cough

Question 1

Neural pathways for cough

Answer 1

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

Question 2

Types of cough receptors and stimuli

Answer 2

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.

Question 3

Remodeling and cough

Answer 3

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

Question 4

1. Understand the function of cough.

Answer 4

Function: defends body by clearing pathogens

Question 5

phases of efferent pathway of cough

Answer 5

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

Question 6

Conditions associated with impaired cough

Answer 6

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

Question 7

Complications of impaired cough

Answer 7

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

Question 8

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

Answer 8

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

Question 9

Life threatening causes of acute cough

Answer 9

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

Question 10

non life threatening causes of acute cough

Answer 10

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

Question 11

Cuases of subacute cough

Answer 11

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

Question 12

Top causes of chronic cough in immunocompetent patient with normal CXR

Answer 12

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

Question 13

Upper airway cough syndrome mechanism and symptoms and signs

Answer 13

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

Question 14

Treatment of upper airway cough syndrome

Answer 14

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

Question 15

Asthma mechanism and symptoms/signs

Answer 15

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

Question 16

Asthma therapy

Answer 16

inhaled corticosteroid + bronchodilator for >8weeks

Question 17

Mechanism of GERD related cough

Answer 17

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

Question 18

GERD symptoms and diagnostic tests

Answer 18

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

Question 19

GERD therapy

Answer 19

Proton pump inhibitor

Question 20

Non-asthmatic eosinophilic bronchitis (NAEB) mechanism

Answer 20

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

Question 21

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

Answer 21

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

Question 22

Treatment of NAEB

Answer 22

•inhaled corticosteroid for ≥ 4 weeks

Question 23

Neuropathic cough mechanism, symptoms

Answer 23

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

Question 24

Neuropathic cough diagnosis and treatment

Answer 24

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

Question 25

Which drug is known to cause cough

Answer 25

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

Question 26

Algorithm for chronic cough

Answer 26

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

Question 27

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

Answer 27

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