APPROACH TO THE PATIENT WITH ACUTE ABDOMINAL PAIN



The evaluation and care of patients with acute abdominal pain (”acute abdomen”) provide one of the great challenges in clinical medicine be­cause of the potentially lethal nature of many of the causes and the frequent need for prompt sur­gical or medical intervention. Although one can enlarge the differential diagnosis, the most com­mon causes are acute appendicitis, cholecystitis or pancreatitis, bowel obstruction, perforated vis-cus, intestinal infarction, strangulated viscus, acute diverticulitis, ruptured ectopic pregnancy, and ruptured aortic aneurysm. During the eval­uation of these patients, it is essential to remem­ber that pulmonary (pneumonia), pelvic, renal (renal stone), hematologic (sickle cell crisis), he­patic (acute hepatitis), and metabolic (acute por­phyria) disorders can cause acute abdominal pain.

The history of patients with acute abdominal pain should focus on the onset, nature, and ra­diation of pain, and the presence of associated symptoms such as fever, nausea, vomiting, con­stipation, and diarrhea. Crucial facts also can come from the patient’s medical history. For ex­ample, prior surgery or peptic ulcer disease might suggest possible bowel obstruction {adhesions) or perforation (ulcer). The physical examination in­cludes observation of the patient for restlessness (more common with intestinal colic) or immobil­ity (more common with diffuse peritonitis), as well as examination for the typical signs of per­itonitis, bowel obstruction, shock, and cardiovas­cular collapse (due to hypovolemia from acute peritonitis, bowel obstruction, or hemorrhage). The chest examination must rule out pulmonary causes of abdominal pain such as pneumonia or hepatic congestion due to congestive heart failure. The abdominal examination particularly ad­dresses the following: (1) the nature of bowel sounds, (2) the presence of localized or diffuse severe tenderness, (3) the presence of masses or incarcerated hernias, and (4) the presence of fluid in the abdomen. Evidence for peritoneal tender­ness and abdominal guarding is best sought with gentle palpation and light percussion. Vigorous palpation and maneuvers to elicit rebound are ex­tremely painful and usually unnecessary. Ade­quate rectal and pelvic examinations are essential and provide important clues to genitourinary, co­lonic, and appendiceal disease.

Useful laboratory tests include a hematocrit, white blood count and differential, urinalysis, and examination of the stool for blood or pus. Tests for serum amylase, bilirubin, and transam­inases and inspection for gross lipid are usually rapidly available and may be helpful. The diag­nosis of acute pancreatitis is one of exclusion be­cause an elevated serum amylase can accompany other causes of abdominal pain, including bowel ischemia, biliary tract disease, perforated ulcer, and ruptured ectopic pregnancy.

Helpful radiographic procedures include plain films of the abdomen in a supine and upright po­sition (to evaluate intestinal gas patterns and search for free intra-abdominal air), as well as a chest x-ray. Certain other tests such as barium or Gastrografin studies of the small bowel or colon, CT imaging, 99nTc-HIDA scans, ultrasound, and endoscopic procedures are useful in selected pa­tients.

Adequate pain relief should be provided to all patients even while awaiting a definitive diag­nosis. Ultimate management depends upon the underlying disease process. Because many dis­orders causing abdominal pain require prompt surgical intervention, surgical consultation should be obtained early. Few pathognomonic signs or symptoms exist for many of the processes under consideration, and an early diagnostic lap­arotomy may sometimes be necessary.