Endocrine Abstracts

Case history: 29 year old lady presented to A&E with UTI. She had a history of emotionally unstable personality disorder and was an elective inpatient in a psychiatric hospital at the time of her presentation. Blood tests done on admission showed that she was hypercalcaemic. She was treated for UTI and referred to endocrinology. Biochemistry tests were in keeping with familial hypocalciuric hypercalcaemia (FHH). It transpired that her father and sister also had hypercalcaemia and both had parathyroidectomies done in different hospitals. We have not been able to obtain information about her father but her sister remains hypercalcaemic after parathyroidectomy. Investigations for her sister are currently on-going.

Investigations: Blood tests for calcium, phosphate, PTH, creatinine, vitamin D, TSH, 24 h urine collection for calcium and creatinine.

Results and treatment: Adjusted calcium was 2.97 mmol/l with previous calcium readings as high as 3.02 nmol/l.

PTH 83 ng/l (15 – 65), Vitamin D 62, Phosphate 0.67 mmol/l. TSH 1.4.

Serum creatinine 60 umol/l, Urine Creatinine 5.8 mmol/l, Urine Calcium 1.1 mmol/l,

Urine Calcium creatinine clearance ratio (UCCCR) was 0.0038.

Genetic test: Heterozygous for AP2S1 mutation.

Conclusions and points for discussion: FHH is a rare, lifelong condition. In FHH 3 (due to mutation of AP2S1) cohort blood calcium levels are much higher. It is important to distinguish FHH from Primary hyperparathyroidism (PHPT). As PTH and serum calcium may be elevated in both conditions urine calcium creatinine clearance ratio must be done to distinguish these two conditions. UCCCR > 0.02 excludes FHH. Failure to diagnose FHH can lead to unnecessary parathyroidectomy.