The goal of physical examination is to identify potential causes of diarrhea and its complications as quickly as possible to reduce morbidity. The physical examination should include vital signs and evaluation of skin turgor and oral mucosa to assess hemodynamic status and dehydration. Abdominal examination includes evaluation for rebound tenderness, guarding, hypoactive or hyperactive bowel sounds, and stool collection. A rectal exam can rule out fecal impaction but should be performed judiciously in neutropenic or thrombocytopenic patients.
Laboratory tests may include stool cultures for bacterial, fungal, and viral pathogens. A complete chemistry panel and hematologic profile can provide information regarding the effect of diarrhea on kidney function and electrolytes as well as identify changes in white blood cell count in response to infection. Urinalysis with specific gravity can provide information regarding hydration status. Stool osmolality may also be measured.
In some cases, radiographic procedures are conducted to identify ileus, obstruction, or other abnormalities. In rare cases, endoscopy may be indicated.
A review of early toxic deaths in two NCI-sponsored cooperative trials of irinotecan plus high-dose fluorouracil and leucovorin for advanced colorectal cancer has led to the revision of previously published clinical practice guidelines for the treatment of cancer treatment-induced diarrhea, with a heightened emphasis on assessment and early aggressive interventions. The guidelines distinguish between uncomplicated and complicated diarrhea.
The current treatment of cancer-related diarrhea is often empiric and nonspecific. Whenever possible, treat underlying causes such as fecal impaction or modify the stimulant laxative regimen as necessary. Medications such as bulk laxatives and promotility agents (e.g., metoclopramide) should be discontinued. Dietary modifications are commonly implemented to stop or lessen the severity of cancer treatment-related diarrhea.[7,23,24,29] One author recommends that patients should consume foods that build stool consistency, are low in fiber, contain minerals, and do not stimulate or irritate the gastrointestinal tract. In some cases, dietary modification for diarrhea management includes advising patients to eat small, frequent meals and avoid lactose-containing food (milk and dairy products), spicy foods, alcohol, caffeine-containing foods and beverages, certain fruit juices, gas-forming foods and beverages, high-fiber foods, and high-fat foods. For mild cases of diarrhea, the BRAT (bananas, rice, apples, toast) diet may reduce the frequency of stools. When experiencing diarrhea, patients should be encouraged to increase clear liquid intake to at least 3 L per day (e.g., water, sports drinks, broth, weak decaffeinated teas, caffeine-free soft drinks, clear juices, and gelatin).[12,31] (Refer to the Diarrhea subsection of the Nutritional Suggestions for Symptom Management section in the PDQ summary on Nutrition in Cancer Care for more information.)
While some case reports suggest the efficacy of glutamine in relieving diarrhea and other gastrointestinal symptoms associated with cancer therapy, one randomized controlled trial that used oral glutamine to prevent pelvic radiation-induced diarrhea was unable to demonstrate any benefit.[Level of evidence: I][33,34]