Sinusitis

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

References:^[1][2][3]

• 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: 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:^[1][5][6]

Condition	Sinusitis	Rhinitis	Additional features
Acute viral rhinosinusitis	Fever (∼ 50% of cases), headaches, general malaise, myalgia Facial pain or pressure, erythema, and swelling over the affected area due to inflammation Maxillary sinuses (most commonly affected): over the cheeks (mimics dental pain) Superomedial location of the draining ostia → drainage of secretions must occur against gravity → stasis of secretions → increased susceptibility to infection Frontal sinuses: lower forehead Ethmoidal sinuses: nasal bridge and/or between the eyes or retro-orbital pain Sphenoid sinuses: located in the sphenoid bones near the optic nerve and pituitary gland. These are the most posterior sinuses. Transillumination may show opacification.	Sneezing, nasal congestion, rhinorrhea, and post-nasal drip Hyposmia/anosmia	Occasionally, acute otitis media (earache) Other manifestations of URTI such as pharyngitis (sore throat, cough)
Acute bacterial rhinosinusitis			Persistent symptoms ≥ 10 days without clinical improvement OR ≥ 3 initial days of severe symptoms, fever (> 39°), facial pain, or purulent nasal discharge OR Symptoms initially improve and then worsen after 5–6 days (double worsening)
Fungal rhinosinusitis			Noninvasive Allergic fungal: features of asthma and other atopic manifestations Fungal mycetoma: unilateral complaints; usually involves the maxillary sinus Invasive Acute fulminant rhino-orbital-cerebral mucormycosis: epistaxis and dark ulcers on the septum, palate and turbinates; acutely ill with altered mental status
Chronic rhinosinusitis	May present acutely without improvement of symptoms or insidiously over months to years ≥ 2 of the following: Mucopurulent drainage (anterior, posterior, or both) Nasal congestion Facial pain Anosmia or hyposmia AND inflammation as suggested by: Purulent mucus or edema in the middle meatus/anterior ethmoidal area during anterior rhinoscopy Polyps in the nasal cavity/middle meatus Imaging showing inflammation of the paranasal sinuses (see “Diagnostics” below)		Allergic fungal: See “Fungal rhinosinusitis” above. Chronic rhinosinusitis with nasal polyps: See “Nasal polyps.” Chronic rhinosinusitis without nasal polyps: anatomical abnormalities (septal deviation, tumors), dental disease

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!

References:^[1][6][3][8]

Nasal polyps ^[9][10]

• 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 polyps, and bronchospasm .
• 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
• Differential diagnosis: nasal papilloma
• Diagnosis
  • 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
• Treatment
  • Topical or systemic glucocorticoids
  • Resection of polyps if symptomatic despite medical therapy but recurrence is common

Primary ciliary dyskinesia ^[11][12]

• 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
• Diagnosis
  • 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.

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)
• Imaging
  • X-ray of sinuses; (poor sensitivity): decreased transparency of sinus, air-fluid levels may be seen
  • CT of sinuses (imaging modality of choice)
    • Soft tissue swelling, mucoperiosteal thickening, and air-fluid levels
    • Bony erosions and extension in cases of invasive mucormycosis infection
    • Fungus balls in the case of chronic aspergillosis infection
  • MRI may be considered to confirm soft tissue extension in invasive disease.
• Nasal endoscopy
  • Mucosal erythema and edema, with sinus ostia and nasal passages blocked by discharge
  • Necrotic mucosa in the case of invasive mucormycosis infection
  • Biopsy and culture may be performed (hyphae in fungal disease, eosinophils in allergic sinusitis).

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.

References:^[8]

• 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:^[13][14]

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