Epidemiology and Prognostic Significance of Cough in Fibrotic Interstitial Lung Disease

Cough and dyspnea management in pulmonary fibrosis

PURPOSE OF THE REVIEW

Pulmonary fibrosis (PF) is characterized by relentless scarring of the lungs, declining lung function, and increasing symptom burden. In PF, dyspnea and cough are the most common symptoms, severely impacting quality of life. This review highlights recent advances in understanding their mechanisms and explores evolving strategies for management of these symptoms.

RECENT FINDINGS

Advances in non-pharmacologic approaches, including hand-held fans, dyspnea services and pulmonary rehabilitation are playing a vital role in dyspnea management. Opioids, while effective in reducing exertional dyspnea in controlled settings, show limited benefit for daily life breathlessness and are associated with significant adverse events, highlighting the need for cautious, individualized use. For refractory cough, promising studies are investigating the role of opioids and neuromodulatory therapies. Non-pharmacologic approaches, including speech therapy, and behavioral interventions, provide complementary approaches. A multidisciplinary approach and individualized care plans to address the multifactorial nature of dyspnea and cough are key.

SUMMARY

Effective management of dyspnea and cough can importantly improve patients' quality of life. Further research is required to refine treatment protocols, optimize palliative care interventions, and identify and test novel therapeutics. Translation of these findings into clinical practice requires a focus on evidence-based, patient-centered care.

Nociceptor neurons suppress alveolar macrophage-induced Siglec-F+ neutrophil-mediated inflammation to protect against pulmonary fibrosis

Pulmonary fibrosis results from persistent and pathological tissue repair, which is therapeutically challenging to attenuate and often fatal. The immune processes involved in fibrosis remain ill defined. Using a bleomycin-induced lung fibrosis murine model, we discovered that vagal TRPV1+ nociceptors are protective. Pharmacological ablation or genetic deletion of nociceptors resulted in worsened fibrosis and outcomes. Without nociceptors, alveolar macrophages aberrantly produced vasoactive intestinal peptide (VIP), leading to cytokine TGF-β1-mediated alternative proinflammatory Siglec-F+ neutrophil recruitment to the lung with a high propensity for neutrophil extracellular trap (NET) formation. VIP inhibition or Vip deletion in hematopoietic cells improved outcomes and attenuated Siglec-F+ neutrophil recruitment to the lungs in nociceptor-deficient mice, while VIP administration had the opposite effect. Thus, nociceptors are essential regulators of inflammation during pulmonary fibrosis. These findings provide mechanistic insights into how the nervous system impacts the progression of fibrotic lung diseases.

Updates on the Prevalence, Quality of Life, and Management of Chronic Cough in Interstitial Lung Diseases

Background: Chronic cough is a common symptom in patients with interstitial lung diseases (ILDs), which significantly affects health-related quality of life (HRQoL). The prevalence of chronic cough varies from 30% to almost 90% in different ILDs, with the highest rate in patients with idiopathic pulmonary fibrosis. However, the pathophysiology of cough in ILDs remains poorly understood, with multiple proposed mechanisms contributing to its development. This knowledge gap complicates both clinical assessment and treatment, as current therapeutic strategies target general cough mechanisms rather than ILD-specific pathways. This review synthesizes existing data to clarify distinct cough mechanisms across ILD subtypes and identify opportunities for more targeted therapeutic strategies in this challenging patient population. Moreover, cough can be a clinical marker of disease severity and a predictor of ILD progression and transplant-free survival. Effective cough-specific therapeutic options that consider potential mechanisms, comorbidities, and individual effects on HRQoL are needed for cough associated with ILD. Therefore, the aim of this review was to analyze the prevalence, the impact on HRQoL, the pathophysiology, and the management of chronic cough in ILDs. Methods: We performed a comprehensive search in PubMed, MEDLINE, Embase, and the Cochrane Library. This review included randomized clinical trials, observational studies, systematic reviews, and meta-analyses in adults with chronic cough comparing ILD types. The following were excluded: commentaries, letters, case reports and case series, conference abstracts, and studies and publications lacking cough-specific outcomes. Results: Several approaches to reduce cough frequency and severity were described: antifibrotic agents, neuromodulators, opiates, inhaled local anesthetics, oxygen, speech therapy, and anti-reflux therapy. Some therapeutic approaches, such as oral corticosteroids and thalidomide, can cause significant side effects. Novel agents, such as P2X3 receptor antagonists, which are in phase III trials (COUGH-1/2), show promising results for refractory cough and may benefit ILD-related cough. Conclusions: Thus, a comprehensive assessment of cough is required for effective cough treatment in patients with ILDs considering possible mechanisms and individual impact on QoL.

