What is the approach to diagnosis and treatment of sinusitis?

Approach to Diagnosis and Treatment of Sinusitis

Diagnostic Approach: Distinguishing Viral from Bacterial Sinusitis

The cornerstone of diagnosis is recognizing that 98-99.5% of acute rhinosinusitis is viral and resolves spontaneously within 7-10 days without antibiotics. 1

Three Clinical Patterns Indicating Bacterial Sinusitis

Diagnose acute bacterial sinusitis (ABS) only when one of these three patterns is present:

• Persistent symptoms: Nasal congestion, purulent discharge, facial pain, or cough lasting ≥10 days without improvement 1, 2
• Severe symptoms: Fever ≥39°C (102.2°F) with purulent nasal discharge for ≥3 consecutive days 1, 3
• Double worsening: Initial improvement from viral URI followed by worsening symptoms within 10 days 1, 2

Physical Examination Findings

• Mucosal erythema and purulent secretions on nasal examination (nasal endoscopy provides superior visualization compared to speculum) 4
• Tenderness overlying sinuses, periorbital edema, or dark circles beneath eyes 4
• Pharyngeal erythema with purulent material in posterior pharynx 4
• Middle ear effusions (frequently associated with eustachian tube dysfunction) 4

Critical Red Flags Requiring Urgent Evaluation

Any patient with these findings needs immediate specialist referral:

• Orbital swelling, pain, proptosis, or diplopia (suggests orbital cellulitis) 4
• Swelling of the forehead (suggests frontal bone osteomyelitis) 4
• Abnormal neurologic signs (suggests intracranial extension) 4
• Unilateral sinus disease or unilateral polyps (suggests fungal sinusitis or tumor—biopsy strongly indicated) 5

When Imaging is Indicated

• Do NOT obtain imaging for uncomplicated acute sinusitis—diagnosis is clinical 1, 2
• DO obtain CT scan for: suspected complications, treatment failure after two appropriate antibiotic courses, recurrent sinusitis, or unilateral disease 1, 5
• Plain radiographs have significant false-positive and false-negative results and should be avoided 4

---

Treatment Algorithm for Acute Bacterial Sinusitis

First-Line Antibiotic Therapy

Amoxicillin is the first-line antibiotic for most patients with acute bacterial sinusitis. 1, 2

Adult dosing:

• Mild-moderate disease: Amoxicillin 500 mg twice daily for 10-14 days 1
• Moderate-severe disease or recent antibiotic exposure: Amoxicillin 875 mg twice daily for 10-14 days 1
• High-dose for resistant organisms: Amoxicillin 1.5-4 g/day divided twice daily 1, 6

Pediatric dosing:

• Standard therapy: Amoxicillin 45 mg/kg/day in 2 divided doses 1
• High-risk children (age <2 years, daycare attendance, recent antibiotics, or high local resistance): Amoxicillin 80-90 mg/kg/day in 2 divided doses 1

Treatment duration: Continue until symptom-free for 7 days (typically 10-14 days total) 4, 1

Reassessment at 3-5 Days

If no improvement after 3-5 days, switch to second-line therapy—do not continue ineffective treatment. 1

Second-line options:

• High-dose amoxicillin-clavulanate: 875 mg/125 mg twice daily (adults) or 90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses (children) 1
• This provides coverage against β-lactamase-producing H. influenzae and M. catarrhalis 1

Penicillin-Allergic Patients

For non-severe penicillin allergy (rash, mild reactions), second- or third-generation cephalosporins are safe and effective. 1

Preferred alternatives:

• Cefuroxime-axetil (second-generation cephalosporin) 1
• Cefpodoxime-proxetil or cefdinir (third-generation cephalosporins with superior H. influenzae coverage) 1
• Risk of cross-reactivity with penicillin allergy is negligible for second- and third-generation cephalosporins 1

For severe Type I hypersensitivity (anaphylaxis):

• Levofloxacin 500 mg once daily for 10-14 days (adults only) 1, 7
• Moxifloxacin 400 mg once daily for 10 days (adults only) 1

What NOT to Use

Critical pitfalls to avoid:

• Never use azithromycin or macrolides as first-line therapy—resistance rates exceed 20-25% for both S. pneumoniae and H. influenzae 1
• Never use trimethoprim-sulfamethoxazole—resistance rates are 50% for S. pneumoniae and 27% for H. influenzae 1
• Never use first-generation cephalosporins (like cephalexin)—inadequate coverage against H. influenzae (50% β-lactamase producing) 1
• Never use clindamycin as monotherapy—lacks activity against H. influenzae and M. catarrhalis (30-40% failure rate) 1
• Reserve fluoroquinolones for treatment failures, severe penicillin allergy, or complicated sinusitis to prevent resistance 1

