Acute peritonitis accounts for 1% of inpatient surgical emergencies and is the second leading cause of sepsis in patients in intensive care departments. Diagnosis through laboratory analysis in bacterial peritonitis focuses mainly on the biomarkers, procalcitonin and C-reactive protein. A 73-year-old male patient presented with meteorism, diarrhea, vomiting, fever, and hypotension. Laboratory investigations showed very high procalcitonin and C-reactive protein values, and abdominal radiography revealed paraumbilical hydroaerial levels, which suggested septic shock of intra-abdominal origin. Emergency laparotomy was performed, which revealed agglutinated intestinal loops in the right iliac fossa with false membranes, purulent fluid, overdistended jejunum and ileum with an occlusive appearance, acute gangrenous appendicitis with perforation, and suppurative omentitis. The intraoperative diagnosis was acute neglected peritonitis in the occlusive phase owing to acute gangrenous appendicitis with perforation and suppurative omentitis. Laboratory analysis in conjunction with imaging provides important information in the early diagnosis of infectious pathology in elderly patients, even if these methods do not accurately identify the cause. The combination of procalcitonin and C-reactive protein biomarker levels successfully contributed to the diagnosis in this case. Notably, the patient's white blood cell counts were inconsistent with the severity of the infection.
Keywords: C-reactive protein; Diagnosis in the elderly; case report; neglected peritonitis; procalcitonin; septic shock.