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Diseases of the paranasal sinuses Ehab ZAYYAN, MD, PhD
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Embryology Ethmoid sinuses: 0- 12 y Frontal sinus: 6- 20 y
Maxillary sinus: y y Radiology: 1 year Sphenoid sinus: 3- 20
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Anatomy of the sinuses Maxillary sinus (Antrum of Highmore)
The largest paranasal sinus 10-20 cc in volume Floor: alveolar process Roof: orbital floor Medial wall: bony+ membranous (ant and post fontanelles) Ostium opens in the middle meatus, in the lower paret of the ethmoid infundibulum. Accessory ostia may be found in the ant or post fontanelle in 25% of people (clinical importance!!)
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Anatomy Ethmoid Sinuses lamina cribrosa (cribriform plate)
Crista galli Perpindicular lamina Lamina paperacea Air cells: (average: 9) in each side
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Relations of the ethmoids:
Anterior: orbit and nasolacrimal duct Posterior: sfenoid sinus, orbital apex, optic nerve Lateral: orbit Superior: skull base
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Anatomy Anterior ethmoid cells drain into the middle meatus
Ground lamella (attachment of the middle turbinate to the lat nasal wall) Posterior ethmoid cells drain into the upper meatus
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Anatomy Uncinate process
Hiatus semilunaris: curved space between the uncinate and ethmoid bulla. Entrance to the ethmoid infundibulum. Ethmoid infundibulum: the drainage site of the maxillary, frontal, anterior ethmoid cells. Bulla ethmoidalis: the most constant and the largest anterior ethmoid cell Ground lamella Posterior ethmoid cells (eg. Onodi cell)
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Frontal Sinus Paired asymmetric sinuses
Absent unilaterally in 12% and bilaterally in 5% Drainage: Frontal ostium→ Nasofrontal duct →Frontal recess →Ethmoid infundibulum
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Sphenoid sinus Lies in the center of the head
- Above : optic nerve and pituitary gland - Laterally: orbital apex, cavernous sinus, carotid arteries - Posterior: basillar artery, pons - Inferiorly: nasopharynx Drainage: sphenoethmoidal recess into the superior meatus
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Histology The nasal vestibule is lined with stratified squamous epithelium with vibrissae, sweat glands, and sebaceous glands. The sinonasal mucous membrane is pseudostratifed, columnar, ciliated epithelium (respiratory epithelium. Olfactory epithelium.
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The sinus mucosa compared to nasal mucosa:
Thinner Shorter epithelium Basal membrane is very thin Less goblet cells Very few seromusinous glands in the submucosa Lamina propria is is very thin and firmly adherent to the periostium
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Physiology The mucous membrane consists of two layers:
Gel layer: thick viscous elastic layer Sol layer: serous layer between the cilia Daily mucous secretion: 600 – 1800 cc Contains a lot of substances mainly lysozymes and immunoglobulins.
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Ciliary movements: cilia/ cell 8-20 beat/ second The movement is towards the natural ostium not towards the gravity. For maximum ciliary activity: Humidity: >85% Temperature: degree C pH: 7- 8
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Normal ventilation Normal drainage Ciliary movements
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Factors negatively affecting the mucociliary activity
Dryness of air Cigarette Temperature Hypoxia Hypercapnia Hypertonic/ hypotonic fluids Dehydration pH changes Cystic fibrosis Primary ciliary dyskinesia Drugs ( phenylphrine, adrenaline, lidocaine, atropine, antihistaminic). Infections Anatomic obstruction (septum, turbinate,..) Foreign body Nasal polyps
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secretions in the sinuses
Hypoxia ↓ Vasodilatation Ciliary dysfunction Mucous gland ↓ dysfunction ↓ Stasis ↓ Transudation Accumulation of thick ← thick fluid secretions in the sinuses Bacterial growth
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Osteomeatal complex The most commonly infected structure in the sinuses Can be obstructed and inflammed easily with even minimal edema Can not be examined by anterior rhinoscopy but with endoscopy Can not be evaluated by conventional radiology but needs CT
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Obstruction of the osteomeatal complex
Anatomic variations Foreign body Mucociliary dysfunction Allergy Infections Local inflammation ↓ Obstruction of the osteomeatal complex Sinusitis
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Osteomeatal complex obstruction, ↓
Decreased ventilation of the sinuses, Decreased drainage of the sinuses pO2 decrease, pCO2 increase, mucous stasis Inflammation and viscous mucous, ciliary movement slowing Stasis and proteolytic enzymes Ciliary damage Anaerobic microrganisms More damage……
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Sinonasal imaging Plain sinus radiographs: Sinus opacifications
