[Severe hypocalcemia and hypomagnesemia in a 14-year-old boy--difficulties in treatment related to silent coeliac disease].

The presence of late-onset hypocalcemia (>3 days of age) associated with hypomagnesemia generates a clinical dilemma. Such a disorder may exist as a result of magnesium deficiency with a secondary hypoparathyroidism, congenital hypoparathyroidism (HPT), phosphorus intoxication, activated mutation of calcium sensing receptor (CASR) or the presence of CASR stimulatory antibodies. In phosphorus intoxication, in contrast to the other reasons, serum PTH level is rather elevated. Calcium and phosphorus compete for intestinal absorption and thus if calcium intake is high then magnesium absorption is reduced and vice versa. Patient's history: 14-year-old boy was admitted to the ward because of tetanic seizure few days before. Severe hypocalcemia (1.49 mmol/L) with hypomagnesemia (13.8 mg/L) as well as metabolic alkalosis pH=7.65) and high phosphorus level (10.5 mg/dL) were noted. The boy was prepubertal, euthyroid and proportionally microsomic. Severely low serum PTH level (2 pg/mL) excluded phosphorus intoxication. Magnesium salts treatment alone (p.o.) was introduced but this treatment did not improve serum magnesium level as well as calcium concentration. Primary magnesium deficiency was excluded and therefore calcium salts supplementation and 1alpha(OH)D3 therapy, typical for HPT, was initiated combined with slow-released magnesium salts. Difficulties in the treatment tended to look for the digestive tract defects and finally, based on endomysial antibodies and duodenal biopsy the coeliac disease was confirmed. With gluten-free diet the significant improvement of calcium-phosphorus parameters has been observed showing that the autoimmune background of hypoparathyroidism is very likely.