ANSWER 12
The acute abdominal pain and the haematuria indicate ureteric colic due to a renal stone. The
polyuria and polydipsia and the mental changes point to hypercalcaemia causing all three
problems. His serum calcium was raised at 3.3 mmol/L (normal range: 2.12–2.65 mmol/L), cor-
rected for serum albumin concentration, the phosphate was reduced at 0.6 mmol/L (normal
range: 0.8–1.45 mmol/L)) and the alkaline phosphatase raised at 587 IU/L (normal range:
30–300 IU/L ). This combination of abnormal bone chemistry indicates hyperparathyroidism
as the cause of the hypercalcaemia, confirmed by a raised serum parathormone (PTH), and
a radio-isotope scan showing a single parathyroid tumour. Other investigations were a
renal ultrasound showing a normal urinary tract with no detectable stones. It was assumed
that the patient had passed a small stone at the time of the ureteric colic and haematuria. A
skeletal X-ray survey was normal, showing no bony metastases and no bony changes of
hyperparathyroidism.
Hypercalcaemia of any cause can cause polyuria and polydipsia, and can affect mental
function. Long-standing hypercalcaemia (therefore not usually in the case of malignancy)
also causes renal stones. For some reason primary hyperparathyroidism causes either
stones or bone disease, rarely both together.
- Hypothyroidism
- Vitamin B 12 deficiency
- Uraemia
- Hypercalcaemia
! Metabolic causes of dementia
- Underlying causes of mental disease must be sought and not ascribed to ageing.
- In a patient with a history of ureteric colic, failure to demonstrate stone(s) in the urinary
tract does not exclude nephrolothiasis.