1. IMAGE CHALLENGE

4. A 72-year-old man presented to the emergency department with severe abdominal pain of two days' duration in the right lower quadrant. He reported recent use of nonsteroidal antiinflammatory drugs for a cold. His medical history was notable for previously treated Helicobacter pylori infection.

6. An abdominal radiograph (Panel A) revealed air around the right kidney (arrows). Transabdominal ultrasonography showed that the right kidney was masked by air in the retroperitoneum, an artifact known as veiled right kidney sign

7. Abdominal computed tomography (Panel B) showed air surrounding the right kidney (arrows) and extending to the retroperitoneum. Thickening of the wall at the second and third portions of the duodenum was also noted.

8. Endoscopy showed multiple gastric and duodenal ulcers. A duodenal ulcer with retroperitoneal perforation presenting with pain in the right lower quadrant (Valentino's syndrome) was diagnosed. The patient was treated with parenteral antibiotics without surgical intervention. His fever subsided in one day, and his recovery was uneventful.

10. A 47-year-old woman of Italian descent with a history of transfusion-dependent β- thalassemia intermedia presented to the emergency department with dyspnea that had worsened during the previous several days.

11. The physical examination revealed 28 respirations per minute, a heart rate of 113 beats per minute, normal oxygenation while the patient was receiving supplemental oxygen, clear lungs, and jugular venous distention. Laboratory analyses showed a hemoglobin level of 4 g per deciliter and a hematocrit of 15%.

13. Chest radiography (Panel A, arrow) and computed tomography (Panel B, arrow) show enlarged central pulmonary arteries owing to pulmonary arterial hypertension. In patients with thalassemia, such enlargement is thought to arise from chronic anemia, hemolysis, and an increased tendency for microscopic thrombi to form within the pulmonary vasculature.

14. Bilateral paravertebral soft-tissue masses (Panel B, arrowheads), as well as marked medullary expansion of the bony structures (with the ribs showing the most pronounced involvement), were also present, findings that are associated with compensatory extramedullary hematopoiesis.

15. The patient received several transfusions and was subsequently transferred to a rehabilitation facility. She sustained bilateral humeral and left femoral fractures during a physical therapy session and was readmitted. Because of her serious coexisting conditions, the fractures were deemed to be inoperable. The patient received palliative care and died a few days later.