From the Guidelines
The diagnostic approach for a patient with watery and bloody diarrhea should begin with a thorough history and physical examination, followed by stool studies including culture, ova and parasite examination, and testing for Clostridioides difficile toxin, as recommended by the 2017 Infectious Diseases Society of America clinical practice guidelines 1. The initial management includes fluid and electrolyte replacement with oral rehydration solution or intravenous fluids if dehydration is severe.
- Key considerations in the diagnostic approach include:
- Identifying the underlying cause of the diarrhea, which could range from infectious colitis to inflammatory bowel disease
- Determining the presence of systemic illness or fever, which may indicate the need for empiric antibiotic therapy
- Assessing the patient's immunocompromised status, which may affect the choice of empiric antibiotic therapy
- Empiric antibiotic therapy may be started with ciprofloxacin 500 mg twice daily or azithromycin 500 mg once daily for 3-5 days if bacterial infection is suspected, particularly with fever or signs of systemic illness, as suggested by the guidelines 1. However, antibiotics should be avoided in suspected E. coli O157:H7 infection due to increased risk of hemolytic uremic syndrome, as stated in the guidelines 1. Additionally, endoscopy with biopsies may be essential in acute severe colitis for diagnosis and excluding other causes of acute colitis, according to the European evidence-based consensus for endoscopy in inflammatory bowel disease 1. Patients should maintain adequate hydration, consume a bland diet, and practice strict hand hygiene to prevent transmission.
- Hospital admission is warranted for:
- Severe dehydration
- Significant comorbidities
- Immunocompromised status
- Persistent symptoms This approach addresses the immediate concerns of fluid loss while identifying the underlying cause, which is crucial as bloody diarrhea can indicate serious conditions requiring specific treatment.
From the Research
Diagnostic Approach
- The diagnostic approach for a patient presenting with watery and bloody diarrhea involves evaluating for risk factors and signs of inflammatory diarrhea and/or severe dehydration 2.
- A history and physical examination can direct any needed testing and treatment, and most patients do not require laboratory workup 2.
- Routine stool cultures are not recommended, but diagnostic investigation should be reserved for patients with severe dehydration or illness, persistent fever, bloody stool, or immunosuppression, and for cases of suspected nosocomial infection or outbreak 2.
Initial Management
- The initial management of acute diarrhea focuses on preventing and treating dehydration, and oral rehydration therapy with early refeeding is the preferred treatment for dehydration 3, 2, 4.
- Antimotility agents should be avoided in patients with bloody diarrhea, but loperamide/simethicone may improve symptoms in patients with watery diarrhea 2.
- Probiotic use may shorten the duration of illness, and when used appropriately, antibiotics are effective in the treatment of shigellosis, campylobacteriosis, Clostridium difficile, traveler's diarrhea, and protozoal infections 5, 2.
- For patients with severe dehydration, intravenous fluids may be necessary, and hospitalization is indicated in infants <3 mo, children with severe dehydration, severe malnutrition, toxic look, persistent vomiting, and suspected surgical abdomen 3.
Treatment of Underlying Infection
- The treatment of underlying infection is crucial in managing acute diarrhea, and antimicrobial agents play a vital role in the management of acute invasive diarrhea, particularly shigellosis and amebiasis 4.
- Azithromycin is the preferred first-line antibiotic for the treatment of acute watery diarrhea, as well as for febrile diarrhea and dysentery 5.
- Levofloxacin and ciprofloxacin are also options for acute watery diarrhea and febrile diarrhea/dysentery, but are becoming less effective due to increasing fluoroquinolone resistance 5.