Cough in idiopathic pulmonary fibrosis: what is new

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive and fatal interstitial fibrosing disease and, despite some well-known risk factors, its cause is still unknown. Cough is experienced by most patients and is commonly chronic and refractory, having a significant impact on quality of life. Its aetiology is complex, combining factors related to interstitial lung disease (ILD) such as an increased sensitivity of cough-sensitive nerves, structural lung changes and inflammation, genetic factors, several comorbidities and medication-adverse effects. Despite the therapeutic advancements in IPF over the past decade with the introduction of antifibrotic drugs that slow disease progression, effective treatment options for cough in IPF remain unavailable. Cough management often relies on empirical approaches based on studies involving chronic cough patients of unspecified causes and ILD physicians' personal experiences. Different classes of medications have been tried over time and, more recently, the focus has turned to neuromodulators and opioids, but several studies have shown suboptimal efficacy in cough. On the other hand, these drugs are associated with significant physical, psychological and economic burdens. However, the future brings us hope to the extent that most current ongoing clinical trials are using new molecules and some have demonstrated promising antitussive effects. This review aims to provide a practical guide to understanding and managing cough in IPF patients, presenting pharmacological and non-pharmacological approaches over time, as well as those treatments that are currently being investigated in clinical settings.

The Clinical Approach to Chronic Cough

Chronic cough remains a significant clinical challenge, affecting approximately 10% of the population and leading to significant impairment in psychological, social, and physical quality of life. In recent years, efforts have intensified to elucidate the mechanisms underlying chronic cough and to focus on investigating and treating refractory chronic cough (RCC). A "treatable trait" approach, which focuses on identifying and addressing the specific associated causes of chronic cough, has gained traction. In some patients, RCC is likely driven by a neuropathic mechanism due to dysregulation of the neuronal pathways involved in the cough reflex, often clinically described as cough hypersensitivity syndrome. Although the initial treatment of underlying conditions remains central to managing treatable traits, the therapeutic options for RCC have expanded to include targeting cough hypersensitivity. First-line treatments now include neuromodulators and speech therapy with one P2X3 receptor antagonist (gefapixant) recently licensed in the European Union, United Kingdom, and Japan. Despite these advances, patient responses remain variable, underscoring the ongoing need for research into the pathophysiology and treatment of RCC. This article reviews current investigations and management options in treating chronic cough and RCC.

Challenges of symptom management in interstitial lung disease: dyspnea, cough, and fatigue

INTRODUCTION

Interstitial lung disease (ILD) is a broad group of conditions characterized by fibrosis of the lung parenchyma. Idiopathic pulmonary fibrosis (IPF) is the most common subvariant. IPF is marked by considerable symptom burden of dyspnea, cough and fatigue that is often refractory to optimal disease-directed treatment.

AREAS COVERED

In this narrative review, we searched MEDLINE for articles related to the current evidence regarding management of chronic dyspnea, cough, and fatigue as three of the most prevalent and distressing symptoms associated with IPF and other ILDs. Each symptom shares common features of multi-factorial etiology and a lack of safe and effective pharmacological therapies. Both corticosteroids and opioids have been utilized in this context, yet there is insufficient evidence of therapeutic benefit and considerable risk of harms. Whilst some may benefit from symptom-directed pharmacological management, usage must be carefully monitored. Use of non-pharmacological strategies, such as breathing techniques and speech therapy represent low risk and low-cost option, yet broader validation of these therapies' effectiveness is needed.

EXPERT OPINION

Symptom management in IPF and other ILDs requires an iterative and individualized approach. Leveraging the expertise of multidisciplinary teams within an integrated care setting is an important opportunity to maximize health outcomes.

Examining Cough's Role and Relief Strategies in Interstitial Lung Disease

Chronic cough is a distressing and prevalent symptom in interstitial lung disease (ILD), significantly impairing quality of life (QoL) and contributing to disease progression, particularly in idiopathic pulmonary fibrosis (IPF). It is associated with physical discomfort, psychological distress, and social isolation and is often refractory to conventional therapies. The pathophysiology of cough in ILD is complex and multifactorial, involving neural hypersensitivity, structural lung changes, inflammatory processes, and comorbid conditions such as gastroesophageal reflux disease (GERD). Evaluating cough in ILD relies on subjective and objective tools to measure its severity, frequency, and impact on daily life, although standardization of these measures remains challenging. Management strategies span pharmacological interventions, including neuromodulators such as opiates, antifibrotic agents, pharmacologic and surgical GERD treatments, and non-pharmacological approaches like behavioral therapies, cough suppression techniques, and pulmonary rehabilitation and physiotherapy. Emerging treatments, such as P2X3 receptor antagonists and airway hydration therapies, offer promising avenues but require further investigation through robust clinical trials. This review aims to demonstrate the importance of addressing cough in ILD as a significant symptom and present objective and subjective methods of quantifying coughs, while providing insights into effective and emerging therapeutic options. By highlighting these potential therapies, we hope to guide healthcare practitioners in considering them through a thorough evaluation of benefits and risks on a case-by-case basis, with relevance both in the U.S. and internationally.

