Emergent Treatment of Gastroenteritis Clinical Presentation

A well-taken history, considering important epidemiologic factors, can help to identify not only the cause of diarrhea but also if the patient is at risk for complications. History in infectious and food poisoning cases varies depending on the agent, with variation in the onset; the frequency and consistency of the stools; the presence or absence of blood and mucus, and associated vomiting, cramps, or fever. The history should also identify risk factors for unusual causes of acute gastroenteritis and possible reasons to suspect noninfectious etiologies. Indications of dehydration or sepsis should also be sought.

As an example, norovirus is usually diagnosed by history. The incubation period for the norovirus is between 12 and 48 hours. Some of the early symptoms include nausea, a sudden onset of vomiting, moderate diarrhea, headache, fever (~50%), chills, and myalgia and will last 12-60 hours. The clinical factors suggestive of norovirus include the patient's presentation and the sudden onset of symptoms, with uncontrolled vomiting being a classic sign. Usually, more vomiting than diarrhea occurs. The natural course of this illness usually provides resolution within 36 hours.

The following discussion involves elements of the history to obtain.

Duration of illness

Duration and rapidity of symptom onset are important in determining the incubation period and possible infecting organism and in directing further care.

Diarrhea that lasts longer than a month requires consideration of a different spectrum of etiologic factors than diarrhea that lasts less than 1-2 weeks.

Fever

The presence of high fever (with or without chills) generally suggests that an invasive organism is the cause of diarrhea, although many extraintestinal illnesses can present with both fever and diarrhea, especially in children.

Vomiting

Vomiting, a symptom common to a host of illnesses, implies proximal bowel involvement, especially with preformed neurotoxin, as elaborated by S aureus and B cereus.

Vomiting is a leading symptom of intestinal obstruction, usually coupled with distention or if the patient has had gastric bypass surgery; however, distention may not be significant if the obstructing lesion is very proximal. Vomiting without diarrhea must always prompt a search for noninfectious causes and cannot be referred to as gastroenteritis.

Pain

The location and character of pain may be indicative of the area of infection because colonic involvement is usually associated with tenesmus and pain in either of the lower quadrants or the lower back, whereas jejunoileal infection may result in periumbilical pain.

Cramps may be caused by an electrolyte imbalance.

Pain, especially in patients older than 50 years, should raise the suspicion of an ischemic process.

Stools

Note the following:

• Frequency, amount, color, consistency (ie, watery, semisolid, odor), and presence of blood and/or mucus are factors that can help to determine the causative agent.

• Large volumes of stool are usually associated with enteric infection, whereas colonic infection results in several small stools.

• The presence of blood may indicate colonic ulceration (bacterial infection, inflammatory disease, ischemia).

• White bulky feces that float (high fat content) are due to a small bowel pathology that leads to malabsorption.

• Copious (rice water) diarrhea is a hallmark of cholera.

Extraintestinal causes

Obtain a history of any nonintestinal illnesses that can lead to diarrhea. Vomiting and/or diarrhea may be a manifestation of that illness or a result of its treatment. Obtaining a history of recent surgery or radiation, food or drug allergies, and endocrine or gastrointestinal disorders is extremely important. The patient should always be questioned regarding prior episodes.

Malaria, Whipple disease, irritable bowel, incomplete bowel obstruction, inflammatory bowel disease, nutritional disease, carcinoid and malabsorption syndromes can all result in diarrhea and are examples of the numerous possible noninfectious causes.

Drugs such as colchicine, quinidine, antimicrobials, cancer chemotherapeutic agents, and magnesium-containing antacids frequently cause diarrhea.

Dehydration

Orthostasis, lightheadedness, diminished urine formation, and a change in mentation are symptoms of marked dehydration, requiring aggressive treatment. These symptoms are particularly important in elderly patients, a group that is most at risk from diarrhea.

Severe dehydration may also be associated with significant electrolyte imbalances.

Epidemiologic factors

Note the following:

• A number of historical questions may provide clues to the etiology of the illness, including foreign travel, recent camping, recent antibiotic use, daycare attendance, and/or ingestion of raw, possibly spoiled, or new marine products, as well as similar illnesses in family, friends, or close contacts.

• An epidemiologic factor may be travel to developing countries where bacterial or parasitic agents are endemic and can cause infection or to campgrounds in developed regions, where agents such as Giardia lamblia, Aeromonas, and Cryptosporidium can contaminate untreated water.

• Enterotoxigenic E coli is the most frequent cause of traveler's diarrhea. Symptoms usually begin within days of arrival in the region and can last from 5 days to 2 weeks.

• Vibrio species are more common in Asia, although epidemics have occurred in Central America within the last 10 years.

• As many as 12% of diarrheal illness cases may be caused by rotavirus in travelers to Asia, Africa, and South America.

• Men who are homosexual are more prone to infection by the usual pathogens (ie, Shigella, Campylobacter jejuni, Salmonella, protozoalike Entamoeba) via the fecal-oral route. Anal receptive intercourse may result in the direct inoculation of Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, and herpes simplex virus. Severely immunocompromised states (CD4 cell count < 200) increase the risk of infection by agents such as Mycobacterium avium complex, microsporidia, cytomegalovirus (CMV), and Isospora belli.

• Recent use of antimicrobial drugs increases the risk of C difficile infection.

• A common source outbreak from contaminated water and food may cause gastroenteritis either by infection (eg, C jejuni, G lamblia) or by ingestion of a preformed toxin (eg, E coli O157:H7, scombroid, ciguatera).

• Infections via the fecal-oral route are prevalent in children who attend daycare centers. Rotavirus has an infection rate of nearly 100% in exposed children younger than 2 years. Other family members are also at risk for infection.

• Exposure to a public vomiting episode in a public location such as cruise ship or casino can lead to exposure to aerosolized norovirus infection.

A thorough physical examination is essential to assess the general state of hydration and nutrition and to exclude extraintestinal causes of diarrhea. Usually, the cause of diarrhea cannot be determined based on the physical findings present, which may be few.

The most important element of the physical examination is the assessment of the patient's hydration status. (Dehydration in children, for example, is classified according to the degree of hydration/percentage deficit as < 3%, none; 3-6%, mild; 6-9%, moderate; and >10%, severe.) Additionally, signs of bacteremia or sepsis should be sought. Patients with chronic diarrhea may need an evaluation of their nutritional status.

A rectal examination should be performed, involving checking for blood and mucus. Rectal examination may reveal abscesses, fistulae, and fissures, which may indicate inflammatory bowel disease. A partially obstructing tumor or a fecal impaction may be discovered as a cause of diarrhea. Finally, the stool can be examined for the presence of blood and pus.

Hydration and nutritional status

Diminished skin turgor, weight loss, resting hypotension and tachycardia, dry mucus membranes, decreased frequency of urination, changes in mental status, and orthostasis can be used to gauge dehydration.

In children, the absence of tears, poor capillary refill, sunken eyes, depressed fontanelles, increased axillary skin folds, and dry diapers all may reflect a dehydrated state.

Muscle wasting and signs of neural dysfunction due to nutritional depletion may be observed in patients with chronic diarrhea.

Abdominal examination

A careful abdominal examination is necessary to exclude causes of diarrhea that may require surgical intervention.

The examiner should look for signs of an acute abdomen, listening for bowel sounds, determining the location of any tenderness, and palpating for masses or organomegaly, rebound, guarding, distension, or rigidity.

Appendicitis in children may manifest as diarrhea.

Extreme caution should be exercised in post gastric bypass bariatric surgery patients, as they may not manifest typical signs/symptoms such as vomiting or distension with obstruction or ischemia.