Sinusitis

Epidemiology and Etiology

Epidemiology

• Incidence: 1 of 7–8 people per year
• Occurs in up to 80% of patients with uncomplicated upper respiratory infections (URIs)
• Bacterial sinusitis is only found in 0.5%–2% of cases
• Peak annual incidence coincides with peak of viral URIs in fall/winter months
• Higher incidence in women and in those aged 45–64 years

Etiology

• Predisposing factors:
  • Anatomic abnormalities of the paranasal sinuses or nasal cavity (deviation in nasal septum, concha bullosa, bony spurs, nasal polyp, choanal atresia)
  • Impairment of ciliary function (cystic fibrosis, primary ciliary dyskinesia, immunodeficiency)
  • Allergic and vasomotor rhinitis
  • Recurrent URIs
  • Asthma and allergies
  • Dental disease
  • Immunodeficiency
  • Older age
  • Smoking
  • Cocaine abuse
  • Air travel
  • Atmospheric pressure change exposure (e.g., deep sea diving)
  • Swimming
  • Foreign body in the nasal cavity
• Acute: lasts ≤ 4 weeks
  • Viral (most common): rhinovirus, coronavirus, influenza virus, adenovirus, parainfluenza virus
  • Bacterial: Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, Escherichia coli, Klebsiella
    • S. pnuemoniae and H. influenzae are responsible for 75% of cases
• Chronic: lasts over 12 weeks; characterized by prolonged inflammation of the sinuses; occasionally associated with immunodeficiency disorders
  • Fungal: Aspergillus, Rhizopus oryzae
  • Bacterial: S. aureus (often methicillin-resistant S. aureus) and anaerobic organisms (Prevotella, Porphyromonas, Fusobacterium, and Peptostreptococcus spp.)

Pathophysiology

Viral

• Inoculation via direct contact with the conjunctiva or nasal mucosa
• Viral replication can be detected via viral levels in nasal secretions within 8–10 hours
• Symptoms can occur after the first day of inoculation

Bacterial

• Most important pathophysiological change: obstruction of sinus drainage 
• Normal metachronous (sequential) movement of mucous toward the natural ostia of the sinuses is usually disrupted by mucosal inflammation → stasis
• Ciliary function impairment leads to a reduction in mucus drainage → stasis
• Stasis of secretions inside the sinuses leads to a proliferation of microorganisms
• Alterations in the composition and quantity of mucus can also contribute to infection; increased mucus production is seen with asthma, rhinitis, and viral URIs

Clinical Presentation

General manifestations

• Nasal congestion and obstruction
• Mucopurulent or purulent nasal discharge
• Headache
• Facial pain or heaviness over the affected sinus (increases with bending forward)
  • Maxillary sinuses: over the cheeks
  • Frontal sinuses: lower forehead
  • Ethmoidal sinuses: nasal bridge or between/behind the eyes
• Fever
• Maxillary tooth discomfort and other facial pain
• General malaise and myalgia

Viral sinusitis

Viral sinusitis usually presents in a milder form and lasts 7–10 days.

Bacterial sinusitis

• Persists for > 10 days without clinical improvement
• Biphasic pattern: may initially improve, then worsens after 5–6 days (“double worsening”)
• Presents with more severe symptoms:
  • High fever
  • Intense facial pain 
  • Hyposmia or anosmia
  • Halitosis
  • Cough
  • Ear pain, pressure, fullness, hearing loss, or tinnitus

Fungal sinusitis

Fungal sinusitis usually presents chronically, with atypical symptoms (epistaxis, dyspnea, and black/brown nasal secretions).

Complications and/or associated conditions

• Acute otitis media
• Pharyngitis
• Meningitis
• Pneumonia
• Subperiosteal/intracranial abscess
• Osteomyelitis (usually of the frontal bone)
• Preseptal/orbital cellulitis
• Septic cavernous sinus thrombosis

Diagnosis

Diagnosis is usually based on clinical symptoms.

