Approaching Common Clinical Problems

1.1 Abdominal Pain

Sx: The hx is the cornerstone of the efficient dx of abdominal pain. There are many different ways to obtain a hx and everyone develops an individual style. It is best to begin by letting the pt describe the pain without any leading questions. Say to the pt, “Tell me the whole story about your pain beginning with the first time in your life you had a pain anything like this.” Many pts will give a neat, chronological story and others will wander. It is worthwhile to give the pt some time to present the story in his or her own way, but it often becomes necessary to direct the pt to establish the following points:

Timing: When did the pain first begin? How often does it occur? When an episode occurs, how long does it last? Is the pt entirely well between episodes, or is the pain always present to some degree? Is the pain present 24 hours a day, 7 days a week? A pain present for years is unlikely to be malignant. Upper abdominal pain that occurs in discrete attacks is more likely to be biliary. Pain that is constant is often functional (eg, IBS in the setting of sexual abuse) or is readily diagnosed with imaging studies, hx, and physical exam (eg, malignancy, musculoskeletal pain, intra-abdominal inflammation or infection).
Character: Ask the pt to describe the pain. If the pt finds the pain indescribable, offer a multiple choice list, such as, “Is the pain sharp, dull, aching, burning, or stabbing?” Asking the pt to characterize the pain is helpful in evaluating pts who have multiple pain complaints, since each of the pains can be referred to separately.
Radiation: Ask the pt if the pain radiates anywhere. Upper abdominal pain radiating to the back suggests biliary colic, PUD, or an esophageal source. Acute perforation of a viscus can cause shoulder pain. Pain radiating to the groin or testicle suggests a urinary tract source. Pain radiating to the leg or thigh suggests a nonabdominal cause. Pain radiating to the neck or arm suggests a cardiac cause.
Relieving or exacerbating factors: Ask the pt, “Is there anything that makes the pain predictably worse, such as eating, BMs, stressful situations, or any kind of position or activity?” Identify factors that predictably bring relief, such as OTC remedies. These points help to establish if the pain is of GI origin and if it is more likely related to the bowel or to the UGI tract.
Associated sx: A complete ROS is necessary. Depending on the nature of the sx, it is important to establish whether there has been weight loss, fever, anorexia, nausea, melena, or hematochezia.
Medications: Many abdominal sx are related to medications, including OTC and herbal preparations. The duration of use should be determined.
Past medical and family hx: These histories help to establish risk factors for specific disorders and the safety and appropriateness of invasive tests.

Si: A complete physical exam is done, including assessment of vitals, skin, lymph nodes, the neck, heart, lungs, and joints; where indicated, a neurologic evaluation is done. The abdomen is usually the most informative part of the exam in creating a diff dx.

General abdominal exam: Bowel sounds are evaluated. Very active bowel sounds suggest the possibility of infection or early obstruction. Bowel sounds may be absent with intraabdominal catastrophe or ileus. The abdomen is assessed for tenderness to percussion. Percussion tenderness suggests peritoneal irritation. Palpation is done to look for masses or tenderness. If a pt seems to react with surprising drama, the exam can be continued while the pt is distracted with questions. If the abdomen is tender, the pt is asked to lift the head and shoulders a few inches off the table to see if the tenderness on palpation changes. Pain that worsens with this maneuver is often from the abdominal wall. Pain that is unchanged or that improves with tensing the abdominal muscles is often from an intra-abdominal source. The costal margins should be carefully examined with firm palpation to look for evidence of the painful rib syndrome (p 213). The aorta should be palpated for tenderness or enlargement.
Inflammation and peritonitis: Percussion tenderness, rebound tenderness, or pain with shaking of the pelvis suggests peritoneal irritation. In diffuse peritonitis, the abdomen may become rigid. A positive psoas sign (pain on extension of the thigh with the pt lying laterally on the opposite hip) may occur with retroperitoneal inflammation. A positive obturator sign (pain on internal rotation of the flexed thigh) may indicate an inflammatory process in the pelvis. A Murphy’s sign (the abrupt cessation of inspiration when examiner is palpating the RUQ because of worsening of the pain) strongly suggests cholecystitis.
Liver and spleen: Hepatomegaly can be assessed by percussion and palpation. Percussion of the upper border should be firm and that of the lower border lighter. The normal liver span is 12-15 cm in the midclavicular line. The normal liver is usually palpable with deep inspiration. It is often easier to palpate the liver edge by using both hands with palms lying on the rib cage and the fingers hooked over the edge of the costal margin. A similar technique is helpful for the spleen. The spleen is usually notpalpable, and percussion in the LUQ may reveal its lower margin.
Stigmata of liver disease: See p 26.
Rectal and pelvic exams are often needed depending on the differential being considered.

