A patient presents with an upper respiratory illness and wants antibiotics. She points out that she always gets antibiotics, and that she always gets better, therefore the antibiotics must be needed. Is this bacterial sinusitis?
The preferred term today is acute rhinosinusitis, which reflects the fact that the mucosa of the nasal and sinus mucosa are continuous and both affected. Upper respiratory infection is common, happening 6 times a year in children and 2-3 times per year in adults. The cause is initially viral in most cases. Bacteria superinfection is rare, occurring in 2-10% of cases. Nonetheless, antibiotics are prescribed in 81% of patients.
Imaging, whether radiographic or CT, does not differentiate bacterial from viral illness. With an ordinary cold, 87% of patients have abnormalities on CT.
Recent IDSA guidelines emphasize knowledge of the natural history of acute viral rhinosinusitis as a means of diagnosing bacterial superinfection. Fever and constitutional symptoms abate within 24-48 hours. Clear mucus becoming thick is normal and expected after about 3-4 days. The illness has peaked by day 5-6 and is starting to get better, even if not fully resolved.
Traditional signs of bacterial infection were a list of major criteria, but essentially they were indicators that the sinuses were either full of purulence or plugged (anterior or posterior purulent drainage, sinus fullness or pain, hyposmia).
To keep it simple, indications for antibiotics would be if the illness is:
-severe (for 3-4 days)
-prolonged (more than 10 days – 61% of taps at this time show bacteria)
Take Home Points:
-Viral acute rhinosinusitis is by far the most common cause
-Imaging does not reliably differentiate bacterial from viral causes
-Antibiotics are indicated when there is inappropriate worsening, severity, or duration
References: Chow, IDSA Guidelines, Clin Infect Dis, 2012