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Flashcards in cough Deck (27):
1

Neural pathways for cough

Cough receptors located in upper airway, tracheobronchial tree, and lower esophagus are stimulated > stimulates afferent Vagus and superior laryngeal nerves > signals cough center in brainstem > efferent pathways > contraction of intercostal muscles, larynx, and diaphragm to produce cough

2

Types of cough receptors and stimuli

rapidly adapting receptors (RARS), C-fibers, and slowly adapting receptors (SARS). RARS and SARS are sensitive to mechanical stimuli (bronchial obstruction, lung inflation), while C-fibers are highly sensitive to noxious chemical stimuli.

3

Remodeling and cough

Subbasement membrane thickening, goblet cell hyperplasia and more blood vessel growth occurs with chronic cough (ie. Due to GERD or chronic rhinitis)

4

1. Understand the function of cough.

Function: defends body by clearing pathogens

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phases of efferent pathway of cough

1. Inspiratory Phase: inhalation ends before closure of the glottis. 2. Compressive Phase: thoracic and abdominal muscles contract against a fixed diaphragm (modified Valsalva maneuver); intrathoracic pressure increases (≤ 300 mm Hg) 3. Expiratory Phase: glottis opens; air is rapidly (≤ 500 miles/hr!) expelled 4. Relaxation Phase: chest wall and abdominal muscles relax

6

Conditions associated with impaired cough

Altered sensorium- anesthesia, narcotics, sedatives, alcohol, coma, stroke, seizure and SLEEP, Laryngeal/ upper airway disorders, Tracheostomy tube
Restrictive and obstructive lung diseases, Neuromuscular diseases, Supine in hospital bedAltered sensorium- anesthesia, narcotics, sedatives, alcohol, coma, stroke, seizure and SLEEP, Laryngeal/ upper airway disorders, Tracheostomy tube
Restrictive and obstructive lung diseases, Neuromuscular diseases, Supine in hospital bed

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Complications of impaired cough

Aspiration of oropharyngeal or stomach contents (bacteria, food, other), Acute airway obstruction, Pneumonia, lung abscess, ARDS, bronchiectasis, pulmonary fibrosis

8

2. Be able to classify cough according to its duration (acute, subacute, chronic).

Acute: 15 yrs. Is it infectious, does it need Abx? Subacute: 3-8 weeks, is it post infectious, does it need Abx? Chronic: >8weeks

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Life threatening causes of acute cough

Congestive heart failure, Pneumonia, Asthma Exac., COPD Exac., Pulmonary Embolism

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non life threatening causes of acute cough

URI, lower respiratory infection, exacerbation of pre-existing condtion (ie. COPD, asthma, bronchiectasis, upper airway cough syndrome), environmental exposure

11

Cuases of subacute cough

Post-infectious (pneumonia, pertussis, bronchitis, new onset/ exacerbation of asthma, GERD) or non posinfectious

12

Top causes of chronic cough in immunocompetent patient with normal CXR

Upper airway cough syndrome, Asthma, Gastroesophageal reflux disease, Non-asthmatic eosinophilic bronchitis, Neuropathic cough

13

Upper airway cough syndrome mechanism and symptoms and signs

Post nasal drip syndrome. Mechanism: secretions from nose/sinuses stimulate upper airway cough receptors; inflammation increases receptor sensitivity. Classic symptoms: “tickle” in throat; throat clearing, hoarseness, nasal congestion. Signs: : inflamed nasal mucosa, secretions in posterior oropharynx

14

Treatment of upper airway cough syndrome

1st generation anti-histamine/decongestant combination medication for 2 weeks

15

Asthma mechanism and symptoms/signs

•Mechanism: inflammatory mediators, mucus, bronchoconstriction stimulate cough receptors. Classic symptoms: intermittent wheeze. Cough may be the only symptom. Signs: expiratory wheezing on chest exam

16

Asthma therapy

inhaled corticosteroid + bronchodilator for >8weeks

17

Mechanism of GERD related cough

stimulation of the afferent limb of the cough reflex by 1) irritation of the upper respiratory tract (e.g., the larynx); 2) irritation of the lower respiratory tract by aspiration of large or small amounts of gastric contents; or 3) an esophageal-bronchial cough reflex, in which refluxate in the distal esophagus alone triggers cough. Cough can increase GERD, resulting in a vicious cycle

18

GERD symptoms and diagnostic tests

symptoms: heartburn, sour taste in mouth, cough. Tests: 24 hr esophageal pH probe (best) or esophagram

19

GERD therapy

Proton pump inhibitor

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Non-asthmatic eosinophilic bronchitis (NAEB) mechanism

•Eosinophilic airway inflammation WITHOUT variable airflow obstruction or airway hyperresponsiveness. May develop from environmental exposures. Stimulation of lower airway cough receptors by inflammatory mediators

21

Non-asthmatic eosinophilic bronchitis (NAEB) symptoms and diagnostic tests

Symptoms: cough without wheezing or dyspnea (indistinguishable from cough-variant asthma). Tests: Spirometry: normal; Methacholine challenge: normal; Induced sputum: >3% eosinophils

22

Treatment of NAEB

•inhaled corticosteroid for ≥ 4 weeks

23

Neuropathic cough mechanism, symptoms

Cough triggered by low-level stimuli such as change in ambient temp, taking a deep breath, laughing. Cuased by neural injury from viral infection, chronic inflammation, environmental pollutants. Symptoms: need to clear throat, globus sensation, tickle in throat

24

Neuropathic cough diagnosis and treatment

Diagnosis: exclusion of other causes of chronic cough. Treatment: manage underlying irritants, amitryptyline or gabapentin

25

Which drug is known to cause cough

ACE-I. -prils. Begins 1 week to 6 mnths after starting drugs and usually resolves 1-7 days after stopping

26

Algorithm for chronic cough

history > exam > CXR . If no diagnosis is found, emperic treatment is started for upper airway cough syndrome, then asthma, etc.

27

6. Be aware of some important differences between chronic cough in children and adults.

Chronic cough in children (4 weeks. Most common cause is viral URI, but can be asthma, sinus disease, GERD, or chronic tobacco smoke