Complications of acute appendicitis

Local (peritoneal) complications

The development of inflammation around a destructive vermiform appendix can proceed either by containment or spreading. Localized forms include:

• Appendiceal infiltrate — a protective reaction of the body in which the zone of destruction is isolated by the omentum and the walls of adjacent organs. It occurs immediately after the acute attack. Unlike specific infectious processes, it is capable of resolving rapidly with appropriate conservative therapy.
• Periappendiceal abscess — forms in the event of purulent melting (suppuration) of a previously formed infiltrate.
• Local localized peritonitis — the zone of inflammation is securely isolated by scars and adhesions, ultimately leading to the formation of a localized intra-abdominal abscess.

If appendiceal perforation occurs in the absence of protective containment, exudate (fibrinopurulent or putrid) freely spills into the abdominal cavity. Generalized (diffuse) purulent peritonitis forms — an extremely severe condition requiring emergency intervention. Any progressive spread of inflammation along the peritoneum inevitably deepens the stage of peritonitis.

Depending on the anatomical position of the appendix, purulent accumulations can localize in various peritoneal recesses. Pelvic, interbow, or subphrenic abscesses are formed. If the appendix was located retrocecally (behind the cecum), the development of severe retroperitoneal phlegmon is possible.

The role of microflora in the course of complications

The purulent process in appendicitis is caused by polymicrobial flora penetrating from the intestinal lumen. In the vast majority of cases (85–90%), the flora is mixed, but with one dominant pathogen. The tendency of inflammation toward containment directly depends on the type of microorganism:

1. Colibacillary infection (E. coli) — Escherichia coli causes the release of exudate extremely rich in fibrin. This promotes rapid tissue adhesion and reliable encystment (containment) of the process.
2. Streptococcal infection — characterized by liquid pus with a minimal fibrin content. Adhesions do not form, inflammation is not contained, and it has a pronounced tendency to spread diffusely throughout the abdominal cavity.

In addition to appendicitis, similar flora causes peritonitis in ulcer perforation, strangulated hernias, acute cholecystitis, and pancreatitis. It is worth noting that peritonitis can begin as aseptic (e.g., due to trauma, drying of the peritoneum during surgery, or chemical burn by antiseptics). By itself, it causes only gastrointestinal paresis without severe intoxication, but the addition of even minimal infection instantly converts it into a purulent form.

Vascular and generalized complications

If the infection was not timely controlled locally, it is capable of spreading hematogenously, affecting the vascular bed and causing systemic catastrophes:

• Pylephlebitis — infectious thrombophlebitis. Inflammation involves the branches of the portal vein that drain blood from the affected appendix area. Infected thrombi are carried by the bloodstream to the liver, causing multiple pylephlebitic liver abscesses.
• Septicemia (sepsis) — massive breakthrough of pyogenic microorganisms into the systemic bloodstream.
• Septic shock — critical impairment of circulation and tissue perfusion against the background of a generalized infection.
• DIC syndrome (disseminated intravascular coagulation) — depletion of blood clotting factors, leading to a paradoxical combination of microthrombosis and profuse bleeding.

Class and exam questions

What else to study on this topic

• Clinical and anatomical forms of uncomplicated acute appendicitis
• The concept of appendicopathy and "false" appendicitis
• Causes and pathogenesis of aseptic peritonitis
• Differential diagnosis of chronic appendicitis
• Acute intestinal obstruction secondary to adhesive disease

Other topics in the "Additional Topics" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.