Cough:Defense Mechanism and

Symptom

Karen A. Fagan, MDAssociate Professor of Medicine

Chief of Pulmonary and Critical Care MedicineJohn and Alice Chair of Pulmonary Medicine

University of South Alabama

Disclosure

• No financial relationships relevant to this presentation or content

• Any off label use of medications will be identified during the lecture

Objectives

• Understand the function and physiological mechanisms of cough.

• Classify cough according to its duration.

• Know the most common causes of acute cough in adults.

• Know the symptoms, signs, and empiric treatment for the 4 most common causes of chronic cough in adults.

Case Study- D.B.47 y/o Caucasian woman, accountant, c/o cough for

3 years. 30 pack-year smoking history, quit in 2001. Traveled to China to adopt baby girl in 2002, caught “bad chest cold”. Recovered, but had “bronchitis” (phlegm, cough) ≥ 8 times/year thereafter. Episodes of “bronchitis” start suddenly, with a sore throat. Antibiotics and prednisone reduce symptoms, but incompletely. Coughs day and night. Told “you’re just getting a lot of colds from your daughter”. Frustrated. Worried about “weird infection.” Demoted at work because of days missed due to illness.

Case Study- D.B.

• Review of Systems:+ Mildly hoarse

+ Several sinus infections since 2002

- Heartburn, regurgitation

- Cardiac disease

- Neuromuscular disease

• Physical Exam:Normal vital signs

Looks depressed

Otherwise, normal

Cough is #1

• The #1 chief complaint in primary care physicians’ offices is cough

• Most-- but not all-- cough seen by PCP’s is acute cough related to viral upper and lower respiratory tract infections

• Chronic cough is one of the most common reasons for consultation with a pulmonologist

• Health care costs for cough exceed several billion dollars annually

Cough: What’s it good for?

• Attract attention

• Signal displeasure

• Protect the airway from pathogens, particulates, food, other foreign bodies

• Clear the airways of accumulated secretions, particles

Cough: Public Health Concern

Cough Reflex: Afferent Pathway• Vagus nerve is major

afferent pathway

• Stimuli arise from:– Ear– Pharynx– Larynx– Lungs– Tracheobronchial tree– Heart– Pericardium– Esophagus

Cough Reflex: Afferent Pathway

Mechanical stimuli:– Rapidly adapting receptors

(RARs)– Slowly adapting stretch

receptors (SARs)

Chemical stimuli:–C-fibers

Efferent Pathway: 4 Phases

1. Inspiratory Phase

2. Compressive Phase

3. Expiratory Phase

4. Relaxation Phase

Impaired Cough: Who’s at risk?• Interruption of afferent and/or efferent pathways of

cough reflex impairs cough• Altered sensorium- anesthesia, narcotics,

sedatives, alcohol, coma, stroke, seizure, SLEEP• Laryngeal/ upper airway disorders• Tracheostomy tube• Restrictive and obstructive lung diseases• Neuromuscular diseases• Supine in hospital bed

Impaired Cough: Consequences• Aspiration of oropharyngeal

or stomach contents (bacteria, food, other)

• Acute airway obstruction• Pneumonia

• Lung abscess• Respiratory failure/ ARDS• Bronchiectasis• Pulmonary fibrosis

Complications of Cough

Complications of Cough

• Result primarily from marked increase in intrathoracic pressure (> 300 mmHg) during cough

• Affect nearly every other organ system

• See Table 1 (handout) for PARTIAL list

• Disruption of surgical wounds

• Negative impact on quality of life, particularly in chronic cough

Complications of Cough

• Scares away big game!

www.biggameproshop.com

“The Silencer is a real hunt saver for:

Spontaneous morning coughsColdFlu and Allergy sufferersAsthma suffersThose on high blood pressure

medications

Excellent for Smoker's cough”

American College of Physicians 2006 Cough Guidelines

• Evidence-based• Includes guidelines for

pediatric cough• Should be used in

conjunction with “clinical judgment”

• Divides cough in adults by duration: acute, subacute, chronic

Acute Cough in Adults

Key questions:1. Is it life-threatening?2. Are antibiotics needed?

