Rhinosinusitis is a mucosal inflammation of both the paranasal sinuses and adjacent nasal cavities. Viral infections are the most common cause of acute rhinosinusitis, with bacterial and fungal infections occurring less often. The primary symptoms are purulent rhinorrhea, nasal obstruction, and facial pain. Acute rhinosinusitis (ARS) is often self-limiting, but antibiotic therapy may be indicated if a bacterial superinfection is suspected. Imaging and endoscopy are reserved for cases of treatment failure, recurrent rhinosinusitis, and chronic rhinosinusitis, as well as in patients with certain risk factors. Complications arise if the infection spreads and may involve the soft tissues, bone, vascular system, and/or central nervous system. Chronic rhinosinusitis (CRS) lasts at least 12 weeks and is viewed as a chronic inflammatory state similar to asthma, which may become complicated by bacterial exacerbations and chronic fungal infections.
- 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 occurring 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
Fungal rhinosinusitis (FRS) 
- Definition: rhinosinusitis caused by a fungal pathogen 
- Classified by:
- Risk factors
- General symptoms: See “ .”
- Noninvasive fungal rhinosinusitis 
- Acute invasive fungal rhinosinusitis : epistaxis and dark ulcers on the septum, palate and turbinates; may be acutely ill with altered mental status 
- CT: Possible findings include fungal balls, bony erosions, and extra sinonasal spread. 
- MRI: may be indicated to assess for cranial or orbital spread, especially in acute invasive fungal rhinosinusitis
- Nasal endoscopy: Findings indicating acute invasive fungal rhinosinusitis include pale mucosa, dark necrotic areas, and crusting/ulcers.
- Fungal culture
- An ENT specialist should manage all cases of suspected fungal rhinosinusitis.
- Patients with acute invasive fungal rhinosinusitis
Diagnostic criteria for acute rhinosinusitis (ARS) 
Purulent nasal drainage with at least one of the following:
- Nasal obstruction
- Facial pain or pressure
- Duration: ≤ 4 weeks
Classification of acute rhinosinusitis 
Viral rhinosinusitis (VRS)
- Clinical features of ARS for < 10 days
- Symptoms do not worsen.
Acute bacterial rhinosinusitis (ABRS)
- Clinical features of ARS not improving within 10 days 
- OR symptoms initially improve but then worsen within 10 days (double worsening)
- Recurrent acute rhinosinusitis: ≥ 4 episodes/year of ABRS with symptom-free intervals
Diagnostic criteria for chronic rhinosinusitis 
- At least two of the following for ≥ 12 weeks:
- PLUS inflammation documented through at least one of the following:
- Acute viral or bacterial rhinosinusitis is a clinical diagnosis and does not require further evaluation in most cases.
- Diagnostic studies are required in the following situations:
Imaging is the initial diagnostic tool for suspected complications.
Sinus CT: standard imaging modality
- Findings may include signs of:
- Rhinosinusitis: opacification, mucosal thickening, air-fluid levels, soft tissue swelling 
- Complications: spread beyond the sinuses
- Underlying causes of CRS: e.g., anatomic abnormalities, osteomeatal obstruction, polyposis
- Aggressive fungal infection or neoplasm: e.g., osseous destruction, extrasinus extension, local invasion 
- Findings may include signs of:
- MRI: can be used to evaluate for intracranial or intraorbital involvement or to differentiate polyps from tumors 
- No longer recommended due to limited sensitivity and specificity
- May show sinus opacification and air-fluid levels
- Indications: evaluation of complicated rhinosinusitis, recurrent ARS, or CRS
- Laboratory studies 
- Bacterial/fungal cultures: obtained endoscopically or by direct sinus aspiration to guide medical therapy
- Biopsy (endoscopic or surgical): to identify an underlying condition (including malignancies) and to enable classification 
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. 
Acute rhinosinusitis: typically managed in an outpatient setting
- Uncomplicated viral rhinosinusitis is usually self-limiting.
- Uncomplicated acute bacterial rhinosinusitis (ABRS)
- Complications of ABRS: Start IV antibiotics and consult ENT.
- Acute invasive fungal rhinosinusitis: Immediately consult ENT and consider ID consult for antifungal therapy (e.g., amphotericin B) and surgery.
- Episode of recurrent ARS or acute exacerbations of CRS: Treat as ABRS initially and involve ENT for further management. 
Symptomatic treatment 
The following options may be offered to all patients with rhinosinusitis.
- Nasal saline irrigation
- Oral analgesics, e.g., ibuprofen or acetaminophen
- Intranasal steroids, e.g., mometasone  
- Decongestants, e.g., oxymetazoline
Antibiotic treatment 
- First-line antibiotic therapy: amoxicillin, with or without clavulanate
- Usual oral treatment duration for adults: 5–10 days 
- Consider risk factors for treatment failure when choosing an appropriate antibiotic.
- Increased risk of bacterial resistance
- Severity of infection
- Patient factors, including smoke exposure, age > 65 years, and comorbidities, e.g., diabetes or cardiac/hepatic/renal disease
- In case of treatment failure, switch to one of the recommended antibiotic regimens from a different class with broader coverage.
|Antibiotic treatment in acute bacterial rhinosinusitis (ABRS) |
|Adults||Children (< 18 years)|
Surgical treatment 
- 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.