Hypocalcemia as a presenting feature of celiac disease in a patient with DiGeorge syndrome

Prevalence of coeliac disease in idiopathic hypoparathyroidism and effect of gluten-free diet on calcaemic control

BACKGROUND

Patients with idiopathic hypoparathyroidism (IH) require variable doses of calcium and 1-α-(OH)D. The reasons for such variability are not clear. As autoimmune mechanisms may play a role in IH, there is a possibility of coexistent coeliac disease with calcium/vitamin D malabsorption.

OBJECTIVE

We assessed the prevalence of coeliac disease and antitissue transglutaminase autoantibodies (anti-tTGAbs) in IH and analysed the effect of a gluten-free diet on calcaemic control.

METHOD

A total of 171 patients with IH and 126 healthy controls were screened for anti-tTGAb. IH patients with anti-tTGAb >20 RU/ml underwent duodenoscopy and intestinal biopsy; those with biopsy-proven coeliac disease were followed up on a gluten-free diet.

RESULTS

Eleven of 171 (6·4%) patients with IH and seven of 126 (5·6%) controls had anti-tTGAb (P = 0·81). There was no difference in the clinical and biochemical parameters at diagnosis and during long-term follow-up of 7·2 ± 4·8 year (mean serum total calcium = 1·88 ± 0·16 vs 1·82 ± 0·36 mmol/l, P = 0·52; phosphorus = 1·81 ± 0·17 vs 1·87 ± 0·36 mmol/l, P = 0·53) in IH patients with and without anti-tTGAb. Although CaSRAb positivity was comparable in the two groups, IH patients with anti-tTGAb had higher TPOAb positivity (45·5% vs 12·8%, P = 0·02). Coeliac disease was diagnosed in only 2/9 patients with IH on biopsy, both of whom showed improved calcaemic control with a gluten-free diet.

CONCLUSION

The prevalence of coeliac autoimmunity (6·4%) and coeliac disease (1·2%) in patients with IH seems to be similar to that in the general population. Notwithstanding this modest prevalence, it is important to be aware of the potential occurrence of coeliac disease with IH and the beneficial effect of a gluten-free diet on calcium control.

Digestive manifestations of parathyroid disorders

The parathyroid glands are the main regulator of plasma calcium and have a direct influence on the digestive tract. Parathyroid disturbances often result in unknown long-standing symptoms. The main manifestation of hypoparathyroidism is steatorrhea due to a deficit in exocrine pancreas secretion. The association with celiac sprue may contribute to malabsorption. Hyperparathyroidism causes smooth-muscle atony, with upper and lower gastrointestinal symptoms such as nausea, heartburn and constipation. Hyperparathyroidism and peptic ulcer were strongly linked before the advent of proton pump inhibitors. Nowadays, this association remains likely only in the particular context of multiple endocrine neoplasia type 1/Zollinger-Ellison syndrome. In contrast to chronic pancreatitis, acute pancreatitis due to primary hyperparathyroidism is one of the most studied topics. The causative effect of high calcium level is confirmed and the distinction from secondary hyperparathyroidism is mandatory. The digestive manifestations of parathyroid malfunction are often overlooked and serum calcium level must be included in the routine workup for abdominal symptoms.