Air-fluid level Mass Fractures
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Water view Best for maxillary sinuses and orbital rims
Blow-out fractures
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Caldwell view Best for frontal sinus
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Lateral view Best for sphenoid sinus and frontal sinus
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Submental vertex (basal) view
Zygomatic archs Sphenoid sinus Lateral walls of the orbit
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Computed tomography Excellent views of the sinuses Coronal section
Best for osteomeatal complex and ethmoidal disease
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MRI Excellent soft tissue definition Neoplastic disease evaluation
Fails to demonstrate bone Expensive Claustra- phobia
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Pathophysiology of sinusitis
4 stages Initial phase Ostium obstruction phase Bacterial phase Chronic phase
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1.Initial phase Edema and hyperemia of the sinus mucosa
Transudate accumulation and serous fluid Reversible If the ostium is not obstructed it resolves spontaneously
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2. Ostium obstruction phase
Sinus drainage and ventilation decreases The secretion becomes thicker and more viscous Ventilation decreases more, pO2 pressure ↓, CO2 ↑ A good media for anaerobes develop
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3. Bacterial phase Rapid bacterial growth Anaerobic bacterial growth
Local inflammation Viscosity increases Ciliary activity decreases If not treated chronic changes start
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4.Chronic phase Immune activities stop Irreversible changes occur
Mucosal destruction Ciliary activity stops The irreversibla changes usually affect some of the mucosa, so if surgery (FESS) is performed, the rest of the mucosa can be saved and start functioning….
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FESS The target of Functional Endoscopic Sinus surgery (FESS) is to remove the pathology of the osteomeatal complex to maintain normal ventilation and drainage to the sinuses. Anatomic variations (septal deviation, concha bullosa, uncinate variations, ….) Foreign body Nasal polyps Chronic sinusitis
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Sinusitis Acute sinusitis - acute - subacute - recurrent acute
Chronic sinusitis - recurrent with acute exacerbations Fungal sinusitis - acute invasive (fulminant) - chronic indolent - Mycetoma (fungus ball) - Allergic fungal
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Acute sinusitis Preceding viral infection is the most common cause
Bacterial etiology: S. pneumonia, H. influenza, M. catarrhalis, S. aureus, S. pyogens Anaerobic (more common in chronic) Nosocomial (gram negative bacteria)
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Symptoms Nasal obstruction Mucupurulent nasal discharge
Headache/ facial pain (eye, teeth, ears, vertex) Postnasal discharge Cough Halitosis Sore throat Fever
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Examination Nasal congestion and discharge Post-nasal discharge
Tenderness over the sinuses Transillumination
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Radiology Plain x- rays: opacity/ air- fluid level in the maxillary, sphenoid, frontal CT: for the ethmoid (not indicated for acute cases)
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Cultures From nasal discharge is unreliable
From the middle meatus are 70% correlated Sinus puncture is the best. Not routinely indicated.
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The diagnosis of acute sinusitis is mainly by history and physical examination.
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Treatment Antibiotics: (10- 14 days) Amoxicillin
Trimethoprim- sulfamethaxazole Amoxicillin- clavulonic acid Cefuroxime and second generation cefalosporins Clarithromycin
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2. Oral decongestants 3. Local decongestants (3- 5 days) 4. Mucolytics 5. Antihistaminics 6. Nasal saline irrigation 7. analgesics/ anti-inflammatory Sinus puncture: in very painful conditions and in non- responsive cases. Frontal sinusitis: close follow up and iv therapy if needed.
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Pediatric sinusitis Can be confused with URTI Rhinosinusitis
URTI symptoms > 5- 7 days. More severe symptoms and high fever. Recurrent sinusitis: 3 or more attacks in 6 months or 4 or more in one year Chronic sinusitis: persistence of symptoms more than 3 months
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Underlying factors for recurrent/chronic sinusitis in periatric population: Allergy, passive cigarette smoking, kindergarten, adenoid vegetation, immunodefeciency, immotile cilia syndrome, cystic fibrosis. Therapy: treat the underlying factors, medical therapy, surgical therapy.
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Chronic sinusitis Persistent signs and symptoms beyond 8 to 12 weeks.
