cough Flashcards
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
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.
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)
- Understand the function of cough.
Function: defends body by clearing pathogens
phases of efferent pathway of cough
- 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
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
Complications of impaired cough
Aspiration of oropharyngeal or stomach contents (bacteria, food, other), Acute airway obstruction, Pneumonia, lung abscess, ARDS, bronchiectasis, pulmonary fibrosis
- 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
Life threatening causes of acute cough
Congestive heart failure, Pneumonia, Asthma Exac., COPD Exac., Pulmonary Embolism
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
Cuases of subacute cough
Post-infectious (pneumonia, pertussis, bronchitis, new onset/ exacerbation of asthma, GERD) or non posinfectious
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
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
Treatment of upper airway cough syndrome
1st generation anti-histamine/decongestant combination medication for 2 weeks
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
Asthma therapy
inhaled corticosteroid + bronchodilator for >8weeks
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
GERD symptoms and diagnostic tests
symptoms: heartburn, sour taste in mouth, cough. Tests: 24 hr esophageal pH probe (best) or esophagram
GERD therapy
Proton pump inhibitor
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
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
Treatment of NAEB
•inhaled corticosteroid for ≥ 4 weeks
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
Neuropathic cough diagnosis and treatment
Diagnosis: exclusion of other causes of chronic cough. Treatment: manage underlying irritants, amitryptyline or gabapentin
