ABSTRACT
Objective: Short Synacthen tests (SSTs) are expensive, dependent on Synacthen availability, and need supervision. To reduce SST testing, we examined the utility of pre-test cortisol (Cort0) and related parameters in predicting outcome. Design and Measurements: We retrospectively examined the following in all SSTs; (i) Cort0 (ii) indications (iii) and time and place of testing. Receiver operated characteristic (ROC) curves were devised for Cort0 to obtain the best cut-off for outcome prediction in those who had SSTs between 8 and 10 am (Group 1) and at other times (Group 2). Results: Of 506 SSTs, 13 were unsuitable for analysis. 111/493 SSTs (22.5%) were abnormal. (1) ROC curves predicted - (a) SST failure with 100% specificity when Cort0 was ⩽124 nmol/L (Group 1), or ⩽47 (Group 2); (b) a normal SST with 100% sensitivity when Cort0 ⩾314 nmol/L (Group 1) and ⩾323 nmol/L (Group 2). (2) There was significant correlation between Cort0 and 30-minute cortisol (rs = 0.65-0.78, P < .001). (3) Median Cort0 was lower in those who failed SSTs compared to those who passed (147 vs 298 nmol/L respectively, P < .001). (4) SST failure was commoner in Group 1 vs 2 (P = .001). (5) There was no difference in outcome between out-patient and inpatient SSTs. (6) SST failure was most common for 'steroid related' indications (39.6%, P < .001). Conclusions: This study indicates that (1) Cort0 ⩾ 323 (Group1) and ⩾314 nmol/L (Group 2) predicted a normal SST with 100% sensitivity; (2) Using these cut offs 141/493 (28.6%) tests may have been avoided; (3) supporting evidence should be considered in those with a lower pre-test predictability of failure.
ABSTRACT
SUMMARY: A 53-year-old man who used growth hormone (GH), anabolic steroids and testosterone (T) for over 20 years presented with severe constipation and hypercalcaemia. He had benign prostatic hyperplasia and renal stones but no significant family history. Investigations showed - (1) corrected calcium (reference range) 3.66 mmol/L (2.2-2.6), phosphate 1.39 mmol/L (0.80-1.50), and PTH 2 pmol/L (1.6-7.2); (2) urea 21.9 mmol/L (2.5-7.8), creatinine 319 mmol/L (58-110), eGFR 18 mL/min (>90), and urine analysis (protein 4+, glucose 4+, red cells 2+); (3) creatine kinase 7952 U/L (40-320), positive anti Jo-1, and Ro-52 antibodies; (4) vitamin D 46 nmol/L (30-50), vitamin D3 29 pmol/L (55-139), vitamin A 4.65 mmol/L (1.10-2.60), and normal protein electrophoresis; (5) normal CT thorax, abdomen and pelvis and MRI of muscles showed 'inflammation', myositis and calcification; (6) biopsy of thigh muscles showed active myositis, chronic myopathic changes and mineral deposition and of the kidneys showed positive CD3 and CD45, focal segmental glomerulosclerosis and hypercalcaemic tubular changes; and (7) echocardiography showed left ventricular hypertrophy (likely medications and myositis contributing), aortic stenosis and an ejection fraction of 44%, and MRI confirmed these with possible right coronary artery disease. Hypercalcaemia was possibly multifactorial - (1) calcium release following myositis, rhabdomyolysis and acute kidney injury; (2) possible primary hyperparathyroidism (a low but detectable PTH); and (3) hypervitaminosis A. He was hydrated and given pamidronate, mycophenolate and prednisolone. Following initial biochemical and clinical improvement, he had multiple subsequent admissions for hypercalcaemia and renal deterioration. He continued taking GH and T despite counselling but died suddenly of a myocardial infarction. LEARNING POINTS: The differential diagnosis of hypercalcaemia is sometimes a challenge. Diagnosis may require multidisciplinary expertise and multiple and invasive investigations. There may be several disparate causes for hypercalcaemia, although one usually predominates. Maintaining 'body image' even with the use of harmful drugs may be an overpowering emotion despite counselling about their dangers.
