MedicineNet

home > digestion center > digestion a-z list > diarrhea index > diarrhea article

Diarrhea (cont.)

Author:
Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

View Full Profile
Editor:
William C. Shiel Jr., MD, FACP, FACR
William C. Shiel Jr., MD, FACP, FACR
William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

View Full Profile

What tests are useful in the evaluation of diarrhea?

Acute diarrhea. Acute diarrhea usually requires few tests.

  • Measurement of blood pressure in the upright and supine (lying) positions can demonstrate orthostatic hypotension and confirm the presence of dehydration. If moderate or severe dehydration or electrolyte deficiencies are likely, blood electrolytes can be measured.
  • Examination of a small amount of stool under the microscope may reveal white blood cells indicating that intestinal inflammation is present and prompting further testing, particularly bacterial cultures of stool and examination of stool for parasites.
  • If antibiotics have been taken within the previous two weeks, stool should be tested for the toxin of C. difficile.
  • Testing stool or blood for viruses is performed only rarely, since there is no specific treatment for the viruses that cause gastroenteritis.
  • If there has been recent travel to undeveloped countries or the mountains, stool may be examined under the microscope for Giardia and other parasites.
  • There are also immunologic tests that can be done on samples of stool to diagnose infection with Giardia.

Chronic diarrhea. With chronic diarrhea, the focus usually shifts from dehydration and infection (with the exception of Giardia, which occasionally causes chronic infections) to the diagnosis of non-infectious causes of diarrhea. (See the prior discussion of common causes of chronic diarrhea.)

  • This may require X-rays of the intestines (upper gastrointestinal series or barium enema), or endoscopy (esophagogastroduodenoscopy or EGD, or colonoscopy) with biopsies. Examination of the small intestine via a camera-containing capsule or specialized endoscopy also can be done.
  • Fat malabsorption can be diagnosed by measuring the fat in a 72 hour collection of stool.
  • Sugar malabsorption can be diagnosed by eliminating the offending sugar from the diet or by performing a hydrogen breath test. Hydrogen breath testing also can be used to diagnose bacterial overgrowth of the small intestine.
  • An under-active pituitary or adrenal gland and an overactive thyroid gland can be diagnosed by measuring blood levels of cortisol and thyroid hormone, respectively.
  • Celiac disease can be diagnosed with blood tests and a biopsy of the small intestine.
Reviewed by William C. Shiel Jr., MD, FACP, FACR on 2/14/2013

Patient Comments

Viewers share their comments

Diarrhea - Effective Treatments Question: What kinds of treatments have been effective for your diarrhea?
Diarrhea - Causes Question: What was the suspected cause of diarrhea in you, a friend, or relative?
Diarrhea - Antibiotics Question: Were you prescribed antibiotics for diarrhea? If so, why and what antibiotic was prescribed.
Diarrhea - Share Your Experience Question: Please share your experience with chronic diarrhea.
Diarrhea - Food Poisoning Question: Did you ever get diarrhea from something you ate? What was the food? Please describe your experience.
Print
MedicineNet Doctors

