H&N14 - Nose, Nasal Cavity & Paranasal Sinuses

Question 1

5 functions of the nose and nasal cavity

Answer 1

1.) Sense of Smell - olfactory mucous membrane houses olfactory receptor neurones

2. ) Route for Inspired Air - slows airflow
   - conchae (turbinates) causes turbulence of airflow and increases SA over which air passes
3. ) Filters Inspired Air - traps particles in hair or mucous
   - vestibule of external nose is lined with skin containing sebaceous and sweat glands and hair
4. ) Moistens and Warms Inspired Air
5. ) Resonating Chamber for Speech

Question 2

4 boundaries of the nasal cavity

Roof x4
Floor x2
Medial Wall x2
Lateral Wall x3

Answer 2

1. Roof - nasal bone, frontal bone, ethmoid bone (cribriform plate), sphenoid bone
2. ) Floor - maxilla, palatine bone (roof of oral cavity)
3. ) Medial Wall - nasal septum (2 parts)
   - bony part: perpendicular part of ethmoid bone and the vomer bone
   - cartilaginous part: septal cartilage
4. ) Lateral Wall - irregular due to bony projections
   - superior and middle conchae part of ethmoid bone
   - inferior conchae is a structure by itself
   - superior, middle, inferior meatus runs underneath the respective conchae (turbinates)

Question 3

Septal Haematoma

Pathophysiology
Clinical Features
Management
Complications

Answer 3

1. ) Pathophysiology - due to trauma causing separation of overlying perichondrium from the septal cartilage
   - this shears blood vessels so blood accumulates in this space (sub-perichondral haematoma)
   - this deprives underlying cartilage of its blood supply
2. ) Clinical Features - seen on anterior rhinoscopy
   - boggy red/purple swelling from the nasal septum
   - fluctuant on palpation with a Jobson Horne probe which helps to differentiate from a deviated septum
3. ) Management
   - incision and drainage under a general anaesthetic
4. ) Complications - untreated causes avascular necrosis of the septal cartilage which leads to:
   - septal abscess: infection develops in haematoma which can cause intracranial or ocular complications
   - saddle-nose deformity: saddling of the nasal dorsum

Question 4

3 features of the nasal mucosa

Olfactory Mucous Membrane
Respiratory Mucous Membrane
Blood Supply

Answer 4

1.) Olfactory Mucous Membrane - contains olfactory receptor neurones, allowing sense of smell (CN I)

2. ) Respiratory Mucous Membrane - pseudostratified columnar ciliated epithelium rich in goblet cells
   - filters (mucous/cilia), humidifies (watery secretions), and warms (rich blood supply) inspired air

3.) Rich Blood Supply - allows for warming and humidification of inspired air

Question 5

4 features of the blood supply to the nasal cavity

Arterial Supply x4
Epistaxis
Management of Epistaxis
Venous Drainage

Answer 5

1. ) Arterial Supply - maxillary (ECA) and ophthalmic
   - sphenopalatine and greater palatine artery (maxillary),
   - anterior and posterior ethmoidal artery (ophthalmic)
   - arteries anastomose in anterior septum forming Kisselbach’s plexus (Little’s area)
2. ) Epistaxis - nose bleeds are common because the mucosa and blood vessels are easily injured
   - source of bleeding is Kisselbach’s plexus (90%)
   - bleeding from sphenopalatine artery is potentially more serious and more difficult to treat
3. ) Management of Epistaxis - commonly treatable by pinching the nose to stop the bleeding, if not:
   - simple cautery if visible bleeding point, if not:
   - anterior packing using nasal tampons, if not:
   - posterior packing +/- surgical intervention
4. ) Venous Drainage - pterygoid venous plexus
   - also into cavernous sinus and facial vein

Question 6

3 conditions affecting the nasal cavity

Nasal Polyps (demographic, appearance, symptoms)
Nasal Tumour
Rhinitis

Answer 6

1. ) Nasal Polyps - bilateral benign swelling of the nasal mucosa
   - demographic: common in > 40-year-olds
   - appearance: pale/yellow, fleshy and reddened
   - symptoms: blocked nose, runny nose, post-nasal drip, reduced smell and taste

