A 6-year-old is brought in by his mother for persistent rhinorrhea. He had what appeared to be a cold about 2 weeks prior but continues to have a stuffy nose and a constant cough, which is worse at night. He has no fever but his mother says that he appears more tired than usual and has a decreased appetite. On examination, the child has a purulent nasal discharge, nasal mucosal erythema, and allergic shiners (Figure 26-1); he otherwise appears healthy. You diagnose acute bacterial sinusitis (ABS) and prescribe oral amoxicillin-clavulanate. You discuss the lack of benefit of antihistamines and decongestants but offer a prescription for nasal corticosteroids, which the parent declines.

Sinusitis is symptomatic inflammation of the sinuses, nasal cavity, and their epithelial lining. Mucosal edema blocks mucous drainage creating a culture medium for viruses and bacteria. Sinusitis is classified by duration as acute (<4 weeks), subacute (4-12 weeks), or chronic (>12 weeks).

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  Approximately 1 percent of children per year develop sinusitis, accounting for 20 million antibiotic prescriptions; 6 percent to 7 percent of children seeking care for respiratory symptoms have acute bacterial sinusitis.¹

  
  
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  Children average six to eight colds per year. Of those, 0.5 percent to 8 percent will develop a sinus infection.^2,3

  
  
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  Risk factors include viral upper respiratory tract infection (URI) (about 80% of cases are preceded by a viral URI),² allergy,⁴ and day care attendance.⁵

  
  
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  Only 1/3 to 1/2 of primary care patients with symptoms of sinusitis actually have bacterial infection.⁶

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  Sinus cavities are lined with mucus-secreting respiratory epithelium. The mucus is transported by ciliary action through the sinus ostia (openings) to the nasal cavity. Under normal conditions, the paranasal sinuses are sterile cavities and there is no mucus retention.

  
  
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  The maxillary and ethmoid sinuses are present at birth and the frontal sinuses develop from the ethmoid sinuses by age 5 to 6 years.

  
  
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  ABS occurs when ostia become obstructed or ciliary action is impaired, causing mucus accumulation and secondary bacterial overgrowth.

  
  
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  The causes of sinusitis include:

  
  
  
  
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    Infection—Most commonly viral (e.g., rhinovirus, parainfluenza, and influenza) followed by bacteria infection (e.g., Streptococcus (S) pneumoniae, Haemophilus influenzae, Moraxella catarrhalis). In the past 10 years, S. pneumoniae has become less common and Haemophilus influenzae more common as the etiologic agent of acute bacterial sinusitis in children.² In immunocompromised patients, fulminant fungal sinusitis can occur.

    
    
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    Noninfectious obstruction—Allergic, polyposis, barotrauma (e.g., airplane travel), chemical irritants, tumors, and conditions that alter mucus composition (e.g., cystic fibrosis).

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  The diagnosis of ABS is clinical. Symptoms arising from a viral URI generally peak by day 5 or before and resolve by day 10.^1,2 ABS is diagnosed when:

  
  
  
  
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    Symptoms are present for 10 days or longer without improvement but less than 30 days.

    
    
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    Symptoms worsen after initial stability or improvement (“double worsening” or “double sickening”).

    
    
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    There are unusually severe signs and symptoms (high fever [>39°C], purulent rhinorrhea) present for at least 3 consecutive days.

  
  
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  Sinusitis can be presumed when there are extra-sinus manifestations of infection (periorbital inflammation, orbital cellulitis, orbital or brain abscess), although these complications of sinusitis are infrequent (Figures 26-2 and 26-3).²

Clinical features

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  Most cases occur as a complication of a viral URI or allergic inflammation.²

  
  
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  Symptoms of URI and ABS overlap to a great extent; thus, it is the persistence of symptoms without improvement that suggests the diagnosis of ABS.

  
  
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  These symptoms include nasal discharge (can be watery, mucoid, purulent or discolored) and daytime cough, which may be worse at night.

  
  
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  Nonspecific symptoms include halitosis, fever, fatigue, headache, and decreased appetite.

  
  
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  Physical examination findings are not particularly helpful in making the diagnosis of ABS. Erythema and swelling of the nasal mucosa are nonspecific findings.

  
  
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  Complications of sinusitis are suspected in children with severe headache, seizures, focal neurologic deficits, periorbital edema, or erythema (Figures 26-2 and 26-3), proptosis, or abnormal intraocular muscle function.²

Typical distribution

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  Most sinus infections involve the maxillary sinus followed in frequency by the ethmoid (anterior), frontal, and sphenoid sinuses; however, most cases involve more than one sinus (Figures 26-4 to 26-6).⁴

  
  
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  Children are more likely to have inflammation in the posterior ethmoid and sphenoid sinuses.⁷