Suggested Reading on Diarrhea by Our Doctors

  • Related Diseases & Conditions

    90 articles
    • Staph Infection (Staphylococcus Aureus)
      • Staphylococcus or Staph is a group of bacteria that can cause a multitude of diseases. Staph infections can cause illness directly by infection or indirectly
    • Hemorrhoids
      • Hemorrhoid is an enlarged vein in the walls of the anus and sometimes around the rectum, usually caused by untreated constipation, but occasionally associated with
    • Abdominal Pain
      • Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an
    • Diverticulitis (Diverticulosis, Diverticular Disease)
      • Diverticulitis is a condition in which diverticuli in the colon rupture. The rupture results in infection in the tissues that surround the colon. Diverticulitis
    • Bladder Infection (Cystitis)
      • Bladder infection is an infection of the bladder, usually caused by bacteria or, rarely, by Candida. Certain people, including females, the elderly,
    • Anal Itching
      • Anal itching is the irritation of the skin at the exit of the rectum, known as the anus, accompanied by the desire to scratch. Causes include everything
    • Upper Respiratory Tract Infection
      • An upper respiratory infection is a contagious infection of the structures of the upper respiratory tract, which includes the sinuses, nasal passages,
    • Colitis
      • Inflammation of the inner lining of the colon is referred to as colitis. Symptoms of the inflammation of the colon lining include diarrhea, pain, and blood
    • Colon Cancer
      • Colon cancer is a malignancy that arises from the inner lining of the colon. Most, if not all, of these cancers develop from colonic polyps. Removal of
    • Crohn's Disease
      • Crohn's disease is a chronic inflammatory disease, primarily involving the small and large intestine, but which can affect other parts of the digestive
    • Dehydration
      • Dehydration is the excessive loss of body water. There are a number of causes of dehydration including heat exposure, prolonged vigorous exercise, and
    • Hyponatremia (Low Blood Sodium)
      • Hyponatremia is a condition where the level of sodium in the blood is low. Causes of hyponatremia can occur from excess fluid in the body, or a loss of
    • Hyperthyroidism
      • Hyperthyroidism is an excess of thyroid hormone resulting from an overactive thyroid gland. Symptoms can include increased heart rate, weight loss, depression,
    • Thyroid Cancer
      • There are four major types of thyroid cancer: papillary, follicular, medullary, and anaplastic thyroid cancer. Tumors on the thyroid are referred to as
    • Migraine
      • Migraine is usually periodic attacks of headaches on one or both sides of the head. These may be accompanied by nausea, vomiting, increased sensitivity
    • Gastroenteritis (Stomach Flu)
      • Gastroenteritis (viral gastroenteritis, stomach flu) is an infection caused by a variety of viruses that results in vomiting and/or diarrhea. Even though
    • Small Intestinal Bacterial Overgrowth
      • Small intestinal bacterial overgrowth (SIBO) refers to a condition in which abnormally large numbers of bacteria (at least 100,000 bacteria per ml of fluid)
    • Intestinal Gas (Belching, Bloating, Flatulence)
      • Gas or "intestinal gas" means different things to different people. Everyone has gas and eliminates it by belching or farting (passing it through the rectum).
    • Pinworms
      • Pinworm infection is an intestinal infection caused by a pinworm, seatworm, or threadworm. Female pinworms leave the intestine through the anus and deposit
    • Clostridium Difficile Colitis (Antibiotic-Associated Colitis, C. difficile colitis)
      • Clostridium difficile (C. difficile) is a bacterium, and is one of the most common causes of infection of the colon. C. difficile spores
    • Ulcerative Colitis
      • Ulcerative colitis is a chronic inflammation of the colon. Symptoms include abdominal pain, diarrhea, and rectal bleeding. Ulcerative colitis is closely
    • Measles
      • Measles (rubeola) is a highly contagious disease that's caused by a virus. Symptoms include a rash, high fever, cough, runny nose, and red eyes. Treatment
    • Celiac Disease
      • Celiac disease is a result of an immune reaction to gluten, a protein found in wheat or related grains and present in many foods that we eat. Celiac disease
    • Roseola
      • Roseola is a viral illness that most commonly affects young children. Symptoms and signs include a sudden high fever that lasts for three to five days,
    • Cystic Fibrosis
      • Cystic fibrosis is a disease of the mucus and sweat glands. Cystic fibrosis is an inherited disease. The outcome of the disease leaves the body malnourished,
    • Rotavirus
      • Rotavirus is the most common cause of severe diarrhea among infants and children throughout the world. Almost all children have become infected with rotavirus
    • Food Allergy
      • The most common food allergies are to eggs, nuts, milk, peanuts, fish, shellfish, strawberries and tomatoes. Symptoms and signs include nausea, vomiting,
    • Stool Color & Texture Changes (Black, Red, Maroon, Green, Yellow, Gray, Tarry, Sticky)
      • Stool color is generally brown. When stool color changes, often, an individual becomes concerned. The presence of the bilirubin in bile is generally responsible
    • Malaria
      • Malaria is an infectious disease transmitted by the bite of an infected Anopheles mosquito. Symptoms of malaria include chills, pain, fever, and sweating.
    • See All Related Diseases & Conditions »

  • Medications

    45 articles

  • Procedures & Tests

    9 articles

  • Pictures, Images & Quizzes

    14 articles

  • Doctor's & Expert's Views

    32 articles

  • Health News

    200 articles

  • Health Features

    21 articles
Privacy Policy

GI Disorders

Get the latest treatment options.

Please acknowledge your agreement

Symptom Checker: Your Guide to Symptoms & Signs: Pinpoint Your Pain

From WebMD

Digestive Disorders Resources
Featured Centers
Health Solutions From Our Sponsors

Get the latest health and medical information delivered direct to your inbox FREE!