THU447 Hungry Bone Syndrome Secondary To Denosumab Use In A Patient With Sleeve Gastrectomy

Disclosure: A. Prabha Kumar: None. M. Shakir: None. B. Sharma: None. O. Syed: None. S. Natarajan: None. M. Dominic: None. Our patient is a 60-year-old woman with significant past medical history of morbid obesity, requiring laparoscopic sleeve gastrectomy, converted to Single Anastomosis Duodeno-Ileostomy (SADI) 4 months ago. Her comorbidities included Crohn’s disease, chronic lower extremity lymphedema treated with torsemide, spironolactone & metolazone, psoriatic arthritis (PsA) & osteoporosis secondary to prolonged use of steroids for suppression of PsA. She was also chronically on proton pump inhibitors (PPIs). Since the SADI, patient had diarrhea, an expected complication & was symptomatically managed. She received Denosumab (Prolia) injections for osteoporosis. Her 1(st) shot was nearly 6 months ago & 2(nd) was 5 days prior to her presentation at the hospital. She presented with symptoms of tingling over bilateral lower extremities and generalized weakness causing dizziness and fall at home. Vitals were positive for orthostasis. Labs revealed serum calcium 6.7 mg/dL (8.4 - 10.2 mg/dL), magnesium 1.3 mg/dL (1.5 - 2.6 mg/dL), potassium 3.1 mmol/L (3.5 - 5.1 mmol/L) phosphorus 1.7 mg/dL (2.5 - 4.8 mg/dL), 25-Hydroxy Vit D 39 ng/mL (30 - 50 ng/mL) & serum PTH 152 pg/mL (15 - 65 pg/mL). Physical examination and EKG were unremarkable. She received aggressive resuscitation of fluids & electrolytes & was discharged on calcium carbonate 600 mg TID, Vit C 500 mg BID, Vit D 1000 units daily and calcitriol 0.5 mcg BID. PPI was discontinued as it is known to reduce calcium & magnesium absorption. Metolazone was discontinued to prevent electrolyte depletion. Serum calcium normalized to 8.4 mg/dL. She was advised to taper off steroids to avoid further progression of osteoporosis, thereby eliminating the need for Prolia. Prolia is a RANK-L inhibitor given as a subcutaneous injection every 6 months. It works by inhibiting the action of osteoclasts, thereby, preventing bone remodeling & bone loss. It has shown to improve bone mass, microstructure & strength, thus reducing fractures. As a result, regular calcium turnover is affected & serum calcium is housed within bones, causing hypocalcemia & state of “hungry bones”. Risk is especially high in patients with reduced renal function, have recently undergone thyroid surgery, are concurrently on meds like loop diuretics which cause calcium loss. Malabsorptive diarrhea after SADI is an understood complication and can result in Vit D deficiency, hypocalcemia with secondary hyperparathyroidism. Daily calcium & Vit D is recommended after gastric bypass & in patients receiving Prolia, if indicated. Another take away for physicians is to pay special attention to medication reconciliation on admission as medications like Prolia could easily be missed given the infrequent administration. Careful risk stratification & prophylactic supplementation is required in such patients to prevent hypocalcemia. Presentation: Thursday, June 15, 2023