Approach to Dyspepsia: Chronic or recurrent pain centered in the upper abdomen is usually referred to as dyspepsia. Many pts with dyspepsia have GERD, which can be suspected based on clues such as retrosternal burning pain, gross regurgitation, or dysphagia to solids. Some GERD pts will have sx exclusively in the epigastrium, and this group may be difficult to identify without additional tests such as EGD, a therapeutic trial of a PPI, or pH probe (p 33).
About 10-25% of pts with dyspeptic sx have peptic ulcer disease (p 68) (GE 1998;114:579). About 60% of pts with dyspepsia never have an organic cause found and are said to have nonulcer dyspepsia (p 76). The remainder of the differential is listed in Table 1.1. The painful rib syndrome (p 213) should be easily identified on physical exam but is often overlooked.

It is often helpful to obtain a CBC, CMP, amylase, and lipase. The AGA has published guidelines for evaluating dyspepsia (GE 2005;129:1753). Pts on NSAIDs with dyspepsia should have the drug stopped/changed or a PPI added. In pts >55 yr of age who have new-onset dyspepsia, EGD is appropriate to rule out gastric cancer. Pts with alarm sx of weight loss, recurrent vomiting, dysphagia, bleeding, family hx of gastric cancer, or anemia should also undergo EGD. Pts <55 yr of age with no alarm features should be tested for Helicobacter pylori (Hp) (p 63), ideally with stool antigen or breath testing. If positive, they are treated and EGD is considered only if sx fail to improve after an additional 4 weeks of PPI rx. If a young pt is Hp negative, an empiric 4- to 8-week course of a PPI is appropriate. EGD is considered only if the pt fails to improve or if sx rapidly recur after stopping rx. There is little point to obtaining a UGI barium study since it is notsensitive enough to be a reliable negative test and a UGI series showing GU or a possible cancer requires EGD.

If no cause of sx is identified at EGD, clinical judgment is used to determine how vigorously to pursue the rest of the diff dx. CT scan and US of the abdomen, gastric
emptying scan, 24-hr pH probe, SBFT, testing for Giardia and other parasites, or dietary trials may be selectively indicated.

Table 1.1 Causes of Dyspepsia

Condition	Discussed on Page
Gastroesophageal reflux disease	33
Peptic ulcer disease	68
Nonulcer dyspepsia	76
Pancreatitis	187
Biliary colic	201
Gastroparesis	77
Pancreatic cancer	195
Lactose intolerance	102
Air swallowing	9
Giardia	163
Gastric cancer	81
Other intra-abdominal neoplasms	—
Crohn’s disease	105
Irritable bowel syndrome	91
Sphincter of Oddi dysfunction	210
Celiac disease	119
Chronic mesenteric ischemia	182
Porphyria	244
Lead poisoning	—
Painful rib syndrome	213
Other parasites	169
Angina	—
Somatization disorder	—

Approach to Attacks of Upper Abdominal Pain: If pain comes in discrete attacks, in between which the pt feels well, then biliary colic (p 201) should be strongly considered. CBC, CMP, amylase, and lipase are generally indicated, and an RUQ US should be obtained. If the US is negative, the differential may need to be broadened to include the causes of dyspepsia (Table 1.1). If further evaluation shows no convincing cause of pain, the possibility of a false-negative US needs to be considered. About 80% of pts with a good story for biliary colic, a negative US, and no other evident cause of dyspepsia will get relief with cholecystectomy. Some physicians use gallbladder emptying tests to select pts for cholecystectomy (Am J Surg 1997;63:769). A radionuclide scan (p 203) with an ejection fraction of <35% (in response to CCK stimulation) is considered abnormal. However, there is no high-quality evidence (ie, an RCT) showing that radionuclide scanning improves outcome for this challenging group of pts (Am J Gastro 2003;98:2605).

