European Respiratory Society
Complex Breathlessness

Complex breathlessness (breathlessness with an unclear cause or that appears disproportionate to underlying causes) is an important and often neglected condition that presents a challenge to both patients and clinicians. This Monograph aims to provide clinicians at all levels with a comprehensive guide to complex breathlessness. Covering all aspects of this challenging clinical scenario, it will prove a useful resource when faced with a symptomatic breathless patient with no obvious underlying cause or with disproportionate symptoms. Several less commonly considered clinical entities and their associated features are highlighted, and approaches to breathlessness management are suggested in the absence of a clear diagnosis or set of abnormalities on investigation.

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  1. Page vii
  2. Page viii
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    1. Page 1
      Abstract
      Corresponding author: Cecilie Svanes (cecilie.svanes@uib.no)

      Breathlessness is a prevalent issue reported in the general population, increasing with advancing age. A variety of analyses have been undertaken to characterise the epidemiological characteristics and demographic patterns of this important symptom. There are several methodological factors that should be considered when assessing the available data in this area, and overall, there remains a paucity of high-quality and robust data. The aim of this chapter is to describe findings from the available published work in this field and to highlight the different approaches that have been used to assess this issue. The chapter addresses differences among populations, risk factors and changes in breathlessness across the lifespan. The chapter also covers health-related events that are associated with breathlessness and concludes by addressing unmet needs and future research priorities.

      Cite as: Ekström M, Johnson MJ, Currow DC, et al. The epidemiology of breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 1–14 [https://doi.org/10.1183/2312508X.10012521].

    2. Page 15
      Abstract
      Corresponding author: Kyle Pattinson (kyle.pattinson@nda.ox.ac.uk)

      For many people suffering breathlessness, its severity is not fully explained by objective measures of disease. This conundrum has puzzled doctors for many years, and has led research efforts towards understanding whether brain perceptual processes may be involved. This chapter explains current theories of perception as applied to the understanding of breathlessness. Emerging evidence in relation to proprioception, pain and somatosensation suggests that perceptions arise from the integration of sensory signals from the periphery with a set of predictions, or expectations held in the brain. Neuroimaging and behavioural studies suggest that this model also applies in the perception of breathlessness. It therefore follows that any process that can influence the brain's set of predictions, such as mood, affective state and aberrant learning, may also influence the severity of breathlessness, independently of underlying pathology. This new theory of perception may help explain some of the benefits of pulmonary rehabilitation, and could help us develop new ways to treat breathlessness. Novel treatments might include drugs that target expectation mechanisms or more focused non-pharmacological interventions, or a combination of the two.

      Cite as: Pick A, Gnanarajah S, Fraser E, et al. The neuroscience of breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 15–23 [https://doi.org/10.1183/2312508X.10012621].

    3. Page 24
      Abstract
      Corresponding author: Karl Peter Sylvester (karl.sylvester@nhs.net)

      Understanding the normal physiological processes associated with ventilatory control and impaired respiratory mechanics allows investigation of where in the pathway an abnormal response may have arisen, resulting in breathlessness. Dyspnoea is driven by an imbalance of the load/capacity of the respiratory muscle pump, the level of neural respiratory drive, and the coupling between neural respiratory drive and mechanical and ventilatory output. Understanding the relative contributions of specific factors leading to breathlessness is assisted by the performance of physiological assessments. Such assessments are now widely available and range from basic tests of respiratory function, such as spirometry, to more complex tests, such as CPET. Advances in physiological measurement have accelerated our understanding of the physiology of breathlessness, and this chapter is supported by such sources of experimental evidence.

      Cite as: Sylvester KP, Rolland-Debord C, Ong-Salvador R, et al. The physiology of breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 24–38 [https://doi.org/10.1183/2312508X.10012721].

