SLA 9 - ENT (B) Flashcards
The skeleton of the external nose is composed of which two components?
Bony component – located superiorly, and is comprised of contributions from the nasal bones, maxillae and frontal bone.
Cartilaginous component – located inferiorly, and is comprised of the two lateral cartilages, two alar cartilages and one septal cartilage. There are also some smaller alar cartilages present.
Outline the pathogenesis of saddle nose deformity.
Nasal trauma causes direct damage to the septal bone or cartilage, resulting in a saddle nose deformity.
Note trauma may also cause a nasal septal haematoma, whcih develops between the cartilage and surrounding perichondrium. This desprives the septum of its blood supply, resulting in avascular necrosis of the cartilaginous septum and deforming the nose.
Give the:
a) sensory
b) motor
innervation to the nose and its respective muscles.
a) External nasal nerve (branch of CN Va)
b) Facial nerve (CN VII)
What are the functions of the nasal cavity?
- warms and humidifies inspired air
- removes and traps pathogens and particulate matter
- sense of smell
- drains paranasal air sinuses and lacrimal ducts
What are the functions of conchae in the nasal cavity?
Increases the surface area of the nasal cavity, so more inspired air comes into contact with cavity walls.
They also disrupt fast, laminar flow of the air to make it slow and turbulent. Thus the air spends longer in the nasal cavity so that it can be humidified.
What are the functions of:
a) nasolacrimal duct
b) Eustachian tube
a) drains tears from the eye, opening into the inferior meatus.
b) allows the middle ear to equilibrise with the atmospheric air pressure, opening into the inferior meatus.
Outline through which route an URTI may cause a middle ear infection.
As the Eustachian tube connects the middle ear and upper respiratory tract, it is a path by which infection can spread from the upper respiratory tract to the ear.
What is epistaxis?
What is the most likely source?
Nosebleed.
It is likely to occur in the anterior third of the nasal cavity, known as Kiesselbach’s area.
Note if bleeding is pronounced or prolonged, the source is likely the sphenopalatine arteries.
The cause can be local (e.g. trauma) or systemic (e.g. hypertension).
What are the functions of the paranasal air sinuses?
- lightening the weight of the head
- supporting immune defence of the nasal cavity
- humidify inspired air
- increasing resonance of voice
Describe the clinical relevance of the sphenoid sinus sitting in close anatomical proximity to the hypophyseal fossa.
The hypophyseal fossa houses the pituitary gland.
This means that - in pituitary pathology - it can be accessed surgically by passing instruments via the sphenoid bone and sinus (ie. endoscopic trans-sphenoidal surgery) without the need for a more extensive craniotomy.
What is acute sinusitis?
An acute infection (<30 days) causing inflammation of the membranous lining of the sinuses.
Note if more than one air sinus is affected, this is known as parasinusitis.
What is the common aetiology of acute sinusitis?
Viral disease if infection <10 days
Bacterial disease if infection >10 days or if symptoms worsen around day 5.
Most common bacterial organisms are:
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
Presentation of acute sinusitis.
- facial discomfort
- nasal abstruction
- nasal discharge or post-nasal drip
- hyposmia / anosmia
- headache
- fatigue
- dental pain
Acute sinusitis causing toothache commonly suggests involvement of which specific paranasal air sinus?
Why does this cause toothache?
Maxillary paranasal air sinus.
Maxillary sinus is innverated by the infraorbital nerve, so pain may be referred to the upper jaw or teeth.
Management of acute sinusitis.
Reassure pts that generally a viral infection that will resolve within 3/52.
Symptom control measures include:
- paracetamol / ibuprofen for pain or fever
- intranasal decongestant
- nasal irrigation with warm saline solution
- warm face packs to provide relief
- adequate fluids and rest
If symptoms persist for 3/52 or pt at high risk of complications, abx should be considered.
First-line: phenoxymethylpenicillin (500 mg qds for five days) or co-amoxiclav if more systemically unwell. Alternatives for those who are allergic to penicillin are doxycycline (200 mg stat then 100 mg od for seven days - not in children aged <12 or pregnant women) or clarithromycin (250 mg-500 mg bd for seven days), or erythromycin.