2.) Nasal Tumour - unilateral polyp/symptoms with bleeding and foul smell suggests a tumour

2. ) Rhinitis - inflammation of the nasal mucosa lining
   - types/causes: - infective (common cold) or allergic
   - symptoms: blocked nose, runny nose, post-nasal drip, sneezing, nasal irritation

Question 7

5 features of the paranasal sinuses

What are they?
Anatomical Relations
Function
Innervation 
Drainage

Answer 7

1. ) What are They? - group of four paired air-filled spaces that are extensions of the nasal cavity
   - frontal, sphenoid, ethmoid, maxillary
   - they are rudimentary or absent at birth

2.) Anatomical Relations - nasal cavity, orbit, anterior cranial fossa, roots of upper teeth can project into maxillary sinus

3. ) Function - also help humidify and warm inspired air
   - lined with respiratory mucosa (ciliated, mucous)
4. ) Innervation - trigeminal nerve
   - ophthalmic (Va): frontal, sphenoid, ethmoid
   - maxillary (Vb): maxillary
5. ) Drainage - all drain into the nasal cavity (meatus) via small channels called ostium/ostia
   - most drain into the middle meatus

Question 8

Acute (Rhino-)Sinusitis

Aetiology
Pathophysiology of Bacterial Rhinosinusitis
Clinical Features/Diagnosis

Answer 8

1. ) Aetiology - symptomatic inflammation of the mucosal lining of the nasal cavity AND paranasal air sinuses
   - viral: rhinoviruses and coronaviruses
   - post-viral: residual mucosal inflammation following a viral infection that produces ongoing symptoms
   - risk factors: cigarette smoke, air pollution, septal deviation, polyps, anxiety/depression, asthma, diabetes
2. ) Pathophysiology of Bacterial Rhinosinusitis
   - primary viral infection leads to reduced ciliary function, oedema, increased secretions
   - impeded drainage from sinuses (mainly maxillary) and stagnant secretions becomes ideal for bacteria
   - common bacteria: S. pneumoniae, H. influenzae, Moraxella catarrhalis, S aureus
3. ) Clinical Features/Diagnosis - 2+ of the following:
   - headache: facial pain behind the nose, forehead and eyes, often tenderness over the affected sinus
   - recent URT infection, fever, altered sense of smell
   - blocked/runny nose (+/- green/yellow discharge)
   - sudden onset of symptoms, sx >10 days (but <12wks) w/o improvement and worsen after initial improvement

Question 9

Management of Acute Rhinosinusitis

Initial Management
Red Flag Symptoms
Specialist Management
Complications

Answer 9

1. ) Initial Management - depends on days of symptoms:
   - <5d or improving: analgesia and nasal decongestants or nasal irrigation w/ saline and steam inhalation
   - >10d or worsening after 5d: topical nasal steroids and oral antibiotics are indicated
   - referral to ENT: no improvement after 7-14 days of treatment or the presence of red-flag symptoms
2. ) Red Flag Symptoms
   - orbital signs: periorbital swelling or erythema, displaced globe, visual changes, ophthalmoplegia
   - headache: severe unilateral headache, bilateral frontal headache, or frontal swelling
   - neuro: neurological signs or reduced consciousness
3. ) Specialist Management
   - nasal endoscopy: abnormal anatomy or pathology
   - nasal discharge cultures: atypical infections
   - CT-paranasal sinuses: extent of the disease, identify any complications or anatomical abnormalities
   - severe infections or complications: oral steroids, intravenous antibiotics, consider surgery
4. ) Complications
   - (peri-)orbital cellulitis or abscesses
   - osteomyelitis: can lead to penetration into the skull vault causing intracerebral complications
   - intracranial abscesses, venous sinus thrombosis
   - Pott’s puffy tumour: osteomyelitis of the frontal sinus can result in a soft boggy swelling over the overlying tissue on the forehead