Approach to Acute Abdominal Pain: If hx suggests that the pain is entirely new (notan exacerbation of a chronic problem) and that the pain is of very recent onset (typically hours), the differential considerations are different (Table 1.2). Appendicitis typically presents with midabdominal pain that later moves to the RLQ but can be variable. Biliary colic, cholecystitis, pancreatitis, and cholangitis usually present with acute upper abdominal pain. Bowel obstruction usually presents as severe, crampy pain and distension usually in a pt with a prior hx of abdominal surgery. In acute mesenteric ischemia, the pain is severe and out of proportion to the initial physical exam findings. In ischemic colitis, there is usually intense, crampy lower abdominal pain with bloody diarrhea. In dissecting abdominal aortic aneurysm, there may be a pulsatile mass and hypotension, but these findings are notuniversal. In diverticulitis, the pain is usually (but notalways) in the LLQ and associated with fever. The pain of renal colic is often in the flank and may radiate to the groin in a pt with a benign belly. Other considerations include perforated ulcer disease, ectopic pregnancy, ruptured ovarian cyst, ovarian abscess or torsion, drug seeking, epiploic appendagitis, and acute presentations of Crohn’s disease.

A CBC, CMP, amylase, lipase, pregnancy test, and UA are generally indicated. A flat and upright view of the abdomen may demonstrate obstruction. In some cases an upright film centered on the diaphragm is done to look for free air. Depending on the severity of the sx, studies such as a CT scan may be warranted.

These considerations are reviewed separately for each disease entity.

Approach to Chronic Lower Abdominal Pain: Pain centered in the lower abdomen often has a colonic source. Crampy pain, diarrhea, relief of pain with passage of BMs, change in BMs, and rectal bleeding are features that suggest a colonic source of sx. Chronic pain from the colon is most often due to irritable bowel syndrome (p 91) or constipation (p 11). Rectal bleeding, weight loss, or a change in bowel habits (BM frequency, caliber) may suggest CRC (p 131). Diverticulitis usually presents with acute pain, but in some pts onset of sx can be more gradual (p 98). If diarrhea is prominent, infectious colitis is a possibility, though most pts with infectious colitis present with acute sx. Chronic bloody diarrhea and weight loss suggest ulcerative colitis (p 113) or Crohn’s colitis (p 105).

If pain seems unrelated to BMs, gynecologic and urinary tract causes should be considered. Musculoskeletal causes of pain are usually evident by hx and exam.

Table 1.2 Causes of Acute Abdominal Pain

Category	Condition	Discussed on Page
Gastrointestinal
	Appendicitis	103
	Perforated ulcer disease	68
	Bowel obstruction	123
	Acute mesenteric ischemia	181
	Ischemic colitis	183
	Infectious gastroenteritis	155
	Diverticulitis	98
	Perforated bowel	—
	Acute presentations of Crohn’s disease	105
	Epiploic appendagitis	129
Pancreatic and Biliary
	Biliary colic	201
	Cholecystitis	201
	Cholangitis	206
	Pancreatitis	187
Urologic
	Renal colic	—
	Pyelonephritis	—
	UTI	—
Gynecologic
	Ectopic pregnancy	—
	Pelvic inflammatory disease	—
	Ruptured ovarian cyst	—
	Ovarian abscess	—
	Ovarian torsion	—
Retroperitoneal
	Retroperitoneal hemorrhage	—
	Dissecting aortic aneurysm	185
	Psoas abscess	—
Thoracic
	Myocardial infarction	—
	Lower lobe pneumonia	—
Other
	Drug seeking	—
	Narcotic withdrawal	—
	Diabetic ketoacidosis	—

If the hx suggests a high probability of cancer or inflammatory bowel disease, colonoscopy is warranted. The approaches to suspected irritable bowel syndrome (p 91) and constipation (p 11) are discussed in separate sections.

