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Basics ⬇

Outline

BASICS

Overview!!navigator!!

Peritonitis is defined as inflammation of the peritoneal cavity. It may be primary or secondary, diffuse or localized, and acute or chronic. Inflammation involves the liberation of many immune system mediators, resulting in the decrease in vascular integrity and a flux of inflammatory cells, protein, red blood cells, and electrolytes into the peritoneal cavity. The disease may range from mild to severe, thereby causing hypovolemic and septic/toxic shock and, ultimately, death.

Systems Affected

  • GI—altered GI motility.
  • Cardiovascular—from mild dehydration to tachycardia to shock.
  • Renal/urologic—primary disease, azotemia.
  • Reproductive—primary disease

Signalment!!navigator!!

Any age, breed, or sex.

Signs!!navigator!!

Primary Disease

  • Depression.
  • Inappetence.
  • Fever.
  • Altered GI motility.
  • Distended abdomen.
  • Splinting of abdomen.
  • Mild colic.
  • Distended viscus; serosal fibrin deposition palpated per rectum

Secondary Disease

  • Signs as listed previously.
  • Colic.
  • Evidence of trauma.
  • Laminitis

Causes and Risk Factors!!navigator!!

Primary

Hematogenous spread of bacteria.

Secondary

  • Loss of GI integrity.
  • Vascular compromise thrombosis or intestinal torsion/volvulus.
  • Trauma.
  • Loss of reproductive tract integrity.
  • Breeding injury.
  • Foaling injury.
  • Wounds—penetrating.
  • Abdominal surgery.
  • Castration.
  • Abscess rupture.
  • Uroperitoneum.
  • Hemorrhage.
  • Neoplasia.
  • Parasite migration

Diagnosis ⬆ ⬇

Outline

DIAGNOSIS

Differential Diagnosis!!navigator!!

  • Includes any pain-causing, inflammatory, or infectious disease involving the GI system specifically.
  • Ovulation, uterine torsion, urinary tract obstruction, cholelithiasis, and cholangitis.
  • Pleuropneumonia

CBC/Biochemistry/Urinalysis!!navigator!!

CBC

  • Neutropenia/neutrophilia.
  • Hypoproteinemia/hyperproteinemia

Biochemistry

  • Hypoproteinemia/hyperproteinemia. Albumin levels may be normal or decreased. Globulin levels variable.
  • Urinalysis—azotemia due to fluid loss.
  • Serum amyloid A protein—increase may be mild to severe.
  • Plasma fibrinogen—may be elevated

Other Laboratory Tests!!navigator!!

Abdominal Paracentesis

  • Appearance—turbid fluid with elevated protein, nucleated cells, or foreign material; green or brown fluid likely contains feed or fecal material.
  • Cytology—there may be an elevated nucleated cell count (>104 nucleated cells/μL), increased proportion of neutrophils, and an elevated protein level (>25 g/L). Bacteria, feed material, and sperm possible.
  • Culture and sensitivity—consider Gram stain and aerobic and anaerobic culture of fluid. False-negative results are frequent.
  • Other peritoneal fluid—serum-to-peritoneal fluid glucose levels >50 mg/dL, decreased glucose level <30 mg/dL, pH <7.3, elevated fibrinogen level >200 mg/dL support septic peritonitis even if bacterial culture does not yield any growth

Imaging!!navigator!!

Radiographs

Helpful in assessing foals’ abdomens or searching for foreign bodies in adult horses.

US

May be used to detect areas of focally increased peritoneal fluid to guide aspiration. Can also be used to assess presence of fibrin deposition and peripheral abscess formation.

Treatment ⬆ ⬇

TREATMENT

  • Resolve primary problem.
  • Abdominal exploration and lavage.
  • Fluid therapy.
  • Protein replacement.
  • Laminitis prophylaxis

Medications ⬆ ⬇

Outline

MEDICATIONS

Drug(s) of Choice!!navigator!!

Antibiotic Therapy

  • Broad spectrum initially (consider parenteral penicillin, cephalosporin, and aminoglycoside); macrolides such as erythromycin, azithromycin, or clarithromycin with/without rifampin (rifampicin) may be indicated in cases of abdominal abscessation; metronidazole should be used if anaerobic bacteria suspected.
  • Antibiotic therapy—adjust to sensitivity pattern of organisms isolated in culture.
  • NSAIDs (analgesia, decrease effects of toxins)

Alternative Drugs

Trimethoprim–sulfonamide (enteral or parenteral); potentiated penicillins (amoxicillin/sulbactam) may be useful.

Contraindications/Possible Drug Interactions!!navigator!!

  • Corticosteroids are contraindicated in peritonitis because a bacterial infection is usually present.
  • Aminoglycoside antibiotics should be used with caution because of nephrotoxicity.
  • Macrolide antibiotics, especially erythromycin, may cause enterocolitis (potentially fatal)

Follow-up ⬆ ⬇

Outline

FOLLOW-UP

Patient Monitoring!!navigator!!

Periodic peritoneal fluid analysis (every 2–3 days or if the patient does not show any improvement).

Possible Complications!!navigator!!

Laminitis and thrombophlebitis are the most common complications. Abscess and adhesion formation may also occur.

Miscellaneous ⬆ ⬇

Outline

MISCELLANEOUS

Age-Related Factors!!navigator!!

Immunodeficiency in the neonate.

Pregnancy/Fertility/Breeding!!navigator!!

Fetal loss may occur.

Abbreviations!!navigator!!

  • GI = gastrointestinal.
  • NSAID = nonsteroidal anti-inflammatory drug.
  • US = ultrasonography, ultrasound

Suggested Reading ⬆ ⬇

Davis JL. Treatment of peritonitis. Vet Clin North Am Equine Pract 2003;19:765–778.

Furst A, Kummer M, Kuemmerle JM, et al. Potential complications in equine colic surgery. Pferdeheilkunde 2012;28:522–530.

Author(s) ⬆

Author: Daniel G. Kenney

Consulting Editors: Henry Stämpfli and Olimpo Oliver-Espinosa