Chronic cough: how do cough reflex sensitivity and subjective assessments correlate with objective cough counts during ambulatory monitoring?

Cough reflex hypersensitivity (CRH) and impaired cough suppression are features of chronic refractory cough (CRC). Little is known about cough suppression and CRH in cough associated with chronic obstructive pulmonary disease (COPD). This study investigated the ability of participants with COPD to suppress cough during a cough challenge test in comparison to participants with CRC and healthy subjects. This study also investigated whether CRH is associated with chronic cough in COPD.Participants with COPD (n=27), CRC (n=11), and healthy subjects (n=13) underwent capsaicin challenge test with and without attempts to self-suppress cough in a randomised order over 2 visits, 5 days apart. For participants with COPD, the presence of self-reported chronic cough was documented, and objective 24-h cough frequency was measured.Amongst participants with COPD, those with chronic cough (n=16) demonstrated heightened cough reflex sensitivity (CRS) compared to those without chronic cough (n=11); geometric mean (sd) capsaicin dose thresholds for 5 coughs (C5) 3.36 (6.88) versus 44.50 (5.90) µmol·L−1 respectively (p=0.003). Participants with CRC also had heightened CRS compared to healthy participants; geometric mean (sd) C5 3.86 (5.13) versus 45.89 (3.95) µmol·L−1 respectively (p<0.001). Participants with COPD were able to suppress capsaicin-evoked cough, regardless of the presence or absence of chronic cough; geometric mean (sd) capsaicin dose thresholds for 5 coughs without self-suppression attempts (C5) and with (CS5) were 3.36 (6.88) versus 12.80 (8.33) µmol·L−1 (p<0.001) and 44.50 (5.90) versus 183.2 (6.37) µmol·L−1 (p=0.006) respectively. This was also the case for healthy participants (C5 versus CS5: 45.89 (3.95) versus 254.40 (3.78) µmol·L−1, p=0.033), but not those with CRC, who were unable to suppress capsaicin-evoked cough (C5 versus CS5: 3.86 (5.13) versus 3.34 (5.04) µmol·L−1, p=0.922). C5 and CS5 were associated with objective 24-h cough frequency in participants with COPD; ρ=−0.430, p=0.036 and ρ=−0.420, p=0.041 respectively.Participants with COPD-chronic cough and CRC both have heightened cough reflex sensitivity but in contrast, only participants with CRC were unable to suppress capsaicin evoked cough. This suggests differing mechanisms of cough between participants with COPD and CRC, and the need for disease specific approaches to its management.

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P242 The order effect of experimental oesophageal acidification on cough reflex sensitivity in chronic cough patients and healthy volunteers: Abstract P242 Table 1

Thorax ◽

10.1136/thoraxjnl-2015-207770.378 ◽

2015 ◽

Vol 70 (Suppl 3) ◽

pp. A198.2-A199

Author(s):

D Valdramidou ◽

H Sumner ◽

E Hilton ◽

S Whiteside ◽

JA Smith

Keyword(s):

Healthy Volunteers ◽

Chronic Cough ◽

Order Effect ◽

Cough Reflex Sensitivity ◽

Cough Reflex

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Relationship Between Cough Reflex Sensitivity and Body Mass Index in Children With Chronic Cough – a Pilot Study

Physiological Research ◽

10.33549/physiolres.934596 ◽

2021 ◽

pp. S463-S470

Author(s):

R PECOVA ◽

J SOJAK ◽

P DURDIK ◽

T ZATKO ◽

E OMAR MOHAMEDOVA ◽

...

Keyword(s):

Body Mass Index ◽

Pilot Study ◽

Body Mass ◽

Chronic Cough ◽

P Value ◽

Low Grade ◽

Significant Relation ◽

Cough Reflex Sensitivity ◽

Cough Reflex ◽

Single Breath

Obesity is characterized by chronic, low-grade systemic inflammation. Obesity may also be associated with chronic cough. The aim of this pilot study was to clarify relation of cough reflex sensitivity and body mass index (BMI) in children with chronic cough. Altogether 41 children having symptoms of chronic cough were submitted to cough reflex sensitivity measurement. We assessed the relation of cough reflex sensitivity (CKR) due to BMI. Cough reflex sensitivity was defined as the lowest capsaicin concentration which evoked two (C2) or five (C5) coughs. Capsaicin aerosol in doubling concentrations (from 0.61 to 1250 µmol/l) was inhaled by a single breath method (KoKo DigiDoser; nSpire heath Inc, Louisville, CO, USA), modified by the addition of an inspiratory flow regulator valve (RIFR; nSpire heath Inc, Louisville, CO, USA). BMI was calculated. Pulmonary function was within normal range. Concentrations of capsaicin causing two (C2) and five coughs (C5) were reported. Children (22 boys and 19 girls, mean age 6.8 years) cough reflex sensitivity (median, with the Inter-Quartile Range) for C2 was 19.5 (73.4) µmol/l; for C5 it was 78.1 (605.5) µmol/l. We have noticed statistically significant relation of the cough reflex sensitivity (C5) and body mass index (P<0.0001); however, the effect size was small, R2=0.03. Increase of body mass index in one unit is associated with -34.959 µmol/l decrease of C5. We did not find a statistically significant relation between C2 and BMI (P=0.41). The median value of CKR (C2) in boys is not statistically significantly different than the median value of CKR (C2) in girls (P-value 0.5). The median value of CKR (C5) in boys is not statistically significantly different than the median value of CKR (C5) in girls (P-value 0.5). Increase of body mass index in children suffering from chronic cough relates to decrease of cough reflex sensitivity (C5 value).

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Cough in Idiopathic Pulmonary Fibrosis

Frontiers in Rehabilitation Sciences ◽

10.3389/fresc.2021.751798 ◽

2021 ◽

Vol 2 ◽

Author(s):

Jennifer Mann ◽

Nicole S. L. Goh ◽

Anne E. Holland ◽

Yet Hong Khor

Keyword(s):

Idiopathic Pulmonary Fibrosis ◽

Pulmonary Fibrosis ◽

Chronic Cough ◽

Multidisciplinary Treatment ◽

Architectural Distortion ◽

Depression And Anxiety ◽

Cough Reflex Sensitivity ◽

Cough Reflex ◽

Recent Developments

Chronic cough is experienced by most patients with idiopathic pulmonary fibrosis (IPF). It is often the first symptom and is associated with reduced quality of life, increased rates of depression and anxiety, more severe physiological impairment, and disease progression. Although not fully understood, recent gains in understanding the pathophysiology of chronic cough in IPF have been made. The pathophysiology is likely multifactorial and includes alterations in mucous production and clearance, architectural distortion, and increased cough reflex sensitivity, suggesting a role for targeted therapies and multidisciplinary treatment. Modifiable comorbidities can also induce cough in patients with IPF. There is a renewed emphasis on measuring cough in IPF, with clinical trials of novel and repurposed therapies for chronic cough emerging in this population. This review provides an update on the clinical characteristics, pathophysiology, and measurement of chronic cough in patients with IPF and summarizes recent developments in non-pharmacological and pharmacological therapies.

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