Approach to Chronic Diffuse Pain: Pts with chronic diffuse pain that occurs 24 hours a day, 7 days a week are challenging. They fall broadly into 2 groups. The first group includes pts
with illnesses such as intra-abdominal malignancy or inflammation who undergo imaging studies or have findings on exam that are diagnostic. The second, more difficult group includes pts with chronic abdominal pain, typically with multiple pain complaints, many prior physician visits, and many diagnostic tests that have been unrevealing. A careful H&P is done to categorize the complaints. It is essential to obtain records of all prior evaluations prior to any new studies. Many of these pts will turn out to have functional or psychiatric diagnoses. It is vital notto overlook the connection between this pattern of complaints, medical evaluations, and hx of physical or sexual abuse (p 96). It is important for the pt to see that the physician has considered each complaint carefully. Do notappear dismissive or trivialize the pt’s difficulties.

1.2 Dysphagia and Odynophagia

GE 1999;117:229

Sx/Si: Dysphagia is the sensation that a swallowed food bolus sticks in the chest. Ask the pt, “If I gave you a bite of steak, bread, or apple to eat and told you that you had to wolf it down, would it stick in your chest?” Pts may perceive the sticking at the sternal notch even though the bolus is at the GE junction. Sometimes the sticking is relieved by swallowing liquid or by lifting the arms over the head or with other body position changes. Amazingly, some pts do notidentify the bolus as stuck, but instead will complain of pain and excessive salivation. Pts often do notreport these episodes unless specifically asked. Some pts have dysphagia to liquids as well as solids. They may experience nasal regurgitation. Many of these pts have motor disorders of the esophagus. Another group has problems with the initial nonesophageal phases of swallowing, called oropharyngeal dysphagia. Sx are usually above the sternal notch, sometimes with aspiration, coughing, or drooling. The physical exam is usually nothelpful in the evaluation of swallowing except for revealing neurologic disease in some pts with oropharyngeal dysphagia.

Odynophagia, or painful swallowing, is less common than dysphagia. Acute odynophagia suggests the possibility of infections (candida, herpes, CMV) or pill esophagitis. There may be evidence of oral thrush or herpes infection of the oropharynx in some pts.

Diff Dx: The causes of dysphagia are listed in Table 1.3. Strictures due to GERD and benign esophageal rings (Schatzki’s rings) are the most frequent causes. In dysphagia due to GERD without a stricture, the sx are usually brief and notassociated with prolonged food impaction. Esophageal cancer is often associated with weight loss. Extrinsic compression of the esophagus is usually due to malignancy. A Zenker’s diverticulum can be associated with a mass in the neck or coughing food debris hours after it was eaten. In congenital esophageal stenosis, the pt may describe a lifetime of being a slow eater.

Dysphagia to liquids raises the possibility of achalasia, diffuse esophageal spasm, and related spastic disorders. The evaluation of oropharyngeal dysphagia usually results in a dx of a neuromuscular or other disorder notrelated to the GI tract and is notfurther discussed in this text (see GE 1999;116:455 for a comprehensive review).

Pill esophagitis is a frequent cause of odynophagia. Doxycycline, alendronate, quinidine, ASA, other NSAIDs, and potassium tabs are the most frequent offenders (J Clin Gastroenterol 1999;28:298). Esophagitis due to candida, herpes, or CMV often presents with
painful swallowing. Idiopathic esophageal ulcer is seen in HIV infection. The other listed causes of dysphagia should also be considered in pts with painful swallowing.

