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