Suggest 5 causes of chronic sinusitis.
- infection with Staphylococcus aureus
- fungal infection
- allergic rhinitis
- nasal polyps
- immunodeficiency
Note sinusitis classed as chronic if classical presenation of sinusitis but sx > 90 days.
Outline the pathogenesis of allergic rhinitis.
IgE mediated inflammation of the nasal mucosa following exposure to allergens, causing the release of histamine. Subsequent increase in epithelial permeability promts migration of inflammatory cells to the area.
Outlinet the symptoms seen in the following response phases of allergic rhinitis:
a) Acute-phase response (minutes)
b) Late-phase response (hours)
a) sneezing occurs within a few minutes of exposure, due to stimulation of afferent nerve endings.
An increase in nasal secretion follows shortly afterwards.
b) nasal obstruction
Define the features of the following categories of allergic rhinitis:
a) seasonal allergic rhinitis
b) perennial rhinitis
c) occupation rhinitis
a) commonly occurs due to pollen or grass cuttings (hayfever), but other triggers include mould spores and weeds.
b) occurs throughout the year (persistent) commonly triggered by dust mites and domestic pets.
c) exposure to allergens at work (e.g. flour, wood dust, latex gloves) trigger.
What are the common causes of the following classes of rhinorrhoea?
a) clear
b) unilateral
c) yellow / green
d) blood tinged (unilateral)
e) blood tinged (bilateral)
a) infection unlikely
b) CSF leak
c) allergy or infection
d) tumour, foreign body or nose picking
e) bleeding points, nose picking
Management of allergic rhinitis.
Allergen identification and avoidance.
Can offer topical nasal antihistamines or oral antihistamines.
Topical intranasal steroids are first line treatment for pregnant or breastfeeding women.
What are the functions of the oral cavity?
- digestion
- communication
- breathing
Outline the physiology of the gag reflex.
The gag reflex is protective against foreign bodies touching the posterior aspects of the oral cavity.
Afferent nerve: Glossopharyngeal nerve (CN IX)
Efferent nerve: Vagus nerve (CN X)
When stimulated, a reflex arc leads to contraction of the pharyngeal musculature and the elevation of the soft palate.
What is the function of the parotid gland?
Produces serous saliva, rich in enzymes, which is secreted into the oral cavity to lubricate and digest food.
Name the neurovascular structures that pass through the parotid gland.
- facial nerve (gives rise to five terminal branches within)
- external carotid artery (gives rise to the posterior aurticular, maxillary and superficial temporal artery)
- retromandibular vein (major vessel responsible for venous drainage of the face)
How do the sensory inputs to the balance system maintain balance?
The vestibulo-ocular reflex collates vestibular and visual inputs to adjust eye position.
The vestibular, visual and proprioceptive sensory inputs are collated to output motor impulses to make postural adjustments.
Which semi-circular canal most often experiences detached otoliths in BPPV?
Posterior semicircular canal ( 90%)
Lateral semicircular canal (10%)
Anterior semicircular canal (<1%)
Which manouvre can be used to check for BPPV in adults with vertigo on head movements?
After carrying out the manouvre, observe the pts eyes for teh development of nystagmus.
Management of BPPV.
Advise symptoms are usually self-limiting, and can be limited by getting out of bed slowly and reducing head movements.
Advise on safety issues (e.g. do not drive while they are dizzy, inform their employer, discuss risk of falling in home).
Repositioning techniques, including Epley’s manoeuvre or Brant-Daroff exercises, can be used to treat.
Refer to a specialist if symptoms are ongoing, recurrent or diangosis is uncertain.
Name the three pairs of salivary glands.
- Parotid glands
- Submandibular glands
- Sublingual glands
Give the three stages of swallowing.
- Oral phase
- Pharyngeal phase
- Oesophageal phase
Presentation of sialothiasis.
- pain in gland
- swelling
- infection