Table 1.3 Causes of Dysphagia and Odynophagia

Dysphagia	Discussed on Page	Odynophagia	Discussed on Page
Esophageal strictures and rings	44	Pill esophagitis	—
GERD without stricture	33	Herpetic esophagitis	60
Esophageal cancer	49	Candida esophagitis	59
Extrinsic compression	—	CMV esophagitis	60
Benign esophageal tumors	62	Idiopathic esophageal ulcer	61
Zenker’s diverticulum	57
Other esophageal diverticula	58
Eosinophilic esophagitis	46
Congenital esophageal stenosis	47
Achalasia	53
Diffuse esophageal spasm	56
Other spastic disorders	56
Oropharyngeal causes	—

Approach to Dx and Rx: Most pts with intermittent solid food dysphagia are best served with EGD for dx and possible rx with esophageal dilatation. Pts with severe sx and those with a story suggestive of a Zenker’s diverticulum (p 57), other proximal lesions, or achalasia (p 53) should have a barium swallow. Some pts with severe sx have long and complex strictures, and a barium swallow helps the endoscopist decide how to proceed with dilatation. A Zenker’s diverticulum presents a perforation risk during endoscopy because it can be difficult to pass the scope beyond the diverticulum. If EGD is normal, biopsies of mid- and lower esophagus should be obtained to rule out eosinophilic esophagitis (p 46). If EGD is normal and the pt has solid food dysphagia, empiric dilatation can be considered in the hope of relieving sx by dilating rings missed at EGD (Clin Gastroenterol Hepatol 2005;3:299). If EGD is notreadily available, a barium swallow with a 13-mm barium tablet is a good test to detect stricture and rule out a mass. However, barium swallow is nottherapeutic and is insensitive for esophagitis. Pts with sx suggesting a motor disorder may be candidates for esophageal manometry testing after a structural abnormality has been excluded.

Pts who are awaiting evaluation need to be cautioned to cut food in small pieces and to chew carefully to avoid food impaction. If sx of GERD are present, it is reasonable to begin a PPI while awaiting diagnostic testing.

1.3 Nausea and Vomiting

GE 2001;120:263

Diff Dx: Nausea is a nonspecific sx with an enormous diff dx. Acute nausea and vomiting without substantial abdominal pain are most often related to infectious gastroenteritis, food poisoning, drugs, systemic infection, metabolic abnormalities, migraine, increased intracranial
pressure, labyrinthitis, or any cause of acute pain. Many other acute illnesses can cause vomiting with pain (eg, obstruction), but usually there are obvious clues. In most cases, the cause of acute nausea and vomiting can be readily determined.

Chronic nausea can be a more difficult problem. Vomiting increases the probability that a structural cause will be found. Some of the many causes of nausea and vomiting are listed in Table 1.4. Morning sickness of pregnancy must notbe overlooked. Numerous drugs cause nausea, including cancer chemotherapy, analgesics, hormonal preparations, antibiotics,
antivirals, and cardiovascular drugs. Structural diseases of the stomach, such as gastric outlet obstruction due to malignancy or ulcer disease, are usually associated with pain or weight loss. Gastroparesis is often considered as a cause of chronic nausea, but the pathogenesis is unclear, and gastroparesis should notbe accepted as the cause without excluding other etiologies. GERD is associated with nausea, and pts may interpret gross regurgitation as vomiting. Labyrinthine disorders are usually associated with clues on exam or hx, such as vertigo or nystagmus. A syndrome of cyclical vomiting that may be a migraine equivalent occurs in children and adults (Dig Dis Sci 1999;44:23S). While many other diseases can present with nausea and vomiting (eg, bowel obstruction, pancreatitis, cholecystitis, hepatitis, adrenal insufficiency, renal failure, electrolyte disorders, narcotic withdrawal), they rarely do without offering some other substantial clinical or laboratory clue to dx.

Table 1.4 Causes of Nausea and Vomiting

Category	Disorder	Discussed on Page
Gastrointestinal
	Infectious gastroenteritis	155
	Food poisoning	170
	Gastric outlet obstruction	—
	Gastroparesis	77
	Gastroesophageal reflux disease	33
	Nonulcer dyspepsia	76
	Bowel obstruction	123
	Intra-abdominal inflammation	—
	Intra-abdominal malignancy	—
	Eosinophilic gastroenteritis	129
	Gastric volvulus	80
	Pseudo-obstruction	125, 126
Medications
	Cancer chemotherapy	—
	NSAIDs	—
	Antibiotics	—
	Digoxin	—
	Many others	—
Central Nervous System
	Eating disorders	—
	Rumination syndrome	58
	Migraine	—
	Increased intracranial pressure	—
	Psychiatric disorders	—
Endocrine and Metabolic
	Fluid and electrolyte disorders	—
	Acute intermittent porphyria	244
	Hyperthyroidism	—
	Addison’s disease	—
	Renal failure	—
Postoperative
	Postoperative	—
Other
	Systemic infection	—
	Morning sickness	—

