Approach to the Patient with Sinusitis

William A. Kormos

Sinusitis is an inflammation of one or more of the four paired paranasal sinuses surrounding the eyes. It is an extremely common but likely overdiagnosed condition, with more than 30 million Americans treated for acute sinusitis annually. Many patients with nasal and sinus symptoms have self-limited viral infections or allergic conditions; the physician must distinguish these patients from the patient with a bacterial infection who may require antibiotics. Although acute sinusitis is often selflimited, there is significant morbidity associated with sinusitis. The extension of infection into the central nervous system and bone may be life threatening, and patients who develop chronic sinusitis rate their quality of life similar to patients with congestive heart failure or chronic obstructive pulmonary disease.

PATHOPHYSIOLOGY AND CLINICAL PRESENTATION (1, 2 and 3)

The normal sinuses are sterile structures lined with ciliated epithelium. Mucus is cleared from the sinus in a directed manner toward the ostia, or openings, which drain into the nasal cavity at the superior meatus and middle meatus. The superior meatus drains the posterior ethmoid and sphenoid sinuses, and the middle meatus drains the frontal, maxillary, and anterior ethmoid sinuses. Occlusion of these ostiomeatal complexes can lead to dysfunction of the normal sinus epithelium and bacterial infection. Although any sinus can become occluded through viral infection, anatomic abnormalities (including septal deviation, tumors, and polyps) or allergies can predispose to infection.

Acute Sinusitis

The common cold is actually a rhinosinusitis that frequently involves the paranasal sinuses. Computed tomographic study of patients with the common cold reveals that more than 85% have a self-limited paranasal sinusitis that resolves without treatment. The maxillary sinuses are the most common sites (87%), followed by ethmoidal (65%), sphenoidal (39%), and frontal (32%) involvement. Rhinorrhea and nasal stuffiness are the typical symptoms. Although symptoms may persist for well more than 10 days, those of uncomplicated viral rhinosinusitis usually start to improve by 7 to 10 days.

Failure to improve suggests bacterial superinfection. In about 0.5% to 2% of cases of the common cold, bacterial infection of the sinuses occurs, resulting in acute purulent bacterial sinusitis. It is characterized by nasal congestion, purulent nasal discharge, facial pain (which classically increases when the patient stoops forward), fever, fatigue, and other constitutional symptoms.

Bacteriology

In most cases of bacterial sinusitis, a single organism accounts for the infection; in about 25%, two organisms are present in high density. In about three fourths of cases, the causative organism proves to be either Streptococcus pneumoniae or Haemophilus influenzae. Other potentially etiologic organisms include Moraxella catarrhalis, Streptococcus pyogenes, and anaerobes (Fusobacterium, Bacteroides, Peptostreptococcus). Anaerobes account for about 6% of all cases of sinusitis and usually occur in the setting of dental infections or chronic sinusitis, especially after recurrent courses of antibiotics. Staphylococcus aureus can be found on nasal culture, but it is less often isolated from sinus aspirates in acute sinusitis. Viruses, especially rhinovirus and influenza virus, have been isolated alone or in combination with bacteria in 15% to 20% of patients. This may represent true causation of the sinusitis or a preceding viral infection, leading to the bacterial superinfection. Mycoplasma pneumoniae and Chlamydia pneumoniae are not believed to be important etiologies for most patients. Rarely, fungi such as Mucor, Rhizopus, and Aspergillus species can produce invasive sinusitis in poorly controlled diabetics, leukemics, or other immunosuppressed hosts.

Clinical Presentation

Sinus pain or pressure and purulent nasal discharge are the defining clinical features of acute sinusitis; fever is present in about half of the cases. The location of the discomfort depends on the sinuses involved. Maxillary sinusitis is the most common and produces pain and tenderness over the cheeks. The pain is referred to the teeth in some patients. Frontal sinusitis produces pain and tenderness over the lower forehead. Ethmoid sinusitis results in retro-orbital pain and may have tenderness over the upper lateral aspect of the nose. Isolated sphenoid sinusitis is uncommon but can present as retro-orbital, frontal, or facial pain. Purulent nasal discharge may be visualized in the middle meatus if the frontal, maxillary, or anterior ethmoid sinus is involved.

Chronic Sinusitis

Symptoms of chronic sinusitis include nasal congestion and purulent discharge, but pain and headache are usually mild or absent, and fever is uncommon. By definition, symptoms should be present for at least 2 to 3 months. The predominant organisms are S. aureus, Enterobacteriaceae, and anaerobic organisms, such as anaerobic streptococci and Bacteroides species. H. influenzae and pneumococcus are less important etiologies in chronic infection. The pathologic importance of anaerobes in chronic sinusitis is reflected by the predominance of anaerobes in brain abscesses of sinus origin.

Atypical organisms may be responsible for some cases in hospitalized and immunocompromised persons. Gram-negative bacilli may cause sinusitis in hospitalized patients who are nasotracheally intubated or immunocompromised. Fungal infection in an immunosuppressed host can lead to chronic invasive sinusitis. Fungal exposure can cause an allergic fungal sinusitis.

Complications

Complications of sinusitis are uncommon in the setting of antibiotic use but can be life threatening. The most serious are osteomyelitis, orbital cellulitis, and cavernous sinus thrombosis.

