Complicated intra-abdominal infections: a focus on appendicitis and diverticulitis

Severe abdominal pain is a common complaint encountered by primary care and emergency room physicians. Caused by many conditions, including appendicitis and diverticulitis, severe abdominal pain may be a diagnostic challenge. Although different in many ways, appendicitis and diverticulitis are caused by obstruction of a blind pouch that leads to inflammation of the structure and surrounding tissue. Appendicitis and diverticulitis are 2 of the most frequently diagnosed causes of complicated intra-abdominal infections. Combined, appendicitis and diverticulitis comprise > 80% of all community-acquired complicated intra-abdominal infections. These conditions are serious and require prompt diagnosis and treatment. Because complicated intra-abdominal infections are typically polymicrobial, a wide variety of causative pathogens are identified, including Gram-positive and Gram-negative aerobic and anaerobic microorganisms. Treatment for these disorders often requires surgical and medical management. Although surgical intervention can be the definitive treatment for complicated intra-abdominal infections, successful management of appendicitis and diverticulitis will depend on appropriate selection of antimicrobials and optimal duration of therapy to maximize the coverage of potential causative pathogens and to minimize the development of resistance. Guidelines for empiric treatment of complicated intra-abdominal infections recommend broad-spectrum antimicrobials as monotherapy or in combinations, including standard antimicrobial regimens, such as piperacillin/tazobactam, imipenem/cilastatin, and piperacillin-tazobactam/amoxicillin-clavulanate regimens, and fluoroquinolone-based regimens. This review article compares the presentations and treatments of these common complicated intra-abdominal infections.