Approach to Dx and Rx: The most efficient approach is usually evident after a careful hx, physical exam, and selective use of laboratory tests (CBC, CMP, pregnancy test, amylase, lipase). In most cases, the cause can be identified and treated. If a dx is notevident after initial evaluation, short-term empiric rx with an antiemetic or prokinetic such as metoclopramide may be appropriate for some pts.

Very few trials have compared antiemetic regimens, and several classes of agents are available (Am Fam Phys 2004;69:1169). Anticholinergics (scopolamine) and antihistamines (meclizine, diphenhydramine, hydroxyzine) are popular for motion sickness and labyrinthine disorders. Phenothiazines (eg, prochlorperazine 5-10 mg po tid-qid or 25-mg supps pr bid or 2.5-10.0 mg iv q 3-4 hr to a maximum of 40 mg daily) are effective in many causes of nausea and vomiting. Other phenothiazines include promethazine, triethylperazine, chlorpromazine, and perphenazine. IV promethazine should notbe routinely used for nausea because of the risk of serious tissue injury. Serotonin antagonists (eg, ondansetron and others) are effective, more expensive, and widely used in chemotherapy pts. The choice of prokinetics is limited, and metoclopramide (5-10 mg po qid) is most frequently used.

For many pts, empiric rx is notappropriate and further evaluation is needed. The selective use of EGD, gastric emptying scan, abdominal CT scan, plain films of the abdomen, MRI of the brain, SBFT, and psychiatric evaluation may be appropriate. The nature, duration, and severity of complaints guide the extent of the evaluation.

1.4 Belching

Postgrad Med 1997;101:263

Diff Dx: Belching (eructation) is the involuntary expulsion of air from the esophagus and stomach. Regurgitation of swallowed air from the stomach is a normal physiological event. Some pts swallow air into the esophagus/hypopharynx and immediately expel it in a belch. Several organic disorders can be associated with belching, including GERD (p 33), gastroparesis (p 77), gastric outlet obstruction due to malignancy (p 87) or PUD (p 68), and achalasia (p 53). Aerophagia (air swallowing) is an unconscious habit or is related to anxiety, chewing gum, tobacco, postnasal drip, COPD, asthma, or ill-fitting dentures. Aerophagia can also be a response to pain in the stomach or esophagus.

Approach to Dx and Rx: If the hx or physical suggests an organic etiology, further testing is needed. A trial of a PPI may be considered for the question of GERD (p 33). If an organic etiology seems unlikely, air swallowing is discussed with the pt. It is most effective if the physician masters air swallowing and is able to match the pt belch for belch during the interview.

Those with suspected aerophagia should be counseled to minimize swallowed air by avoiding chewing gum, hard candy, smoking, and carbonated beverages. Pts should be educated that their sx are notcaused by production of gas by the stomach. A pencil held clenched between the teeth is said to decrease air swallowing but the value of this technique has been questioned (Am J Gastroenterol 1998;93:2276).

1.5 Bloating

Clin Perspect Gastro 2000;July:209; Postgrad Med 1997;101:263

Diff Dx: Bloating can be a sx associated with many organic diseases including GERD, gastroparesis, PUD, pancreatic disease, malabsorption, intestinal infection, constipation, diverticular disease, drug side effects, and intra-abdominal malignancy. While this is a daunting list, it is rare that bloating would be the sole sx in these disorders. Bloating as a single sx (or associated with generalized discomfort) is usually notrelated to the excess production of gas (Gut 1991;32:662), but is probably a manifestation of IBS (p 91). Dietary management to minimize gas production may benefit these pts because they have abnormal sensitivity to volumes of gas that pts without IBS do notfind distressing.