  4. Page 39
    1. Page 39
      Abstract
      Corresponding author: Hayley Lewthwaite (Hayley.Lewthwaite@newcastle.edu.au)

      Many tools have been developed to assess various aspects of breathlessness in daily life or in response to exercise provocation. These aspects include the sensory–perceptual experience (intensity and sensory qualities), the associated affective distress and/or the functional and emotional impact. While the number of tools available highlights progress in the breathlessness field, including recognition of breathlessness as a complex and multidimensional sensation, this may pose a barrier to identifying which tool is best suited for a specific purpose or context. When selecting a tool, the clinician or researcher must consider which aspect of breathlessness is to be assessed, the level of resources available for breathlessness assessment, and the capacity of the tool to assess change over time and/or utilisation as a therapeutic outcome measure. Importantly, with breathlessness often assessed in time-constrained settings, tools exist that are freely available online and take <10 min to complete, with psychometric properties to assess change. Such tools can be used to start important conversations around breathlessness.

      Cite as: Lewthwaite H, Jensen D. Tools for assessing complex breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 39–60 [https://doi.org/10.1183/2312508X.10012821].

    2. Page 61
      Abstract
      Corresponding author: Stephen J. Fowler (stephen.fowler@manchester.ac.uk)

      Patients presenting with complex breathlessness need to have a comprehensive review of their current diagnoses, previous investigations and treatments, alongside multidisciplinary input that focuses on the nature and impact of their symptom(s). An individualised management plan to investigate and treat comorbidities should be made in each case and usually needs to be enacted before any BPD or ILO is treated. Treating any relevant comorbidities may have a significant positive impact on breathlessness, even if it is thought to be due to BDP or ILO. Patients will often have been through many (unsuccessful) treatment trials before, and taking time to explain the options and involving them in decision-making is essential.

      Cite as: Fowler SJ, Pantin CT. A systematic approach to assessing complex breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 61–74 [https://doi.org/10.1183/2312508X.10012921].

    1. Page 75
      Abstract
      Corresponding author: Jemma Haines (jemma.haines@mft.nhs.uk)

      When healthy, the larynx fulfils highly integrated, synchronised roles of respiration, airway protection, swallowing and phonation. When normal laryngeal function is disrupted, a range of symptoms may arise, affecting breathing, voice and sensation. Laryngeal dysfunction provides a unifying concept to describe overlapping laryngeal symptoms and is an important consideration in the assessment and management of complex breathlessness. A conceptual framework is presented that proposes a common, mechanistic link between different manifestations of laryngeal dysfunction, i.e. that laryngeal hypersensitivity leads to sensory hyperresponsiveness. Guided by this framework, various forms of laryngeal dysfunction are presented, with a holistic and multidisciplinary approach to assessment and management.

      Cite as: Haines J, Slinger C, Smith JA, et al. Laryngeal considerations in complex breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 75–91 [https://doi.org/10.1183/2312508X.10013021].

    2. Page 92
      Abstract
      Corresponding author: Adnan Majid (amajid@bidmc.harvard.edu)

      Large airway collapse (LAC) during exhalation is uncommon yet increasingly recognised as a cause of breathlessness. Its two primary forms are tracheobronchomalacia and EDAC, the latter frequently coexisting with more common respiratory disorders such as COPD or asthma. The aetiology of breathlessness in LAC is complex and often multifactorial. There is no specific pattern on PFTs that can accurately diagnose or exclude LAC. While dynamic CT chest imaging offers excellent sensitivity for LAC, the gold standard for diagnosis, classification and assessment of severity is dynamic flexible bronchoscopy. Treatment is focused on airway stabilisation via stenting followed by tracheobronchoplasty, as well as adjunctive treatments for concurrent respiratory disorders.

      Cite as: Swenson KE, Majid A. Breathlessness in large airway collapse. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 92–108 [https://doi.org/10.1183/2312508X.10003022].

