Download Clinical physiology*ENT

Clinical physiology—ENT:
Prof James Ker
MBChB, MMED, MRCP, FRCP, PhD,
FESC, FACC, L.Akad.SA
The nose:
• The nose presents a large mucosal surface
area through the folds of the turbinates.
• Serves to adjust the temperature and
moisture content of inhaled air.
• Filters out particulate material >10 ᵤm in size
• Does this by impingement in a mucous blanket
• Ciliary action moves the entrapped particles
toward the pharynx
• Entrapment of pollen in mucous blanket:
• Digestion of the outer coat by mucosal
enzymes (such as lysozymes)
• This releases protein allergens (10 000-40 000
molecular weight)
• This interaction between protein allergens and
mast cells: 2 types
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Intraepithelial and perivenular mast cells
Both are sensitized with specific IgE
Which Ig`s in mucous layer: IgA , E or both
IgE diffuses from plasma cells
IgA secreted
IgE fixes to mucosal and submucosal mast
cells
• Clinical response related to pollen dose
For clinical insight:
• Antigens
• Haptens
• Superantigens
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Immediate hypersensitivity reactions
Delayed hypersensitivity reactions
Cytotoxic reactions
Immune complex formation
• Clinical implications:
• Immediate vs late clinical presentations
• Vasculitic associations of allergic disease
Sinusitis:
• This term refers to an inflammatory condition
involving one or more of the four paired
structures surrounding the nasal cavities.
• Maxillary sinus most commonly involved
• Then: Ethmoid, frontal and sphenoid
• Each sinus is lined by respiratory epithelium
that produces mucus.
• Mucus: Transported out by ciliary action
through sinus ostia and into the nasal cavity.
• Mucus remain sterile, despite the proximity to
bacteria filled nasal passages
3 physiological disturbances that lead
to infective sinusitis:
• Obstruction of the ostia
• Impaired clearance of mucus due to ciliary
dysfunction
• Immunological disturbance
• Immunoglobulin deficiency (IgG1-4)
• Cystic fibrosis
• Primary ciliary disorders
Primary ciliary diskinesia:
• Inherited in autosomal recessive fashion
• Numerous defects:
• Structural abnormalities in dynein arms, radial
spokes, microtubules.
• The cilia become dyskinetic and their
coordinated, propulsive action is diminished
• Thus, bacterial clearance is impaired
Clinical effects:
• Recurrent upper and lower respiratory tract
infections,such as sinusitis, otitis media,
bronchitis, pneumonia
• Long term: Bronchiectasis
• Impaired motility of sperm: Infertility
• Situs inversus: Kartagener`s