Sinusitis

Rhinosinusitis is a mucosal inflammation of both the paranasal sinuses and adjacent nasal cavities. Viral infection is the most common cause of acute rhinosinusitis (ARS); bacterial and fungal infections also occur. The characteristic symptoms of rhinosinusitis are purulent rhinorrhea, nasal obstruction, and facial pain. ARS is often self-limiting, but antibiotic therapy may be indicated in the case of suspected or diagnosed bacterial superinfection. Imaging and endoscopy are reserved for patients with recurrent sinusitis, red flags for rhinosinusitis, or certain risk factors (e.g., immunosuppression). Rarely, the infection may spread to the soft tissues, bone, vascular system, and/or central nervous system. Chronic rhinosinusitis (CRS), a chronic inflammatory state similar to asthma, lasts at least 12 weeks and may be complicated by bacterial exacerbations or chronic fungal infections. Diagnosis is confirmed by findings of inflammation on imaging, anterior rhinoscopy, or nasal endoscopy. Underlying comorbidities, such as allergy, cystic fibrosis, and immunodeficiency, should be ruled out. First-line treatment of CRS is intranasal steroids and nasal irrigation for symptomatic relief. Patients with persistent symptoms may require surgery.

• 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

References:^[1][2]

• 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: ♀ > ♂

References:^[3]

Epidemiological data refers to the US, unless otherwise specified.

• Pathogens
  • Viral (most common): rhinovirus, coronavirus, adenovirus, influenza, and parainfluenza viruses
  • Bacterial: particularly S. pneumoniae, H. influenzae, M. catarrhalis, S. aureus, E. coli, and Klebsiella.
  • Fungal: e.g., Aspergillus, Rhizopus oryzae
• Route of transmission: droplet transmission, particularly in winter months
• Risk factors
  • Preexisting viral upper respiratory tract infection (URTI): most common; leads to superimposed bacterial infections
  • Ventilation disorders of the sinuses
    • Hypertrophy of nasal turbinates, nasal polyps, deviation of nasal septum
    • Impairments of ciliary function such as cystic fibrosis, primary ciliary dyskinesia, granulomatosis with polyangiitis, allergic inflammation , and immunodeficiency
    • Concha bullosa (also known as a middle turbinate pneumatization)
  • Foreign body lodged in the nasal cavity (particularly seen in children).
  • Odontogenic infection: leads to unilateral maxillary sinusitis
  • Rhinitis: spread of pathogens via nasal mucosa
  • Bronchial asthma
  • Analgesic (NSAIDs, aspirin) intolerance

References:^[4]

• Sinusitis is triggered by three factors: obstruction of sinus drainage pathways (sinus ostia) due to mucosal edema, 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.

References:^[5]

Acute rhinosinusitis ^[6]

Rhinitis

• Sneezing, nasal congestion, rhinorrhea, and postnasal drip
• Hyposmia/anosmia

Sinusitis

• Unspecific symptoms: fever; (∼ 50% of cases), headaches, general malaise, myalgia
• Facial pain/pressure, erythema, and swelling over the affected area due to inflammation
  • Maxillary sinuses are most commonly affected.
    • Since maxillary ostium, which drains the maxillary sinuses, is located posteriorly and medially near the roof of the maxillary sinus, secretions are drained against the pull of gravity (i.e., upwards), causing secretions to accumulate and increasing the susceptibility to infection.
    • Inflammation of mucosa → sinus ostial blockage → drainage into the ostiomeatal complex → ↑ mucus production by the nasal mucosa → congestion and swelling of the nasal passages → sinus cavity hypoxia and mucus retention → ↓ function of nasal cilia → ↓ transportation of mucus and debris from the nose → creation of ideal conditions for bacterial growth → ↑ susceptibility to infection
    • Manifests with pain in jaw region (mimics dental pain)
  • Frontal sinuses: pain in the lower forehead
  • Ethmoidal sinuses: pain in the nasal bridge region or retroorbital pain
  • Sphenoid sinuses: located in the sphenoid bones near the optic nerve and pituitary gland
• Transillumination may show opacification.

Subtypes

• Acute viral rhinosinusitis
  • May occur with acute otitis media
  • May manifest with other symptoms of URTI (e.g., sore throat, cough)
• Acute bacterial rhinosinusitis
  • Severe symptoms (including fever > 39°C, facial pain, purulent nasal discharge)
  • Symptoms typically remain stable or improve for 5–6 days and then worsen (double worsening).
• Fungal rhinosinusitis: See “Fungal rhinosinusitis.” ^[4]

Chronic rhinosinusitis ^[6]

Chronic rhinosinusitis can manifest acutely with exacerbation of symptoms or take an insidious course with low-grade symptoms persisting over months to years.

