• Cause: infrequently occur as a sequel to strangles, respiratory infections, septicemia or umbilical infections. Infection often localizes in mesenteric lymph nodes where it may or may not lead to adhesions and bowel obstruction.
• Signs: commonly presents with 3 syndromes:
  • Chronic loss of weight.
  • Chronic low-grade colic.
  • Acute severe colic is occasionally seen.
• Diagnosis: rectal palpation, +/- ultrasonography, clinicopathological data, peritoneal fluid collection and examination are all helpful, but laparoscopy/laparotomy may be required for definitive diagnosis.
• Treatment: long-term antimicrobial therapy, often with penicillin, for a minimum of 30 days, supportive care and in selected cases surgical intervention.
• Prognosis: varies according to size, location, causative agent and secondary involvement but guarded to poor.

Presenting signs

• Very variable and are related to the size and position of the abscess, degree of bowel involvement, and degree of associated peritonitis.
• Two common clinical syndromes:
  • Chronic weight loss.
  • Chronic low-grade colic.
• Depression.
• Inappetence or anorexia.
• Chronic weight loss   Weight loss: overview  .
• Intermittent or prolonged low-grade abdominal pain   Abdomen: pain - adult  .
• May present for acute colic   Abdomen: pain - adult  ; however, there is often a history of previous depression, weight loss or colic attacks.
• Intermittent/continuous pyrexia often of an unknown origin.
• Previous history of strangles   Strangles (Streptococcus equi infection)  , respiratory or systemic infection.
• Occasionally diarrhea, especially in young foals infected byRhodococcus equi  Rhodococcus equi  .

Acute presentation

• Acute abdominal pain (colic) is rarely seen due to compression of the bowel, traction on mesentery, adhesions or acute rupture and peritonitis.

Geographic incidence

• Those countries and environments with higher incidence of predisposing factors, especially infections such as Strangles.

Age predisposition

• May be more common in young adults <5 years old.

Cost considerations

• Costs of diagnosis and subsequent treatment can be substantial, especially if prolonged and/or surgery is involved.
• In severe cases euthanasia or death of the affected animal may occur.