Autonomic dysfunction and post-COVID-19 syndrome: A still elusive link

Editorial:

Infection from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the long-lasting pandemic coronavirus disease 2019 (COVID-19), with dramatic clinical, social, and economic implications. Importantly, evolving experience consistently shows that, in addition to issues related to the acute phase, patients who recover from COVID-19 may present a wide variety of bothersome symptoms, which may be debilitating and significantly impair their quality of life. This condition, when it persists beyond 12 weeks after recovery, is defined as “post–COVID-19” or “long COVID-19” syndrome.

Some of the symptoms, including tachycardia/palpitations, chest pain, fatigue, and dyspnea with reduced effort tolerance, suggest a possible cardiovascular cause, whereas others (eg, muscle and/or joint pain, headache, memory loss, nausea, mood disturbances) suggest involvement of other systems. Symptoms may occur independently of the severity of COVID-19, although patients with more severe symptoms in the acute phase experience a higher rate of symptom persistence during follow-up. , 

Importantly, careful diagnostic assessment usually fails to identify specific causes of post–COVID-19 syndrome. However, it has been suggested that at least some post–COVID-19 symptoms, including those of potential cardiovascular origin, might be related to abnormalities of the autonomic nervous system (ANS). The pathophysiological mechanisms responsible for ANS impairment remain speculative and might include direct damage of the ANS (ganglia and/or nerve terminations) by the virus, a toxic effect of inflammatory cytokines released during the acute infection, and an immune-mediated response triggered by some viral component(s). ,  Independent of the mechanism, the possibility of ANS involvement in SARS-CoV-2 infection is supported by the frequent occurrence of neurologic symptoms (eg, anosmia, dysgeusia) as well as the sporadic occurrence of clinical conditions typically related to ANS dysfunction (eg, orthostatic hypotension, orthostatic tachycardia) in post–COVID-19 syndrome. Furthermore, patients with COVID-19, compared to healthy subjects, have been found to show reduced heart rate variability (HRV) parameters 20 weeks after recovery from the illness. However, a pathogenetic relationship between dysautonomia and post–COVID-19 syndrome remains to be demonstrated. Establishing such a relationship would be of importance because it might help guide the management of this clinical condition.

The study by Ladlow et al in this issue of Heart Rhythm Journal is welcome because it attempts to clarify whether any association exists between dysautonomia and symptoms, as well as objective evidence of exercise intolerance, in patients with post–COVID-19 syndrome. In their study, Ladlow et al enrolled 205 patients referred to a post–COVID-19 clinic who fulfilled specific eligibility criteria (hospitalization and desaturation ≤95% on a Harvard step test or chest pain with electrocardiographic [ECG] changes during acute illness and life-limiting symptoms persisting for >12 weeks). All patients underwent bicycle cardiopulmonary exercise testing (CPET) and were divided into 1 of 2 groups according to evidence or no evidence of dysautonomia.

Dysautonomia was diagnosed based on 3 heart rate (HR) parameters that Jouven et al found to be associated with total mortality and sudden death in a population of asymptomatic subjects: (1) resting HR >75 bpm; (2) increase in HR during exercise <89 bpm; and (3) HR reduction <25 bpm during the first minute of recovery from peak exercise. HRV was also assessed by calculating the root mean square of the squared differences of adjacent RR intervals (RMSSD) on a 1-minute 12-lead ECG at rest and on 30-second ECGs during the first 3 minutes of recovery after peak exercise.

Patients were studied 183 ± 77 days (∼6 months) from COVID-19 disease, and dysautonomia was found in 51 patients (25%). Per definition, these patients had higher HR at rest (95 ± 12 bpm vs 81 ± 12 bpm; P <.001) and lower HR increase during CPET (75 ± 12 bpm vs 96 ± 13 bpm; P <.001) and HR recovery after peak exercise (17 ± 4 bpm vs 31 ± 17 bpm; P <.001) compared to those without dysautonomia.

