Impact of chest computed tomography scan on the management of patients with chronic cough

Productive cough, a forgotten phenotype of refractory chronic cough

BACKGROUND

Refractory chronic cough (RCC) patients typically complain of a dry cough. Sputum production in these patients has rarely been described in the literature. However, sputum production in RCC may be common, troublesome and particularly challenging to manage.

AIMS

We aimed to characterise patients referred to our regional specialist cough clinic who have significant sputum production (≥1 teaspoon of sputum daily) and compare their demographics, symptomatology and investigation results to those presenting with a dry RCC.

METHODS

A retrospective case note analysis of all consecutive referrals to a tertiary cough clinic identified as having a productive cough (≥1 teaspoon of sputum daily) was performed over a 12-month period. They were compared to a paired number of patients with dry RCC.

RESULTS

Patients with productive cough represented nearly a quarter (98/398, 24.6 %) of new patient referrals to the clinic. Demographic information, symptomatology and investigation results were comparable to those with a dry RCC. Over a third, 35.8 % of patients with a productive cough reported expectorating an egg-cupful of sputum or more a day. Nearly half, 40% of those with high volume sputum production (≥egg-cupful daily) had both a normal CT thorax and normal spirometry.

CONCLUSIONS

Patients with RCC can expectorate significant volumes of sputum in the absence of underlying lung disease. This group have similar demographics to those with dry RCC. This is the first piece of work to our knowledge to describe this cohort. Future work needs to acknowledge this forgotten phenotype to ensure that they receive comprehensive evaluation and evidenced based treatment.

Guidelines for the management of chronic cough in adults. Endorsed by the French speaking society of respiratory diseases (Société de Pneumologie de Langue Française, SPLF), the Société Française d'Oto-Rhino-Laryngologie et de Chirurgie de la Face et du Cou (SFORL), the Société Française de Phoniatrie et de Laryngologie (SFPL), the Société Nationale Française de Gastro-entérologie (SNFGE)

Patients with chronic cough experience a high alteration of quality of life. Moreover, chronic cough is a complex entity with numerous etiologies and treatments. In order to help clinicians involved in the management of patients with chronic cough, guidelines on chronic cough have been established by a group of French experts. These guidelines address the definitions of chronic cough and the initial management of patients with chronic cough. We present herein second-line tests that might be considered in patients with cough persistence despite initial management. Experts also propose a definition of unexplained or refractory chronic cough (URCC) in order to better identify patients whose cough persists despite optimal management. Finally, these guidelines address the pharmacological and non-pharmacological interventions useful in URCC. Thus, amitryptilline, pregabalin, gabapentin or morphine combined with speech and/or physical therapy are a mainstay of treatment strategies in URCC. Other treatment options, such as P2 × 3 antagonists, are being developed.

CT airway remodelling and chronic cough

RATIONALE

Structural airway changes related to chronic cough (CC) are described in the literature, but so far reported data are rare and non-conclusive. Furthermore, they derive mainly from cohorts with small sample sizes. Advanced CT imaging not only allows airway abnormalities to be quantified, but also to count the number of visible airways. The current study evaluates these airway abnormalities in CC and assesses the contribution of CC in addition to CT findings on the progression of airflow limitation, defined as a decline in forced expiratory volume in 1 s (FEV1) over time.

METHODS

A total of 1183 males and females aged ≥40 years with thoracic CT scans and valid spirometry from Canadian Obstructive Lung Disease, a Canadian multicentre, population-based study has been included in this analysis. Participants were stratified into 286 never-smokers, 297 ever-smokers with normal lung function and 600 with chronic obstructive pulmonary disease (COPD) of different severity grades. Imaging parameters analyses included total airway count (TAC), airway wall thickness, emphysema as well as parameters for functional small airway disease quantification.

RESULTS

Irrespective of COPD presence, CC was not related to specific airway and lung structure features. Independent of TAC and emphysema score, CC was highly associated with FEV1 decline over time in the entire study population, particularly in ever-smokers (p<0.0001).

CONCLUSION

The absence of specific structural CT features independently from COPD presence indicate that other underlying mechanisms are contributing to the symptomatology of CC. On top of derived CT parameters, CC seems to be independently associated with FEV1 decline.

