An elderly woman with chest pain and constipation

An 89 year old woman with chronic obstructive pulmonary disease presented to the emergency department with worsening shortness of breath (87% oxygen saturation in room air), retrosternal chest pain, mild abdominal pain, and subacute partial bowel obstruction over the past six days. On physical examination she was dehydrated and she had tachycardia (105 beats/min), diffusely decreased breath sounds, audible crackles at the base of the right lung, and absent breath sounds on the left side pulmonary base. Her abdomen was distended but soft overall, the epigastrium and right hypochondium were slightly tender on deep palpation, and her rectum was empty. Her blood pressure was 130/85 mm Hg. Electrocardiography and troponin (measured at admittance and checked again after six and 12 hours) excluded myocardial infarction. Laboratory studies were unremarkable except for a mild microcytic anaemia (haemoglobin 115 g/L (reference range 120-160), mean cell volume 78.6 fL (80-96). Urgent chest radiography was requested (fig 1⇓).