Cough lasting less than 3 weeks

Acute Cough

Life-threatening Dx Non-life-threatening DxHistory,

Examination, Investigations

Pneumonia, severe exacerbation of asthma or COPD, PE, Heart Failure, other serious disease

Infectious Exacerbation of pre-existing condition

Environmental or Occupational

URTI LRTI Asthma Bronchiectasis UACS COPD

Figure 1: The acute cough algorithm for the management of patients aged ≥ 15years with cough lasting < 3 weeks. For diagnosis and treatment recommendationsrefer to the section indicated in the algorithm. PE = pulmonary embolism; Dx =diagnosis; Rx = treatment. For other abbreviations, see handout.

Acute Cough: Life-Threatening

• Congestive heart failure

• Pneumonia• Asthma Exac.• COPD Exac.• Pulmonary

Embolism• Other

Acute Cough: Non-Life-Threatening

• Upper respiratory tract infection (URTI or URI)-- “The Common Cold”– Caused by viruses, e.g. rhinoviruses– Nasal congestion, drainage– Post-nasal drainage irritates larynx– Inflammatory mediators increase sensitivity of

sensory afferents – Antibiotics are NOT indicated– Decongestants, cough suppressants of

questionable value

Acute Cough: Non-Life-Threatening

• Lower respiratory tract infection-- “Acute Bronchitis”– Cough, with or without phlegm – Most bronchitis in otherwise healthy adults is

caused by viruses (rhinovirus, adenovirus, RSV)– If it’s likely viral in origin, do not prescribe

antibiotics– Bacterial causes to consider:

• Mycoplasma pneumoniae, chlamydophila pneumoniae

• Bordetella pertussis (whooping cough)

– Make sure it’s not pneumonia

Acute Cough: Non-Life-Threatening

• Exacerbation of pre-existing condition– COPD: always consider bacterial infection– Asthma: try to identify the underlying cause

(exposure, viral URTI, viral LRTI, other)– Bronchiectasis: always consider bacterial infection

(gram negative rods, staph. aureus, organisms resistant to antibiotics)

– Upper airway cough syndrome (UACS)

• Environmental or occupational exposure: allergens, irritants

Subacute Cough in Adults

Key questions:

1. Is it post-infectious?

2. If post-infectious, are antibiotics needed?

Cough lasting 3-8 weeks

Subacute Cough

Post-infectious Non-postinfectiousHistory and

Physical Exam

Pertussis

Pneumonia and other serious diseases New onset or exacerbation of pre-

existing condition

Workup same as chronic cough

AECBNAEB

Asthma BronchitisUACS GERD

Figure 2: Subacute cough algorithm for the management of patients aged ≥ 15 yearswith cough lasting 3 to 8 weeks. For diagnosis and treatment recommendations referto section indicated in algorithm. AECB = acute exacerbation of chronic bronchitis.For other abbreviations, please see syllabus.

Bronchitis

Subacute Cough:

Pneumonia

Chronic Cough in Adults

• Cough lasting longer than 8 weeks• Top 4 in immunocompetent patient with normal

CXR: – Upper airway cough syndrome– Asthma– Gastroesophageal reflux disease– Non-asthmatic eosinophilic bronchitis

• Cough may have more than one cause-- a diagnostic challenge!

Upper Airway Cough Syndrome (UACS)

• Also called “Post-nasal drip syndrome” (PNDS)

• Mechanism: secretions from nose/sinuses stimulate upper airway cough receptors; inflammation increases receptor sensitivity

• Classic symptoms: “tickle” in throat; throat clearing, hoarseness, nasal congestion

• Cough may be the only symptom in ~ 20%

Upper Airway Cough Syndrome (UACS)

• Signs (may be absent): inflamed nasal mucosa, secretions in posterior oropharynx

• Consider underlying causes: allergies, chronic sinusitis, overuse of alpha-agonist nasal sprays

• Diagnostic/Therapeutic trial: 1st generation anti-histamine/decongestant combination medication for 2 weeks

Asthma

• Mechanism: inflammatory mediators, mucus, bronchoconstriction stimulate cough receptors

