From the Guidelines
Diagnosing the cause of rhinosinusitis involves a combination of clinical evaluation, physical examination, and sometimes imaging studies, with a focus on identifying symptoms such as nasal congestion, facial pain, and purulent nasal discharge, and their duration, to determine if the cause is viral, bacterial, or other. The diagnosis of rhinosinusitis should be based on clinical criteria, including symptoms such as nasal congestion, facial pain, purulent nasal discharge, and decreased sense of smell, along with their duration 1. Acute rhinosinusitis (less than 4 weeks) is typically viral in origin, while persistent symptoms may indicate bacterial infection or other causes.
Clinical Evaluation
A thorough medical history is taken to identify symptoms and their duration. Physical examination includes anterior rhinoscopy and nasal endoscopy to visualize the nasal mucosa, looking for purulent discharge, mucosal inflammation, or polyps. Transillumination of the sinuses may help detect fluid accumulation.
Imaging Studies
For cases with severe, persistent, or recurrent symptoms, imaging studies like CT scans can reveal sinus opacification, mucosal thickening, or anatomical abnormalities. However, radiographic imaging of the paranasal sinuses is unnecessary for diagnosis in patients who already meet clinical diagnostic criteria for acute bacterial rhinosinusitis (ABRS) 1.
Laboratory Tests
In specific situations, nasal cultures may be obtained to identify bacterial pathogens, particularly in cases of chronic or recurrent infections. Allergy testing might be warranted if allergic rhinitis is suspected as a contributing factor. Additional testing for immunodeficiencies, ciliary dysfunction, or fungal infections may be necessary for patients with atypical presentations or treatment-resistant cases.
Diagnosis Considerations
The diagnosis should consider both infectious causes (viral, bacterial, fungal) and non-infectious causes (allergic, anatomic abnormalities, immunologic disorders) to guide appropriate treatment. According to the American College of Physicians and the Centers for Disease Control and Prevention, acute rhinosinusitis is usually caused by a viral pathogen, and acute bacterial rhinosinusitis (ABRS) is considered to be a secondary infection resulting from obstruction of the sinus ostia that leads to impaired mucosal clearance as a result of a viral upper respiratory tract infection (URI) 1.
Key Points
- Clinical evaluation and physical examination are essential for diagnosing the cause of rhinosinusitis.
- Imaging studies like CT scans may be necessary for cases with severe, persistent, or recurrent symptoms.
- Laboratory tests such as nasal cultures and allergy testing may be warranted in specific situations.
- The diagnosis should consider both infectious and non-infectious causes to guide appropriate treatment.
- The most recent and highest quality study, 1, provides guidance on the diagnosis and management of acute rhinosinusitis, and should be prioritized when making a definitive recommendation.
From the FDA Drug Label
Appropriate culture and susceptibility tests should be performed before treatment to determine the causative organism and its susceptibility to azithromycin. The cause of rhinosinusitis can be determined by culture and susceptibility tests to identify the causative organism.
- These tests should be performed before treatment to guide the selection of appropriate antimicrobial therapy.
- Local epidemiology and susceptibility patterns may also contribute to the empiric selection of therapy in the absence of culture and susceptibility data 2.
From the Research
Diagnosis of Rhinosinusitis
To diagnose the cause of rhinosinusitis, several factors are considered, including:
- Patient symptomatology
- Physical and endoscopic findings
- Computed tomography scan scores
- Culture results 3
- Cardinal features of acute bacterial rhinosinusitis, such as unilateral facial pain or pressure, fever greater than 102°F (39°C), and purulent nasal discharge with obstruction of the nasal passages 4
Diagnostic Testing
Diagnostic testing for acute rhinosinusitis may include:
- Antral puncture, although this is impractical due to its invasiveness 4
- Point-of-care testing for elevated C-reactive protein, which may be helpful but is not widely available 4
- Computed tomography scans, which can be used to support the diagnosis and identify any complications 4, 3, 5
- Nasal endoscopy, which can be used to visualize the nasal passages and sinuses 3, 6, 7
Objective Evidence
Objective evidence of chronic rhinosinusitis may be obtained on physical examination (anterior rhinoscopy, endoscopy) or radiography, preferably from sinus computed tomography 5. A definitive diagnosis of chronic rhinosinusitis requires physical evidence of mucosal swelling or discharge appreciated during physical examination coupled with CT imaging if inflammation does not involve the middle meatus or ethmoid bulla 6.
Challenges in Diagnosis
There are challenges in distinguishing between the symptoms of bacterial and viral sinusitis 4, and a correct diagnosis is essential to directed therapy 7. The presence of chronic inflammation with a Th2 cytokine predominance in sinus tissues should be kept in mind, especially in patients with coexistent morbidities such as allergic rhinitis and asthma 3.
Consideration of Underlying Causes
Underlying systemic causes of refractory sinusitis, such as immunodeficiency and systemic granulomatous and eosinophilic syndromes, should be considered 7. Other less common etiologies of chronic rhinosinusitis include inflammation, fungal sinusitis or bacterial sinusitis with or without associated biofilm formation, gastroesophageal reflux, smoke and other environmental exposures, immune deficiencies, genetics, and aspirin-exacerbated respiratory disease 6.