Patients with dysautonomia were older, had a higher body mass index (BMI) (P = .013) and waist circumference (WC) (P = .003), and had a lower basal RMSSD (P <.001). Furthermore, at rest, dysautonomic patients showed a higher breathing rate (P = .006) and lower forced vital capacity (P = .031), forced expiratory volume in 1 second (P = .036), and ventilatory efficiency (Ve/Vco 2) (P = .036).

When assessing symptoms that showed prevalence >25%, a significant association with dysautonomia was found for low mood (P = .007), headache (P = .026), and poor attention (P = .047). However, other symptoms, including some of potential cardiovascular origin (eg, shortness of breath, fatigue), showed no significant association with dysautonomia.

Patients with dysautonomia, however, showed a lower performance on CPET. In particular, HR at peak exercise (170 ± 13 bpm vs 177 ± 15 bpm; P = .003), maximal work rate (219 ± 37 W vs 253 ± 52 W; P <.001), and maximal oxygen consumption (VO2) (30.6 ± 5.5 mL/kg/min vs 35.8 ± 7.6 mL/kg/min; P <.001) all were significantly lower in patients with dysautonomia than in those without dysautonomia, suggesting a role of ANS dysfunction in their physical limitation.

Ladlow et al should be congratulated for performing this large study on post–COVID-19 syndrome. However, possible alternative interpretations of the data suggest caution in deriving definitive conclusions from their results.

Although the study shows the lack of significant relationship between dysautonomia and most post–COVID-19 symptoms, including, in particular, some symptoms of possible cardiovascular origin, the method applied to identify patients with an impairment of ANS function presents some limitations. Both higher HR at rest and lower HR recovery after exercise suggest an imbalance of sympathovagal tone toward adrenergic predominance in their patients with dysautonomia. However, rather than reflecting a primary impairment of the ANS, these findings simply might have been related to differences between the 2 groups with regard to some basal clinical characteristics, including higher BMI/WC, lower efficiency in respiratory function, and lower mood in dysautonomic patients. In addition, the lower increase in HR during maximal exercise in patients with dysautonomia might have been a mere consequence of their having a higher HR at rest and, given their older age, a lower maximal theoretical HR for age. The percent of predicted maximal HR for age achieved during CPET, in fact, did not differ between the 2 groups. The possibility that the differences in HR behavior might have not been related to a primary abnormality of the ANS is also suggested by the fact that, despite the basal difference, RMSSD values were similar during exercise recovery in the 2 groups of patients, suggesting a similar ANS response to exercise interruption in the 2 groups.

Future studies should clarify whether different results regarding the relationship between ANS dysfunction and post–COVID-19 symptoms might be obtained using more comprehensive and better validated methods for the diagnosis of ANS dysfunction, such as standard tests of autonomic function and HRV assessed from its multiple (short-term and long-term) components.

Of note, although the results of CPET in the study by Ladlow et al suggest lower performance by patients classified with dysautonomia, exercise tolerance was largely normal in these subjects, who achieved >100% of the predicted maximal oxygen consumption and an average maximal work rate of 219 W, with only small differences compared to patients without dysautonomia, possibly explained, again, and at least in part, by some demographic (age) and clinical (BMI, respiratory function) differences.

In conclusion, the study by Ladlow et al provides interesting data on the clinical characteristics and objective physical performance of patients with post–COVID-19 syndrome. However, the role of ANS in determining symptoms (particularly those of potential cardiovascular origin) and physical limitation in these patients still has not been fully elucidated by their data, making necessary further studies applying more comprehensive and valuable methods for the assessment of ANS function.

