RSV vs Influenza and adenovirus
How to tell RSV and Influenza and adenovirus apart when a board question makes them look alike.
RSV = infant bronchiolitis/wheeze; influenza = abrupt systemic myalgias; adenovirus = pharyngoconjunctival fever or hemorrhagic cystitis.
Side by side
RSV causes bronchiolitis and pneumonia in infants/young children with rhinorrhea, cough, wheeze, crackles, apnea risk, and hyperinflation.
Influenza causes abrupt systemic fever/myalgias/cough; adenovirus can cause pharyngoconjunctival fever, pneumonia, hemorrhagic cystitis, or gastroenteritis.
RSV infects small airways and causes bronchiolar inflammation, mucus plugging, and air trapping.
Influenza is systemic respiratory orthomyxovirus infection; adenovirus is a nonenveloped DNA virus with respiratory, ocular, GI, and urinary syndromes.
Infant bronchiolitis, wheezing, crackles, winter season, RSV PCR/antigen, and supportive care needs support RSV.
Abrupt myalgias and flu testing support influenza; conjunctivitis with pharyngitis or hemorrhagic cystitis supports adenovirus.
The trap
Respiratory viruses overlap by fever and cough, so age and syndrome pattern decide. RSV (respiratory syncytial virus) is the most common cause of BRONCHIOLITIS and pneumonia in infants under 2 years (especially under 6 months); presents with rhinorrhea, cough, expiratory wheeze, retractions, and apnea in young infants; treat supportively with hydration and oxygen; consider palivizumab prophylaxis for high-risk preterm infants and infants with congenital heart disease or chronic lung disease. INFLUENZA causes abrupt-onset high fever, severe MYALGIA, headache, dry cough, malaise in patients of all ages, peaks December to February in Northern Hemisphere; complications include bacterial superinfection (especially Staph aureus pneumonia post-influenza, classic cause of post-flu deaths); treat with oseltamivir (or baloxavir, peramivir, zanamivir) within 48 hours of symptom onset; annual vaccination. ADENOVIRUS causes pharyngoconjunctival fever (sore throat, conjunctivitis, fever in swimmers and school outbreaks), acute hemorrhagic cystitis, gastroenteritis, and severe pneumonia in military recruits; no specific antiviral treatment in most cases.
The repair move
For respiratory viruses, match the age and organ pattern rather than cough alone.
Try a free question
CoreA 4-month-old in winter has rhinorrhea, cough, tachypnea, wheezing, crackles, poor feeding, and hyperinflation on chest radiograph. Which virus is most likely?
Show answer and explanation
Answer: A. RSV. Infant bronchiolitis with wheezing, crackles, and hyperinflation in winter supports RSV.
Why the other choices are tempting
- B. Influenza causes abrupt systemic fever/myalgias/cough.
- C. Adenovirus can cause pharyngoconjunctival fever, pneumonia, or hemorrhagic cystitis.
- D. EBV causes mononucleosis.
- E. Hepatitis C causes bloodborne hepatitis.
Flashcards
Tap a card to flip it.
What syndrome does RSV classically cause in infants?
RSV classically causes bronchiolitis in infants.
What lung findings support RSV bronchiolitis?
Wheezing, crackles, tachypnea, and hyperinflation support RSV bronchiolitis.
Quick answers
What is the fastest way to tell RSV from Influenza and adenovirus?
RSV = infant bronchiolitis/wheeze; influenza = abrupt systemic myalgias; adenovirus = pharyngoconjunctival fever or hemorrhagic cystitis.
What is the key clue for RSV?
RSV causes bronchiolitis and pneumonia in infants/young children with rhinorrhea, cough, wheeze, crackles, apnea risk, and hyperinflation.
What is the key clue for Influenza and adenovirus?
Influenza causes abrupt systemic fever/myalgias/cough; adenovirus can cause pharyngoconjunctival fever, pneumonia, hemorrhagic cystitis, or gastroenteritis.
What is the common trap with RSV vs Influenza and adenovirus?
Respiratory viruses overlap by fever and cough, so age and syndrome pattern decide. RSV (respiratory syncytial virus) is the most common cause of BRONCHIOLITIS and pneumonia in infants under 2 years (especially under 6 months); presents with rhinorrhea, cough, expiratory wheeze, retractions, and apnea in young infants; treat supportively with hydration and oxygen; consider palivizumab prophylaxis for high-risk preterm infants and infants with congenital heart disease or chronic lung disease. INFLUENZA causes abrupt-onset high fever, severe MYALGIA, headache, dry cough, malaise in patients of all ages, peaks December to February in Northern Hemisphere; complications include bacterial superinfection (especially Staph aureus pneumonia post-influenza, classic cause of post-flu deaths); treat with oseltamivir (or baloxavir, peramivir, zanamivir) within 48 hours of symptom onset; annual vaccination. ADENOVIRUS causes pharyngoconjunctival fever (sore throat, conjunctivitis, fever in swimmers and school outbreaks), acute hemorrhagic cystitis, gastroenteritis, and severe pneumonia in military recruits; no specific antiviral treatment in most cases.