Background: Patients with hypoparathyroidism may present acutely with hypocalcaemia and these patients may have multiple admissions; however, data on the incidence of acute and recurrent acute hypoparathyroidism are scarce in the literature.
Aim: We wished to determine: (1) the causes of severe hypocalcaemia amongst A&E attendances (2) the incidence of acute hypocalcaemia due to hypoparathyroidism amongst A&E attendances, and (3) the incidence of recurrent acute hypoparathyroidism.
Methods: All samples sent from a single A&E department for calcium measurement over a 3 year period (20142016) were screened. Severe hypocalcaemia was defined as a corrected calcium of <1.90 mmol/l. Samples were excluded if they were duplicates (from the same patient within 24 h) or if they were spurious (haemolysed or resolved on repeat). From the total patient cohort diagnoses were ascertained from the clinical record to ascribe a cause of hypocalcaemia. Recurrent hypocalcaemia was defined as two or more attendances with severe hypocalcaemia within 12 months.
Results: After excluding duplicates (7%) and spurious samples (35%), there were a total of 234 samples from 185 patients (mean age 56 year; 54% male) with one or more admission. Causes of severe hypocalcaemia included (% of patients): chronic kidney disease (28%), GI loss±hypomagnesaemia (19%), alcohol±hypomagnesaemia (13%), vitamin d deficiency (7%), hypoparathyroidism (11%) other/unknown (22%). 26 patients had recurrent episodes of acute hypocalcaemia: 4/26 surgical, 1/26 Di George and 1/22 CaSR mutation.
|% Severe hypocalcaemia (n=185)||% Recurrent severe hypocalcaemia (n=26)|
|Chronic kidney disease||28||37|
|GI loss =/− low Mg||19||11|
|Alcohol XS +/− low Mg||13||7|
|Vit D defciency||7||4|
|Note: percentages do not add up to 100.|
Conclusions: Given a local catchment area of approximately 700,000 the incidence of acute hypocalcaemia due to hypoparathyroidism was 13 per million per year. Recurrent acute hypoparathyroidism had an incidence of approximately 23 per million per year. Recurrent hypocalcaemia due to hypoparathyroidism is an uncommon presentation.