Source: Lanza GA. Autonomic dysfunction and post-COVID-19 syndrome: A still elusive link. Heart Rhythm. 2022 Apr;19(4):621-622. doi: 10.1016/j.hrthm.2021.12.027. Epub 2021 Dec 28. PMID: 34968741; PMCID: PMC8712711. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8712711/ (Full study)

Serological Biomarkers at Hospital Admission Are Not Related to Long-Term Post-COVID Fatigue and Dyspnea in COVID-19 Survivors

Abstract:

Objective: The aim of this study was to investigate the association between serological biomarkers at the acute phase of infection at hospital admission with the development of long-term post-COVID fatigue and dyspnea.

Methods: A cohort study including patients hospitalized due to COVID-19 in one urban hospital of Madrid (Spain) during the first wave of the outbreak (from March 20 to June 30, 2020) was conducted. Hospitalization data, clinical data, and eleven serological biomarkers were systematically collected at hospital admission. Patients were scheduled for an individual telephone interview after hospital discharge for collecting data about the presence of post-COVID fatigue and dyspnea.

Results: A total of 412 patients (age: 62 years, standard deviation: 15 years; 47.5% women) were assessed with a mean of 6.8 and 13.2 months after discharge. The prevalence of post-COVID fatigue and dyspnea was 72.8% and 17.2% at 6 months and 45.4% and 13.6% at 12 months after hospital discharge, respectively. Patients exhibiting post-COVID fatigue at 6 or 12 months exhibited a lower hemoglobin level, higher lymphocyte count, and lower neutrophil and platelets counts (all, p < 0.05), whereas those exhibiting post-COVID dyspnea at 6 or 12 months had a lower platelet count and lower alanine transaminase, aspartate transaminase, and lactate dehydrogenase (LDH) levels (all, p < 0.05) than those not developing post-COVID fatigue or dyspnea, respectively. The multivariate regression analyses revealed that a lower platelet count and lower LDH levels were associated but just explaining 4.5% of the variance, of suffering from post-COVID fatigue and dyspnea, respectively.

Conclusion: Some serological biomarkers were slightly different in patients exhibiting post-COVID fatigue or dyspnea, but they could not explain the long-COVID problems in those patients.

Source: Fernández-de-Las-Peñas C, Ryan-Murua P, Rodríguez-Jiménez J, Palacios-Ceña M, Arendt-Nielsen L, Torres-Macho J. Serological Biomarkers at Hospital Admission Are Not Related to Long-Term Post-COVID Fatigue and Dyspnea in COVID-19 Survivors. Respiration. 2022 Apr 5:1-8. doi: 10.1159/000524042. Epub ahead of print. PMID: 35381597. https://www.karger.com/Article/FullText/524042 (Full text)

Coronary microvascular health in patients with prior covid-19 infection: implications for long-covid syndrome

Background: SARS-CoV-2 infection has been shown to directly infect coronary vascular endothelium, causing inflammation and plaque instability. We aimed to assess the vascular health of patients with prior COVID-19 using Positron emission tomography (PET) derived coronary flow reserve (CFR).

Methods: A prospective cohort of consecutive patients with PCR confirmed prior COVID-19 infection undergoing clinically indicated PET myocardial perfusion imaging were included and compared to patients with no prior COVID19. CFR was determined by PET and microvascular dysfunction (CMD) was defined as CFR<2.

Results: The study population consisted of 2316 patients (4.4% prior COVID 19, 52% male, mean age 67±12 years, 55% hypertensive, 32% diabetic, 41% dyslipidemia). The mean duration between COVID19 diagnosis and PET was 191 (±131) days. CMD was more prevalent in those with prior COVID19 (58% vs 46%, p=0.012). After adjusting for baseline and clinical characteristics, patients with prior COVID19 had statistically significant higher odds of CMD (OR 1.8, p=0.008). Results were consistent in subgroups of patients with no clinical risk factors and normal stress tests.

Conclusion: Our analysis shows that patients with prior COVID19 have higher rates of CMD. This may in part explain the long-COVID symptoms. The prognostic implications of these findings need to be determined.

