Acute Diarrhea





A Guide to Assessment and Management

By Emlyn T. Tobillo, MSN, CCRN, NP-C,

and Steven M. Schwartz, DO

In the primary care setting, acute diarrhea is a common presenting symptom. With signs and symptoms ranging from transient discomfort to devastating dehydration and electrolyte imbalance, acute gastrointestinal illnesses rank second only to acute upper respiratory illnesses as the most common diseases worldwide.1

In most cases, the initial evaluation and treatment of this disorder are the responsibility of the primary care provider. Only a small percentage of patients require specialty consultation.2


Illnesses presenting with acute diarrhea are prevalent worldwide. In the United States, acute diarrhea is responsible for 500 deaths a year among children aged 1 to 4.3,4 Poverty and poor access to health care correlate with increased mortality from diarrhea. The elderly are also at increased risk for mortality from the complications of illnesses presenting with acute diarrhea. Between 1979 and 1987, for example, 28,500 people–most of them older than 65 years–died of diarrhea in the United States.5 The very young and very old are at greatest risk for morbidity and mortality from the complications of diarrhea.

Diarrhea is defined as a change in normal bowel pattern, with increasing frequency, volume or fluidity of excreted feces. In an adult with relatively low fiber intake, the average daily stool weighs less than 200 g and the average frequency is three bowel movements per day or less. Therefore, diarrhea can also be defined as a stool volume greater than 200 g/d or a frequency of three or more bowel movements a day. However, the term diarrhea always implies a substantial increase of water volume in the stool as well.5,6

Case Presentation

A 48-year-old woman presented to the emergency department with complaints of spasmodic abdominal pain, nausea, vomiting and diarrhea for 2 days. She had been unable to eat since the symptoms began and had experienced four to five episodes of bloody diarrhea per day. She had not taken her temperature, but has had chills, mild headache and generalized malaise. She cooked pork chops a day before the symptoms began, but her boyfriend also ate the pork chops and did not get sick. Also prior to the symptoms, she ate in a seafood restaurant but had no seafood. The patient had not traveled to a foreign country or any known endemic area. She recently moved from a nearby state. She had no pertinent past medical history for any illnesses, including chronic gastrointestinal illnesses.

Examination of the patient revealed a pale woman in moderate distress secondary to pain. Bowel sounds were present and hyperactive. She was diffusely tender without rigidity or peritoneal signs. She was anicteric. Her lungs were clear on auscultation, and her heart rate was rapid and regular. Examination of her extremities revealed no abnormalities, and a brief neurological exam revealed no deficits. She had orthostatic blood pressure and pulse changes and was extremely dizzy in the sitting and standing positions. She appeared clinically toxic.



Diarrhea can result from damage to the intestinal lining caused by viruses or bacteria, malabsorption, inflammatory processes, bile salt and pancreatic enzyme deficiency, abnormal motility, or the presence of osmotically active solutes in the gut.4,5 Careful history taking must distinguish new-onset diarrhea from acute exacerbation of chronic recurrent diarrhea, since the latter suggest a different group of etiologies.6 It is also useful to classify diarrhea as infectious or noninfectious and secretory or osmotic.5 Table 1 lists the most common causes of diarrhea.7,8

Making the Diagnosis

While it is important to elicit information to determine the possible cause of diarrhea, be sure to check circulatory status first. Some patients may need rehydration therapy more urgently than a diagnosis. If the patient is hemodynamically stable, the next step is to obtain pertinent historical information that will classify the patient into one of the categories listed in Table 1. Keeping the most likely possibilities in mind will make history-taking more efficient and the list of differentials brief. A markedly shortened differential list will reduce the number of diagnostic tests required.7


Every evaluation begins with a thorough history (Table 2). A comprehensive review of systems will elicit information that may seem unimportant to the patient but will assist you in arriving at the correct diagnosis. The interview will provide clues about the nature of the disorder or disease process. Bloody diarrhea suggests an inflammatory, infectious or neoplastic disease. Pus or exudate in stool suggests inflammation or infection; nonbloody mucus and diarrhea alternating with constipation suggests irritable bowel syndrome. “Mushy,” foul-smelling stools that are frothy, greasy or contain oil suggest malabsorption.8

Symptoms of malabsorption require a dietary history for possible offending agents such as lactose products.

Ask the patient about recent travel, changes in diet and exposure to possible contaminated water or food sources. Ask about food intake in the past 48 to 72 hours. Inquire about use of any prescription or over-the-counter medications, including antibiotics. Antacids, antiarrhythmics, antineoplastics, laxatives and NSAIDs are a few of the most common offenders. Antibiotics can cause pseudomembranous colitis weeks after they are discontinued.7 Foreign travel associated with gradual onset of gastrointestinal symptoms that develops over the course of 2 or more weeks suggests parasitic infestation.

