Index of Suspicion * Case 1: Leg Cramps, Hand Spasms, Diarrhea, and Substantial Weight Loss in a 12 Year Old * Case 2: Hypothermia, Hypoglycemia, and Hyperbilirubinemia in a Neonate * Case 3: Recurrent Fevers, Abdominal Pain, and Cervical Lymphadenopathy in a 7 Year Old

Abstract

A 12-year-old previously healthy boy presents with leg cramps for 2 weeks and spasms of his hands since yesterday. He also complains of nausea, bloating, epigastric pain, and recurrent watery and loose stools for 1 month. Currently, he is taking lansoprazole for epigastric pain without any relief. He also has a history of involuntary weight loss of 10 lb over 2 months. The family history contains no findings of note. On physical examination, the boy's weight is 36 kg (25th percentile) and height is 140 cm (10th percentile) and he exhibits a positive Trousseau sign and negative Chvostek sign. Remaining physical signs, including on abdominal examination, are normal. Laboratory evaluation shows hypocalcemia (total calcium of 5.3 mg/dL [1.3 mmol/L], ionized calcium of 2 mg/dL [0.5 mmol/L], and corrected calcium of 6.1 mg/dL [1.5 mmol/L]) as well as hypoalbuminemia (3 g/dL [30 g/L]). Serum magnesium measures 1.6 g/dL. CBC shows Hgb of 9.3 g/dL (93 g/L), Hct of 29% (0.29), WBC count of 9.9×103/μL (9.9×109/L), platelet count of 471×103/μL (471×109/L), mean corpuscular volume of 67 fL, and reticulocyte count of 1% (0.01). Results of the iron studies are consistent with iron deficiency anemia, with a serum iron concentration of 6 μg/dL (1.07 μmol/L) (31 to 144 μg/dL [5.5 to 25.8 μmol/L]), transferrin saturation of 3% (0.3), and serum ferritin less than 5 ng/mL (11.23 pmol/L) (21 to 275 ng/mL [47.2 to 617.9 pmol/L]). ESR is 46 mm/h and CRP is 9.5 mg/dL (normal <0.05 mg/dL). His serum 25-hydroxyvitamin D concentration is low at 5.7 ng/mL (14.2 nmol/L) (normal, 32 to 100 ng/mL [79.9 to 249.6 nmol/L]) and serum parathyroid hormone, urine calcium, and creatinine values are within normal limits. His tetany and hypocalcemia resolve with calcium replacement. Additional evaluation leads to the diagnosis. …