Source: Ahmed A, Saad J, Han Y, et al. CORONARY MICROVASCULAR HEALTH IN PATIENTS WITH PRIOR COVID-19 INFECTION: IMPLICATIONS FOR LONG-COVID SYNDROME. J Am Coll Cardiol. 2022 Mar, 79 (9_Supplement) 1822. https://doi.org/10.1016/S0735-1097(22)02813-3

Cardiovascular impairment in long covid one year post-sars-cov-2 infection

Background: Long Covid is associated with multi-organ inflammation, hypercoagulability, and several symptoms (fatigue, dyspnoea etc). Varying levels of cardiac involvement have been reported by cardiac magnetic resonance (CMR). We now describe longitudinal cardiovascular impairment in patients with Long Covid at 6 and 12 months post-SARS-CoV-2 infection.

Methods: 524 participants with Long Covid underwent a baseline scan at 6 months post infection (ClinicalTrials.gov: NCT04369807) and were rescanned 12 months post-infection if abnormal findings were reported at baseline. CMR (T1 and T2, cardiac mass, volumes, function, and strain), along with multi-organ MRI and blood samples were collected. Cardiovascular impairment was defined as one or more of: low left ventricular ejection fraction (LVEF), high left ventricular end diastolic volume (LVEDV), elevated native T1 in 3 or more cardiac segments. A significant longitudinal change was reported if greater than the repeatability coefficients derived from a population of 92 healthy controls.

Results: In 70 patients with cardiovascular impairment and Long Covid at baseline, 48 had complete paired data at 1 year, and of those 54% had not fully resolved. 19 (27%) patients with cardiovascular impairment had required hospitalization for acute COVID-19. Troponin or BNP were not predictive of CMR findings; however, hospitalization at the acute stage, male sex, kidney fibroinflammation and serum bicarbonate were. Individual symptoms were not specific to cardiovascular impairment or disease course.

Conclusion: CMR shows that cardiovascular impairment persists in Long Covid in some patients beyond 12 months post infection; however, this impairment may have pre-existing origin. Although there is an association with acute COVID-19 hospitalisation, male gender and high serum bicarbonate were predictive of cardiovascular impairment, subtypes of disease (based on symptoms, examination, and investigations) are yet to be established. Therefore, interventional trials with pre-specified subgroup analysis are required to inform therapeutic options.

Source: Roca-Fernandez A, Wamil M, Telford A, et al. CARDIOVASCULAR IMPAIRMENT IN LONG COVID ONE YEAR POST-SARS-COV-2 INFECTION. J Am Coll Cardiol. 2022 Mar, 79 (9_Supplement) 1312. https://doi.org/10.1016/S0735-1097(22)02303-8

Course of post COVID-19 disease symptoms over time in the ComPaRe long COVID prospective e-cohort

Abstract:

About 10% of people infected by severe acute respiratory syndrome coronavirus 2 experience post COVID-19 disease. We analysed data from 968 adult patients (5350 person-months) with a confirmed infection enroled in the ComPaRe long COVID cohort, a disease prevalent prospective e-cohort of such patients in France. Day-by-day prevalence of post COVID-19 symptoms was determined from patients’ responses to the Long COVID Symptom Tool, a validated self-reported questionnaire assessing 53 symptoms.

Among patients symptomatic after 2 months, 85% still reported symptoms one year after their symptom onset. Evolution of symptoms showed a decreasing prevalence over time for 27/53 symptoms (e.g., loss of taste/smell); a stable prevalence over time for 18/53 symptoms (e.g., dyspnoea), and an increasing prevalence over time for 8/53 symptoms (e.g., paraesthesia). The disease impact on patients’ lives began increasing 6 months after onset. Our results are of importance to understand the natural history of post COVID-19 disease.