TRIAL REGISTRATION NUMBER

NCT00920348.

[Guidelines for the management of chronic cough in adults]

Patients with chronic cough experience major alteration in their quality of life. Given its numerous etiologies and treatments, this disease is a complex entity. To help clinicians involved in patient management of patients, guidelines have been issued by a group of French experts. They address definitions of chronic cough and initial management of patients with this pathology. We present herein the second-line tests that might be considered in patients whose coughing has persisted, notwithstanding initial management. The experts have also put forward a definition of unexplained or refractory chronic cough (URCC), the objective being to more precisely identify those patients whose cough persists despite optimal management. Lastly, these guidelines indicate the pharmacological and non-pharmacological interventions of use in URCC. Amitriptyline, pregabalin, gabapentin or morphine combined with speech and/or physical therapy are mainstays in treatment strategies. Other treatment options, such as P2X3 antagonists, are being developed and have generated high hopes among physicians and patients alike.

Diagnostic yield of chest radiograph in management of adults with difficult-to-treat chronic cough-retrospective study

Background

Chest radiograph (CXR) is a routine imaging test in adults with chronic cough (CC), while value of thoracic computed tomography (CT) in these patients is still a matter of discussion. The aims of the study were to assess the diagnostic yield of CXR and to evaluate the impact of thoracic CT on management of patients with difficult-to-treat CC referred to our cough clinic.

Methods

The retrospective analysis of paired CXR and CT results was performed in 189 consecutive adults treated due to CC between 2015-2019 in our cough clinic. CC was defined as cough >8 weeks being the main or isolated ailment. The sensitivity, specificity, negative/positive predictive value (NPV, PPV) and diagnostic accuracy of CXR were calculated based on chest CT scan as the "gold standard". Only those CT scans which revealed abnormalities potentially related to CC and were associated with the changes in further diagnostic or therapeutic approach were construed as relevant CT findings during final analysis.

Results

The median age of patients (male/female ratio 53/136) was 58 years (IQR 44-67), only 6 subjects (3.0%) were active smokers, median CC duration was 48 months (IQR 24-120). CXR revealed abnormal findings in 23/189 (12.2%) patients. Normal CXR was confirmed by CT in 141 subjects (141/166; 84.9%). In 25/166 (15.1%) patients, CT showed abnormalities that could explain the cause of CC and changed either the diagnostic protocol or therapy. In patients with abnormal CXR, CT confirmed abnormal findings in 8 cases (8/23, 34.8%). The sensitivity, specificity, PPV, NPV, diagnostic accuracy were 24.2%, 90.4%, 34.8%, 84.9% and 78.8%, respectively.

Conclusions

CXR shows a limited diagnostic yield in adults with difficult-to-treat CC referred to cough clinic. Chest CT scan may add significant data impacting the diagnostic and therapeutic approach in these patients.

De-labeling severe asthma diagnosis: the challenge of DIPNECH

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pulmonary disease characterised by neuroendocrine cell hyperplasia within the bronchial epithelium [1]. The clinical presentation is characterised by nonspecific respiratory symptoms such as chronic cough, dyspnoea and bronchospasm. Given the rarity of the disease and the low specificity of symptoms, the diagnosis of DIPNECH is challenging and the time between symptom onset and diagnosis is long [1]. DIPNECH comprises a generalised proliferation of scattered neuroendocrine cells, small nodules (neuroendocrine bodies) or a linear proliferation of pulmonary neuroendocrine cells. It has been suggested that DIPNECH may mimic [2] or precede [3] asthma. The role of products of neuroendocrine cells such as substance P, which contribute to eosinophil migration, has been suggested to explain asthma symptoms in DIPNECH [3]. However, the characteristics of patients with DIPNECH who have symptoms suggestive of asthma have never been described. The aim of our study was to determine whether patients diagnosed with DIPNECH and initially referred for severe asthma management had specific characteristics.

DIPNECH is a differential diagnosis of severe asthma with no specific biomarkers. Chronic cough and multiple nodules on CT should prompt clinicians to consider this diagnosis. Differentiating DIPNECH from severe asthma remains crucial.https://bit.ly/3mmFbQn