Approach to Dx and Rx: The H&P is used to determine if there are clues that may take the clinician in a direction other than irritable bowel syndrome. Dietary hx as detailed for the flatulent pt (p 10) is appropriate. In the absence of other clues, the approach is that outlined for IBS (p 91). Measures to decrease flatus (described in the next section) can be tried.

1.6 Flatulence

Clin Perspect Gastro 2000;July:209; Postgrad Med 1997;101:263

Diff Dx: Normal subjects produce up to 2500 mL of flatus a day and pass it up to 20 times daily. Rectal gas is a combination of swallowed air (rich in nitrogen) and gas produced from colonic bacterial metabolism that produces hydrogen, methane, and malodorous sulfur gases (Gut 1998;43:100). Some pts will complain of frequent passage of flatus because of poor sphincter tone. A small number of pts will have excess gas from serious malabsorptive diseases (p 19) such as celiac disease, small bowel bacterial overgrowth, and pancreatic insufficiency. The remainder have an anatomically normal gut and have excessive flatus either from air swallowing or from gas produced by bacterial fermentation of carbohydrates.

Excessive colonic production of gas may be of a variety of dietary sources. Lactose intolerance is a frequent cause (p 102). Fructose (found in high concentration in figs, dates, prunes, pears, apples, grapes, some vegetables, and in soft drinks sweetened with high
fructose corn syrup) can cause flatulence because it is less efficiently absorbed than other sugars (Am J Gastro 2004;99:2046). Sorbitol (found in sugarless gum, many hard candies, and food sweetened for diabetics, as well as in apples, pears, prunes, and peaches) is minimally absorbed and causes distressing sx due to bacterial fermentation (Gut 1988;29:44). Legumes (such as beans, broccoli, cabbage, and cauliflower) have complex carbohydrates that cannot be fully digested because humans lack α-galactosidase. Starches and dietary fiber also provide substrates for intestinal gas production.

Approach to Dx and Rx: The H&P is used to look for clues to serious underlying disease and to assess rectal tone. Dietary hx is obtained for lactose, fructose, sorbitol, legumes, and fiber. The pt is watched for evidence of air swallowing. If there are clues to serious disease, further evaluation is indicated (see Malabsorption, p 19). Those with poor sphincter tone are educated as to the nature of the problem, and incontinence is treated (p 176). Flatus passed more than 20 times daily is abnormal. Colonic fermentation should be suspected if the flatus is especially malodorous, nocturnal, or meal related. The pt can be evaluated for lactose intolerance (p 102) and can be given diets low in offending carbohydrates. Those with odorless flatus, belching, and bloating may be suspected of air swallowing, but dietary trials are still worthwhile. Collection of rectal gas to distinguish air swallowing (flatus high in nitrogen) from colonic fermentation (high in methane and hydrogen) has been reported but is impractical for widespread use (Am J Gastroenterol 1998;93:2276).

Oral activated charcoal is of no benefit (Am J Gastroenterol 1999;94:208), but a charcoallined pillow (Toot Trapper) is effective at reducing noxious odor (Gut 1998;43:100). Beano, a commercially available α-galactosidase preparation, is effective in reducing flatulence associated with legumes.

1.7 Constipation

Am J Gastro 2005;100 Suppl 1:S1; GE 2000;119:1766; Cleve Clin J Med 1999;66:41

Sx: Constipation is a term used by pts to describe a wide variety of complaints related to defecation. To the physician, constipation is usually defined as a BM frequency of less than 3 per week. More complex definitions have been proposed but are notof practical significance except for scientific study (Gut 1999;45[suppl 2]:II43). Pts may use the term constipation to mean excessive straining, painful defecation, hard stools, abdominal pain, or the failure to have a daily BM. The quality and time course of each complaint should be noted. The use of mechanical means (vaginal or perineal pressure, a finger in the rectum, enemas) to evacuate stool suggests pelvic floor dysfunction. Dietary hx is crucial since in many cases dietary fiber is inadequate. Ask the pt to describe a typical breakfast, lunch, and dinner. Determine servings of cereal, whole-grain bread, rice, pasta, vegetables, and fruit as a rough method of determining dietary fiber. Many pts will eat only 1 or 2 servings daily of high-fiber foods, and the most likely cause of their sx becomes evident quickly.