Source: Tran VT, Porcher R, Pane I, Ravaud P. Course of post COVID-19 disease symptoms over time in the ComPaRe long COVID prospective e-cohort. Nat Commun. 2022 Apr 5;13(1):1812. doi: 10.1038/s41467-022-29513-z. PMID: 35383197. https://www.nature.com/articles/s41467-022-29513-z (Full text)

Comments to “Fluvoxamine and long COVID-19: a new role for sigma-1 receptor (S1R) agonists” by Khani and Entezari-Maleki

To the Editor:

The coronavirus disease 2019 (COVID-19) pandemic causes short-term and long-term health problems in survivors after infection of SARS-CoV-2 (severe acute respiratory syndrome-coronavirus-2). A recent systematic review using 57 studies with 250,351 survivors of COVID-19 shows that the median proportion of COVID-19 survivors experiencing at least 1 PASC (post-acute sequelae of COVID-19) was 54% at 1 month (short-term), 55% at 2–5 months (intermediate-term), and 54% at 6 or more months (long-term) [1]. The most common sequelae involved neurologic symptoms (i.e., headaches, memory deficits, difficulty concentrating, cognitive impairment), psychiatric symptoms (i.e., depression, anxiety, sleep disorders), pulmonary abnormalities (i.e., dyspnea, cough, increased oxygen requirement, pulmonary diffusion abnormalities, chest imaging abnormalities), and functional mobility impairment (i.e., impairment in general functioning, mobility decline, reduced exercise tolerance). However, there are no therapeutic drugs for long-term symptoms in survivors of COVID-19.

The precise mechanisms underlying SARS-CoV-2 induced long-term detrimental effects remain unclear. Infection of SARS-CoV-2 can damage endothelial cells leading to inflammation, thrombi and brain damage. SARS-CoV-2-associated systemic inflammation leads to decreased monoamines and neurotrophic factors, and microglial activation in the brain, resulting in long-term neurological and psychiatric symptoms in COVID-19 survivors [2]. A retrospective study of Wuhan University (Wuhan, China) reported that patients with Epstein-Barr virus (EBV)/SARS-CoV-2 coinfection have about 3-fold risk of having a fever symptom than patients with SARS-CoV-2 infection alone, and that levels of C-reactive protein and aspartate aminotransferase in patients with EBV/SARS-CoV-2 coinfection were higher than those in patients with SARS-CoV-2 infection alone [3]. This report suggests that EBV reactivation may be associated with the severity of clinical symptoms after SARS-CoV-2 infection.

Interestingly, approximately 67% of patients (20/30) with long-term sequelae of COVID-19 were positive for EBV reactivation based on positive titers for EBV early antigen-diffuse IgG or EBV viral capsid antigen IgM [4]. Thus, EBV reactivation may play a role in long-term symptoms in COVID-19 survivors although further study using a large sample size is needed. The authors suggest that most of long-lasting symptoms in COVID-19 survivors following the recovery from SARS-CoV-2 infection might not be directly affected by the virus but probably result from SARS-CoV-2-associated inflammation and EBV reactivation [4].

In the issue, Khani and Entezari-Maleki proposed that fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), may be a new therapeutic drug for long-term consequences of COVID-19 survivors [5]. Fluvoxamine has been demonstrated to prevent clinical deterioration in early-stage subjects with COVID-19 [6]. In addition of serotonin transporter inhibition, sigma-1 receptor chaperone in the endoplasmic reticulum (ER) and acid sphingomyelinase might play a role in the mechanisms of beneficial action of fluvoxamine for patients with SARS-CoV-2 infection [6,7,8]. It is also reported that sigma-1 receptor agonists such as fluvoxamine could produce potent anti-inflammatory actions by the prevention of inositol requiring enzyme 1α (IRE1) and X-box binding protein-1 (XBP-1) pathway [9]. Collectively, it is likely that sigma-1 receptor agonists such as fluvoxamine could produce potent anti-inflammatory effects through sigma-1 receptor/IRE1/XBP-1 pathway in the ER [6,7,8,9].

