Sinusitis is an inflammation of the mucous membrane of the paranasal sinuses. It rarely occurs without concurrent inflammation of the nasal mucosa (rhinitis) and is therefore commonly referred to as rhinosinusitis. While the etiology is typically viral, it may also be bacterial or fungal (especially in immunocompromised patients). The condition is usually self-limiting, but if it lasts longer than 12 weeks it is considered chronic. The primary symptoms are purulent rhinorrhea and facial pain (particularly when leaning forward). Antibiotic therapy is only indicated if a bacterial superinfection is suspected. Imaging and endoscopy is reserved for cases that persist or worsen despite initial antibiotic therapy. Local extension of the disease may occur in cases that are complicated or that have not received adequate treatment, potentially resulting in frontal bone osteomyelitis, meningitis, or brain abscess.
- Pansinusitis: inflammation of all sinuses on one or both sides
- Acute sinusitis: inflammation of the sinuses for < 4 weeks
- Subacute sinusitis: progressive symptoms of sinus inflammation occuring over 4–12 weeks; represents a transition from acute to chronic infection
- Chronic sinusitis: persistent symptoms of sinus inflammation > 12 weeks
- Recurrent acute sinusitis: four or more separate episodes of acute sinusitis that occur within 1 year, with at least 8 weeks of symptom resolution between episodes
- Rhinosinusitis: simultaneous inflammation of the nasal mucosa and sinuses
- Incidence: Sinusitis is one of the most commonly diagnosed conditions in the USA, affecting an estimated 35 million individuals per year.
- Peak incidence: early fall to early spring
- Sex: ♀ > ♂
Epidemiological data refers to the US, unless otherwise specified.
- Route of transmission: droplet transmission, particularly in winter months
- Preexisting viral upper respiratory tract infection (URTI): most common; leads to superimposed bacterial infections
- Ventilation disorders of the sinuses
- Foreign body lodged in the nasal cavity (particularly seen in children).
- Odontogenic infection: leads to unilateral maxillary sinusitis
- mucosa : spread of pathogens via nasal
- Bronchial asthma
- Analgesic (NSAIDs, aspirin) intolerance
- Sinusitis is triggered by three factors: obstruction of sinus drainage pathways (sinus ostia), ciliary impairment, and altered mucus quantity and quality → stasis of secretions inside the sinuses → proliferation of various pathogens → sinusitis
- Recurrent, untreated/complicated acute sinusitis may lead to chronic sinusitis.
|Acute viral rhinosinusitis|| |
|Acute bacterial rhinosinusitis|
|Chronic rhinosinusitis|| |
Subtypes and variants
Nasal polyps 
- Definition: benign lesions of the nasal mucosa or paranasal sinuses due to chronic mucosal inflammation
- Risk factors
- Clinical features
- Special form: choanal polyp
- Differential diagnosis:
- Topical or systemic glucocorticoids
- Resection of polyps if symptomatic despite medical therapy but recurrence is common
Primary ciliary dyskinesia 
- Definition: rare autosomal recessive disorder characterized by absent or dysmotile cilia caused by a defect in the dynein arm of microtubules
- Chronic productive cough
- Recurrent otitis, sinusitis, and nasal polyps
- Conductive hearing loss
- Displaced heart sounds (as a result of dextrocardia)
- Infertility in men due to decreased sperm motility as a result of defective flagella
- Reduced fertility in women (and rarely ectopic pregnancy) due to defective cilia in fallopian tubes
- Kartagener syndrome: classic triad of situs inversus, recurrent sinusitis, and bronchiectasis
- Treatment: depends on individual clinical presentation and course
Diagnosis of acute cases is usually established clinically; . However, imaging or endoscopy should be considered if symptoms fail to improve within 7 days of diagnosis or worsen during the initial management of acute bacterial rhinosinusitis.
- Laboratory tests: to determine underlying condition if suspected (e.g., nasal cytology allergic rhinitis, HIV test, sweat chloride test for cystic fibrosis)
- X-ray of sinuses; (poor sensitivity): decreased transparency of sinus, air-fluid levels may be seen
- CT of sinuses (imaging modality of choice)
- MRI may be considered to confirm soft tissue extension in invasive disease.
- Nasal endoscopy
A clinical diagnosis of chronic sinusitis should be confirmed with objective documentation of sinonasal inflammation, which may be accomplished using anterior rhinoscopy, nasal endoscopy, or computed tomography.
|Condition||General approach||Additional treatment|
|Viral infection|| |
|Bacterial infection|| |
- Local spread
- Spread to the orbit
- Intracranial spread
- Systemic complications
Orbital and intracranial necrotic spread is especially common in invasive fungal sinusitis.
We list the most important complications. The selection is not exhaustive.