Index of Suspicion

Case 1 Presentation

An 18-month-old boy presents with a 1-year history of poor weight gain and vomiting. He weighed 3.3 kg when born at term and was growing well until 6 months of age, when he was switched from human milk to formula. His appetite is poor and he vomits intermittently, some weeks with every meal. The emesis is nonbilious, is nonbloody, and usually occurs within 30 minutes of eating but occasionally several hours after eating. The vomiting seems to be worse when he is lying down and has not improved with metoclopramide, lansoprazole, or formula change. He has had no swallowing difficulty or choking. The parents report no recent fever, diarrhea, rash, sick contacts, trauma, or travel. His development is normal.

Physical examination reveals a playful but thin boy. His temperature is 36.7°C, heart rate is 130 beats/min, blood pressure is 92/58 mm Hg, respiratory rate is 26 breaths/min, and oxygen saturation is 98% on room air. His weight is 6.9 kg, length is 73.7 cm, and head circumference is 46 cm, all below the 3rd percentile. He has an open and flat anterior fontanelle, decreased subcutaneous fat, and no skin lesions. The rest of the physical findings are normal without focal neurologic signs.

Laboratory evaluation includes CBC, electrolyte assessment, renal and liver function tests, urinalysis, urine toxicology screen, sweat chloride test, tests for metabolic disorders, thyroid-stimulating hormone assessment, abdominal radiography and ultrasonography, upper GI barium study, pH probe study, upper GI endoscopy, brain CT scan, and EEG. All results are normal. His bone age is delayed significantly. Additional evaluation leads to the diagnosis.

Case 2 Presentation

A 9-year-old previously healthy girl presents with a history of fever, headache, and sore throat. She has a positive rapid streptococcal antigen test and is treated with amoxicillin. However, she does not improve, starts vomiting, and develops dark-colored …