Among the SSRIs, fluvoxamine was the most potent at sigma-1 receptor in the brain [6,7,8]. Given the link between EBV reactivation and XBP-1 [10], it is possible that the potent sigma-1 receptor agonist fluvoxamine may have beneficial effects for long-term consequences in COVID-19 survivors through sigma-1 receptor/IRE1/XBP-1 pathway [4]. Therefore, it is of great interest to examine whether fluvoxamine can improve long-term sequelae in COVID-19 survivors.

Source: Hashimoto Y, Suzuki T, Hashimoto K. Comments to “Fluvoxamine and long COVID-19: a new role for sigma-1 receptor (S1R) agonists” by Khani and Entezari-Maleki. Mol Psychiatry. 2022 Apr 6:1–2. doi: 10.1038/s41380-022-01546-2. Epub ahead of print. PMID: 35388183; PMCID: PMC8985059. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8985059/ (Full text)

Post-COVID-19 syndrome: persistent neuroimaging changes and symptoms 9 months after initial infection

Abstract:

A previously healthy and active middle-aged woman acquired COVID-19 as an occupational exposure with subsequent persistent post-COVID-19 symptoms including headache, dyspnoea on exertion, chest pressure, tachycardia, anosmia, parosmia, persistent myalgia, vertigo, cognitive decline and fatigue. She presented to a tertiary medical centre for further evaluation after 9 months of persistent symptoms and had a largely unremarkable workup with the exception of a persistently elevated monocyte chemoattractant protein 1, blunted cardiovagal response and non-specific scattered areas of low-level hypometabolism at the bilateral frontal, left precuneus, occipital and parietal regions on PET scan.

Source: Grach SL, Ganesh R, Messina SA, Hurt RT. Post-COVID-19 syndrome: persistent neuroimaging changes and symptoms 9 months after initial infection. BMJ Case Rep. 2022 Apr 8;15(4):e248448. doi: 10.1136/bcr-2021-248448. PMID: 35396239. https://casereports.bmj.com/content/15/4/e248448.long (Full text)

The use of amantadine in the prevention of progression and treatment of COVID-19 symptoms in patients infected with the SARS-CoV-2 virus (COV-PREVENT): Study rationale and design

Abstract:

Background: COVID-19, a disease caused by infection with the SARS-CoV-2 virus, is asymptomatic or mildly symptomatic in most cases. Some patients, usually burdened with risk factors develop acute respiratory failure and other organ dysfunction. In such cases, the mortality rate is very high despite the use of intensive therapy. Amantadine has complex activity including antiviral, antiinflammatory and dopaminergic effects. This clinical trial will assess the efficacy and safety of amantadine in the prevention of COVID-19 progression toward acute respiratory failure and neurological complications.

Methods and results: The trial will enroll 200 patients who are positive for SARS-CoV-2 infection and have one or more risk factors for worsening the disease. These patients will be included as hospitalized or ambulatory subjects for early treatment of illness. The recruitment will take place in 8 centers covering different regions of Poland. For 14 days they will be given either 200 mg of amantadine a day or placebo. Our hypothesis is a considerable reduction in the number of patients with progression toward respiratory insufficiency or neurological complications thanks to the treatment of amantadine.

Conclusions: Demonstrating the efficacy and safety of amantadine treatment in improving the clinical condition of patients diagnosed with COVID-19 is of great importance in combating the effects of the pandemic. It has potential to influence on the severity and course of neurological complications, which are very common and persist long after the infection as long-COVID syndrome.

Clinical trial registration: www.

Clinicaltrials: gov identification no. NCT04854759; Eudra CT number: 2021-001144-98 (dated 27 February 2021).

