000-110 000)

• Bilirubin concentration 13 μmol/l (0-19)

• Alkaline phosphatase concentration 60 U/l (35-120)

• Alanine aminotransferase concentration 24 U/l (0-45)

• Thyroid stimulating hormone concentration <0.05 mIU/l (0.3-4.7)

• Free thyroxine concentration 19 pmol/l (11-23)

• Free triiodothyronine concentration 6.6 pmol/l (3.5-6.5)

• Thyroid peroxidise antibody concentration 39 kU/l (0-60)

Her thyroid function was subsequently monitored (table⇓).

Questions

• 1 What is the biochemical abnormality at initial presentation?

• 2 What do the subsequent thyroid function tests show?

• 3 What are …