UPPER RESPIRATORY TRACT INFECTIONS: ACUTE SINUSITIS
Sinusitis is perhaps the most misunderstood infection of the upper respiratory tract. Sinusitis is defined as inflammation of the paranasal sinuses and contiguous nasal mucosa, regardless of the cause. Acute sinusitis is among the most common conditions treated by primary care physicians and is a common reason for the administration of antibiotics. Many clinicians consider sinusitis to be primarily of bacterial origin, but this is untrue. Although acute bacterial sinusitis does occur, acute sinusitis is often viral and therefore does not necessitate treatment with antibiotics. Distinguishing viral from acute bacterial sinusitis is difficult, and this has led to the widespread overuse of antibiotics for the treatment of sinusitis.The clinical features of sinusitis include purulent nasal discharge, nasal congestion, facial pain, maxillary toothache, and occasionally fever or cough. The clinical features of viral rhinosinusitis and acute bacterial sinusitis are similar. However, acute bacterial sinusitis typically develops secondarily to viral rhinosinusitis. During a viral upper respiratory tract infection, thick nasal secretions accumulate in the sinuses. Bacterial super-infection can subsequently result. Some authors have suggested that the high intranasal pressures generated during nose blowing may be a contributing factor for the introduction of bacterial pathogens into the sinus cavities. Other causes of acute bacterial sinusitis are less common and include seasonal allergies, mechanical obstruction of sinus drainage, swimming, prolonged nasal intubation, and extension from a dental infection into the sinus cavity.No diagnostic test easily distinguishes between viral rhinosinusitis and acute bacterial sinusitis. Sinus aspiration, although performed in some research studies, is not practical for routine diagnosis of acute bacterial sinusitis. The value of radiologic studies, including computed tomographic scans of the sinuses, is also limited because radiographic studies are unable to distinguish changes due to viral rhinosinusitis from those caused by acute bacterial sinusitis.18The decision to treat patients with antibiotics most often must be made on clinical grounds alone. Acute bacterial sinusitis is unlikely in patients whose symptoms are less than 7 days in duration. Patients whose symptoms have lasted more than 7 days are more likely to have bacterial sinusitis. However, the duration of illness alone is insufficient to suggest bacterial sinusitis. As discussed earlier, up to 25% of patients with viral rhinosinusitis will still have symptoms at 14 days. Other clinical predictors that suggest acute bacterial sinusitis include maxillary tooth or facial pain (especially unilateral), unilateral sinus tenderness, and mucopurulent nasal discharge. Worsening of symptoms after initial improvement is another clue to acute bacterial sinusitis.Even if a patient is suspected of having an acute bacterial sinusitis based upon these clinical predictors, it is often not necessary to prescribe antibiotics. A recent meta-analysis showed that although there is some benefit to treating patients with acute bacterial sinusitis, the benefit is small, and resolution of symptoms typically occurs without antibiotics. Patients with mild or moderate symptoms can be treated with nasal decongestants and analgesics, as discussed in the previous section. Current recommendations suggest the use of antibiotics in patients with severe symptoms of acute bacterial sinusitis, as outlined earlier. Even if antibiotics are used, decongestants should be administered to maintain sinus drainage.The choice of initial antibiotic therapy is empiric and based on knowledge of the organisms likely to cause acute bacterial sinusitis. Failure of treatment should result in a broadening of the antibiotic spectrum and prompt consideration of diagnostic sinus aspiration.Complications of bacterial sinusitis are rare but can be serious. These complications include meningitis, brain abscess, and periorbital cellulitis. Currently, there are no data to suggest that early treatment prevents the development of these complications.The possibility of fungal sinusitis should be strongly considered in the immunocompromised host. Rhinocerebral mucormycosis is an acute invasive fungal sinusitis that typically occurs in patients with organ transplants, diabetes mellitus, or neutropenia (due to hematologic malignancy or immunosuppressive medications). It rarely affects hosts with a normal immune system. A black necrotic palatal or nasal eschar may be seen and is a clue to the diagnosis. When an invasive fungal sinusitis is suspected, therapy with intravenous amphotericin В should be initiated, and urgent surgical consultations should be obtained.*35/348/5*