Source: Rejdak K, Fiedor P, Bonek R, Goch A, Gala-Błądzińska A, Chełstowski W, Łukasiak J, Kiciak S, Dąbrowski P, Dec M, Król ZJ, Papuć E, Zasybska A, Segiet A, Grieb P. The use of amantadine in the prevention of progression and treatment of COVID-19 symptoms in patients infected with the SARS-CoV-2 virus (COV-PREVENT): Study rationale and design. Contemp Clin Trials. 2022 Apr 4;116:106755. doi: 10.1016/j.cct.2022.106755. Epub ahead of print. PMID: 35390511; PMCID: PMC8978450. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8978450/ (Full text)

Small fiber neuropathy underlying dysautonomia in COVID-19 and in post-SARS-CoV-2 vaccination and long-COVID syndromes

Letter:

We eagerly read the excellent editorial by Gemignani and the corresponding original article by Abrams et al. about the suspected involvement of small fibers (small fiber neuropathy [SFN]) in acute severe, acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and in long-coronavirus disease (COVID) syndrome.12 It was speculated that at least some of the clinical manifestations of long-COVID syndrome could be attributed to involvement of small nerve fibers by the viral infection. The authors believe that studies are needed that investigate the role of autonomic dysfunction in long-COVID syndrome and the prevalence of SFN by means of the 13-item SFN symptom inventory questionnaire. The papers are appealing but raise some concerns that require discussion.

I do not agree with the notion that long-COVID syndrome is the same as post-COVID syndrome.1 Acute COVID-19 usually lasts one to 4 wk. Subacute COVID-19 lasts 5 to 12 wk. When clinical manifestations of COVID-19 persist beyond 12 wk, the condition is termed post-COVID syndrome. Both subacute COVID-19 and post-COVID syndrome are included under the overarching term long-COVID-syndrome. Differentiating long-COVID syndrome from post-COVID-syndrome is crucial for their management and for assessing long-term outcomes.

An issue not addressed in the paper is Guillain-Barre syndrome (GBS) due to an infection with SARS-CoV-2.3 There is ample evidence that the immune response to the virus can trigger autoimmune reactions, including those that are involved in the development of GBS. There is evidence accumulating that mRNA- and vector-based anti-SARS-CoV-2 vaccines can trigger the development of GBS.4 GBS can affect not only motor and sensory fibers, but also peripheral autonomic fibers, particularly in the GBS subtype of acute motor and sensory axonal neuropathy (AMSAN). There is a subtype of GBS that may exclusively affect autonomic fibers and present with pure dysautonomia.5 Because GBS may be mild, it can go unrecognized; because patients often have a long recovery time, autonomic manifestations in long COVID syndrome could be explained by incomplete recovery from autonomic involvement in abortive GBS.

Not addressed in the articles is the involvement of the central autonomic nervous system (ANS). There are several reports demonstrating that a SARS-CoV-2 infection can be complicated by hypophysitis.6 Furthermore, patients with a pre-existing pituitary micro- or macro-adenoma have an increased risk of pituitary apoplexy during SARS-CoV-2 infection.7 Accordingly, the hypophysial-pituitary-adrenergic axis can be impaired,8 thus leading to autonomic dysfunction.

Autonomic dysfunction may not always be recognized by those involved in the management of COVID-19 patients. Thus, patients with SARS-CoV-2 infection are often not investigated sufficiently for their symptoms of autonomic dysfunction, such as insomnia, fatigue, cognitive impairment, hypersensitivity to light, blurred vision, dry eyes or mouth, drooling, palpitations, syncope, orthostatic dizziness, hot flashes, dysphagia, bowel or bladder dysfunction, sexual dysfunction, changes in skin, hair, and nails, or abnormalities of sweating. Studies that may be performed to assess ANS involvement are a contrast-enhanced magnetic resonance imaging (MRI) of the pituitary gland, determination of releasing factors, pituitary stimulating hormones, and hormones of peripheral endocrine organs, and diagnostic testing for involvement of the peripheral ANS. Several of the latter tests are not widely available and their sensitivity and specificity may be low if portions of the peripheral ANS are tested that are not affected.