    1. Page 109
      Abstract
      Corresponding author: Mark Hew (M.Hew@alfred.org.au)

      BPD, also known as dysfunctional breathing, may be defined as breathlessness with no underlying organic cause, or that is out of keeping with the underlying condition, and that results in impairment of function. It is commonly encountered either as a standalone condition, or in conjunction with other respiratory diseases. Contributors include maladaptive changes in chest wall mechanics, biochemical homeostasis, psychological factors and the response to exertion. A number of (often overlapping) patterns are observed, encompassing mouth breathing, apical predominance, structural abnormality, hyperventilation, thoraco-abdominal asynchrony and breathing pattern irregularity. Following evaluation for other defined lung diseases, further assessment generally requires a specialised physiotherapist. Methods of assessment include diagnostic questionnaires and exercise testing. BPD appears responsive to breathing retraining across multiple domains.

      Cite as: Denton E, Bondarenko J, Hew M. Breathing pattern disorder. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 109–122 [https://doi.org/10.1183/2312508X.10013221].

    1. Page 123
      Abstract
      Corresponding author: Guy Scadding (g.scadding@rbht.nhs.uk)

      Allergy is a relevant issue for many individuals presenting with complex or unexplained breathlessness. A pathophysiological interaction between allergy and several common respiratory conditions is well recognised (e.g. allergic asthma), but it is less often considered that allergic-mediated sensitisation to environmental triggers can cause upper-airway inflammation and allied symptoms of rhinitis, leading to nasal occlusion and interplaying with conditions such as ILO. Other allergic conditions such as mast cell disorder may be overlooked. In this chapter, the assessment and management of common and relevant allergic conditions are described, and more uncommon conditions are discussed.

      Cite as: Scadding G. Complex breathlessness: allergic factors. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 123–139 [https://doi.org/10.1183/2312508X.10013321].

    1. Page 140
      Abstract
      Corresponding author: Gulammehdi Haji (gulammehdi.haji@nhs.net)

      Disorders of the pulmonary vascular interface are uncommon but are often overlooked causes of exertional breathlessness. In the context of an individual with unexplained or complex breathlessness, it is common for clinicians to have considered airway-focussed causes (e.g. asthma or COPD) but in the absence of cardiac symptoms, conditions impacting the pulmonary vascular interface are often overlooked. This chapter will explore the haemodynamics of the pulmonary circulation at rest and under stress in healthy and pathological states. We will discuss swimming and high-altitude pulmonary oedema, as well as pulmonary veno-occlusion, which should be considered as a differential diagnosis in those presenting with features of pulmonary capillary stress failure. We will provide some insight into the use of invasive CPET to help diagnose pre-load failure in cases of normal noninvasive physiology but with troublesome unexplained exertional symptoms.

      Cite as: Joseph T, Howard L, Haji G. Pulmonary vascular causes of complex breathlessness: exercise pulmonary hypertension, pulmonary veno-occlusive disease and pre-load failure. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 140–152 [https://doi.org/10.1183/2312508X.10013421].

    2. Page 153
      Abstract
      Corresponding author: Alexander R. Lyon (a.lyon@imperial.ac.uk)

      In this chapter, we review cardiovascular pathologies that can lead to breathlessness, including both common causes (heart failure, valvular heart disease, atherosclerotic epicardial coronary disease) and rarer causes such as cardiomyopathies, vasospastic and microvascular angina, and pericardial disease. The aetiology, diagnostic workup and initial management are detailed, as well as discussion of the mechanisms through which breathlessness results from the pathology.

      Cite as: Kerrigan WJ, Murphy T, Lyon AR. Cardiovascular causes of complex breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 153–172 [https://doi.org/10.1183/2312508X.10013521].

    1. Page 173
      Abstract
      Corresponding author: Nicholas Gall (nicholasgall@nhs.net)

      Breathlessness can occur in a number of autonomic conditions, often in the form of dysfunctional breathing. The exact mechanism remains uncertain, but reduced perfusion of blood pressure receptors and chemoreceptors in the carotid sinus and carotid body, leading to hyperventilation, is postulated. This is recognised to occur in vasovagal syncope and in cases of significant autonomic dysfunction. It also occurs in PoTS, a condition predominantly affecting young women and often precipitated by another illness and increasingly by coronavirus disease 2019. It is characterised by cardiovascular and respiratory symptoms when upright, is relieved by recumbency and is associated with a significant heart rate increase. Other autonomic symptoms of organ dysfunction can occur, in the gastrointestinal and genitourinary system for example. There are guidelines and therapies that can produce significant symptomatic improvements, but maintaining a high level of suspicion for the diagnosis is important, as it can easily be overlooked.

