Chronic cough

Chronic refractory cough is defined as a persistent cough of more than 8 week duration despite assessment and treatment in specialist clinics – diagnosis would be established by secondary care. This is a diagnosis of exclusion Also known as – Chronic idiopathic cough , Unexplained chronic cough There is no identifiable cause.
Acute cough-less than 3 weeks duration. common causes include Lung cancer Upper respiratory tract infection –> most common cause Acute bronchitis and Pneumonia Asthma COPD acute exacerbation Pertusis ( whooping cough ) Acute exacerbation of bronchiectasis.
Also consider Suspected PE or pneumothorax Serious illness suspected
○ RR > 30 /min
○ tachycardia > 130
○ systolic BP < 90 or diastolic < 60 (unless this is normal for them )
○ saturation < 92 % or central cyanosis
○ peak expiratory flow < 33 % predicted
○ altered level of consciousness
○ resp distress –> use of accessory muscles Foreign body aspiration 

Subacute cough is 3-8 weeks duration. Most commonly caused by airway hyper-responsiveness following specific infections ( including M.pneumoniae ) Ongoing infections. Also consider Lung cancer Pulmonary tuberculosis Post- infectious cough
○ adv that cough may persist for several months
○ re-attend for assessment if cough does not improve after 2 months Bronchiectasis and Pneumonia Asthma Pertusis
Chronic cough > 8 weeks duration consider Lung cancer Pulmonary TB Smoking related cough –> adv to quit smoking ACE inhibitor- induced cough 
○ stop ACE and prescribe an alernative
○ most cases cough resolves within 1 months but ocassionally may persist for several months Upper airway cough syndrome – post nasal drip
○ prescribe nasal corticosteroid and review after 2-8 weeks Asthma
○ ICS and review after 6-8 weeks Gastro-oesophageal reflux disease
○ Prescribe PPI and review after 6-8 weeks Cough -variant asthma and eosinophilic bronchitis
○ manage with inhaled ICS
○ as per current BTS asthma guidelines Chronic obstructive lung disease ( COPD )
○ refer to COPD management Pertusis Heart failure Bronchiectasis Interstitial lung disease
○ spirometry
○ CXR
○ if based on above ILD suspected–> refer chest clinic.
Chronic refractory cough clinical features –Dry cough that occurs in intermittent bouts throughout the day Often originates from laryngeal region Triggers often include
○ non tussive stimuli such as air conditioners and phonation
○ low doses of tussive stimuli
○ laryngeal discomfort and paraesthesia Cough can persist for months or yrs ↑ common in women Often happens following an episode of viral infection Laryngeal symptoms in addition to cough
○ dysphonia
○ talking is a common trigger
○ laryngeal hypersensitivity and cough reflex hypersensitivity.
CRC pathophysiology – Cough reflex hypersensitivity – underlying sensory neuropathy
○ key feature of CRC
○ involves both peripheral and central sensitizations of the cough reflex
○ inflammatory neuropathic changes in sensory nerves ie possible sensorry nerve damage caused by inflammatory , infective and allergic factors
 Peripheral sensitization- occurs in areas with sensation mediated by the vagus nerve -such as
○ larynx
○ esophagus
○ pharynx
○ nasal cavity
○ bronchi

Reduced threshold for cough
 Central sensitization ↑ excitabiity in central sensory pathways
 Paradoxical vocal fold movement
○ abnormal laryngeal motor pattern with adduction of the vocal folds during inspiration after a stimulus
○ symptoms –> dyspnea , stridor & throat tightness.
red flags – Haemoptysis Smoker with > 20 pack yrs smoking hx Smoker > 45 yrs with 
○ new cough
○ altered cough
○ cough with voice disturbance Prominent dyspnea –> especially at night Substantial sputum production > than 1 tablespoon/ day Hoarseness Systemic symptoms –> fever , weight loss Complicated GORD symptoms
○ weight loss
○ anaemia
○ GI bleeding – hematemesis and melena
○ severe symptoms
○ dysphagia
○ odynophagia
○ failure of emperic treatment for GORD Recurrent pneumonia Abnormal clinical respiratory examination Abnormal CXR.
Management principles – Non- pharmacological therapies
○ speech pathology intervention
○ physiotherapy
 Pharmacological therapy
○ Neuromodulators -
 ♦ gabapentin , pregabalin
 ♦ morphine
 ♦ amitriptyline
 ♦ baclofen
 Inhaled corticosteroids
○ effective in eosinophilic airway inflammation
○ requires measurement of 
 ♦ eosinophils from induced sputum or bronchioalveolar lavage
 ♦ exhaled nitric oxide
 Combined pharmacological and non-pharmacological therapy
 Other treatments
○ High dose esomeprazole for GORD
○ Use of Ipratropium bromide has been investigated in CRC.
Patient education – ○ cough can be triggered by irritation
○ cough is not always necessary
○ cough has limited physiological benefit
○ cough is under automati voluntary control Symptom control techniques
○ cough suppression swallow
○ cough control breathing
○ paradoxical vocal fols movement release breathing
○ release of laryngeal constriction Reducing laryngeal irritation
○ behavioural management of reflux
○ reduce phanotraumatic behaviors
○ hydration
○ minimize exposure ti irritating substances Psychoeducational counseling




LINKS AND RESOURCES

PATIENT INFORMATION
American Thoracic Society PIL on cough https://www.thoracic.org/patients/patient-resources/resources/cough.pdf
Patient education chronic cough from Isle of Wight NHS Trust https://www.iow.nhs.uk/Downloads/Patient%20Information%20Leaflets/chronic_cough_help_v1.pdf
A very education focussed information leaflet from European Lung Foundation https://www.europeanlung.org/assets/files/factsheets/chronic_cough_en.pdf
INFORMATION FOR CLINICIANS
Patient Info on chronic cough https://patient.info/doctor/chronic-persistent-cough-in-adults-pro
Treatment of Unexplained Chronic Cough from Chest Journal – open access https://journal.chestnet.org/article/S0012-3692(15)00038-0/fulltext
AAFP Chronic cough evaluation and management –https://www.aafp.org/afp/2017/1101/p575.html
 
References– 


1. Management of chronic refractory cough BMJ 2015;351:h5590
2. Chronic cough in adults BMJ 2009;338:b1218
3. Treatment of Unexplained Chronic Cough Chest ,2016-01-01 , Volume 149, Issue 1, Pages 27-44
4. American College of Chest Physicians Treatment of unexplained chronic cough : CHEST guideline and Expert Panel report.Chest 2016 Jan;149(1) 27-44
5. PubMed Unexplained chronic cough in adults- Approach to the patient with Chronic Cough Middleton’s Allergy , Principles and Practice January 2016
6. Diagnosis and Investigations of Chronic Cough Murray and Nadel’s textbook of Respiratory Medicine Jan 2016
7. Cough- CKS NHS June 2015
8. Refractory Chronic Cough : New Perspectives in Diagnosis and Treatments Arch Bronconeumol 2013;49:151-7-Vol.49 Num.4 DOl:10.1016/j.arbr.20113.02.002
9. The Problem of Treating Unexplained Chronic Cough Chest 2016 ;149(3):613-614. doi:10.1016/j.chest.2015.12.008
10. Approach to chronic cough : neuropathic basis for cough hypersensitivity syndrome Vol 6, Supplement 7 
( October 2014 ) : Journal of Thoracic Disease ( Chronic Cough )
11. Recommendations for the management of cough in adults- BTS guideline