Differential Diagnosis: Upper Respiratory Infection with Diarrhea

Primary Diagnostic Considerations

The American Academy of Otolaryngology-Head and Neck Surgery suggests that norovirus is the leading cause of acute gastroenteritis in the United States, characteristically presenting with vomiting and nonbloody diarrhea lasting 2-3 days or less, often accompanied by low-grade fever during the first 24 hours in 40% of infections 3
Norovirus accounts for 58% of gastroenteritis cases and is responsible for nearly 1 million ambulatory care visits annually, according to the Infectious Diseases Society of America 1, 2
Concurrent viral URI symptoms can occur with the same or different viral pathogens, as multiple respiratory viruses circulate simultaneously, as noted by the American Academy of Otolaryngology-Head and Neck Surgery 4, 5

The Infectious Diseases Society of America recommends stool testing when fever and bloody or mucoid stools are present, or when severe abdominal cramping or signs of dysentery are observed 7, 3
Stool testing is not routinely needed for acute watery diarrhea <7 days without fever or blood, according to the Infectious Diseases Society of America 7, 1

The American Academy of Pediatrics states that antibiotics provide no benefit for uncomplicated URI or viral gastroenteritis and expose patients to unnecessary harm, with antibiotic-associated adverse events occurring in 5-44% of patients 11
The American Academy of Otolaryngology-Head and Neck Surgery recommends first-line treatment with amoxicillin or amoxicillin-clavulanate for bacterial rhinosinusitis, and fluoroquinolones or azithromycin for adults with bacterial diarrhea, and third-generation cephalosporins or azithromycin for children 4, 6, 8

The American Academy of Otolaryngology-Head and Neck Surgery advises against prescribing antibiotics based solely on purulent nasal discharge, as this can occur normally after several days of viral URI due to neutrophil influx 4, 5
The Infectious Diseases Society of America warns against assuming all URI with diarrhea requires antibiotics, as most cases are viral and self-limited, and against testing for bacterial pathogens in uncomplicated acute watery diarrhea without fever or blood 7, 3