2. Cough is an explosive
expiration that provides a
normal protective
mechanism for clearing
the tracheobronchial tree
of secretions and foreign
material.
DEFINITION
3. The bronchi and trachea
are so sensitive to light
touch that excessive
amounts of foreign
matter or other causes of
irritation initiates the
cough reflex.
4. Coughing may be initiated
either voluntarily or
reflexively
As a defensive reflex it has
both afferent and efferent
pathways
5. The afferent limb includes receptors
within the sensory distribution of the
trigeminal, glossopharyngeal,
superior laryngeal, and vagus nerves.
The efferent limb includes the
recurrent laryngeal nerve and the
spinal nerves.
6. COUGH RECEPTORS RECIDES IN
PHARYNX, PARANASAL SINUSES,
STOMACH AND EXTRA-AUDITORY
CANAL
CAUSE OF COUGH MAY BE
EXTRAPULMONARY.
7. Mechanism
About 2.5L of air is
inspired
Epiglottis closes,
vocal cords shut
tightly to entrap the
air within the lung
8. Abdominal muscles contract
forcefully, pushing against
the diaphragm
Internal intercosatal muscles also
contract forcefully
Pressure in the lungs rises to
100mmHg or more. Markedly
positive intrathoracic pressure
causes narrowing of the trachea.
9. Vocal cords and epiglottis
suddenly open widely .
The large pressure differential
between the airways and the
atmosphere coupled with tracheal
narrowing produces rapid flow
rates through the trachea.
Air is expelled at velocities ranging
from 75 to 100 miles/hr.
10. The shearing forces that develop aid in the
elimination of mucus and foreign materials
Cough is therefore PROTECTIVE
11.
12. MECHANISM OF COUGH
• How Do We Cough_ - The Mechanism of
Coughing - Cough Reflex Animation - Learn
Human Body.mp4
16. D/D
• Onset- sudden onset after choking episode-
foreign body, recurrent- atopic type, chronic- TB,
bronchiectasis
• Productive- older children with early morning
severe expectoration- Bronchiectasis, non-
productive and only when awake- habitual
• Character- Barking- croup, spasmodic- atopic type
• Variation- nocturnal and early morning- atopic
type, lying down- GERD
21. CAUTION
• Pneumonia- involves parenchyma
• Cough receptors may not be involved in the
early stages
• Hence cough may be a late feature of lobar
pneumonia- Fever with tachypnea +/-
retractions is diagnostic of pneumonia
22. Productive cough: significant amount of sputum;
Blood- hemoptysis; smell- putrid smell- lung
abscess
Color of sputum- no bearing on the diagnosis
Large amounts:-
a)regular coughing up-bronchiectasis
b)Single occasion-lung abscess,empyema
c)Pink frothy-Pulmonary edema
27. 1.Diurnal variation
Cough which gets worse in night and
early morning :- Asthma
2.Postural variation
Bronchiectasis, Lung abscess
Lying down- postnasal drip, GERD,
cardiac cause- pulmonary congestion
3.Seasonal variation
Asthma, C/c bronchitis
28. Aggravating & Relieving factors
Cold,smoke,dust,exertion: asthma
Cough and choking on swallowing of
liquids: Neuromuscular disorders-
affects swallowing
Solids- Oesophageal motility problems
Otogenic cough: impacted wax or
foreign body in external auditory
meatus- subsides with removal of
cause
29. Associated symptoms
Fever: Pneumonia, lung abscess- clubbing also+
Chest pain: Pneumonia with pleuritis
Pleuritic chest pain: lateral part of chest with
associated splinting- increases on deep inspiration/
cough- Pleurisy, pleural effusion, bronchiectasis
Frequent hawking of throat, Nasal discharge, snoring,
tickling sensation in throat- Post nasal drip
Cough with associated dyspnea on exertion/
palpitations- Cardiac cause