B3. Intraabdominal abscesses.

Intraabdominal (or intraperitoneal) abscesses are serious conditions which usually develop secondary to a pre-existing or concomitant abdominal infection. It can involve any abdominal organ, be located between bowel loops, or be free within the cavity. They may lead to organ failure, sepsis, shock, and death, and as such have a high mortality rate of 10 – 40%.

Etiology

• Abdominal surgery
• Perforated hollow organ (appendicitis, peptic ulcer)
• Crohn disease
• Diverticulitis
• Intestinal ischaemia
• Pancreatic necrosis
• Gangrenous cholecystitis
• Abdominal trauma (blunt or penetrating)

Classification

• Intraperitoneal abscess
  • Subphrenic abscess
  • Interloop abscess
  • Paracolic abscess
  • Pelvic abscess
• Retroperitoneal abscess
  • Pancreatic abscess
  • Perinephric abscess
• Visceral abscess
  • Hepatic abscess
  • Splenic abscess

Clinical features

Intraabdominal abscess commonly presents with abdominal pain (usually corresponding to the area of the abscess) and fever. The mass may be palpable. There may be symptoms of the infection source. There’s often a history of surgery, trauma, or known intra-abdominal infection. Subphrenic abscesses may cause chest symptoms or shoulder pain.

Untreated abscess may rupture, form fistulae, or erode into vessels, potentially causing sepsis or haemorrhage.

Diagnosis and evaluation

Labs will show elevated inflammatory parameters. Blood cultures are often negative. Ultrasound may be used first, but contrast CT is the modality of choice, as it’s the best modality to show the abscess and its borders.

Treatment

Treatment is, as for most abscesses, IV antibiotic therapy and drainage. Drainage may be percutaneous or surgical. Abscesses located in the pelvis may be drained transrectally or transvaginally. Patients should also receive supportive therapy with fluids.