• Symptoms
  • Facial pain
  • Mucopurulent drainage (anterior, posterior, or both)
  • Anosmia or hyposmia
  • Nasal congestion
• Signs of inflammation
  • Purulent mucus or edema in the middle meatus/anterior ethmoidal area seen in anterior rhinoscopy
  • Polyps in the nasal cavity/middle meatus

Subtypes

• Chronic fungal rhinosinusitis: See “Fungal rhinosinusitis” below.
• Chronic rhinosinusitis with nasal polyps: Pathogenesis is not fully understood, but there is an association with asthma, allergic rhinitis, and cystic fibrosis. ^[7]
• Chronic rhinosinusitis without nasal polyps: Pathogenesis is associated with anatomical abnormalities (e.g., septal deviation, tumors) and dental disease (i.e., sinusitis of dental origin).

Nasal polyps ^[7][8]

• Definition: benign lesions of the nasal mucosa or paranasal sinuses due to chronic mucosal inflammation
• Risk factors
  • Chronic rhinosinusitis
  • Cystic fibrosis (CF)
  • Aspirin exacerbated respiratory disease (AERD; aspirin or NSAID induced): triad of asthma, chronic sinusitis with recurrent nasal polyps, and sensitivity to aspirin and other NSAIDs ^[9]
• Clinical features
  • Postnasal drip
  • Bilateral nasal obstruction
  • Frequently impaired olfactory function (from hyposmia to anosmia)
  • Fever and severe facial pain are uncommon.
• Special form: choanal polyp
  • Definition: isolated, soft nasal polyp that originates in the mucous membrane of the maxillary sinus (rarely in ethmoidal cells) and grows from the middle nasal meatus into the nasopharynx
  • Clinical features: nasal obstruction or features of sinusitis
  • Treatment: complete endoscopic excision
• Diagnostics
  • Nasal cytology for eosinophilia
  • Evaluate for associated conditions (e.g., sweat chloride test for CF)
  • Nasal endoscopy: bilateral grey polypoid mucosa hypertrophy
  • CT
    • Determines the exact location and extent of polyps
    • Also useful to exclude other causes of nasal obstruction
• Differential diagnosis: nasal papilloma
• Treatment
  • Topical or systemic glucocorticoids
  • Resection of polyps if symptomatic despite medical therapy but recurrence is common

Primary ciliary dyskinesia ^[10][11]

• Definition: rare autosomal recessive disorder characterized by absent or dysmotile cilia caused by a defect in the dynein arm of microtubules
• Clinical features
  • Chronic productive cough
  • Recurrent otitis, sinusitis, and nasal polyps
  • Bronchiectasis
  • 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
• Diagnostics
  • Nasal nitric oxide test: reduced nasal nitric oxide (screening test)
  • Genetic tests for dynein arm mutations
  • Chest x-ray: bronchiectasis, dextrocardia, and situs inversus (suggests Kartagener syndrome)
  • Electron microscopy: abnormal cilia
• Treatment: depends on individual clinical presentation and course

You can memorize the cause of Kartagener syndrome by thinking of Kartagener's restaurant that only has 'take-out' service because there is no dine-in (dynein).

Kartagener syndrome is a subtype of primary ciliary dyskinesia characterized by the triad of situs inversus, chronic sinusitis, and bronchiectasis.

Fungal rhinosinusitis (FRS) ^[4][12][13]

• Definition: rhinosinusitis caused by a fungal pathogen ^[12]
• Classified by:
  • Duration: acute (< 4 weeks) and chronic (≥ 12 weeks)
  • Histopathology: invasive (e.g., acute invasive fungal rhinosinusitis) or noninvasive (e.g., fungal ball, allergic fungal rhinosinusitis, etc.)
• Risk factors
  • Sinus surgery or trauma may lead to fungal colonization.
  • Immunosuppression (e.g., immunodeficiency, chronic steroid use) and uncontrolled diabetes mellitus are risk factors for invasive fungal rhinosinusitis.
• Clinical features
  • General symptoms: See “Acute rhinosinusitis.”
  • Noninvasive fungal rhinosinusitis ^[4]
    • Allergic fungal: features of asthma and other atopic manifestations
    • Fungal mycetoma: unilateral complaints; usually involves the maxillary sinus
  • Acute invasive fungal rhinosinusitis : epistaxis and dark ulcers on the septum, palate and turbinates; may be acutely ill with altered mental status ^[4]
• Diagnostics
  • CT: Possible findings include fungal balls, bony erosions, and extra sinonasal spread. ^[14][15]
  • 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
  • Biopsy
• Management
  • An ENT specialist should manage all cases of suspected fungal rhinosinusitis.
  • Patients with acute invasive fungal rhinosinusitis
    • Admit as an inpatient and consult ENT and ID services immediately.
    • Treatment may include surgical debridement of necrotic tissue, systemic antifungal therapy (e.g., amphotericin B), and reversal of immunosuppression if possible. ^[13]

