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The cough reflex arc. nTS: Nucleus tractus solitarius. CPG: Central pattern generator. https://doi.org/10.1371/journal.pone.0283758.g001
Source publication
Background:
Despite being a new entity, there is a large amount of information on the characteristics of SARS-CoV-2 infection and the symptoms of the acute phase; however, there are still many unknowns about the clinical features and pathophysiology of post-COVID syndrome. Refractory chronic cough is one of the most prevalent symptoms and carries...
Context in source publication
Context 1
... cough reflex arc is made up of three main pathways, the sensory afferent pathway, central pathway, and motor efferent pathway, as shown in Fig 1. Airway sensory nerves activated in response to a stimulus travel through the internal laryngeal nerve, the superior laryngeal nerve, and vagus nerve to the medulla and terminate in the nucleus tractus solitarius (nTS). The respiratory central pattern generator (CPG) modifies the activity of the inspiratory and expiratory muscles and leads to cough. ...
Citations
... The mechanisms underlying cough hypersensitivity syndrome are not completely understood, but it is believed to occur due to neuronal dysfunction as a consequence of three main processes that lead to increased activation of the neuronal pathways mediating cough 26,27 : i) excessive activation of airway vagal afferent terminals (e.g. by mucus, ATP, eosinophils), ii) neuroplastic changes in vagal afferent fibres, iii) neuroplastic changes in the central nervous system, i.e. central sensitization and/or impaired inhibitory control 28 . The exact cause of why these changes occur is unclear but they may result from chronic inflammation, viruses 29,30 , or other pathological processes that lead to the neuronal dysfunction 6 . ...
Introduction/framework/objectives
After a few years of exposure to different strains of COVID-19, there is a large percentage of infected individuals worldwide, most ofwhom are of working age. Taking into account that in a substantial fraction of these there were prolonged symptoms and with somecapacity to alter work capacity, a review was initiated in order to summarize the most pertinent information published on this subject.
Methodology
This is a Bibliographic Review, initiated through a search carried out in April 2023, in the databases “CINALH plus with full text, Medlinewith full text, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, Cochrane Database ofSystematic Reviews, Cochrane Methodology Register, Nursing and Allied Health Collection: comprehensive, MedicLatina andRCAAP”.
Content
This syndrome is a set of multiorgan symptoms/sequelae that affects previously infected individuals, sometimes lasting several months.It is a chronic complication, due to a persistent hyperinflammatory state (although the pathophysiology is not clearly known) and evenafter the COVID test is negative. It may be justified by inflammatory, hypoxic, microvascular and neurodegenerative changes; by directdamage caused by the virus itself and/or by secondary effects of therapy and co-existing morbidities. The emotional part may beassociated with the fear of infecting family members, the economic problems associated with the costs of medical care (in countrieswith more privatized healthcare systems) and/or the stigma of the infection itself.
The diagnosis is clinical and appears both in individuals who have been hospitalized and who have not.
It can involve morbidity, overload on the health system and financial resources.
It is also called Long COVID Syndrome, a term that actually emerged on social media.
Discussion and Conclusions
Given the temporality, the articles published on the topic are reasonably recent, and there is no previous bibliography on this subject todiscuss the data obtained; although some symptoms may also be due to other more prevalent and/or old infections, possibly due to asimilar pathophysiological mechanism.
All evolutions are possible: from asymptomatic individuals during and after the infection to others with very debilitating symptoms thatlimit their ability to work. It is necessary for the occupational health team to evaluate each case, using the aptitude classification to helpadapt tasks and obtain greater performance, job satisfaction and profit.
Purpose
Evidence for the pathogenesis and treatment of post-acute coronavirus disease 2019 (COVID-19) (long COVID) is lacking. As long COVID symptoms are predicted to have an impact on the global economy, clarification of the pathogenesis is urgently needed. Our experiences indicated that some symptoms were complicated by diseases established before the COVID-19 pandemic.
Methods
Using a retrospective, cross-sectional study, we aimed to evaluate the diseases complicating long COVID. Using the medical records of patients with confirmed severe acute respiratory syndrome coronavirus 2 infection exhibiting residual symptoms lasting ≥ 60 days post-infection who visited our clinic in January 2021–February 2023, we investigated the symptoms and diseases observed. We identified diseases that occurred after COVID-19 infection and excluded those that were exacerbations of existing diseases. Results: During the first visit, the most common symptoms reported in a total of 798 patients were fatigue (523 patients), anxiety (349 patients), and lack of motivation (344 patients). Complicating diseases were observed in 452 patients (57%). There were 115, 65, and 60 patients with postural tachycardia syndrome, postural syndrome without tachycardia, and mood disorders, respectively. Some diseases requiring immediate treatment included pulmonary thromboembolism, purulent shoulder arthritis, cerebellopontine angle tumors, myasthenia gravis, and cervical myelopathy.
Conclusion
All symptoms that occur after COVID-19 infection should not be treated as long COVID. Similar to normal medical treatment, a list of differential diagnoses should be maintained based on symptoms to obtain definitive diagnoses.
Objective(s)
The aim was to investigate the utilization and efficacy of bilateral superior laryngeal nerve block in patients with refractory chronic cough.
Methods
A retrospective chart review of 164 patients with refractory chronic cough who underwent bilateral SLN block at a single institution between November 2018 and September 2022 was performed. Demographics, comorbidities, and patient‐reported outcomes including pre‐ and postinjection Leicester Cough Questionnaire (LCQ) scores were collected and analyzed.
Results
The cohort underwent an average of 2.97 bilateral injections (range 1–22), containing either corticosteroid and local anesthetic or corticosteroid alone. Notably, 116 of 164 of patients reported an average of 67.3% reduction in their symptoms, with the treatment effect lasting 7.60 weeks on average. The average pre‐ and postinjection LCQ scores were 9.70 and 13.82, respectively. A lower LCQ score represents a greater impairment of health status due to cough, and the minimum important change is 1.3 points between questionnaires. The average improvement on LCQ following bilateral SLN block was 4.11 points for this cohort.
Conclusion
The use of in‐office bilateral SLN block is an effective treatment that can be used alone or in conjunction with oral medications for the treatment of refractory chronic cough.
Level of Evidence
4 Laryngoscope , 2023
