Rhinosinusitis is defined as an inflammation of the lining of the membranes of one or more of the paranasal sinuses. It can be divided into acute (=< 4 weeks), subacute (1-3 months), chronic (>=3 months) and recurrent acute (>= 4 episodes/past year) (1). These temporal distinctions can be made via an appropriate patient evaluation and are the basis for appropriate management decisions.

Clinical Examination

Rhinosinusitis is considered a clinical diagnosis (2,3,4). The following signs and symptoms are suggestive of sinusitis (1):

• Nasal congestion
• Posterior or anterior nasal drainage
• Purulent nasal discharge
• Facial pain and pressure
• Headache
• Fever and cough (usually in children)
• Decreased sense of smell
• Dental pain
  

Headache, facial pain and dental pain are less reliable for the diagnosis of rhinosinusitis in children (5,6).

Treatment Options

Most patients improve either spontaneously or after completing a course of conservative management (5,7). Initial management of acute rhinosinusitis is generally empirical (7). It should be aimed at the underlying infectious and inflammatory state of the disease.

Patients failing to respond to initial therapy, or who develop recurrent sinus symptoms, should be considered for more aggressive medical management such as a prolonged course of appropriate antibiotics, antihistamines, decongestants, nasal steroids, nasal vasoconstrictors and/or nasal lavage (8,9).

Surgery is generally reserved for patients who fail 3 to 6 months of appropriate medical management or who have complications (8).

Clinical Indications for Diagnostic Imaging

Diagnostic imaging is not indicated in acute, uncomplicated rhinosinusitis or to confirm the resolution of rhinosinusitis in patients who are asymptomatic following treatment (6,8,10).The value of diagnostic imaging is in its ability to provide information not readily apparent on history and physical exam, when such information is likely to impact patient management.

The goal of sinus imaging is to visualize the sinuses to determine if there is an underlying anatomical disorder contributing to the persistence or recurrence of symptoms. For patients with chronic and recurrent rhinosinusitis, nasal endoscopy may be used to determine if the patient has an indication for surgical intervention (11). CT scans are useful in mapping regional anatomy in those patients being considered for surgical intervention (11,12).

Plain (X-Rays) Sinus Films

Conventional radiographs of the paranasal sinuses are rarely indicated in the evaluation of rhinosinusitis because they are notorious for both underestimating and overestimating disease and the results rarely impact patient management (5,8). Consider the following:

• Plain films do not differentiate the etiology of rhinosinusitis (infectious vs. noninfectious inflammatory) (2,6,10).
• Results correlate poorly with clinical events (2,6,10).
• Plain films subject patients to ionizing radiation.
• Over 80% of children with persistent respiratory symptoms have abnormal findings on plain films, but the films do not clearly differentiate between viral, bacterial and allergic conditions (6).
• There is poor correlation between X-ray and CT scan findings (14).
  

In conclusion, plain film radiography of the sinuses is rarely indicated and the results should be interpreted with caution.

 

Computerized Tomography of the Sinuses

CT scanning is not indicated as part of the initial evaluation of sinusitis due to its poor predictive accuracy, high cost and the radiation dose provided (12). This modality is, therefore, only indicated when the results of the study are likely to impact patient management. Ordering a CT scan prematurely represents an unnecessary expenditure and has no impact on the patient outcome.

CT scans are appropriate if the disease becomes recurrent, persistent or chronic, despite conservative measures and in rare clinical situations. They serve primarily as a planning investigation in patients being considered for surgical intervention (12). Results must be interpreted in the context of the clinical presentation because they can overestimate and underestimate sinus disease. Consider the following:

• Follow-up diagnostic imaging is rarely indicated to confirm resolution of rhinosinusitis in asymptomatic patients.
  
• Incidental findings are most frequently seen in children (30-40%) and infants (50-70%) and up to 40% of adults (15,16,17,18,19).
  

When imaging is appropriate, CT scans are superior to plain films in the evaluation of the paranasal sinuses, bony margins and surrounding tissue. CT should be performed after completion of medical therapy to minimize the presence of inflammation so regional anatomy can be visualized to allow for surgical planning (13).

CT scanning of the sinuses is indicated to evaluate sinusitis under the following circumstances:

• Recurrent or chronic sinus disease when surgery is being considered because patient failed to respond to intensive medical treatment (5,6,11).
• Complicated rhinosinusitis with signs of extension beyond the bony sinus (5,6).
• Bony changes of chronic inflammation from osteitis (3).
• Recurrent or persistent mucoceles (11).
• Large polyps on physical exam (11).
• Sinus tumors/malignancy.

 

MRI of the Sinuses

MRI is not the study of choice to image the sinuses, except in unusual circumstances (8,20):

• Fungal rhinosinusitis, to look for soft tissue involvement (11).
• To evaluate suspected intracranial or orbital involvement of complicated rhinosinusitis (20).
• Mapping of sinonasal neoplasms (11,20).

Conclusion

Most cases of rhinosinusitis can be diagnosed clinically. Patients with acute rhinosinusitis often improve spontaneously following a course of empirical antibiotics.

Patients who fail to respond to an initial course of treatment often benefit from more aggressive multitherapy. Diagnostic imaging is indicated in patients with recurrent or chronic rhinosinusitis who fail to respond to conservative management. The goal of the imaging is to delineate the extent of the disease and to identify predisposing factors.

Aggressive medical management is often preferred over surgery. In most cases, surgery is considered only after a patient has failed a 3- to 6-month course of aggressive medical management.

When imaging of the sinuses is clinically warranted, computed tomography has emerged as the gold standard. In most instances, limited coronal CT scans are sufficient to define sinus disease. In some instances, nasal endoscopy is superior to CT scans of the sinuses to define the nature and extent of disease.

To avoid unnecessary exposure to ionizing radiation, plain films of the sinuses are not indicated in untreated children with a clinical diagnosis of rhinosinusitis and no evidence of complications.

We would like to acknowledge the editorial assistance of:

Jack B. Anon, M.D. F.A.C.S.  
Associate Clinical Professor 
Department of Otolaryngology
University of Pittsburgh

References

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