The especially challenging task is to distinguish viral from bacterial sinusitis (1)
- in most patients, rhinoviral illness improves in 7 to 10 days therefore, a diagnosis of acute bacterial sinusitis requires the persistence of symptoms for longer than 10 days or a worsening of symptoms after 5 to 7 days
- symptoms of viral sinusitis, including fever, mimic those of bacterial sinusitis, although the color and quality of nasal discharge — classically, clear and thin during viral sinusitis and yellow-green and thick during bacterial sinusitis — may help to differentiate the two
With respect to bacterial sinusitis, the organisms usually implicated are (1):
- Streptococcus pneumoniae and Haemophilus influenzae are the major bacterial pathogens in adults with sinusitis
- other species (including β-hemolytic and α-hemolytic streptococci, Staphylococcus aureus, and anaerobes) have also been cultured from adults with sinusitis but are much less frequent
Acute frontal sinusitis is most commonly preceded by a viral upper respiratory tract infection (2)
- with respect to viral upper respiratory tract infection, human rhinovirus is implicated in 50 % of cases, but other viruses may include coronavirus, influenza, parainfluenza, respiratory syncytial virus, adenovirus, and enteroviru
- the primary predisposing factor for acute rhinosinusitis (ARS) is an antecedent upper respiratory viral infection
- approximately 0.5–2 % of viral upper respiratory tract infections are complicated by acute bacterial infection
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