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Acree M, Davis AM. Acute diarrheal infections in adults. JAMA. 2017;318(10):957-958.
This article is a synopsis of the 2016 American College of Gastroenterology (ACG) clinical guideline for the diagnosis, treatment, and prevention of acute diarrheal infection in immunocompetent adults. The guideline is an update of the prior guideline, released in 1997. The guideline does not include recommendations for the evaluation and management of Clostridium difficile infection. Important recommendations include when to consider empiric antibiotic therapy in acute diarrheal infections (such as traveler-associated diarrhea [TD]) and when to consider further testing of the stool. Other recommendations are provided regarding the use of probiotics and oral rehydration therapy.
Acute gastroenteritis is a common clinical presentation, with an estimated 179 million cases per year in the United States. The most common cause of gastroenteritis in the United States is norovirus, which carries significant morbidity and mortality, especially in patients aged ≥ 65 years. In most patients without a travel history, the cause of acute diarrheal illness is not identified. In contrast, in patients with TD, a pathogen can be identified in 50% to 94% of cases.
The ACG Practice Parameters Committee updated the 1997 guideline after conducting a comprehensive literature review. Antibiotics are not recommended for routine acute diarrheal infections or mild TD. For severe TD with a fever and disabling symptoms, the patient should be treated with empiric antibiotics, preferably azithromycin (1 g as a single dose or 500 mg once daily for 3 days). The literature has demonstrated a clear improvement in the duration of symptoms of TD with antibiotic therapy, with azithromycin found to be as efficacious as fluoroquinolones, with a lower risk of Clostridium difficile colitis. In patients being treated for TD, the evidence supports concomitant use of antidiarrheal medications; adjunctive loperamide can decrease the duration of diarrhea and increase the chance of recovery. Although there is no strong evidence in support of a specific antidiarrheal medication, a 2008 study showed increased benefit of loperamide over bismuth salicylate with regard to symptom duration in travelers.
Prophylaxis can be considered in patients who will be traveling and who would suffer from serious health consequences if they were to develop TD or if TD would impact the reason for travel. There is evidence for use of bismuth salicylate and antimicrobials (fluoroquinolones or rifaximin) for prophylaxis. Rifaximin has become preferred due to its more favorable safety profile compared to fluoroquinolones and its lower risk for development of more-serious bacterial infections.
Probiotics are not recommended for most acute diarrheal illnesses, except for diarrhea occurring after a patient has taken antibiotics. The guideline also recommends against routine stool testing; however, culture-independent stool testing (such as polymerase chain reaction testing) can be used in adult patients with grossly bloody stools, moderate to severe diarrhea, or symptoms lasting > 7 days. If diarrhea is persistent (lasting 14-30 days), then it should be evaluated with stool culture and/or culture-independent microbiologic testing.
In adults with acute diarrhea, further recommendations include using an algorithmic approach based on disease severity and recent travel history. Severity is assessed based on the presence of grossly bloody stools, fever ≥ 38.3ºC (101ºF), and the effect on the patient’s life (change in activities vs total disability due to diarrhea). This approach is meant to identify patients who are at increased risk for a bacterial infection, in order to determine the need for antibiotic therapy. In all cases, oral rehydration should be attempted, if feasible. Although these recommendations do not address the management of C difficile infections, they do reinforce the evidence that antibiotic use is not without risk. Antibiotic use has been identified as an independent risk factor for the development of C difficile colitis or extended-spectrum beta-lactamase-producing Enterobacteriaceae.
In the setting of increasing concern for drug resistance due to antimicrobial overuse, one aim of this article and the ACG guideline is to dissuade clinicians from prescribing antibiotics to patients with community-acquired diarrhea because the risks outweigh any potential benefits, given that the vast majority of these cases are of viral etiology.
This article is a synopsis of the ACG guideline, and the authors succinctly summarized the major points that can be incorporated into practice. The recommendations are practical and can be used to build an algorithmic approach to managing patients presenting with an acute diarrheal illness. For example, even when antibiotics are not indicated, the use of antidiarrheal medications, such as bismuth salicylate1 and loperamide, can be recommended. The ACG guideline also provides the strength of recommendations and the quality of the evidence. While all of the major recommendations are strong, the strength of the supporting evidence varies. However, since the majority of community-acquired cases of diarrhea are viral, there is a fairly high level of evidence endorsing supportive therapy outside of antimicrobials.
Acute diarrheal infections present a major public health issue. The ACG guideline also discusses potential downsides of widespread testing, but balances this against the need to discover antibiotic susceptibilities. Overall, this article and the ACG guideline clearly emphasize that acute diarrhea carries a significant burden of disease, but note that the cause of most community-acquired cases is viral. The article also notes that there are serious risks associated with the overuse of antibiotics,2 testing may be useful in certain cases, and supportive care is always appropriate. Using this guideline, clinicians can further screen patients who are at higher risk for bacterial infections.