Intestinal perforation can occur as a result of iatrogenic or accidental injuries or can be secondary to inflammation or malignancies. It can progress rapidly to life-threatening shock and should be diagnosed early to prevent morbidity and mortality.
Intestinal perforation is an acute or subacute condition prevalent in all age groups. In adults, it presents with sudden onset of acute pain in the abdomen. It should be differentiated from other causes of abdominal pain as the manifestations of the different etiologies can be diverse with abdominal rigidity being common to all  . The disastrous onset of diffuse abdominal pain may be associated with nausea, vomiting, hiccups, inability to pass flatus, constipation and referred pain to the shoulder. Abdominal pain may be minimal in elderly patients. The condition can deteriorate rapidly to tachycardia, diaphoresis, dyspnea and shock. Intestinal perforation secondary to inflammation is often small in the beginning with the omentum walling it off. This leads to localized pain and a slow progression of the symptoms.
Intestinal perforation in infants is associated with difficulty feeding, bilious vomiting typically after feeds, abdominal distension, hematochezia and features of sepsis such as apneic episodes, respiratory distress, thermo-instability, listlessness, and excessive crying. Premature infants are more susceptible to necrotizing enterocolitis with intestinal perforation than full-term neonates.
The diagnosis of intestinal perforation in the setting of an emergency can be made from a detailed history, physical examination, laboratory and radiological tests . The onset, duration, location, and progression of abdominal pain provides an approximate clue about the organ involved e.g. pain in perforated appendicitis is often located in the right lower abdominal quadrant; pain in diverticulitis is in the left lower quadrant and pain secondary to duodenal perforation is typically in the epigastric region. It is important to inquire about foreign body ingestion, especially in children; chronic use of medications like steroids or aspirin; recent history of gastrointestinal endoscopy    ; and a history of travel to exclude salmonella gastroenteritis perforation. Physical examination may reveal abdominal guarding, rigidity, signs of injury or even shock. A rectal and vaginal examination should be a part of the workup to exclude appendicitis, diverticulitis and tubo-ovarian abscess as the cause for the symptoms.
Laboratory workup should include a complete blood count, erythrocyte sedimentation rate, packed cell volume, liver transaminases and renal function tests. In presence of leukocytosis indicative of infection, a blood culture should be performed.
Plain X-ray abdomen in the standing position is the best initial investigation in intestinal perforation  as the gas under the diaphragm is diagnostic of a perforated viscus. However, the patients are often too sick and unable to stand erect for a radiogram. In such patients, an abdominal ultrasound is useful as an initial tool in the workup and computed tomography (CT) scan is obtained in patients with nonspecific ultrasound results .
In some cases, a diagnostic peritoneal tap may be indicated to detect intra-abdominal blood or to drain pus for microbiological culture sensitivity testing. In presence of blunt trauma, peritoneal lavage is used to measure alkaline phosphatase levels and a level > 10IU/L is a strong indicator of an occult small intestinal perforation.