Gastrointestinal Problems

General Principles

Exercise does not favor the gastrointestinal (GI) system. During exercise, blood flow is diverted from the splanchnic circulation and preferentially distributed to demanding peripheral muscles. An additional antagonist to normal GI functioning is the persistent mechanical movement of internal organs during exercise. These two factors are thought to be major underpinnings to various GI problems. Fortunately, despite almost 90% of some populations reporting exercise-associated GI complaints, the severity of illness is usually mild.

Approach to GI Problems in Athletes

History

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Differentiate upper GI from lower GI symptoms: nausea, cramping, bloating, and diarrhea
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Determine severity of disease: hematochezia and melena
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Consider effects of foods and beverages, anxiety/stress, caffeine, tobacco, alcohol, nonsteroidal anti-inflammatory drugs (NSAIDs) or other medications, drugs of abuse or other supplements
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Assess possibility of undiagnosed systemic disease (e.g., celiac or inflammatory bowel disease)

Physical Exam

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Signs of abnormal palpatory exam: localized or generalized abdominal tenderness, organomegaly, mass, hernia, and peritoneal signs
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Signs of volume depletion: orthostatic hypotension and tachycardia
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Signs of inflammatory bowel disease: oral ulcers, dermatologic and ocular signs, and joint manifestations
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Signs of thyroid disease: thyromegaly, altered reflexes, and dermatologic and ocular manifestations
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Signs of systemic wasting: temporal wasting, lymphadenopathy, hepatomegaly, and splenomegaly

Differential Diagnosis ( Table 30.1 )

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Infectious: gastroenteritis and hepatitis
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Neoplastic: GI tract cancer and lymphoma
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Endocrine: hyperthyroidism, hypothyroidism, and pancreatic disease
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Autoimmune: Crohn’s disease, ulcerative colitis, and celiac disease
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Trauma: GI and genitourinary organs
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Vascular: cardiac and mesenteric ischemia
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Other: peptic ulcer disease, irritable bowel syndrome, constipation, medication or supplement-induced disorder, and problems related to food or beverage intake

TABLE 30.1

GASTROINTESTINAL PROBLEMS

Upper GI Problems	Lower GI Problems	General GI Problems
Angina/Cardiac Ischemia	Runner’s Diarrhea	Anxiety/Stress
Gastroesophageal Reflux	Lower GI Bleed	Acute Gastroenteritis
Gastritis	Ischemic Colitis	Traveler’s Diarrhea
Peptic Ulcer Disease	Cecal Slap Syndrome	Celiac Disease
Delayed Gastric Emptying	Celiac Artery Compression Syndrome	Irritable Bowel Syndrome
Upper GI Bleed		Inflammatory Bowel Disease
Exercise-Associated Transient Abdominal Pain

Laboratory Data

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Determine the necessity of tests based on the severity of symptoms. Tests may include cell blood count, iron studies, hepatic function panel, Helicobacter pylori testing, electrolytes, thyroid studies, and occult blood in stool and other stool studies

Upper GI Problems

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Upper GI pain related to training and competition often presents a diagnostic dilemma as both serious and benign etiologies often have similar presentations. Common symptoms include epigastric pain, dysphagia, dyspepsia, nausea, vomiting, and heartburn.
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During exercise, central blood volume is maintained by redirecting blood away from internal organs, particularly the splanchnic bed. Studies have revealed that splanchnic blood flow declines from 1.56 L/minute at rest to 0.3 L/minute at maximal exercise.
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Possible negative effects of exercise-induced shunting: Decreased esophageal motility, erosive hemorrhagic gastritis, delayed gastric emptying, diarrhea, and intestinal bleeding
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Angina or cardiac ischemia: Should always be entertained as a possible diagnosis in epigastric pain, particularly in older athletes
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Gastroesophageal reflux (GER)
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  Vigorous exercise causes GER in healthy subjects, notably in runners, bicyclists, and weightlifters.
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  Frequency, amplitude, and duration of esophageal contractions decline with increasing exercise intensity.
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  Hypoperfusion resulting from physiologic arterial shunting to muscles and skin may cause reduced esophageal motility.
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  Treatment: H ₂-blockers or proton pump inhibitors 4 hours before exercise, standard medical management for GER, alteration of oral intake (avoid symptom-triggering foods and beverages, no food for 3 hours before exercise)
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Gastritis: Erosive gastritis may be induced by exercise-related hypoperfusion, mechanical forces, or NSAIDs: often hemorrhagic. Treat with proton pump inhibitors, H ₂-blockers, and antacids ( Fig. 30.1 ).

Figure 30.1

Gastroesophageal reflux.
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Peptic ulcer disease is as common in runners as in the general population; use standard medical management ( Fig. 30.2 ).

Figure 30.2

Upper GI problems.
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Delayed gastric emptying may be related to bloating, reflux, or both; likely only at severe exercise; may be caused by hypoperfusion, resulting from arterial shunting away from the splanchnic bed
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Upper GI bleeding: May be related to hemorrhagic gastritis or peptic ulcer disease (see the Gastritis section); mechanical cause is proposed in some cases. Gastric fundus is the most common site for gastric bleeding because the shearing force from the adjacent diaphragm may be the source.
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  Evaluate and treat using standard upper GI methodologies.
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  Improve hydration before and during performance. Increased plasma volume may reduce ischemia.
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Exercise-associated transient abdominal pain (ETAP): Often referred to as a “side-stitch”; presents as pain, most often in the lateral aspect of the midabdomen. Incidences decline with age. Proposed mechanisms include diaphragm spasm, exertional irritation of parietal peritoneum, compression of thoracic intercostal nerves, and trapped gas in hepatic or splenic flexure. Avoid solid meals before exercise.