What is the initial approach to managing left-sided sinusitis?

Differential Diagnosis for Left-Sided Sinusitis

When evaluating unilateral (left-sided) sinusitis, you must urgently consider fungal disease and neoplasm in addition to bacterial infection, as unilateral presentation warrants heightened suspicion for serious pathology. 1

Critical Red Flags for Unilateral Sinusitis

Unilateral polypoid disease or unilateral sinus involvement frequently indicates fungal sinusitis or tumor (such as inverted papilloma) rather than simple bacterial infection, and biopsy should be strongly considered. 1

Primary Differential Diagnoses to Consider:

Fungal Sinusitis:

• Fungus ball (mycetoma) - typically presents as unilateral maxillary sinus disease and requires surgical intervention 1
• Allergic fungal sinusitis - characterized by thick, tenacious secretions and nasal polyps, requires surgery 1
• Invasive fungal sinusitis - life-threatening condition requiring urgent surgical debridement 1

Neoplastic Disease:

• Inverted papilloma - benign but locally aggressive tumor that commonly presents as unilateral disease 1
• Sinonasal tumors - must be excluded in unilateral presentations 2

Bacterial Sinusitis:

• Acute bacterial rhinosinusitis - less likely with purely unilateral presentation but possible 3
• Chronic bacterial sinusitis - may present unilaterally with ostiomeatal complex obstruction 1

Dental Pathology:

• Odontogenic sinusitis - dental infections can cause unilateral maxillary sinusitis 2

Structural Abnormalities:

• Anatomic variations causing unilateral ostiomeatal complex obstruction 1
• Nasal polyps - though often bilateral, can present unilaterally 1

Initial Diagnostic Approach

Obtain a detailed history focusing on:

• Duration of symptoms (acute <4 weeks vs chronic >3 months) 3
• Presence of pain, purulent nasal discharge, nasal obstruction 3, 4
• History of dental problems or recent dental procedures 2
• Immunocompromised status (critical for invasive fungal disease) 2
• Environmental exposures and smoking history 1

Physical examination must include:

• Anterior rhinoscopy looking for purulent discharge, polyps, or masses 3, 4
• Transillumination (useful if negative, suggesting fluid or obstruction) 4
• Dental examination for maxillary tooth tenderness 4

Imaging and Further Workup

CT scan of the sinuses is strongly recommended for unilateral sinusitis to identify extent of disease, anatomical abnormalities, and characteristics suggestive of fungal disease or tumor 2. Standard radiographs have high false-positive and false-negative rates and should be avoided 3.

Nasal endoscopy should be performed to directly visualize the ostiomeatal complex, identify masses or polyps, and potentially obtain tissue for biopsy 1. The nasal telescope has significantly improved visualization of the ostiomeatal complex, which is poorly seen on anterior rhinoscopy 1.

Biopsy is indicated when unilateral polypoid disease is identified on endoscopy or imaging, as this appearance frequently results from fungal disease or tumor 1.

Initial Management Strategy

For presumed bacterial sinusitis (after excluding red flags):

• Start with amoxicillin for 10-14 days as first-line therapy 3
• Add nasal saline irrigation and intranasal corticosteroids 2, 3
• Analgesics and adequate hydration 3

If no improvement after 3-5 days:

• Switch to high-dose amoxicillin-clavulanate (90 mg/kg amoxicillin component, not exceeding 2g every 12 hours) 2, 3
• Continue nasal corticosteroids 2, 3

If symptoms persist beyond 3 weeks:

• Reassess for fungal disease, tumor, or structural abnormalities 2
• Obtain CT imaging if not already done 2
• Consider specialist referral 2

When to Refer Immediately

Refer urgently to otolaryngology when:

• Unilateral polypoid disease is identified 1
• CT shows findings suspicious for fungal disease or mass 1
• Patient fails to respond to appropriate antibiotic therapy 1, 2
• Complications develop (orbital or intracranial extension) 1

Common Pitfall: Treating unilateral sinusitis as simple bacterial infection without considering fungal disease or neoplasm can lead to delayed diagnosis of serious pathology. The unilateral nature of the presentation should always prompt more aggressive investigation. 1