Discussion

▪ Whenever possible, the cause of vomiting should be ascertained and specific treatment for an underlying cause initiated—particularly when emergent conditions, such as central nervous system (CNS) lesions, myocardial infarction, acute abdomen, bowel obstruction, endocrine/metabolic disorders, are suspected. As mentioned above, always consider pregnancy in women of childbearing age who present with vomiting. Consider bowel obstruction if there is distention and pain on abdominal palpation. Feculent vomiting is concerning for large bowel obstruction. Patients may present with a chief complaint of vomiting and, on exam, have nystagmus; these patients should be evaluated and treated for vertigo. Eating disorders must also be considered. In the diabetic, gastroparesis may be the cause. Frequent use of marijuana may be associated with recurrent vomiting as well. Many prescription drugs may cause nausea and vomiting, and these will be cured with cessation of the drug; so, take a good medication history, asking about both prescribed and nonprescribed drugs. However, in most cases of simple, uncomplicated vomiting with gastroenteritis or foodborne illness, the precise cause need not be determined, and therefore symptomatic treatment is all that is required.

▪ Many of the symptoms accompanying any gastroenteritis seem to be related to electrolyte disturbances and dehydration, which can be substantial even in the absence of copious vomiting and diarrhea. Lactated Ringer solution is considered the choice for IV rehydration by many clinicians, because it approximates normal serum electrolytes and can be infused rapidly. Lactated Ringer approximately replaces the electrolytes lost in diarrhea, although normal saline has more of the chloride lost by vomiting. Both work quite well in the acute setting for either diarrhea or vomiting or a combination of the two.

▪ Most food items that cause foodborne illness are raw or undercooked foods of animal origin, such as meat, milk, eggs, cheese, fish, or shellfish. A clearly implicated food source may give a clue to the cause: shellfish suggesting Vibrio parahaemolyticus; rice suggesting Bacillus cereus; meat or eggs suggesting staphylococci, Campylobacter organisms, clostridia, salmonellae, shigellae, enteropathic Escherichia coli, or Yersinia sp.

▪ Vibrio bacteria, so named because they are so motile that they appear to vibrate, are most common in states bordering the Gulf of Mexico. These flagellated bacteria inhabit marine environments and can cause gastroenteritis, wound infections, and septicemia. V. vulnificus infection more often follows ingestion of raw or undercooked oysters, and V. parahaemolyticus infection is more likely to be associated with eating shrimp or crabs. Fever, chills, and headache, in addition to the gastrointestinal symptoms, are common manifestations of this infection. Patients with liver disease, impaired immune systems, and diabetes are at increased risk for fulminant infections.

▪ B. cereus causes an acute emetic syndrome, most commonly within 1 to 6 hours of ingesting fried rice obtained from a Chinese restaurant. B. cereus also causes a less common diarrheal syndrome with an onset 8 to 16 hours after ingestion. There is no role for antimicrobial therapy in the treatment of these syndromes.

▪ The most common food poisoning seen in most emergency departments is caused by the heat-stable toxin of staphylococci, which is introduced into food from infections in handlers and grows when the food sits warm. Foods that are frequently incriminated in staphylococcal food poisoning include meat and meat products; poultry and egg products; salads, such as egg, tuna, chicken, potato, and macaroni; bakery products, such as cream-filled pastries and cream pies; and milk and dairy products. Foods containing the toxins usually look and taste normal. Sudden onset of nausea, vomiting, abdominal pain, and watery diarrhea usually occurs 30 minutes to 8 hours after eating contaminated food. Because these symptoms are toxin mediated, antibiotics are not indicated.