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Gastroenteritis (cont.)

When to Seek Medical Care

Most often gastroenteritis is self-limiting, but it can cause significant problems with dehydration. Should that be a concern, contacting a primary care professional is reasonable.

Vomiting blood or having bloody or black bowel movements are not normal, and emergency care should be sought. Some medications such as iron or bismuth subsalicylate (Pepto-Bismol) can turn stool black in color.

Fever, increasing severity of abdominal pain, and persistent symptoms should not be ignored and seeking medical care should be considered.

Gastroenteritis Diagnosis

Gastroenteritis is often self-limiting, and the care is supportive designed to control symptoms and prevent dehydration. Tests may not be needed. The health care professional often may make the diagnosis based on history of symptoms and physical examination.

If the symptoms persist for a prolonged period of time blood and stool tests may be appropriate to determine the cause of the vomiting and diarrhea.

Patient History and Physical Examination

Taking a thorough history and physical examination is very helpful in making the diagnosis.

Questions asked by the health care professional may include:

  1. Have any other family members or friends had similar exposure or symptoms?
  2. What is the duration, frequency, and description of the patient's bowel movements, and is vomiting present?
  3. Can the patient tolerate any fluids by mouth?

These questions help determine the potential risk of dehydration. Other questions to help assess hydration also may include the amount and frequency of urination, weight loss, lightheadedness, and fainting (syncope).

Other information in the medical history that may be helpful in the diagnosis of gastroenteritis include:

  • Travel history: Travel may suggest E. coli bacterial infection or a parasite infection acquired from something the patient ate or drank. Norovirus infections tend to occur when many people are confined to a close space (for example, cruise ship).
  • Exposure to contaminated water: Swimming in contaminated water or drinking from suspicious fresh water such as mountain streams or wells may indicate infection with Giardia - an organism found in water.
  • Diet change, food preparation habits, and storage: When the disease occurs following exposure to undercooked or improperly stored or prepared food (for example foods at picnics and BBQs that should be refrigerated to avoid contamination), food poisoning must be considered. In general, symptoms caused by bacteria or their toxins will become apparent after the following amount of time:
    • Staphylococcus aureus in 2 to 6 hours
    • Clostridium 8 to 10 hours
    • Salmonella in 12 to 72 hours
  • Medications: If the patient has used antibiotics recently, they may have antibiotic-associated irritation of the gastrointestinal tract, caused by Clostridium difficile infection.
  • Toxins and poisons: Gastrointestinal symptoms can occur following exposure to a variety of toxins and poisons, which can occur in association with job-related or recreational activities.

Physical examination will look for other causes of vomiting and/or diarrhea unrelated to gastroenteritis. If there are specific tender areas in the abdomen, the doctor may want to determine if the patient has one of the following, or any other conditions that may be the cause of the patient’s symptoms:

Other noninfectious gastrointestinal diseases such as Crohn's disease, ulcerative colitis, or microscopic colitis also must be considered. The doctor will feel the abdomen for masses. A rectal examination may be considered, where the physician inspects the anus for any abnormalities and then inserts a finger into the rectum to feel for any masses. Stool obtained during this test may be tested for the presence of blood.

The doctor may order other laboratory tests, including:

Stool samples may be collected and tested for white blood cells, red blood cells and different types of infections.

Medically Reviewed by a Doctor on 2/11/2016

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