Introduction to Diagnosis of Bowel Problems
Evaluation of a patient with a bowel disease begins with careful history and physical examination. Subsequent investigation is indicated in selected cases only. Some patients have normal findings on diagnostic testing, so a diagnosis of a functional bowel problem or IBS is often given to them.
Symptoms of long duration are generally due to chronic inflammation, cancer or a functional bowel disorder. If symptoms are worsened by meal, they may arise from stomach ulcer, mechanical obstruction, ischemia, inflammatory bowel disease (IBD), rapid stomach emptying, food allergy, mal-absorption, irritation by food or stress (in irritable bowel syndrome – IBS). If symptoms are relieved by meal or antacids they are probably due to duodenal ulcer. An exaggerated gastro-colic reflex (bowel movement immediately after eating) may be due to IBS or IBD; defecation relieves discomfort in both. Functional bowel disorders are aggravated by stress, and sudden awakening from sound sleep suggests organic disease. Diarrhea from mal-absorption generally improves with fasting, but secretory diarrhea persists even during fasting. Read more about types of diarrhea and causes of chronic diarrhea.
An abdominal surgery can cause abdominal adhesions and consequent constipation, or bowel obstruction; loose stools may appear after removal of the stomach, or gallbladder excision. Bowel problems after travel suggest traveler’s diarrhea. Certain medications (NSAIDs – non steroidal anti-inflammatory drugs) may produce pain, altered bowel habits, or bleeding, so medication history is important. Anemia (pale skin, tiredness) may be due to celiac disease or gastrointestinal bleeding.
Fever may appear in inflammation (Crohn’s disease), infection (food poisoning, diverticulitis) or cancer.
Inspection can reveal abdominal distention from obstruction, tumor or ascites.
Palpation of abdominal wall can assess enlarged liver or spleen, inflammatory mass in appendicitis, abdominal tumor (but not likely colorectal cancer) or hernia. Intestinal ischemia may cause severe pain but elicits little tenderness (pain on pressure).
Percussion (tapping with the finger upon abdominal wall) can assess liver size and can detect shifting dullness due to ascites (fluid in abdominal cavity).
Loss of bowel sounds on auscultation (listening with a stethoscope) speaks for ileus (temporary paralysis of the intestine), while high pitched, hyperactive sounds are characteristic of intestinal obstruction.
Rectal examination (can be manual, or by using anal speculum; patient need to undress) can detect blood indicating a damage of the bowel mucosa or colorectal cancer.
Symptoms of Bowel Problems
Bloating or flatulence is due to presence of excessive gas in the stomach or intestine. Bloating is seen in some bowel problems, like irritable bowel syndrome, lactose or fructose malabsorption. A doctor will likely ask when bloating has started, is it related to certain food, time of the day when it appears, and so on. On percussion there will be tympanic (drum-like) sound due to gas in the stomach or intestine.
Abdominal pain may be caused by an ulcer (in the stomach, duodenum, small or large intestine), gastrointestinal obstruction, diverticulitis, inflammatory bowel disease, functional bowel disorder, infectious enterocolitis, worm infestation, appendicitis, and other disorders. The most common causes of abdominal pain are IBS and functional dyspepsia. Type of pain (mild, moderate or severe pain, or sharp, stabbing, dull aching pain), relation of abdominal pain with other factors like food, sudden onset, previous surgery in the GIT, will be enquired about by the doctor.
Location of abdominal pain can suggest its cause:
- Epigastric pain (in the middle upper abdomen where ribs meet): stomach or duodenal ulcer, heart or heart sac (pericard) disease
- Upper right abdominal pain: inflammation of gallbladder, bile duct (cholangitis), pancreas, pneumonia, empyema (pus between two lung membranes), pleurisy (inflammation of membrane covering of lungs), sub-diaphragmatic abscess, hepatitis, Budd-Chiari syndrome (obstruction of hepatic veins)
- Upper left abdominal pain: spleen disorder, gastritis (inflammation of stomach), gastric ulcer, pancreatitis, sub-diaphragmatic abscess
- Lower right abdominal pain: Crohn’s disease, appendicitis, inguinal hernia
- Pain around the navel: bowel obstruction, gastroenteritis, appendicitis
- Left lower abdominal pain: diverticulitis, IBD, inguinal hernia, colorectal cancer, IBS
- Diffuse abdominal pain: constipation, severe bloating, bowel obstruction, gastroenteritis, IBS, peritonitis, mesenteric ischemia
Diarrhea can be defined as the passage of abnormally liquid stools at an increased frequency (for adults on a typical Western diet, stool weight more than 300 g/day). Diarrhea can be acute (lasting less than 3 weeks) or chronic (more than 3 weeks). Bowel problems that can cause diarrhea are gastrointestinal infection, IBD, IBS, colitis, celiac disease, lactase deficiency, mal-absorption of fats due to gallbladder or pancreas disease, medications, intestinal ischemia, and others. Mucus in the stool may appear in IBS, intestinal parasites or colonic ischemia while pus (whitish or yellowish/greenish, not translucent) may appear in intestinal inflammation.