      Cite as: Gall N, Reilly C. Complex breathlessness in postural tachycardia syndrome and autonomic dysfunction. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 173–185 [https://doi.org/10.1183/2312508X.10013621].

    1. Page 186
      Abstract
      Corresponding author: Vanessa M. McDonald (vanessa.mcdonald@newcastle.edu.au)

      Breathlessness is a complex and multidimensional symptom that warrants a holistic, systematic process to identify and manage contributory factors that impact breathlessness beyond the underlying condition. Suboptimal treatment adherence, whether intentional or not, has the potential to play a role in amplifying the complexity of breathlessness and its management. The ability to accurately measure treatment adherence is critical in determining whether lack of clinical improvement is due to treatment ineffectiveness or to the treatment regimen not being followed as prescribed. As there is currently no gold standard treatment adherence assessment method, it is recommended that a multimeasure approach using at least two methods is applied. This chapter discusses the concept of adherence, types of suboptimal adherence, and methods for identifying and addressing treatment non-adherence. We also discuss the potential applications of the “treatable traits” paradigm to further optimise the management of complex breathlessness.

      Cite as: McLoughlin RF, McDonald VM. Complex breathlessness: assessment of treatment adherence and treatable traits. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 186–205 [https://doi.org/10.1183/2312508X.10013721].

  5. Page 206
    1. Page 206
      Abstract
      Corresponding author: James H. Hull (J.Hull@rbht.nhs.uk)

      The previous chapters in this Monograph provide a comprehensive overview of the various clinical conditions that can cause or contribute to complex breathlessness. For some individuals with persistent breathlessness, despite comprehensive assessment, diagnosis may remain unclear or be complicated by the presence of comorbidities and contributory factors. For patients suffering with this issue, there are usually three main concerns: 1) satisfaction that no pathological explanation has been overlooked; 2) acknowledgement of the impact of symptoms; 3) reassurance that there is a logical approach to treatment. For the clinician managing this clinical scenario, challenges include professional uncertainty and concern associated with the lack of a clear diagnosis, as well as the inability to provide a complete “answer” and evidence-based treatment plan. The aim of this chapter is to address several of these challenges with focus on the consultation process, delivery of treatment and assessment of outcome in complex breathlessness.

      Cite as: Hull JH. Challenges in the approach to the management of complex or unexplained breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 206–214 [https://doi.org/10.1183/2312508X.10013821].

    2. Page 215
      Abstract
      Corresponding author: Rachael A. Evans (re66@le.ac.uk)

      Chronic breathlessness can be hard to make sense of and manage because its severity is often unrelated to the severity of the underlying medical conditions. Treatments for the underlying conditions may help breathlessness but rarely ameliorate it. This chapter will review the latest evidence for the nonpharmacological and pharmacological management of chronic breathlessness using a transdiagnostic approach. These approaches will be discussed using the Breathing, Thinking, Functioning framework, which conceptualises breathlessness in a way that helps understand the symptom and provides a rationale for symptom management. Although developed in a palliative breathlessness setting, the model can be used when a patient first presents with chronic breathlessness. Each element of this model can be addressed through different techniques such as breathing exercises and positioning, anxiety management, exercise rehabilitation and pharmacotherapy. To help clinicians provide holistic breathlessness management, a “breathlessness toolbox” and an outline of “very brief advice” for short consultations are provided.

      Cite as: Evans RA, Spathis A, Daynes E, et al. The management of chronic breathlessness. In: Hull JH, Haines J, eds. Complex Breathlessness (ERS Monograph). Sheffield, European Respiratory Society, 2022; pp. 215–233 [https://doi.org/10.1183/2312508X.10013921].