Key Points for This Section
Diarrhea is frequent, loose, and watery bowel movements. Acute diarrhea lasts more than 4 days but less than 2 weeks. Symptoms of acute diarrhea may be loose stools and passing more than 3 unformed stools in one day. Diarrhea is chronic (long-term) when it goes on for longer than 2 months.
Causes of diarrhea in cancer patients include the following:
- Cancer treatments, such as chemotherapy, radiation therapy, bone marrow transplant, and surgery.
- Some chemotherapy drugs cause diarrhea by changing how nutrients are broken down and absorbed in the small intestine. More than half of patients who receive chemotherapy have diarrhea that needs to be treated.
- Radiation therapy to the abdomen and pelvis can cause inflammation of the bowel. Patients may have problems digesting food, and have gas, bloating, cramps, and diarrhea. These symptoms may last up to 8 to 12 weeks after treatment or may not happen for months or years. Treatment may include diet changes, medicines, or surgery.
- Patients who are having radiation therapy and chemotherapy often have severe diarrhea. Hospital treatment may not be needed. Treatment may be given at an outpatient clinic or with home care. Intravenous (IV) fluids may be given or medicines may be prescribed.
- Patients who have a donor bone marrow transplant may develop graft-versus-host disease (GVHD). Stomach and intestinal symptoms of GVHD include nausea and vomiting, severe abdominal pain and cramps, and watery, green diarrhea. Symptoms may show up 1 week to 3 months after the transplant.
- Surgery on the stomach or intestines.
- The cancer itself.
- Stress and anxiety from being diagnosed with cancer and having cancer treatment.
- Medical conditions and diseases other than cancer.
- Antibiotic therapy for certain infections. Antibiotic therapy can irritate the lining of the bowel and cause diarrhea that often does not get better with treatment.
- Fecal impaction in which the stool leaks around the blockage.
- Certain foods that are high in fiber or fat.
Because diarrhea can be life-threatening, it is important to find out the cause so treatment can begin as soon as possible. The doctor may ask the following questions to help plan treatment:
- How often have you had bowel movements in the past 24 hours?
- When was your last bowel movement? What was it like (how much, how hard or soft, what color)? Was there any blood?
- Was there any blood in your stool or any rectal bleeding?
- Have you been dizzy, very drowsy, or had any cramps, pain, nausea, vomiting, or fever?
- What have you eaten? What and how much have you had to drink in the past 24 hours?
- Have you lost weight recently? How much?
- How often have you urinated in the past 24 hours?
- What medicines are you taking? How much and how often?
- Have you traveled recently?
Tests and procedures may include the following:
- Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken. The exam will include checking blood pressure, pulse, and breathing; checking for dryness of the skin and tissue lining the inside of the mouth; and checking for abdominal pain and bowel sounds.
- Digital rectal exam (DRE): An exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the lower part of the rectum to feel for lumps or anything else that seems unusual. The exam will check for signs of fecal impaction. Stool may be collected for laboratory tests.
- Fecal occult blood test : A test to check stool for blood that can only be seen with a microscope. Small samples of stool are placed on special cards and returned to the doctor or laboratory for testing.
- Stool tests: Laboratory tests to check the water and sodium levels in stool, and to find substances that may be causing diarrhea. Stool is also checked for bacterial, fungal, or viral infections.
- Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:
- The number of red blood cells, white blood cells, and platelets.
- The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
- The portion of the blood sample made up of red blood cells.
- Electrolyte panel: A blood test that measures the levels of electrolytes, such as sodium, potassium, and chloride.
- Urinalysis : A test to check the color of urine and its contents, such as sugar, protein, red blood cells, and white blood cells.
- Abdominal x-ray : An x-ray of the organs inside the abdomen. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body. Abdominal x-rays may also be done to look for a bowel obstruction or other problems.
Treatment depends on the cause of the diarrhea. The doctor may make changes in medicines, diet, and/or fluids.
- A change in the use of laxatives may be needed.
- Medicine to treat diarrhea may be prescribed to slow down the intestines, decrease fluid secreted by the intestines, and help nutrients be absorbed.
- Diarrhea caused by cancer treatment may be treated by changes in diet. Eat small frequent meals and avoid the following foods:
- Milk and dairy products.
- Spicy foods.
- Foods and drinks that have caffeine.
- Certain fruit juices.
- Foods and drinks that cause gas.
- Foods high in fiber or fat.
- A diet of bananas, rice, apples, and toast (the BRAT diet) may help mild diarrhea.
- Drinking more clear liquids may help decrease diarrhea. It is best to drink up to 3 quarts of clear fluids a day. These include water, sports drinks, broth, weak decaffeinated tea, caffeine-free soft drinks, clear juices, and gelatin. For severe diarrhea, the patient may need intravenous (IV) fluids or other forms of IV nutrition. (See the Diarrhea section in the PDQ summary on Nutrition in Cancer Care for more information.)
- Diarrhea caused by graft-versus-host-disease (GVHD) is often treated with a special diet. Some patients may need long-term treatment and diet management.
- Probiotics may be recommended. Probiotics are live microorganisms used as a dietary supplement to help with digestion and normal bowel function. A bacterium found in yogurt called Lactobacillus acidophilus, is the most common probiotic.
- Patients who have diarrhea with other symptoms may need fluids and medicine given by IV.