• Classic symptoms: intermittent wheeze• Cough may be the only symptom in 7-57%

patients (depends on study)-- “Cough-variant asthma”

• Signs (often absent): expiratory wheezing on chest exam

Asthma• Diagnostic tests:

– Spirometry, before and after bronchodilator: partially reversible airflow obstruction

– Methacholine inhalation challenge: positive •Diagnostic/

Therapeutic trial: inhaled corticosteroid + bronchodilator for≥ 8 weeks

Gastroesophageal Reflux Disease (GERD)

A Vicious Cycle

COUGH

REFLUX INCREASED ABDOMINAL PRESSURE

Gastroesophageal Reflux Disease (GERD)

• Classic symptoms: heartburn, sour taste in mouth

• Cough may be only symptom in 75% patients with chronic cough

• Diagnostic tests:– 24-hour esophageal pH

probe (best)– Esophagram

Gastroesophageal Reflux Disease (GERD)

• Diagnostic/Therapeutic trial: gastric acid suppression with proton pump inhibitor (e.g. omeprazole) for ≥ 2 months, combined with diet and lifestyle modification

Non-Asthmatic Eosinophilic Bronchitis (NAEB)

• Eosinophilic airway inflammation WITHOUT variable airflow obstruction or airway hyperresponsiveness

• Diagnostic tests:- Spirometry: normal- Methacholine challenge: - normal- Induced sputum: >3% eosinophils

• Diagnostic/Therapeutic trial: inhaled corticosteroid for ≥ 4 weeks

A) Prescribe a 1st generation antihistamine/decongestant

B) Prescribe an inhaled corticosteroid for asthmaC) Order an induced sputum to look for eosinophilsD) Order a chest x-rayE) All of the above

A 67 y/o man, life-long non-smoker, complains of 12 weeks of non-productive cough. He’s had a couple of “colds” this winter. He has no current nasal or sinus symptoms, rarely has heartburn, and never wheezes. He’s on no meds. Vitals and physical exam are normal. Your next step would be:

Case Study: C.F

All that coughs is not UACS, asthma, GERD, or NAEB!

ACE-inhibitor therapy

• Angiotensin converting enzyme (ACE) inhibitors (enalapril, captopril, lisinopril, ramipril, etc.)

• Dry cough in 3-30% patients

• Begins 1 week to 6 months after drug started

• Usually resolves 1-7 days after stopping therapy, but can take 4 weeks

Continued on next slide…

Chronic Cough, continued:

Bronchiectasis

Chronic Aspiration, Resulting in Bronchiectasis

Bronchiectasis in patient withCommon Variable Immunoglobulin Deficiency

Idiopathic Pulmonary Fibrosis

Subglottic Stenosis

Subglottic Stenosis

Case Study- D.B.47 y/o Caucasian woman, accountant, c/o cough for

3 years. 30 pack-year smoking history, quit in 2001. Traveled to China to adopt baby girl in 2002, caught “bad chest cold”. Recovered, but had “bronchitis” (phlegm, cough) ≥ 8 times/year thereafter. Episodes of “bronchitis” start suddenly, with a sore throat. Antibiotics and prednisone reduce symptoms, but incompletely. Coughs day and night. Told “you’re just getting a lot of colds from your daughter”. Frustrated. Worried about “weird infection.” Demoted at work because of days missed due to illness.

Case Study- D.B.

• Diagnostic Test Data:– PFTs: consistent with asthma– Methacholine challenge: positive – CXR / Chest CT: mild emphysema– Sinus CT: normal– pH probe: couldn’t place-- too much coughing– Esophagram: severe GERD– Laryngoscopy: interarytenoid erythema, c/w reflux– PPD: negative

Case Study- D.B.

• Diagnosis: Chronic cough related to asthma, early COPD, GERD

• Treatment: inhaled corticosteroid/bronchodilator, proton pump inhibitor

• Outcome: at 2 months, cough significantly better, no urgent visits to PCP for cough, no need for corticosteroids or antibiotics

Esther Langmack, MD“cough” specialist