It is important to note that, while these body fluids are sterile at first, they frequently become infected once they leak out of their organ, leading to infectious peritonitis within 24 to 48 hours. Sterile abdominal surgery, under normal circumstances, causes localised or minimal generalised peritonitis, which may leave behind a foreign body reaction or fibrotic adhesions. However, peritonitis may also be caused by the rare case of a sterile foreign body inadvertently left in the abdomen after surgery (e.g., gauze, sponge). Much rarer non-infectious causes may include familial Mediterranean fever, TNF receptor associated periodic syndrome, porphyria, and systemic lupus erythematosus. Risk factors
Previous history of peritonitis
History of alcoholism
Liver disease
Fluid accumulation in the abdomen
Weakened immune system
Pelvic inflammatory disease

Diagnosis
A diagnosis of peritonitis is based primarily on the clinical manifestations described above. Rigidity (involuntary contraction of the abdominal muscles) is the most specific exam finding for diagnosing peritonitis. If focal peritonitis is detected, further work-up should be done. If diffuse peritonitis is detected, then urgent surgical consultation should be obtained, and may warrant surgery without further investigations. Leukocytosis, hypokalemia, hypernatremia, and acidosis may be present, but they are not specific findings. Abdominal X-rays may reveal dilated, edematous intestines, although such X-rays are mainly useful to look for pneumoperitoneum, an indicator of gastrointestinal perforation. The role of whole-abdomen ultrasound examination is under study and is likely to expand in the future. Computed tomography (CT or CAT scanning) may be useful in differentiating causes of abdominal pain. If reasonable doubt still persists, an exploratory peritoneal lavage or laparoscopy may be performed.
In medicine, an external cause is a reason for the existence of a medical condition which can be associated with a specific object or acute process that was caused by something outside the body. Such causes are classified as "E codes" in ICD 9.External Cause of Injury Codes (E codes) are ICD-9-CM codes or ICD-10 codes that are used to define the mechanism of death or injury, along with the place of occurrence of the event. [1] E codes are assigned on death certificates based on the manner of death. ICD-10 codes in the range V01–X59 refer to unintentional injuries. Codes in the range X60–X84 refer to intentional self-harm. Codes in the range Y85–Y09 refer to assault, and codes in the range Y10–Y34 refer to events of undetermined intent.E codes are well-collected on death certificate data, but less so on hospital discharge data. Numerous initiatives have increased the percentage of records coded (CDC, MMWR March 28, 2008 / Vol. 57 / No. RR-1). == References ==