The patient’s history provides the most helpful information that a doctor uses to determine the cause of abdominal pain. The characteristics of the pain (sharp, dull, cramping, burning, twisting, tearing, penetrating), its location and relation to eating or to having a bowel movement are important clues. Additional factors that are useful include the pattern of pain, its duration, radiation (spread) to other areas of the body, and its association with other symptoms, such as jaundice (yellow skin), nausea, vomiting, bleeding, diarrhea or constipation.
Findings on physical examination also are helpful. Key findings include areas of tenderness, the presence or absence of bowel sounds or abdominal distention, masses, organ enlargement, and evidence of blood in the stools.
Based on the history and physical examination the doctor may or may not have a clear idea about the cause of pain. Sometimes a diagnosis is made and treatment can be started. In other circumstances diagnostic tests are used to confirm or to exclude a specific diagnosis. Many tests can be ordered for these purposes. Frequently used tests include analysis of blood, urine and stool samples, x-rays of the abdomen, and endoscopy.
Blood tests include complete blood counts (analysis of the numbers of white cells that fight infections, red cells that carry oxygen and that are reduced in anemia, and platelets that help the blood to clot), chemistry tests (liver and kidney tests, blood mineral levels, and enzymes released when organs like the liver or pancreas are injured), and serology tests that measure antibody levels to various infections. Urine tests include urinalysis (measurement of characteristics and chemicals in urine along with microscopic inspection of a drop of urine), and urine culture for bacterial infection. Stools can be analyzed for blood and pus (markers of inflammation, infections, or tumors), fat (evidence of impaired digestion and absorption of food), and the presence of germs.
X-ray and Imaging Tests
Many different kinds of x-ray and imaging tests are used to make pictures of the interior of the body. These include barium studies in which barium sulfate (a material that shows up on x-rays) is swallowed (barium swallow, upper gastrointestinal series, small bowel follow-through examination) or injected by a tube into the small intestine (enteroclysis) or colon (barium enema). Computerized tomography (CT scan) is a very sophisticated technique for reconstructing cross-sectional x-ray images of the body with the help of a computer. Magnetic resonance imaging is a similar technique in which radio waves and magnets are used to make pictures of the internal organs. Sonography uses high frequency sound waves to peer into the body and to visualize the internal structures. Nuclear medicine scans use isotopes to identify body parts and to examine their function.
Endoscopy involves the use of special instruments to look into the hollow organs of the digestive tract. Upper gastrointestinal endoscopy uses a flexible tube with a television camera in its tip and a lighting system to examine the esophagus, stomach, and duodenum (the part of the intestine just beyond the stomach). Special tools can be passed through the tube to remove polyps or to obtain biopsy specimens to be viewed under a microscope. Longer tubes can reach well into the small intestine and similar tubes can be introduced through the rectum to view the colon (colonoscopy). Special endoscopes have been designed to look at the bile ducts and pancreatic duct and to obtain sonograms from inside the gut ERCP (Endoscopic Retrograde Cholangiopancreatography) and EUS (Endoscopic Ultrasound), respectively). Another diagnostic test is capsule endoscopy in which a capsule containing a tiny camera, broadcasting station and antenna sends pictures to a special belt that is worn around the abdomen. Pictures can be obtained from throughout the small intestine as the device is propelled through the gut.
While the technology behind these tests is impressive, a cause for abdominal pain can be made in most patients by means of a history, physical examination, and a few simple tests. Every patient does not require a full panel of diagnostic tests.