Si: Rectal exam is done to look for evidence of masses, fissures, strictures, painful spasm of the sphincter, or impaction. The pt is asked to strain in simulated defecation while the examiner watches for prolapse or paradoxical contraction of the anal sphincter. Paradoxical
contraction of the sphincter when simulating defecation suggests pelvic floor dysfunction. Rectocele is detected by vaginal examination. Neurologic exam may be appropriate.

Diff Dx: (Am J Gastroenterol 1999;94:567) The common causes of constipation are listed in Table 1.5. There are 2 primary mechanisms for constipation. In slow transit constipation, feces is moved slowly from cecum to rectum because of decreased contractions. Alternatively, uncoordinated contractions of the left colon may act as a functional barrier. In pelvic floor dysfunction, feces is stored in the rectum for an excessive period because of lack of coordinated mechanisms for rectal emptying. There are numerous secondary causes of constipation. Inadequate dietary fiber, inadequate fluid, and ignoring the urge for a BM are frequent causes. Constipation can be secondary to structural lesions, drugs, IBS, neurologic diseases, or metabolic causes.

Approach to Dx: The H&P is used to evaluate the probability of a secondary cause of constipation. In general, obstructing colon cancer should be considered in new-onset
constipation in a pt over 50 yr and in selected younger pts. Alarm sx such as weight loss, hematochezia, and sudden constipation in older pts prompt colonoscopy. Colonoscopy has the advantage in older pts of allowing highly effective CRC screening (by detection and removal of polyps incidental to the pts’ sx), but flex sig and BE are adequate if the only purpose is to rule out obstruction. BE alone is notadequate because of poor visualization of the rectum and limited views of overlapping loops of sigmoid colon. A TSH, electrolytes, and serum Ca⁺⁺ should be considered.

Table 1.5 Causes of Constipation

Cause	Example
Slow transit constipation	—
Pelvic floor dysfunction	—
Dietary	Inadequate fiber, inadequate fluids
Behavioral	Ignoring urge for BM
	Psychiatric illness
Structural	Colon cancer
	Colonic stricture
	Volvulus
	Anal fissure with spasm
	Rectal prolapse
	Rectocele
Systemic	Hypercalcemia
	Hypothyroidism
	Hypokalemia
	Diabetes
	Addison’s disease
	Scleroderma
Neurologic	Parkinson’s disease
	Multiple sclerosis
	Spinal cord injury
	Autonomic neuropathy
	Hirschsprung’s disease
Drugs	Multiple causes including:
		Iron
		Narcotics
		Cholestyramine
		Calcium channel blockers
		Anticholinergics
Functional	IBS

If no secondary cause of constipation is found, empiric rx with a 25-gm fiber diet, six 8-oz glasses of water daily, moderate exercise, and planned time for BMs (15 min bid) is appropriate. If pts do notrespond to these measures, a colonic transit study may be helpful. Pts are given a gelatin capsule containing 24 radio-opaque rings (commercially available in the U.S. as Sitzmarks [Konsyl Pharmaceuticals, New Jersey]), and 5 days later a KUB is done (Gut 1969;10:842). If there are 5 or fewer markers remaining, transit is normal. There are numerous variations of this test in which markers are ingested on multiple days to allow colonic transit times to be calculated for right and left colon. This may yield additional diagnostic information (GE 1987;92:40). If transit time is normal, “constipation” may be IBS (p 91), or the problem may be of psychogenic origin. Slow transit constipation is diagnosed when more than 5 markers are scattered through the colon. Pelvic floor dysfunction is suspected when markers bunch up in the rectosigmoid. Other clues to pelvic floor dysfunction include excessive straining, paradoxical tightening of the sphincter with attempts to simulate defecation on physical exam, and manual attempts using pressure or a finger to evacuate stool. Some pts have features of both disorders.

Some specialized centers perform anorectal manometry, balloon expulsion tests, and barium defecography to evaluate pelvic floor dysfunction, rectocele, and Hirschsprung’s disease. These techniques are notwidely available, and their role in selecting rx is notwell established (GE 1999;116:735; Am J Gastro 2005;100:1605).

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