Mostly headache, chronic nasal obstruction, postnasal discharge. Microbiology: common m.o. + anaerobes Diagnosis: paranasal sinus CT Treatment: 4 weeks second line antibiotics+ coverage for anaerobes (Metronidasole, clindamycin) Usually needs surgical intervention
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Acute fulminant (invasive)fungal sinusitis (Mucormycosis)
Rapidly progressive disease caused by family of Mucoracea: Rhizopus, Mucor, Absida. Less commonly due to Aspergillus species. Occurs only in immunocopromized patients.
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The fungi invade the blood vessel walls producing thrombosis, ischemic infarction, and necrosis and allowing spread of the disease. The necrotic tissue provides ideal medium for fungal growth. Patients are acutly ill, fever, lethargy, facial pain. Examination: dark, necrotic turbinates and septum. Black facial necrosis and perforations of the septum and the palate. Can invade the brain, the orbit and other vital structures.
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Diagnosis: staining and cultures, CT, MRI.
Treatment: Control of the underlying disease (DM…) Radical debridement of all necrotic tissue. IV amphotericin B for several months.
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Chronic indolent fungal sinusitis
Endemic in hot dry areas like Sudan and India Mainly by Aspergillus Immunocompetent non-atopic patients The same symptoms of chronic sinusitis Slowly progressive invasive disease causing bone necrosis and chronic granulomatous infiltrate. Diagnosis: demonistration of tissue invasion Treatment: surgical removal + antifungal agents
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Mycetoma (fungus ball)
Chronic non-invasive fungal infection. Usually affects a single maxillary sinus. Immunocompetent nonatopic hosts. Aspergilloma (caused by aspergillus) Treatment: surgical removal.
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Allergic fungal sinusitis
5 to 10% of chronic sinusitis cases Atopic young adults/ adolescents with history of recurrent sinusitis and surgeries. Nasal polyposis and positive skin tests are common Rubbery green/ brown mucoid discharge and nasal polyps. Staining of mucous: extramucosal hyphae, eosinophils, Charcot- Leyden crystals (Allergic mucin) IgE can be elevated, positive fungal skin test
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Allergic mucin
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CT: unilateral involvement of multiple sinuses, bony erosions, metalic density of the mucous
Treatment: Antibiotics Steroids Antifungals FESS
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Sinobronchial syndrome
25% of patients with nasal polyps develop asthma and vice versa. Bronchial asthma and sinusitis are manifestations of the same underlying respiratory system disorder. Bronchial smooth muscles↔ nasal mucosa venous sinusoids Causes of asthma in chronic sinusitis Nasal obstruction Postnasal drip Reflex bronchospasm (trigeminal vagal reflex)
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Samter syndrome Bronchial asthma Nasal polyposis Aspirin intolerence
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Complications of sinusitis 1. local complications
Mucocele Primary mucocele (mucous retention cyst): due to obstruction of the minor salivary glands and usually seen in the maxillary sinus. Silent. Secondary mucocele: due to sinus ostia obstruction. Most commonly in the frontal sinus. Slow growth, bony erosions. Expand in the orbit and the cranial cavity.
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Osteomyelitis Most frequently in the frontal bone Erosion through the anterior wall and development of subperiosteal abcess produces forehead swelling called Pott`s puffy tumor. Intracranial extention may happen. Treatment: iv AB + debridment
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2. Orbital complications
Preseptal cellulitis Orbital cellulitis Periorbital abcess Orbital abcess Cavernous sinus thrombosis
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3. Intracranial complications
Meningitis Epidural abcess Subdural abcess Brain abcess
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Surgical management of sinusitis
Traditional sinus surgery Caldwell- Luc operation Nasal antral window Intranasal ethmoidectomy External ethmoidectomy External frontoethmoidectomy Osteoplastic frontal sinus surgery …….
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Functional endoscopic sinus surgery (FESS)
Indications: Chronic sinusitis Polyposis Mucocele Fungal sinusitis Benign tumors CSF rinorrhea Orbit decompression (Graves disease) Optic nerve decompression DCR (dacrocystorhinostomy) Pitiutary adenoma
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Complications: Hemorrhage CSF fistula Orbital injury Lacrimal system injury
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Benign masses and tumors
Nasal polyps Sinunasal papilloma Hemangioma Juvenile nasopharyngeal angiofibroma Osteoma Fibrous dysplasia
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Malignant SCC (80%) Salivary gland tumors (adenoidcystic CA) Sarcoma
Malignant melanoma lymphoma
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