Osteomyelitis

Frontal sinusitis can lead to osteomyelitis of the frontal bones, especially in children. Patients present with headache, fever, and a characteristic doughy edema over the involved bone, which is termed “Pott puffy tumor.” The organisms involved are the same as those responsible for the underlying sinusitis, except that S. aureus may also be involved. Osteomyelitis of the maxilla is an
infrequent complication of maxillary sinusitis. Orbital cellulitis is most frequently a complication of ethmoid sinusitis due to the direct extension of infection through the lamina papyracea. It usually begins with edema of the eyelids and rapidly progresses to ptosis, proptosis, chemosis, and diminished extraocular movements. Patients are usually febrile and acutely ill. Pressure on the optic nerve can lead to visual loss, which can be permanent, and retrograde spread of infection can lead to intracranial infection.

Cavernous Sinus Thrombosis

Retrograde extension of infection along venous channels from the orbit, ethmoid or frontal sinuses, or nose can produce septic cavernous sinus thrombophlebitis. These patients are highly febrile and appear “toxic.” Lid edema, proptosis, and chemosis are present, but unlike uncomplicated orbital cellulitis, third, fourth, and sixth cranial nerve palsies are prominent; the pupil may be fixed and dilated; and funduscopic examination may reveal venous engorgement and papilledema. Although the process is usually unilateral at first, spread across the anterior and posterior intercavernous sinuses results in bilateral involvement. Patients may exhibit alterations of consciousness.

Intracranial Suppuration

Sinusitis can lead to intracranial suppuration either by direct spread through bone or via venous channels. A great variety of syndromes can result, including epidural abscess, subdural empyema, meningitis, and brain abscess. Clinical findings vary greatly, ranging from subtle personality changes with frontal lobe abscesses to headache, symptoms of elevated intracranial pressure, alterations of consciousness, visual symptoms, focal neurologic deficits, seizures, and, ultimately, coma and death.

DIFFERENTIAL DIAGNOSIS (1,4, 5 and 6)

The common cold and allergic or vasomotor rhinitis are by far the most common causes of “sinus” symptoms, but polyps, tumors, dental infections, foreign bodies, and vasculitides such as Wegener granulomatosis occasionally produce symptoms resembling sinusitis (see Chapter 222). Patients with migraine headaches often have bifrontal pain and nasal symptoms, leading to an erroneous diagnosis of sinus headache.

WORKUP (1,4, 5 and 6)

Clinical findings can be very helpful in the diagnosis of sinusitis, especially when findings are considered in combination. In a prospective study comparing historical and physical findings with sinus films, no single feature had a likelihood ratio of greater than 2.5 in predicting a positive x-ray, but when five individually predictive findings (see later discussion) were considered together, the likelihood ratio rose to 6.4 if all were present and fell to 0.1 if none was found.

History

The diagnosis of acute bacterial rhinosinusitis (ABRS) is entertained in the patient with symptoms of nasal congestion and purulent discharge that persist beyond the expected 7 to 10 days of the common cold. The classic symptom of frontal, maxillary, retro-orbital, or vertex pain that worsens on bending forward has not been found independently to predict radiographic sinusitis in several studies. A history of purulent rhinorrhea, however, has been associated with ABRS in several studies (positive likelihood ratios of 1.5 to 3.5). In addition, a prospective study in the primary care setting comparing clinical findings and radiographs in adult males presenting with symptoms suggestive of sinusitis also revealed that maxillary toothache and poor response to decongestants were useful predictors of radiologically confirmed sinusitis (the positive likelihood ratio was 2.5 and 2.1, respectively). In a study from ear, nose, and throat practice using maxillary aspiration of purulent material for diagnosis, unilateral sinus pain also correlated with outcome. Persistent fever (temperature >102°F) for more than 3 days suggests bacterial rather than a viral infection. Finally, the symptom of double sickening (upper respiratory infection symptoms with initial improvement, followed by increasing nasal symptoms) had a positive likelihood ratio of 2.8 for ABRS in one primary care study. Risk factors for sinusitis include nasal polyps, deviated nasal septum, trauma, foreign bodies, poor dentition, and rapid changes in altitude. A history of allergies or asthma indicates a predisposing factor to sinus inflammation. Special attention should be paid to toxic symptoms of high fever and rigors in association with complaints suggestive of the extension of infection, such as edema of the eyelids and diplopia.

Physical Examination

One should examine the nasal cavity for purulent discharge draining from one of the turbinates and transilluminate the maxillary sinuses for impaired light transmission. Transillumination must be performed in a completely darkened room with a strong light source. The nasal cavity should also be inspected for possible etiologies for sinus obstruction (deviated septum, nasal polyps, tumors). In a few patients, tapping the maxillary teeth may reveal a dental source of maxillary sinus infection. In the prospective study alluded to earlier, the best independent physical examination predictors of sinusitis were impaired transillumination (positive likelihood ratio, 1.6) and mucopurulent nasal discharge (likelihood ratio, 2.1). Other studies have found transillumination either more or less useful, which is partly explained by observer experience with transillumination. Palpation over the maxillary and frontal sinuses is often performed to elicit sinus tenderness. Although physicians often use this as a criterion to diagnose sinusitis, it does not appear reliably to distinguish between patients with and without sinusitis.

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