Acute invasive fungal rhinosinusitis is a life-threatening diagnosis with a mortality rate of 50–80%. If suspected, immediately admit the patient and consult ENT. ^[13]

General principles ^[1][6][14]

• Acute viral/bacterial rhinosinusitis is a clinical diagnosis.
  • Assess patients using diagnostic criteria for acute rhinosinusitis.
  • Imaging is only required for patients with any of the following:
    • Red flags for rhinosinusitis
    • Risk factors for complications (e.g., immunosuppression, diabetes, history of facial trauma)
    • Recurrent ARS
• Chronic rhinosinusitis diagnosis is confirmed by findings of inflammation on one of the following:
  • CT scan ^[16][17]
  • Direct visualization
• Additional studies should be performed in the following cases:
  • CRS or recurrent ARS (to rule out comorbid conditions that affect management)
  • Treatment failure
  • Diagnostic uncertainty

A clinical diagnosis of chronic sinusitis should be confirmed with objective documentation of sinonasal inflammation, which can be accomplished via anterior rhinoscopy, nasal endoscopy, or CT scan. ^[6]

Red flags for rhinosinusitis ^[1][6][14]

Patients with red flag symptoms require urgent imaging; ENT may recommend further diagnostic studies.

• Focal neurologic deficits (including cranial nerve palsies)
• Severe headache
• Facial edema
• Altered mental status
• Ophthalmic complications (e.g., blurred vision, proptosis, impaired ocular movements)
• Fever > 39°C (102°F) and/or that lasts > 3 days
• Symptoms not improving despite adequate antibiotic therapy

Imaging ^[6][14][17]

• CT maxillofacial with or without IV contrast
  • Indications ^[17]
    • CRS or recurrent ARS
    • Acute rhinosinusitis in patients with risk factors for complications or red flags for rhinosinusitis
  • Findings may include signs of:
    • Rhinosinusitis: opacification, mucosal thickening, air-fluid levels, soft tissue swelling ^[15]
    • 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 ^[6][13]
• MRI with and without IV contrast: can be used to evaluate for intracranial or intraorbital involvement or to differentiate polyps from tumors ^[6][14][17]
• X-ray sinuses
  • No longer recommended due to limited sensitivity and specificity
  • May show sinus opacification and air-fluid levels

Direct visualization

• Indications: evaluation of complicated rhinosinusitis, recurrent ARS, or CRS
• Modalities
  • Nasal endoscopy (preferred)
  • Anterior rhinoscopy
• Findings
  • Signs of rhinosinusitis: mucosal erythema, edema, osteomeatal blockage with purulent drainage ^[6]
  • Detection of structural abnormalities or masses, if present
  • Signs of fungal rhinosinusitis: necrosis

Pale or dark necrotic mucosa with crusting or ulcers indicates acute invasive fungal rhinosinusitis, which is a medical emergency. ^[18]

Anterior rhinoscopy may miss smaller polyps and/or more posterior disease because it only visualizes the anterior third of the nasal cavity. If anterior rhinoscopy findings are normal, perform nasal endoscopy. ^[6]

Additional studies

• Evaluation for comorbid conditions: Perform for patients with recurrent ARS and CRS. ^[6]
  • Allergic rhinitis: Consider allergen testing. ^[6]
  • Clinical features of asthma: Perform diagnostic studies for asthma.
  • Clinical features of cystic fibrosis: Perform diagnostic evaluation for CF. ^[6]
  • Otitis media, bronchiectasis, or pneumonia
    • Refer to immunologist for immunodeficiency evaluation. ^[6]
    • If primary ciliary dyskinesia is suspected, refer to pulmonologist for biopsy and/or genetic testing. ^[6]
  • Rheumatologic disorders: Choice of further studies depends on clinical features (e.g, diagnostic evaluation for sarcoidosis, workup for vasculitic syndrome). ^[16]
• Bacterial/fungal cultures: Request in cases of treatment failure.
• Biopsy (endoscopic or surgical): to identify an underlying condition (including malignancies) and to enable classification ^[19]

