What are the causes and management of acute gastroenteritis in adults?

From the Guidelines

Gastroenteritis in adults should be managed primarily with oral rehydration solutions and symptom management using loperamide and ondansetron, as recommended by the 2017 Infectious Diseases Society of America clinical practice guidelines 1. The primary treatment focuses on preventing dehydration through oral rehydration solutions (ORS) like Pedialyte or a homemade solution of 1 teaspoon salt, 8 teaspoons sugar, and 1 liter of clean water. Adults should drink small amounts frequently, aiming for 2-3 liters daily. For symptom management,

• loperamide (Imodium) 4mg initially followed by 2mg after each loose stool (maximum 16mg daily) can help control diarrhea 1,
• while ondansetron 4-8mg every 8 hours can manage nausea and vomiting 1. Follow a BRAT diet (bananas, rice, applesauce, toast) initially, gradually reintroducing normal foods as symptoms improve. Antibiotics are generally not recommended for most cases as they're ineffective against viral causes and may worsen certain bacterial infections 1. Seek medical attention if experiencing severe dehydration (extreme thirst, dry mouth, little or no urination), bloody diarrhea, persistent vomiting, high fever above 102°F (39°C), or symptoms lasting more than 3 days. Most cases resolve within 1-3 days with proper hydration and rest, as the body's immune system fights the infection while the gastrointestinal tract heals. Some key points to consider:
• The use of antimotility agents like loperamide may be beneficial in controlling diarrhea, but should be used with caution in certain cases, such as suspected or proven toxic megacolon or inflammatory diarrhea with fever 1.
• Antimicrobial agents should be avoided in most cases of acute gastroenteritis, except in severe infections or in immunocompromised hosts 1.
• The choice of antimicrobial agent may change due to evolving resistance patterns, and fluoroquinolone resistance in US and Canadian patients without international travel remains low 1.

From the FDA Drug Label

Ciprofloxacin Tablets USP, 250 mg, 500 mg and 750 mg is indicated for the treatment of infections caused by susceptible strains of the designated microorganisms in the conditions and patient populations listed below... Infectious Diarrhea caused by Escherichia coli (enterotoxigenic strains), Campylobacter jejuni, Shigella boydii†, Shigella dysenteriae, Shigella flexneri or Shigella sonnei† when antibacterial therapy is indicated.

Gastroenteritis in adults can be treated with ciprofloxacin if the cause is a bacterial infection, such as those caused by Escherichia coli, Campylobacter jejuni, or Shigella species, as listed in the indications for use 2.

• Key points to consider:
  • The diagnosis of gastroenteritis should be made based on clinical evaluation and laboratory tests.
  • Ciprofloxacin is not effective against viral causes of gastroenteritis.
  • Loperamide may be used for symptomatic relief of acute nonspecific diarrhea in patients 2 years of age and older, but it does not treat the underlying cause of the infection 3.

From the Research

Definition and Prevalence

• Gastroenteritis is a common condition that affects adults, with approximately 178 million cases occurring annually in the United States, resulting in 473,000 hospitalizations and 5000 deaths 4.
• The majority of these cases are caused by viral infections and are self-limited, requiring only supportive care 4.

Diagnosis and Management

• The diagnosis and management of acute gastroenteritis in adults involve assessing the severity of illness and tailoring fluid and electrolyte replacement and symptomatic therapy accordingly 5.
• Oral rehydration solutions, such as Pedialyte and Gatorade, are commonly used to treat dehydration in viral gastroenteritis, but their efficacy and safety have been studied in various trials 6.
• A randomized, controlled trial found that Pedialyte, Gatorade, and a New Oral Rehydration Solution (N-ORS) were equally effective in correcting dehydration and improving bowel symptoms in adults with viral gastroenteritis 6.

Treatment Options

• Antiemetics can be used to improve tolerance of oral rehydration solutions and decrease the need for intravenous fluids and hospitalization 7.
• Probiotics, prebiotics, and zinc have been proposed as additions to oral rehydration salts to increase tolerability, shorten the duration of diarrhea, and improve parental quality of life 8.
• Antibiotics are seldom indicated for acute gastroenteritis, and their use should be guided by a rational, informed choice based on the severity of illness and differential diagnosis 5.

Complications and Prevention

• Severe dehydration and hypoglycemia can develop in cases of prolonged vomiting and diarrhea, and patients at high risk due to extremes of age or immunosuppression often require specific therapy to ensure resolution of symptoms 4, 7.
• Narrowing the considerations in differential diagnosis can help guide decision making about the need for diagnostic tests, specific therapy, and public health intervention 5.