Things are not always what they seem

A 80-year-old woman, heavy ex-smoker (60 pack-years) affected by chronic obstructive pulmonary disease (COPD), presented to the emergency department with worsening dyspnea in the previous three hours, metabolic alkalosis (pH 7.55, pO2 33 mmHg, pCO2 34 mmHg, HCO3 30 mmol/L, lactates 3.3 mmol/L) and persistent epigastric pain for one week. She was under treatment with low-dose aspirin, metoprolol, atorvastatin, pantoprazole, ramipril, salmeterol and fluticasone propionate, tiotropium bromide, allopurinol, benserazide, diazepam, furosemide. On physical examination, she presented with tachypnea (30 beats/min) and reduced peripheral oxygen saturation on room air (83%); her remaining vital signs were normal and there were no signs of peritonism. Blood tests revealed an increase of white blood cell (11.07 x 109/l) and neutrophil (9.73 x 109/l) count, glycemia (217 mg/dl), C-reactive protein (2.49 mg/dl; normal values < 0.5 mg/dl) and B-type natriuretic peptide (259 pg/mL; normal values <100 pg/mL) levels. Estimated glomerular filtration rate was moderately to severely decreased (36 mL/min/1.73 m^2). Remaining blood exams (including hepatic function and coagulation time) were normal, in particular lactate dehydrogenase levels (200 U/L; normal values < 248 U/L). Chest X-ray showed a small amount of abdominal free air below the right hemidiaphragm (Figure 1, red arrow) and subcutaneous emphysema in the right lateral abdominal wall (Figure 1, white arrow). A subsequent thoraco-abdominal comupted tomography (CT) scan documented severe pulmonary emphysema (Figure 2 A), abundant and widespread accumulation of air in the intestinal walls (Figure 2 B and C), large amount of free air in the mediastinum (Figure 2 A) and abdomen (Figure 2 B and C).