CO19 | Calcium addicted room-mates: malabsorption of calcium and levothyroxine in SIBO, a case report

Premises: Small intestinal bacteria overgrowth (SIBO) is a condition characterized by an high count of bacteria in the small bowel. Several situations predispose to SIBO, such as motility and anatomical disorders, immunodeficiencies and others. Typical clinical presentation is characterized by diarrhea, bloating, and malabsorption.Description of the Case report: An 82-years-old woman came to our emergency department complaining limbs paresthesia. Around forty years ago she underwent a total thyroidectomy for multinodular struma that lead to hypothyroidism and hypoparathyroidism. She also referred an IgA deficiency and a long story of unexplained anemia. She assumed high doses of thyroid hormones (2 mcg/kg/die), calcium (6 g/die), calcitriol (1 mcg/die), and cholecalciferol (800 UI/die). Despite this therapy blood exams showed persistent severe hypocalcemia. Celiac disease, atrophic autoimmune gastritis, and Helicobacter Pylori infection were excluded. A glucose breath test allowed a diagnosis of SIBO and the patient was treated with rifaximin 1200 mg/die. After therapy there was a rapid increased in calcium and thyroid hormones levels and she was discharged with 2g/die of calcium, 0.25 mcg/die of calcitriol and 1.4 mcg/kg/die of levothyroxin. Conclusions: Epidemiology and physiopathology in SIBO are not yet completely known. In some conditions, like IgA deficiency, there is an higher risk for this disorder. Patients with risk factors complaining of gastrointestinal symptoms and/or sign of malabsorption must be investigated for SIBO and treated with specific therapy.