---

Adjunctive Therapies

Intranasal Corticosteroids (Strongly Recommended)

Intranasal corticosteroids reduce mucosal inflammation and improve symptom resolution—use as adjunct to antibiotics in both acute and chronic sinusitis. 1

• Mometasone, fluticasone, or budesonide twice daily 1
• Strong evidence from multiple randomized controlled trials 1

Oral Corticosteroids (Limited Use)

• Short-term oral corticosteroids (typically 5 days) may be reasonable for patients with marked mucosal edema, nasal polyposis, or failure to respond to initial treatment 4, 1
• Never give systemic corticosteroids without antibiotics when bacterial sinusitis is suspected—may suppress immune response and allow bacterial proliferation 1

Symptomatic Relief

• Analgesics: Acetaminophen or NSAIDs for pain and fever 1
• Saline nasal irrigation: Provides symptomatic relief and removes mucus 1
• Decongestants: Pseudoephedrine (systemic) or topical decongestants as needed (limited evidence for efficacy) 1
• Supportive measures: Adequate hydration, warm facial packs, steam inhalation, sleeping with head elevated 1, 6

---

Watchful Waiting Option

For adults with uncomplicated acute bacterial sinusitis, watchful waiting without immediate antibiotics is appropriate when follow-up can be assured. 1

• Start antibiotics only if no improvement by 7 days or worsening at any time 1
• Number needed to treat with antibiotics is 10-15 to get one additional person better after 7-15 days 1
• Approximately 90% of patients improve naturally within 7-15 days without antibiotics 1

---

Treatment of Complicated or Refractory Sinusitis

When to Escalate to Parenteral Therapy

Ceftriaxone is indicated when oral antibiotics fail, patients cannot tolerate oral medications, or moderate-to-severe disease with recent antibiotic exposure. 1

• Adults: Ceftriaxone 1-2 g IM or IV once daily for 5 days 1
• Children: Ceftriaxone 50 mg/kg IM or IV once daily for 5 days 1
• Achieves 90-92% predicted clinical efficacy with excellent coverage against drug-resistant S. pneumoniae and β-lactamase-producing organisms 1

Frontal, Ethmoidal, or Sphenoidal Sinusitis

Reserve fluoroquinolones for non-maxillary sinusitis due to potential for serious complications. 1

• Levofloxacin 500-750 mg once daily or moxifloxacin 400 mg once daily for 10-14 days 1, 7
• These locations have higher risk of intracranial or orbital complications 1

---

Chronic Rhinosinusitis and Recurrent Acute Sinusitis

Diagnostic Criteria

• Chronic rhinosinusitis: Symptoms persisting ≥12 weeks 2
• Recurrent acute rhinosinusitis: ≥3 episodes per year 1

Evaluation for Underlying Factors

Assess for modifying factors that require specific management: 1, 2

• Allergic rhinitis (consider antihistamines and allergy testing) 1
• Anatomic abnormalities (nasal polyps, septal deviation) 4
• Immunodeficiency (obtain immune function testing) 1
• Cystic fibrosis (especially in children with nasal polyps) 4
• Ciliary dyskinesia 2
• Gastroesophageal reflux disease 6

When to Refer to Specialist

Refer to otolaryngology when: 1

• Symptoms refractory to two courses of appropriate antibiotics 1
• Recurrent sinusitis (≥3 episodes per year) 1, 6
• Suspected complications (orbital cellulitis, meningitis, brain abscess) 1
• Unilateral disease or unilateral polyps (rule out fungal disease or tumor) 5
• Need for sinus aspiration/culture in immunocompromised patients 1
• Chronic rhinosinusitis requiring surgical intervention 2

---

Special Populations

Pediatric Considerations

• Children may exhibit increased irritability, vomiting with gagging on mucus, or prolonged cough 4
• Nasal polyps in children are uncommon—evaluate for cystic fibrosis 4
• Reassess at 72 hours if no improvement on antibiotics 1

Immunocompromised Patients

• Higher risk for invasive fungal sinusitis (life-threatening—requires urgent surgical debridement) 5
• Consider sinus aspiration for culture to guide therapy 1

Dental-Related Sinusitis

• Assess for recent dental procedures or dental disease (especially maxillary sinusitis) 5
• May require dental evaluation and treatment in addition to antibiotics 5