Explore the patient’s motives for seeking medical attention. Patient concerns may include food poisoning, infectivity, cancer or a simple interest in symptom relief.7 Table 2 suggests some important historical questions to ask patients who present with diarrhea.

Physical Examination

First, assess the patient for signs and symptoms of dehydration. Early signs and symptoms include thirst, dry mouth and mucous membranes, decreased axillary sweat and decreased pulse pressure. Signs of moderate dehydration include tachycardia, orthostatic hypotension, poor skin turgor and sunken eyes. Severe dehydration is indicated by worsening orthostatic hypotension, tachycardia, decreased urine output and shock, all signs of increasing volume depletion.1 In infants, lack of tears may signal mild dehydration, while decreased urine output, sunken fontanelles, delayed capillary refill and increasing lethargy may signal moderate dehydration. Assess cardiovascular status, such as heart rate and orthostatic blood pressure readings.

After assessing the patient’s hydration status, perform a complete physical examination. Of particular interest should be findings such as: abdominal mass, abdominal bruit, perianal fistula or abscess, signs of anemia, fever, edema, lymphadenopathy, hyperpigmentation, skin lesions, purpura, neuropathy, goiter, hepatosplenomegaly, ascites, gaseous abdominal distention, reduced anal sphincter tone, and rectal mass or impaction.7 In some instances, low abdominal tenderness suggests infectious colitis (Shigella, Campylobacter, E. histolytica) compared to middle or upper abdominal tenderness, which may suggest Salmonella or viral gastroenteritis. Significant abdominal tenderness, rebound and guarding indicate severe disease and warrant prompt surgical consultatation. Table 3 provides a summary of signs, symptoms and associated diseases.

Diagnostic Approach

After determining the severity of the illness, you must distinguish between inflammatory and non-inflammatory disease.1,8 Use the history and clinical features listed in Table 4 to help you evaluate the need for further efforts to define a specific etiology, as well as the need for therapeutic intervention. Personally inspect the stool specimen and note its consistency and color; observe for the presence of gross blood, mucus, pus, oil or froth, and note any excessive odor. All stool should be examined microscopically for fecal leukocytes. If the stool is greasy, oily or particularly foul-smelling, it should also be examined microscopically for fecal fat, a test whose results are readily available. This is in contrast to stool cultures, which take several days. If no fecal leukocytes are present in the stool specimen, consider antidiarrheal medications. If fecal leukocytes are present, antidiarrheals should not be prescribed.

Acute infectious diarrhea is often self-limiting, resolving by the time the patient seeks medical help. Due to cost associated with stool cultures and other diagnostic tests, considerable clinical judgment is required to decide which patients need further evaluation. The cornerstone of diagnosis in patients with severe and bloody diarrhea, especially with a suggestive epidemiologic history, is bacterial culture and stool for ova and parasites.1

Sigmoidoscopy and colonoscopy are generally reserved for patients with persistent bloody diarrhea. After 10 days or more of bloody diarrhea, referral for endoscopic examination is prudent. These tests will aid you in diagnosing patients with suspected pseudomembranous colitis, amebic dysentery or ischemic colitis.1,2

Treatment and Management

The main goals of treatment are to prevent dehydration and correct electrolyte imbalance, to provide supportive and symptomatic therapy, and to treat underlying disease. In most cases, a specific diagnosis is not necessary to guide initial treatment. Information gleaned from the history, stool examination and evaluation of hydration status are usually sufficient to proceed with initial management. The mainstay of therapy is to rest the intestinal tract and provide adequate rehydration when necessary. Most symptoms can be managed with clear liquids, chicken broth, fruit juices, flavored gelatin, water or Gatorade. Small and frequent sips of clear liquids are recommended. Feeding should begin as soon as possible to aid in healing of the intestinal mucosa.1,2,8 With time, the diet can be advanced to include bananas, rice, applesauce and toast.

Oral rehydration solutions for infants are available over the counter. Fruit juices, Kool-Aid and soda are inappropriate for infants and young children. Formula should be reintroduced slowly in a diluted form (1/4 or 1/2 strength) within the first 8 hours of rehydration. In moderate to severe dehydration, intravenous fluid therapy may be indicated.4

Supportive and symptomatic therapy should include use of hycosamine with atropine (Lomotil) or loperamide (Imodium) for temporary relief of uncontrollable diarrhea.8 Keep in mind that these agents may be contraindicated in certain types of infectious diarrhea, since they slow peristalsis and delay intestinal emptying of the infective organisms. This may result in continued contact between toxins and the intestines.1,9 To help the patient alleviate discomfort, recommend:

* after each bowel movement, gentle washing with absorbent cotton dampened with warm water

* avoidance of soap, toilet paper, washcloths and towels

* keeping perianal area dry

* taking sitz baths for 10 minutes two to three times per day

* using protective barrier creams.