• Uncomplicated sinusitis: < 4 weeks of purulent nasal discharge + nasal obstruction or facial pain/pressure/fullness or both
• Complicated sinusitis: When signs and symptoms extend beyond paranasal sinuses and nasal cavity, urgent evaluation is required.
  • Signs: severe/persistent headache, vision changes, periorbital edema, abnormal extraocular movements with or without pain, altered mental status, meningeal signs, signs of increased intracranial pressure

To differentiate viral sinusitis from bacterial sinusitis:

• Viral rhinosinusitis is diagnosed clinically when symptoms last 7–10 days and do not worsen.
• Bacterial rhinosinusitis is diagnosed clinically when symptoms last > 10 days or are of a biphasic pattern (see “double worsening,” above) and are more severe in nature. Requires antibiotics for resolution

Laboratory tests

• Indicated if no response to treatment or worsening is observed
• Leukocytosis is rarely seen.
• May help determine the underlying cause:
  • Allergic rhinitis confirmed with a radioallergosorbent test, allergen skin test, or smear of nasal secretions showing eosinophilia
  • Sweat chloride test for cystic fibrosis

Culture

Presence of more than 10⁴ colony-forming units/mL on bacterial culture is confirmatory for bacterial sinusitis in children.

Imaging

• Not recommended unless complicated sinusitis arises
• Skull X-rays show decreased transparency of sinus and air-fluid levels.
• Computed tomography is the modality of choice and shows mucoperiosteal thickening, air-fluid levels, and soft tissue extension in case of complications (e.g., orbital cellulitis).
• Nasal endoscopy may be used to exclude structural lesions.

Biopsy

Only needed if infection recurs or if there is no response to different empiric therapies.

Management

General supportive care

• Acetaminophen or nonsteroidal anti-inflammatory drugs should be given for facial pain and, if present, fever.

Viral sinusitis

• Aims only to provide symptomatic relief, as viral sinusitis is self-limiting
• Nasal lavage with hypertonic NaCl solution 
• Decongestants (e.g., xylometazoline nasal spray) or sympathomimetics (e.g., pseudoephedrine) 
• Antihistamines (e.g., loratadine) if concurrent allergy symptoms are present
• Intranasal steroids (e.g., fluticasone) to relieve mucosal swelling/facial pain
• Mucolytics (e.g., guaifenesin) can thin secretions and promote drainage

Bacterial sinusitis

• First-line: amoxicillin, with or without clavulanate for 5–10 days
• Second-line:
  • IV ceftriaxone is used for children who are unable to tolerate oral medication.
  • Oxycycline, levofloxacin, or moxifloxacin are used in case of penicillin allergy.
  • Levofloxacin, moxifloxacin, or clindamycin are used if symptoms persist > 14 days or no improvement is seen within the first 3 days of treatment.
• Chronic bacterial sinusitis: broad-spectrum aminopenicillin + beta-lactamase inhibitor 
• Decongestants and antihistamines are not recommended.

Fungal sinusitis

• Antifungal therapy (e.g., amphotericin B)
• Management of immunocompromising conditions (e.g., AIDS, HIV, cancer, etc.)
• If the infection is chronic and invasive, it may require surgical debridement of necrotic tissue.

Clinical Relevance

The following are potential underlying conditions or differential diagnoses of sinusitis:

• Cystic fibrosis: an autosomal recessive disorder caused by mutation of the CFTR gene, which leads to defective chloride channels and hyperviscosity of exocrine gland secretions
• Primary ciliary dyskinesia: an autosomal recessive disease associated with sinusitis, situs inversus, recurrent respiratory infections, and bronchiectasis, among other abnormalities
• Dental abscess: a collection of pus in the pulp of a tooth that can spread to local or regional structures, including the gums, facial bones, tongue, and facial muscles
• Foreign nasal body: common in children < 5 years old. Often involves food items or small toys. Presents with unilateral rhinorrhea that can become foul-smelling or purulent, signs of nasal obstruction, or epistaxis
• Migraine: a type of headache characterized by recurrent, debilitating episodes that are typically unilateral, throbbing and/or pulsatile in quality, and frequently accompanied by nausea, vomiting, and sensitivity to light and sound
• Rhinitis: an inflammation of the nasal mucosa, classified into allergic, non-allergic, and infectious
• Asthma: a chronic inflammatory disease of the respiratory system characterized by bronchial hyperresponsiveness, episodic exacerbation, and reversible airflow obstruction. 
• Otitis media: an infection of the middle ear that typically follows an upper respiratory tract infection in children < 5 years old. Most commonly caused by S. pneumoniae. Presents with otalgia and fever. Examination shows a bulging tympanic membrane.
• Granulomatosis with polyangiitis: an antineutrophil cytoplasmic antibody–associated vasculitis leading to inflammation of small- and medium-sized blood vessels. Results in damage to several organ systems of the body, most often the respiratory tract and kidneys.