Patient presents with signs and symptoms suggestive of intra-abdominal infection (IAI).  Presenting complaints include abdominal pain, localized or diffuse, with varying intensity.  Fever, chills, nausea, vomiting, and anorexia may also be present.  Physical examination reveals tenderness to palpation, guarding, rebound tenderness, and potentially abdominal distension.  Depending on the source and severity of the infection, the patient may exhibit signs of sepsis, such as tachycardia, hypotension, and altered mental status.  Laboratory findings may reveal leukocytosis, elevated inflammatory markers (CRP, ESR), and positive blood cultures if bacteremia is present.  Imaging studies, such as CT abdomen and pelvis with IV contrast, ultrasound, or diagnostic laparoscopy, are crucial for identifying the source of infection (e.g., appendicitis, diverticulitis, perforated viscus, abscess) and guiding treatment.  Differential diagnoses include gastroenteritis, inflammatory bowel disease, and other abdominal pathologies.  Treatment for intra-abdominal infection typically involves intravenous antibiotics targeting suspected pathogens, fluid resuscitation, and pain management.  Surgical intervention, such as drainage of abscesses or resection of the infected source, may be necessary depending on the specific etiology and severity of the IAI.  The patient's clinical status will be closely monitored for response to therapy and potential complications, such as septic shock, multi-organ dysfunction, and abdominal compartment syndrome.  Patient education regarding medication adherence, wound care (if applicable), and follow-up appointments is essential.