Obviously, identifying the underlying cause of the diarrhea will result in the most efficient therapy. This is not possible in many cases. When the etiology of the diarrhea does become clear, therapy can be directed to the specific cause. For example, prednisone may be used to reduce symptoms associated with inflammatory bowel disease and cholestyramine may be used to treat bile acid malabsorption.9

Antibiotic therapy for bacterial diarrhea is controversial. Broad-spectrum antibiotics such as ciprofloxacin (Cipro) are commonly used in two clinical scenarios: as prophylaxis for traveler’s diarrhea and to treat profound symptoms such as severe diarrhea, fever, chills, tachycardia, rectal bleeding or abdominal pain. Since the incidence of bacterial enteritis is high, there is rationale for empirical treatment with broad-spectrum antibiotics, which can be more cost-effective than stool cultures. This is because some bacterial infections of the bowel respond to antibiotic therapy. The quinolones (levofloxacin, norfloxacin and ciprofloxacin) are still effective against diarrheal pathogens such as E. coli, Shigella, Salmonella and Yersinia.2 But some clinicians believe that empirical use of antibiotics should be reserved for patients who are febrile and toxic and only for specific organisms against which they are proven effective. In some infections, such as salmonellosis, antibiotic therapy is contraindicated because it may prolong the carrier state.1,8 The treatment of parasite-induced diarrhea requires appropriate antimicrobial therapy. Table 6 lists some of the common, nonviral organisms responsible for diarrhea and the drug therapy commonly recommended for each.8

Patient and Family Education

Your treatment of the patient with acute diarrhea should include patient and family education. Stress these points:

* Observe good handwashing techniques to limit fecal-oral spread of enteric pathogens.1

* To reduce risk of traveler’s diarrhea, eat only hot, freshly cooked food when visiting other countries. Avoid raw vegetables, salads and unpeeled fruits, and drink boiled or treated water only, avoiding ice. Bismuth subsalicylate (Pepto-Bismol) may be used as prophylaxis against traveler’s diarrhea.1

* Emphasize the importance of oral rehydration therapy at home for mild cases of diarrhea, especially for the very young and very old.

* Avoid contaminated sources. Cook meat properly. Clean and scrub kitchen work areas with soap and water in between uses.

Case Resolution

Our patient was hydrated with intravenous fluids and stool specimen was examined microscopically for fecal leukocytes. The test detected white cells too numerous to count. No parasites were present. The patient had not been on antibiotics recently, so we did not order a Clostridium difficile toxin. A CBC found a white blood cell count of 11,900 and an Hgb of 15.8. Her electrolyte status was normal except for a potassium of 3.0. Potassium 20 mg was added to her second liter of IV fluids. Compazine (prochlorperazine maleate) IV and Bentyl (dicyclomine hydrochloride) IM were administered and produced minimal improvement. We admitted the patient to the hospital for intravenous fluid replacement and further management. Subsequent stool culture report showed moderate growth of Salmonella. The patient recovered uneventfully.


1. Fauci AS, et al. Harrison’s Principles of Internal Medicine. 14th ed. New York: McGraw-Hill; 1998; 237-242;796-801.

2. Noble J. Textbook of Primary Care Medicine. 2nd ed. St. Louis: Mosby; 1996; 682-689.

3. Berkowitz CD. Pediatrics. A Primary Care Approach. Philadelphia: W.B. Saunders Company; 1996; 344-348.

4. Burns CE, et al. Pediatric Primary Care: A Handbook for Nurse Practitioners. Philadelphia: W.B. Saunders Company. 1996; 674-677.

5. Derksen DJ. Diarrhea. In: Medicine. A Primary Care Approach. Rubin RH, et al. eds. Philadelphia: W.B. Saunders Company; 1996; 172-175.

6. Avunduk C, Patwardhan R. Diarrhea. In Clinical Medicine. 2nd ed. Greene H, ed. St. was Louis: Mosby; 1996; 310-314.

7. Sleisenger MH, Fordtran JS. Gastrointestinal Disease: Pathophysiology/Diagnosis/ Management. 5th ed. Philadelphia: W.B. Saunders Company; 1993; 1047-1062.

8. Tintinalli JE. Emergency Medicine: A Comprehensive Study Guide. 4th ed. New York: McGraw-Hill; 1996; 488-495.

9. Bennett JC, Plum F. Cecil Textbook of Medicine. Philadelphia: W.B. Saunders Company; 1996; 690-695.