Early, integrated palliative care for people with chronic respiratory disease: lessons learnt from lung cancer

Lung cancer and chronic non-malignant respiratory disease cause pervasive, multifactorial suffering for patients and informal carers alike. Palliative care aims to reduce suffering and improve quality of life for patients and their families. An established evidence base exists that has demonstrated the essential role of specialist palliative care for people with lung cancer. Emerging evidence supports similar benefits among people with chronic respiratory disease. Many lessons can be learnt from lung cancer care, particularly as the model of care delivery has transformed over recent decades due to major advances in the diagnostic pathway and the development of new treatments. This narrative review aims to summarize the evidence for specialist palliative care in lung cancer and chronic respiratory disease, by highlighting seven key lessons from lung cancer care that can inform the development of proactive, integrated models of palliative care among those with chronic respiratory disease. These seven lessons emphasize (1) managing challenging symptoms; (2) the efficacy of specialist palliative care; (3) the importance of providing specialist palliative care integrated with disease-directed care according to patients' needs not prognosis; (4) the need for new models of collaborative palliative care, (5) which are culturally appropriate and (6) able to evolve with changes in disease-directed care. Finally, we discuss (7) some of the critical research gaps that persist and reduce implementation in practice.

Patient-centered care in pulmonary fibrosis: access, anticipate, and act

Comprehensive care integrates individual patient needs and is highly valued for patients with pulmonary fibrosis (PF). The importance of a patient-centered care approach is rooted in the unpredictable progressiveness of the disease course in PF. The respiratory impairment associated with PF has a major impact on the quality of life for both patients and their caregivers. We believe that prioritizing patient preferences could improve the shared decision making process and may ultimately lead to better health outcomes. Despite the growing emphasis for this approach, it remains challenging to adopt it in clinical practice. In this review, we propose the comprehensive Triple A Care Model, consisting of the domains Access, Anticipate, and Act, which emphasizes core elements of patient-centered care for patients with PF. We will provide an overview of the unmet needs in care for patients with PF and elaborate on the current methods for delivering patient-centered care. The latest insights into symptom management and supportive measures and several approaches to improving access to care are discussed, in line with the most recent guidelines.

What causes cough in pulmonary fibrosis, and how should we treat it?

PURPOSE OF REVIEW

To review the current understanding of the impact, mechanisms and treatments for cough in patients with interstitial lung disease (ILD). Evidence suggests that cough is a prevalent symptom in patients with ILD and has a significant impact on patients.

RECENT FINDINGS

There is increasing interest in the role of cough hypersensitivity as seen in chronic refractory cough in patients with ILD, and encouraging recent results suggest that ILD-associated cough responds to opiate therapy.

SUMMARY

Understanding the aetiology of cough in patients with ILD is crucial to continue to develop therapies which might be effective in reducing cough and increasing quality of life.

Patient Perception of Cough in Interstitial Lung Disease; Impact of Cough Hypersensitivity

INTRODUCTION

Cough is common in interstitial lung disease (ILD) and is associated with disease progression, yet its mechanisms are understudied. We investigated cough hypersensitivity features and impact in ILD.

METHODS

Participants with ILD and cough (n = 195) completed a multiple choice and free text questionnaire on cough sensations/triggers and impacts.

RESULTS

The majority of participants were male (54%), aged > 65 (64%), with idiopathic pulmonary fibrosis (IPF, 75%). Common cough triggers were body position (74%), physical activity (72%), and talking (62%). Common laryngeal sensations were globus (43%), and itch/tickle (42%). Cough impacted everyday life in 55%, and all activities in 31%, causing exhaustion (59%), social embarrassment (70%), urinary incontinence (46% females), and syncope/pre-syncope (12%). The total number of cough-provoking sensations/triggers correlated with impacts; ρ = 0.73, p < 0.001.

CONCLUSION

Cough hypersensitivity symptoms are prevalent in ILD and detrimentally affect quality of life. Further studies investigating mechanisms of cough hypersensitivity and targeted pharmacotherapy are warranted.