Introduction
Chronic appendicitis is a long-standing or recurrent inflammatory condition of the vermiform appendix that presents as intermittent pain in the right iliac fossa. Unlike acute appendicitis, it is a less clear-cut diagnosis, and the concept itself is debated. This note covers the definition, causes and pathology, clinical picture, diagnosis and differential diagnosis, treatment, and complications and prognosis.
Definition and controversy
Chronic appendicitis is usually defined as persistent or recurrent right lower quadrant pain lasting several weeks or longer, with histological evidence of chronic inflammation in the appendix after its removal. Some authors describe it as a low-grade inflammatory process that follows an episode of acute appendicitis or a partial obstruction that subsides. Many surgeons regard it as a diagnosis confirmed retrospectively, because the pathologist is the one who establishes the chronic changes. In the exam, state this reservation clearly: the diagnosis is uncertain before surgery and is confirmed by histology.
Causes and pathology
The underlying mechanism is usually partial obstruction of the appendiceal lumen, which causes repeated episodes of distension and ischaemia of the wall.
- Partial luminal obstruction by fibrosis, a faecal concretion (faecolith), lymphoid hyperplasia or parasites such as Enterobius vermicularis
- Fibrous obliteration after a previous acute attack, leaving a scarred, kinked or adherent appendix
- Chronic mucosal and wall changes: lymphoplasmacytic infiltration, fibrosis and sometimes lumen narrowing or obliteration
- Recurrent episodes of luminal distension that cause pain and then settle spontaneously