Diagnostic criteria for acute rhinosinusitis ^[6]

• Purulent nasal drainage with at least one of the following:
  • Nasal obstruction
  • Facial pain or pressure
• Duration: ≤ 4 weeks

Classification of acute rhinosinusitis ^[6]

• Viral rhinosinusitis (VRS)
  • Clinical features of ARS that improve within 10 days
  • Symptoms do not worsen.
• Acute bacterial rhinosinusitis (ABRS)
  • Clinical features of ARS that do not improve within 10 days ^[1]
    OR
  • Symptoms initially improve but then worsen within 10 days (double worsening).
• Recurrent acute rhinosinusitis: ≥ 4 episodes of ABRS per year with symptom-free intervals

Acute bacterial rhinosinusitis should be suspected in patients with a preexisting viral URTI and symptoms that do not improve after 10 days or initially improve and then worsen at any time.

Diagnostic criteria for chronic rhinosinusitis ^[6]

• At least two of the following for ≥ 12 weeks:
  • Mucopurulent nasal drainage
  • Nasal obstruction and/or congestion
  • Facial pain and/or pressure
  • Anosmia or hyposmia
• PLUS inflammation identified through at least one of the following:
  • Imaging: signs of inflammation (paranasal sinuses)
  • Direct visualization of sinuses and nasal cavities (on endoscopy or anterior rhinoscopy)
    • Purulent mucus or edema
    • Polyps ^[6][16]

Approach to treatment of rhinosinusitis ^[6]

• Acute rhinosinusitis
  • Uncomplicated viral rhinosinusitis is usually self-limiting.
  • Uncomplicated ABRS
    • Treat with antibiotics or, if follow-up is assured, observe for up to 7 days; before initiating antibiotics.
    • If symptoms worsen at any time or fail to improve with treatment, reconsider the diagnosis and initiate or switch antibiotic treatment.
  • 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: Treat as ABRS initially and involve ENT for further management. ^[16][20]
• Chronic rhinosinusitis
  • Treat acute exacerbations as ABRS. ^[16]
  • Advise nasal saline irrigation for symptomatic relief.
  • Treat the underlying inflammation with corticosteroids. ^[16][20]
    • All patients: intranasal for at least 8–12 weeks ^[6]
    • Patients with nasal polyps and severe symptoms: Consider addition of a short course (3 weeks) of oral therapy. ^[16]
  • If there is no response to medical management, or if red flags for sinusitis are present, refer to ENT.

In patients with CRS, do not prescribe antifungals (topical or systemic) and only use systemic antibiotics for the treatment of acute exacerbations. ^[6][16][20]

Symptomatic treatment ^[1][6]

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 ^{[21] [6]}
• Decongestants, e.g., oxymetazoline

Antibiotic treatment ^[6]

• Indications
  • Acute bacterial rhinosinusitis (initially or if symptoms worsen or do not improve during observation)
  • Episode of recurrent bacterial rhinosinusitis
  • Acute exacerbation of chronic rhinosinusitis
• Regimens
  • First-line antibiotic therapy: amoxicillin, with or without clavulanate
  • Usual oral treatment duration for adults: 5–10 days ^[1][6]
  • 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.

Surgery ^[1][16][23]

• Indications
  • Evidence of structural abnormalities: e.g., polyps, masses, or anatomical obstructions
  • Treatment failure or complications of rhinosinusitis
  • Acute invasive fungal rhinosinusitis
• Objective
  • Improving aeration through sinus opening and drainage
  • Debridement of necrotic tissue or abscess drainage
  • Correction/removal of anatomic obstructions
  • Obtaining intraoperative cultures and biopsy for histopathology if the diagnosis remains unclear

• Local spread
  • Mucoceles
  • Osteomyelitis, especially of the frontal bone (also known as Pott's puffy tumor): subperiosteal abscess with local pain and edema that requires antibiotic treatment and surgery
• Spread to the orbit
  • Preseptal/orbital cellulitis
  • Orbital abscess
  • Cavernous sinus thrombosis
  • Cavernous sinus syndrome
• Intracranial spread
  • Subdural abscess: most common
  • Meningitis
  • Brain abscess
• Systemic complications
  • Bacteremia/sepsis
  • Pneumonia
  • Multiple organ failure
  • Untreated chronic sinusitis can lead to life-threatening complications, as may be seen in patients with cystic fibrosis.

Orbital and intracranial necrotic spread is especially common in invasive fungal sinusitis.

References:^[24][25]

We list the most important complications. The selection is not exhaustive.