Pathophysiology- Scharf

Question 1

Treatment for dyspnea

Answer 1

Treat underlying disorder
Decrease respiratory drive
(opiates, benzodiazepines
Trigeminal stimulation (Nasal O2, cold air on face)
vagal block
chest vibration)
Change central perception/affect/associations
(anti depressant/anxiolytic
Opiates
Exercise training)

Question 2

What are the afferent inputs for coughing?

Answer 2

All vagal: Ear canal, pharynx, larynx, tracheobroncial tree (to resp bronchioles)

Receptors: most sensitive in larynx and TB tree

polymodal - respond to a number of types of stimuli
RAR - irritant, no RARs no cough (mouse) - epithelial, C-fibers (TB tree)
RARs in alveolar walls (J receptors) - dyspnea not cough
SAR’s (Herring Breuer) - enhance cough

Question 3

What chemical mediators stimulate RARs (Rapid Adapting Receptors)?

Answer 3

Bradykinin
kinins
hypo/hypertonic saline
SO2
Acid, etc

Sensory:
congestion
atelectasis
bronchoconstriction

Question 4

What is the pathway from RARs to the cough?

Answer 4

RARs–>Cough center in medulla–> Vagus -> NTS -> vent resp group to larynx, bronchi and resp. muscles motor response (inspiratory, compressive, expulsive)

Question 5

Phases of cough meechanics

Answer 5

1. Inspiratory phase (less larynx, more TB stimulation: increase lung volume, elastic recoil, better mechanical advantage of expiratory muscles
2. Expiratory com[ressive phase (200ms): close glottis, increase Ppl -> 300 mm Hg. Needs expiratory muscles, exp. Intercostals, abdominals
3. Expiratory expulsive phase: 28000 cm/s: removes secretions

Question 6

What is the most common cause of chronic cough?

Answer 6

Chronic sinusitis

Question 7

Tietze’s syndrome

Answer 7

Swelling/redness over CC junctions, dull achy pain often confused for MI pain. Caused by costochondritis.