Sinusitis

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

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, Wegener granulomatosis, 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” below. ^[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

• Allergic fungal: See “Fungal rhinosinusitis” below.
• Chronic rhinosinusitis with nasal polyps
  • Clinical features
    • Rhinorrhea/postnasal drip, nasal congestion, hyposmia, facial pressure/pain
    • Presence of nasal polyps (for details, see “Nasal polyps” below)
  • Treatment: topical corticosteroids or sinus surgery
• 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]

Diagnostic criteria for acute rhinosinusitis (ARS) ^[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 for < 10 days
  • Symptoms do not worsen.
• Acute bacterial rhinosinusitis (ABRS)
  • Clinical features of ARS not improving within 10 days ^[1]
    OR
  • Symptoms initially improve but then worsen within 10 days (double worsening)
• Recurrent acute rhinosinusitis: ≥ 4 episodes/year of ABRS 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 worsen after initial improvement.

Diagnostic criteria for chronic rhinosinusitis ^[6]

• At least two of the following for ≥ 12 weeks:
  • Purulent nasal drainage
  • Nasal obstruction
  • Facial pain or pressure
  • Anosmia or hyposmia
• PLUS inflammation documented through at least one of the following:
  • Imaging: signs of inflammation (paranasal sinuses)
  • Endoscopic findings
    • Purulent mucus or edema
    • Polyps

Approach ^[1][6][14]

• 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:
  • Suspected complications of rhinosinusitis
  • Risk factors for invasive fungal rhinosinusitis (e.g., immunosuppression, diabetes mellitus)
  • Recurrent ARS or chronic rhinosinusitis

Imaging ^[6][14][16]

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 ^[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: can be used to evaluate for intracranial or intraorbital involvement or to differentiate polyps from tumors ^[14]
• Sinus x-ray
  • No longer recommended due to limited sensitivity and specificity
  • May show sinus opacification and air-fluid levels

Endoscopy

• 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. ^[17]

Additional studies

• Laboratory studies ^[6]
  • May be indicated in patients with recurrent ARS or CRS
  • Evaluate and consider testing for underlying medical conditions, e.g., allergic rhinitis, immunodeficiency, asthma, cystic fibrosis, or ciliary dyskinesia. ^[18]
• 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 ^[19]

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. ^[6]

Approach ^[6]

• Acute rhinosinusitis: typically managed in an outpatient setting
  • Uncomplicated viral rhinosinusitis is usually self-limiting.
  • Uncomplicated acute bacterial rhinosinusitis (ABRS)
    • Treat with antibiotics or observe for up to 7 days before initiating antibiotics if follow-up is assured.
    • If symptoms worsen at any time or fail to improve, 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 or acute exacerbations of CRS: Treat as ABRS initially and involve ENT for further management. ^[20][21]

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 ^{[22] [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.

Surgical treatment ^[1][21][24]

• 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:^[25][26]

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