Not addressed was the role of anti-COVID-19 drugs in the development of SFN. There is increasing evidence that some of the compounds administered to infected patients are neurotoxic and can be responsible for polyneuropathy. Some of these compounds, such as lopinavir, ritonavir, daptomycin, and linezolid, may also damage autonomic fibers.

I agree that there is a need to investigate the involvement of the central and peripheral ANS in some patients with acute SARS-CoV-2 infections or long-COVID syndrome. Such patients should be investigated not only by use of questionnaires and the Quantitative Sudomotor Axon Reflex Test (QSART) but particularly by quantitative sensory testing (QST), micro-neurography of C-fibers of the superficial peroneal nerve, sensory stimulation tests, the deep breathing test, the Valsalva maneuver, tilt testing, cerebral blood flow velocity measurements, pain-related evoked potentials (PREP), laser speckle contact analysis (LASCA), laser Doppler flowmetry, laser Doppler imaging, contact heat-evoked potentials (CHEP), corneal confocal microscopy (CCM), and proximal or distal skin biopsy stained with protein gene product (PGP) 9.5. Furthermore, hormone levels should be determined and autopsy of COVID-19 patients should include histological investigations of central and peripheral autonomic pathways.

Source: Finsterer J. Small fiber neuropathy underlying dysautonomia in COVID-19 and in post-SARS-CoV-2 vaccination and long-COVID syndromes. Muscle Nerve. 2022 Apr 6. doi: 10.1002/mus.27554. Epub ahead of print. PMID: 35385125.  https://onlinelibrary.wiley.com/doi/10.1002/mus.27554 (Full text)

COVID-19 patients require multi-disciplinary rehabilitation approaches to address persisting symptom profiles and restore pre-COVID quality of life

Abstract:

Background: Long-COVID diagnosis is prominent, and our attention must support those experiencing debilitating and long-standing symptoms. To establish patient pathways, we must consider the societal and economic impacts of sustained COVID-19. Accordingly, we sought to determine the pertinent areas impacting quality of life (QoL) following a COVID-19 infection.

Research methods: Three hundred and eighty-one participants completed a web-based survey (83% female, 17% male) consisting of 70 questions across 7 sections (demographics, COVID-19 symptoms; QoL; sleep quality; breathlessness; physical activity and mental health). Mean age, height, body mass and body mass index (BMI) were 42 ± 12 years, 167.6 ± 10.4 cm, 81.2 ± 22.2 kg, and 29.1 ± 8.4 kg.m2, respectively.

Results: Participant health was reduced because of COVID-19 symptoms (‘Good health‘ to ‘Poor health‘ [< 0.001]). Survey respondents who work reported ongoing issues with performing moderate (83%) and vigorous (79%) work-related activities.

Conclusions: COVID-19 patients report reduced capacity to participate in activities associated with daily life, including employment activities. Bespoke COVID-19 support pathways must consider multi-disciplinary approaches that address the holistic needs of patients to restore pre-pandemic quality of life and address experienced health and wellbeing challenges.

Plain Language Summary: The long-term impact of long-COVID has a dramatic impact upon daily activities and lifestyle. The development of bespoke support pathways to support patients must address the physical and psychological considerations to adequately restore pre-COVID quality of life and address broader societal and economic implications, especially for those that are of working age.

Source: Faghy MA, Maden-Wilkinson T, Arena R, Copeland RJ, Owen R, Hodgkins H, Willmott A. COVID-19 patients require multi-disciplinary rehabilitation approaches to address persisting symptom profiles and restore pre-COVID quality of life. Expert Rev Respir Med. 2022 Apr 18:1-6. doi: 10.1080/17476348.2022.2063843. Epub ahead of print. PMID: 35385677. https://www.tandfonline.com/doi/full/10.1080/17476348.2022.2063843 (Full text)