When is pneumonia not pneumonia?

A 34-year-old man was admitted to hospital via the accident and emergency department with severe right-sided abdominal pain and raised inflammatory markers. His pain settled with analgaesia and he was discharged with a course of oral co-amoxiclav. He was readmitted to the hospital 7 days later reporting cough and shortness of breath. His chest X-ray showed a raised right hemi-diaphragm, presumed consolidation and a right-sided effusion. As a result, he was treated for pneumonia. Despite antibiotic therapy his C reactive protein remained elevated, prompting an attempt at ultrasound-guided drainage of his effusion. Finding only a small amount of fluid, a CT of the chest was performed, and this showed a subphrenic abscess and free air under the diaphragm. A CT of the abdomen was then carried out, showing a perforated appendix. An emergency laparotomy was performed, the patient's appendix was removed and the abscess drained.