nasal resistance and rhinosinusitis

Nasal resistance
The nose accounts up to half of the total airway resistance.
The resistance is made by two elements
A is essentially fixed made by bone,cartilage and attached muscle
B is variable made by mucosa
The nasal resistance is high in infants who initially are obligatory nasal breathers
Removal of nasal resistance by tracheostomy reduce the dead space but results in a degree of alveolar collapse
Factors decrease nasal resistance
Exercise
Sympathmymetic
Rebreathing
Atrophic rhinitis
Erect position
Factors increase nasal resistance
Infective rhinitis
Allergic rhinitis
Vasomotor rhinitis
Aspirin
Ingestion of alcohol
Cold air
Supine position
Hyperventilation
Sympthatic antagonists
Factors decrease nasal resistance
Exercise
Sympathmymetic
Rebreathing
Atrophic rhinitis
Erect position
Factors increase nasal resistance
Infective rhinitis
Allergic rhinitis
Vasomotor rhinitis
Aspirin
Ingestion of alcohol
Cold air
Supine position
Hyperventilation
Sympthatic antagonists
Factors that influence nasal resistance is nasal cycle
Nasal cycle
Demonstrated in over 80% of adults but it is more difficult to demonstrate in children.
The cycle consists of alternate nasal blockage between passages.
Cyclical changes occur between 4-12 hours;they are constant for each person
Various factors may modify the nasal cycle include
Allergy
Infection
Exercise
Hormones
Pregnancy
Fear
Emotiom
Autonomic nervous symptom vagal overactivity cause nasal obstruction
Drugs the anticholinergic effects of antihistamine can block the parasympthatic activity and produce an increase of sympthatic tone ,hence improve airway
Rhinosinusitis
Rhinitis is defined as inflammation of the lining of the nose,characterized by one or more of the following symptoms
1 Nasal congestion
2 Rhinorrhea
3 Sneezing and itching
The term sinusitis refers to a group of disorder charecterized by inflammation of the mucosa of paranasal sinuses.
Because the inflammation always also involve the nose ,it is now generally accepted that "Rhinosinusitis" is preferred term to desecribe the inflammation of the nose and paranasal sinusesThe ciliated mucosa of the nose and paranasal sinuses are contiguous and it would be rare for one to be affected without the other so the term rhinosinusitis always used
Differential diagnosis
Polyp
Mechanical factors
NSD
Hypertrophic turbinate
Obstruction OMC
F.B
Choanal atrasia
Tumours..Benign or malignant
Granuloma
CSF Rhinorrhea
Acute rhinosinusitis ARS is acute infection of sudden onset with duration of less than four weeks, 7 days to four weeks as viral rhinosinusitis follow viral URTI and mimic it`s symptoms so five to seven days was recommended perior to an acute bacterial rhinosinusitis.
Subacute rhinosinusitis SRS the duration is last for 4- 12 weeks
Recurrent acute infection RARS are defined by four or more episodes per year
Chronic rhinosinusitis CRS occur when the duration of symptoms is greater than 12 weeks
Acute exacerbation of chronic rhinisinusitis AECRS is is sudden worsening of CRS with return to baseline CRS
Signs and symptoms
Rhinosinusitis requires two major factors,or one major and two minor
Major symptoms
1Facial pain\ pressure
2Facial congestion/fullness
3Nasal obstruction
4Nasal discharge/purulent/posterior drainage
5Hyposmia/Anosmia
6Purulence on nasal examination
7Fever (acute rhinosinusitis only)
Minor symptoms
1Headache
2Fever (non acute)
3Halitosis
4Fatigue
5Dental pain
6Cough
7Ear pain/pressure/fullness
Microbiology of acute bacterial rhinosinusitis
Streptococcus pneumoniae 20-43%
Haemophilus influenzae 22-35%
Strep species
Anaerobes
Moraxella catarrhlis
Staphylococcus aureas
Predisposing factors
Either
Local or general
? mucosal obstruction ,deviation,polyp
? obstruction of the sinus ostea by allergic rhinitis
? neighbouring infection especially in children
General factors
?immunedifficiancy
?mucocilliary disorder
? allergy
Treatment
Medical
1 treatment of infection
Systemic penicilline always effective
If not do culture and sensitivity
2 treatment of pain
Asprin or codien
3 establishment of drainage of sinus
Either local like ephedrine and normal saline or systemic by pseudoephedrine and antihistamine.
Always be aware of Rebound phenomenon on using common nasal decongestant!!
Surgical operations for chronic sinusitis
? maxillary sinuses
?antral washout
??intranasal antrostomy
?Middle meatus antrostomy (endoscopic)
?Inferior meatus antrostomy
?Caldwell-Luc operation
Frontoethmoidospheno ?
?Trephenation of frontal sinuses
??Intranasal ethmoidectomy
???FESS Functional endoscopic sinus surgery
????Transnasal ethmoidectomy
?????external frontoethmoidosphenoidectomy
Atopy is a tendency to develop an exaggerated IgE antibody response
Allergy is the clinical presentation of atopic disease in the presence of allergen
Aetiology
Genetic and family history
Environmental factors like exposure to allergen ,air pollution and irritant, occupational allergen like flour, wood dust, latex in surgical gloves,tobacco,detergents and bleach.
Food occasionally provoke IgE allergic rhinitis, it may be due to sensitivity to preservatives, some type of food contain histamine like cheese and wine
Drugs like penicilline, asprin, antihypertensive, B-blocker, ACE inhibitor
The allergic responses can be divided into two phases. The first is an acute response that occurs immediately after exposure to an allergen. This phase can either subside or progress into a "late phase reaction" which can substantially prolong the symptoms of a response, and result in tissue damage
Pathogenesis
IgE has a property of binding to high affinity receptor on the mast cell and basophil .the interaction of allergen with IgE initiate secretion of active mediators that cause clinical manifestation,thes mediators either preformed mediators (histamine, proteases, chemokines, heparine); or newly formed mediators (prostaglandins, leukotrienes, thromboxanes)