Seminar

1. - Dr Sujay Iyer
General Medicine
Postgraduate student

2.  Introduction
 Mechanism
 Cough Reflex
 Classification
 Dry Cough
 Epidemiology
 Etiology
 Management Algorithm
 Treatment
 Complications

3.  Cough is an explosive expiration that
provides a normal protective mechanism for
clearing the tracheobronchial tree of
secretions and foreign material.
 It is one of the most common symptoms for
which patients seek medical attention

4.  Coughing may be initiated either voluntarily
or reflexively.
 It is a protective reflex serving a normal
physiologic function of clearing excessive
secretions and debris from the pulmonary
tract.
 The Cough Reflex has three components:
- Afferent Limb
- Efferent Limb
- Central Processing Center

5.  Afferent Limb consists of the Vagus,
Glossopharyngeal and Trigeminal nerves that
supply pathways for cough receptors.
 The Vagus Nerve, through its Pharyngeal,
Superior Laryngeal and Pulmonary branches
supply majority of the receptors.

6.  Three types of Cough receptors are
predominant:
- RARS (Rapidly Adapting Receptors)
- SARS (Slowly Adapting Stretch Receptors)
- C- Fibers
 Receptors are located throughout the airway
with greatest concentration in Larynx, Carina
and bifurcation of larger bronchi.

7.  The Afferent impulses are transmitted to the
Cough Center located in the Nucleus Tractus
Solitarius in the Medulla Oblongata of the
Brainstem which in itself is connected to the
Central Respiratory Generator.

8.  Efferents leave the Medulla and travel to the
Larynx and the Tracheobronchial tree via the
Vagus nerve while the Phrenic nerve and
Spinal Motor nerves of C3 to S2 supply
intercostal muscles, abdominal wall,
diaphragm and pelvic floor.
 Cough Reflex is considered neuroplastic.

10.  Inspiratory Phase: Deep inspiration
 Compression Phase: Closure of Glottis in
combination with contraction of muscles of
chest wall and diaphragm resulting in
increased intrathoracic pressure.
 Expiratory Phase: Opening of the Glottis
resulting in high expiratory flow.

11.  ACUTE (Less than 3 weeks)
 SUBACUTE (3 to 8 weeks)
 CHRONIC (More than 8 weeks)
Cough is also classified as
- Productive cough
- Non-productive (Dry Cough)
Our focus today is primarily going to be on Dry
Cough.

12.  Any cough that does not produce
expectoration is termed as dry cough.
 Usually, dry cough is chronic.
 Up to 46% of patients with dry cough have
unexplained etiology.
 Patient presents with either cough as the only
symptom or in collaboration with other
symptoms.

13.  According to one study (ERJ; WJ Song), dry
cough affects 9.6% of the world population.
 Another study tells us that dry cough affects
11 to 20% of the population (NEJM; RS Irwin).
 The symptomatic burden of cough has been
found to be reduced in India, 5%; although
this needs to be further evaluated with
greater in-depth study.
 Supposed to affect Females more than Males.

14. RESPIRATORY NON-RESPIRATORY
Upper Airway Cough Syndrome Gastroesophageal Reflux Disease
Cough Variant Asthma ACE Inhibitor induced
Nonasthmatic Eosinophilic Bronchitis Psychogenic
Mediastinal Tumors Idiopathic
Pleural Disease Smoking
Early Interstital Fibrosis
Postinfectious induced
UACS, Asthma and GERD account for majority of the
causes.
Recent research has brought up the term of Cough
Hypersensitivity Syndrome.

16.  Myriad of rhinosinus conditions that include:
- Postnasal Drip Syndrome
- Acute Bacterial Sinusitis
- Allergic Fungal Sinusitis
- Allergic Rhinitis
- Nonallergic Rhinitis
 Considered most common cause (87%)
 Mechanical stimulation of cough receptors in
the hypopharynx and larynx either directly or
indirectly through inflammatory mediators is
the mechanism.

17.  Hallmarks of Asthma are variable airflow
obstruction and airway hyperresponsiveness,
which manifest as wheezing, dyspena and
cough.
 Cough occurs in al Asthmatics, and in a
subset of patients with Cough-variant
Asthma (CVA), it is the only presenting
symptom.

18.  Cough may be the sole clinical manifestation
of GERD.
 Two mechanisms have been postulated for
GERD-associated cough:
- Distal esophageal acid exposure that
stimulates cough reflex via Vagus nerve.
- Microaspiration of esophageal contents.
 Laryngopharyngeal Reflux or Extraesophageal
GERD does not manifest as traditional
heartburn and tends to occur when patient is
upright.

19.  It is characterized by eosinophilic inflitration
of the bronchial tree as well as the absence of
variable airflow obstruction and airway
hyperresponsiveness.
 Differs from Asthma in the localization of
mast cells within the airway wall. Airway
smooth muscle infiltration occurs in Asthma
and epithelial infiltration in NAEB.

20.  ACE Inhibitors
 Smoking
 Respiratory Causes: Usually present with
complaints including dyspnea, wheezing and
have significant radiographic findings.

22.  Use of antitussives such as Codeine (opioid),
Dextromethorphan (non-opioid),
Levodropropizine (peripheral) is debatable as
they have been shown to have limited or no
efficacy in treatment of dry cough.
 Use of Benzonatate may be helpful.
 Treatment with newer experimental options
such as Gabapentin and Amitriptyline is still
under debate.
 Cessation of smoking and use of ACE
Inhibitors in patients.

23.  Avoiding environmental irritants and
offending antigens, treating sinusitis with
antibiotics, and weaning patients off nasal
decongestants for rhinitis. Allergy testing for
allergic rhinitis.
 Empiric therapy should be instituted with a
combination of antihistamine and
decongestants.
 First generation antihistamines are more
effective than newer less-sedating ones.

24.  After undergoing spirometry and
bronchoprovocation challenge, patients
should be started on Beta-2 Agonists and
Inhaled Corticosteroids.
 Leukotriene Inhibitors and Oral
Corticosteroids may also be instituted.

25.  Inhaled Corticosteroids
 Oral Corticosteroids for refractory cases.

26.  Lifestyle modifications including limiting fat
intake, avoiding caffeine, chocolate, mints,
citrus products, alcohol and smoking.
 Acid suppressive medications like Histamine
2 Blockers and Proton Pump Inhibitors.

28.  Harrison’s Principles of Internal Medicine
 Crofton and Douglas’s Respiratory Diseases
 Physical Diagnosis - Vakil and Golwalla
 Manual of Practical Medicine – R Alagappan
 Supplement to Journal of the Association of
Physicians of India
 www.medscape.com
 www.ncbi.nlm.nih.gov

29. Thank You!