CASE 79: CONFUSION
History
A 79-year-old woman is brought to hospital by her daughter because of increasing con-
fusion. This has developed over the last 3 weeks and prior to this her daughter says that
she had normal cognitive function. She also complains of loss of her appetite, headache
and muscle cramps. She had hypertension diagnosed 5 years ago and was on treatment
with atenolol but this was stopped 2 months ago because she complained of cold hands
and feet. Her medication was changed to bendroflumethiazide 2.5 mg once a day and she
has had no problems with these tablets. She lives on her own with her daughter nearby.
She neither drinks alcohol nor smokes. She is on no other medication although she takes
vitamins that she buys from the chemist.
Examination
Her skin turgor is normal. Her pulse is 80/min regular, blood pressure 146/90 mmHg, jugu-
lar venous pressure normal, heart sounds normal with no peripheral oedema. Respiratory
and abdominal systems are normal. Her abbreviated mental test score is 6/10 with disorien-
tation in time and place. There is no focal neurology. Funduscopy shows silver-wiring and
arteriovenous nipping but no papilloedema.
NormalHaemoglobin 12.2 g/dL 11.7–15.7 g/dL
White cell count 6.2% 109 /L 3.5–11.0% 109 /L
Platelets 172 % 109 /L 150–440% 109 /L
Sodium 113 mmol/L 135–145 mmol/L
Potassium 3.3 mmol/L 3.5–5.0 mmol/L
Urea 3.4 mmol/L 2.5–6.7 mmol/L
Creatinine 64 &mol/L 70–120&mol/L
Glucose 5.0 mmol/L 4.0–6.0 mmol/L
Albumin 36 g/L 35–50 g/L
Urinary osmolality 318 mosmol/kg 360–1200 mosmol/kg
Urinary sodium 55 mmol/L 5–300 mmol/L
Urinalysis: no protein; no blood
Chest X-ray: normalINVESTIGATIONS
Questions
- What is the likely cause of this patient’s confusion?
- How would you correct this problem?