cough Flashcards
2 mechanisms of cough?
central and peripheral
what is central cough mechanism?
cough centre in medulla receives stimuli and initiates reflex
what is the peripheral mechanism?
cough receptors in pharynx/trachea/lungs are stimulated by air or dryness
3 predominant types of cough receptors?
- rapidly adapting receptors RARs
- slowly adapting receptors SARs
- nociceptors on c-fibres
what are exogenous sources of cough?
smoke or dust
what are endogenous sources of cough?
upper airway secretions, gastric contents
what is a productive cough?
wet cough
secretions are expectorated
what is a non-productive cough?
dry cough
no sputum
what is classified as an acute cough?
< 3 weeks
most often due to upper resp infection
what is classified as a sub acute cough?
3-8 weeks
post-infectious, persistent inflammation
what is classified as a chronic cough?
> 8 weeks
raises possibility of copd/asthma/cancer
summary of mechanism of coughing?
1) stimulation of mechano/chemoreceptors
2) afferent impulses to cough centre
3) efferent impulses to diaphragm, intercostal muscles and lung via parasympathetic and motor nerves
4) increased contraction of muscles cause cough
what are anti-tussive medicines?
cough suppressants
Example of narcotic suppressant?
codeine/ hydrocodone - centrally acting
need a Rx
example of non-narcotic cough suppressant?
dextromethorphan - centrally acting
OTC, acts on brain so no pain relief
examples of peripherally acting anti-tussives?
lidocaine/ antihistamines
example of locally acting antitussive?
throat lozenge
what do expectorants do? example
liquify secretions for removal by cough
guaifenesin - not recommended by many authorities
what do mucolytics do? examples
break down mucus to help cough up
sodium chloride and acetylcysteine
examples of topical treatment options?
menthol/camphor
anaesthetic action of vapour
what is cough variant asthma?
asthma with only a dry cough as a symptom
signs of cough variant asthma?
coughing nocturnally or after exercise