Constipation refers to infrequent defecation, straining at defecation, passage of hard stools or a sense of incomplete bowel evacuation. The bowel problems that can cause constipation are intestinal obstruction (due to stricture, neoplasm, diverticulitis, ischemia), anal sphincter spasm (due to fissure, painful hemorrhoids), IBS, colonic pseudo-obstruction (megacolon due to Hirschsprung’s disease, Chagas disease) disorders of rectal evacuation, anismus, rectal mucosal prolapse, rectocele), side effects of some medicines.
Nausea and Vomiting
Gastrointestinal obstruction, acute and chronic infection of GIT, disorders of gut motility (gastroparesis and intestinal pseudo-obstruction) or medications can cause nausea and vomiting.
Gastrointestinal (GI) Bleeding
Generally, upper GI (from the mouth to stomach) bleeding presents with melena (passing of black color stool) or hematemesis (blood in the vomit), whereas lower GI (from the duodenum to anus) bleeding causes bright red or maroon stools. Common bowel diseases with gastrointestinal bleeding are stomach or duodenal ulcer, inflammation of the stomach or duodenum, tears across the gastro-esophageal junction, colorectal cancer, hemorrhoids, anal fissures, diverticula, ischemic colitis, IBD, infectious colitis (in food poisoning), drug-induced colitis, vascular lesions in GIT.
A hemorrhoid is tortuous and dilated vein in the wall of the rectum (may be due to straining during bowel movement due to lack of fiber intake in the food or irregular bowel habits).
Internal hemorrhoids cause painless bright red bleeding or prolapse associated with defecation. Rarely, they may cause severe pain if they become thrombosed.
External hemorrhoids can swell or cause bright red bleeding.
Abdominal hernia is the protrusion of the intestine through its covering.
- A ventral hernia is the protrusion of the intestine through the anterior abdominal wall (can be spontaneous or acquired – like after surgery)
- An epigastric hernia appears anywhere between the bottom of the breastbone and the navel.
- An umbilical hernia appears around the navel.
- A hypogastric hernia appears below the navel.
- An incisional hernia occurs at the site of surgical wound (incision).
Abdominal wall should be diligently examined in standing position and also in supine (lying) position. Valsalva maneuver (closing the nose and blowing to increase abdominal pressure) is useful to demonstrate the site and size of a hernia. Uncommon hernias can be diagnosed with abdominal CT or MRI.
Investigations for Bowel Problems
In general, a patient with bowel problems can expect the following investigations:
- Radiological examinations: plain radiograph (X-ray of abdomen), barium studies (to assess the break in the lining of the intestine, abnormality in the mucosa), barium swallow and barium meal examination, follow through barium examination (in this investigation barium is observed during passage through small intestine and radiographs are taken at regular interval), barium enema, CT.
- MRI of abdomen.
- Ultrasonograhy (ultrasound) can be used safely during pregnancy. It can detect large intestinal tumors. But ultrasonography usually can not detect intestinal ulcers and functional bowel disorders. However, ultrasonography is a good diagnostic tool for non-bowel abdominal problems (gallbladder, liver, spleen, and pancreatic disorders and abdominal tumors).
- Radio-nucleotide imaging is done for assessment of Meckel’s diverticulum, and detection of GI bleeding. A contrast substance labeled with radioactive element like 99mTc is injected into a vein, and if there is intestinal bleeding, radioactive substance will leak into intestine together with the blood, what can be detected with a radio-detector.
- Endoscopy: lower proctoscopy (examination of rectum by endoscope), sigmoidoscopy, colonoscopy.
- Other investigations:
- Biopsy of the stomach or duodenal intestinal mucosa during upper endoscopy
- Secretory studies, like pentagastrin test, insulin test
- Stool tests: bacteriological studies, ova and parasites (O&P), occult blood
- Blood tests: electrolytes, liver and pancreatic enzymes, bilirubin, ferritin, red and white cells
- Breath tests with lactose is a safe, simple and non invasive method of assessing absorption. The test depends upon the metabolism by the intestinal bacteria or flora of a nutrient that is labeled with radioactive material and followed by exhalation of radioactive metabolite carbon-dioxide or hydrogen, that is than measured in the breath.