Effectiveness and Safety of Outpatient Treatment of Uncomplicated Acute Diverticulitis Without Antibiotics

The surgeon must reassess the patient at 72 hours, with a complete history of the new clinical status, physical examination, and blood tests (with the same parameters). This visit will check treatment adherence and early clinical response. If the patient shows unfavorable progress or clear clinical deterioration, a new imaging test will be considered, and the assigned therapeutic option will be considered a failure. Follow-up will be completed with a face-to-face consultation one month after the episode and another (face-to-face or telematic) at six months.

Inclusion criteria

• Patients over 18 years old with clinical and radiological diagnosis of acute sigmoid or descending colon diverticulitis (left-sided acute diverticulitis) not complicated.
• Radiological diagnosis of acute uncomplicated diverticulitis by CT (Modified Hinchey Classification 0-Ia).
• First episode or previous history of acute diverticulitis (both complicated and uncomplicated), with ≥6 months between the last episode and the current clinical presentation).
• Informed consent to participate in the study.

Exclusion criteria

• Age >80 years.
• Patients eligible for hospital admission and/or intravenous antibiotic therapy (at the time of diagnosis).

• Repeated vomiting or oral intolerance.
• Need for intravenous fluid therapy and/or close monitoring.
• Peripheral body temperature >38ºC.
• Deterioration of general condition and/or clinical suspicion of sepsis.
• Significant or decompensated comorbidity: ASA IV Classification (anesthetic risk of American Society of Anesthesiologists).
• Immunocompromised patients: Hematological cause, HIV with low CD4+ levels, immunosuppressive treatment, prolonged corticosteroid therapy, chemotherapy, transplanted or splenectomized patients, predisposing genetic alterations (severe combined immunodeficiency, etc.).
• Oral or intravenous antibiotic therapy 2 weeks before the onset of symptoms for another cause.
• Pregnancy.
• Inflammatory bowel disease (Crohn's disease, ulcerative colitis).
• Lack of social and home support making outpatient treatment and follow-up impossible.