Sympathetic skin response in patients with systemic sclerosis and rheumatoid arthritis

Autonomic dysfunction in systemic sclerosis: A scoping review

INTRODUCTION

Over the years several lines of evidence have implied a pathological involvement of autonomic nervous system (ANS) in systemic sclerosis (SSc). However, the relationship between autonomic dysfunction and SSc is not yet fully understood. The aims of this scoping review were to map the research done in this field and inform future research to investigate pathogenic hypotheses of ANS involvement.

METHODS

We performed a scoping review of publications collected through a literature search of MEDLINE and Web of Science databases, looking for dysautonomia in SSc. We included original data from papers that addressed ANS involvement in SSc regarding pathogenesis, clinical presentation and diagnostic tools.

RESULTS

467 papers were identified, 109 studies were selected to be included in the present review, reporting data from a total of 2742 SSc patients. Cardiovascular system was the most extensively investigated, assessing heart rate variability with 24 h HolterECG or Ewing's autonomic tests. Important signs of dysautonomia were also found in digital vasculopathy, gastrointestinal system and SSc skin, assessed both with non-invasive techniques and histologically. Research hypotheses mainly regarding the relationship between sympathetic system - ischemia and the role of neurotrophins were then developed and discussed.

CONCLUSION

We described the currently available evidence on pathogenesis, clinical presentation and diagnostic assessment of dysautonomia in SSc patients. A strong influence of ANS deregulation on SSc clearly emerges from the literature. Future research is warranted to clarify the mechanisms and timing of autonomic dysfunction in SSc.

Evaluation of peripheral nerve involvements in patients with familial Mediterranean fever

Objectives

The aim of this study was to evaluate possible peripheral and autonomic nerve involvement in familial Mediterranean fever (FMF) patients with nerve conduction studies, sympathetic skin response (SSR) and RR interval variability (RRIV).

Patients and methods

The comparative case series was conducted with 76 participants between November 2017 and December 2018. Forty-six FMF patients, [12 with amyloidosis (5 males, 7 females; mean age: 44.7±13.9 years) and 34 without amyloidosis (14 males, 20 females; mean age: 35.9±8.7 years)], and 30 healthy volunteers (11 males, 19 females; mean age: 38.4±10 years) were included in this study. Nerve conduction parameters, SSR latency and amplitude from palmar and plantar responses, and RRIV at rest and deep breathing were studied in all the subjects. Neuropathic symptoms of the patient group were evaluated using the survey of autonomic symptoms scale and the neuropathy disability score.

Results

Nerve conduction studies of the patient group revealed polyneuropathy in seven (15.21%) patients and carpal tunnel syndrome in six (13.04%) patients. The mean amplitudes of SSR measured from the soles were significantly lower than the control group (p=0.041). The mean values of RRIV during rest and hyperventilation were lower in the patient group compared to the control group, but no statistically significant difference was found (p=0.484, p=0.341).

Conclusion

We detected that the prevalence of carpal tunnel syndrome in our patient population (13.04%) was higher than in the general population. Most of the changes in the range of parameters of SSR and RRIV determined in the patient group did not reach statistical significance, suggesting subclinical dysautonomia in FMF patients.

Sudomotor dysfunction in diabetic peripheral neuropathy (DPN) and its testing modalities: A literature review

Long term consequences of diabetes mellitus (DM) may include multi-organ complications such as retinopathy, cardiovascular disease, neuronal, and kidney damage. One of the most prevalent complication is diabetic peripheral neuropathy (DPN), occurring in half of all diabetics, and is the main cause of disability globally with profound impact on a patient's quality of life. Small fiber neuropathy (SFN) can develop in the pre-diabetes stage preceding large fiber damage in DPN. Asymptomatic SFN is difficult to diagnose in early stages, with sudomotor dysfunction considered one of the earliest manifestations of autonomic neuropathy. Early detection is crucial as it can prevent potential cardiovascular events. Although punch skin biopsy is the gold-standard method for SFN diagnosis, implementation as routine screening is hindered due to its invasive, impractical, and time-consuming nature. Other sudomotor testing modalities, most of which evaluate the postganglionic cholinergic sympathetic nervous system, have been developed with varying sensitivity and specificity for SFN diagnosis. Here, we provide an overview on the general mechanism of DPN, the importance of sudomotor assessment for early detection of autonomic dysfunction in DPN, the benefits and disadvantages of current testing modalities, factors that may affect testing, and the importance of future discoveries on sudomotor testing for successful DPN diagnosis.

Serum sclerostin and sympathetic skin response: relationship with myeloma bone disease

Background

Myeloma bone disease (MBD) is a common complication that significantly contributes to morbidity and mortality in multiple myeloma (MM). Serum sclerostin level and sympathetic activity can affect MBD. The purpose of this study is evaluation of serum sclerostin level and sympathetic activity (using sympathetic skin response “SSR”) in MM patients, and studying the relationship between both of them as well as their relationship with MBD. 35 smoldering myeloma patients (group I) and 35 newly diagnosed MM (group II) and 35 controls (group III) were included in the study. All the participants were subjected to complete history taking, and clinical examination. Assessment of serum sclerostin level, SSR, MM stages [by the international staging system (ISS)], MBD grading (according to the Durie–Salmon staging system) were done for all patients within 7 days from the diagnosis.

Results

Undetectable and decreased SSR amplitude are significantly more detected in group I and II (compared with group III). Autonomic manifestations, and loss of SSR is significantly more detected in group II than group I. Autonomic manifestations were absent in group III. SSR amplitude of median and tibial nerves is significantly decreased in group II than group I and III. MBD was detected in all patients of group II. Serum sclerostin and LDH were significantly increased in group II than group I. Group I and II had significantly higher levels of sclerostin when compared with group III. Group II had significantly higher levels of sclerostin and lower levels of ALP in comparison with group I. Serum sclerostin level was correlated positively with LDH and negatively with ALP and SSR amplitude. MBD was significantly affected by ISS stage III, LDH level, SSR affection and serum sclerostin level ≥ 0.40 ng/ml. SSR response affection was the most significant risk factor for advanced MBD followed by increased sclerostin level.

Conclusions

Serum sclerostin level was significantly increased and sympathetic activity was significantly decreased in MBD. Loss of the SSR response was the most significant risk factor for advanced MBD followed by increased sclerostin level.

Recommendations

Potentially validating the use of bone-turnover markers in larger studies, in addition to electrophysiological examination of SSR to stratify patients who are at high-risk for progressive MBD, as the use of newer agents with anabolic effects such as anti-sclerostin antibodies have shown potential in repair of MBD. These newer agents could potentially change the treatment landscape in patients with MBD.

Is there any Sympathetic Skin Response Abnormality in Raynaud Phenomenon?

OBJECTIVES

This study aimed to evaluate sympathetic skin response (SSR) among patients with Raynaud phenomenon (RP). SSR is a technique for assessment of the damage of peripheral neuropathies and the disorders of the sympathetic system.

METHODS

Between January 2015 and December 2018, approximately 20 patients with RP and 20 healthy subjects (control group) were recruited from patients referred to the outpatient clinics of Shiraz University of Medical Sciences, Shiraz, Iran. All participants were clinically examined and the SSR was evaluated using a standard protocol. SSR is abnormal when the latency is prolonged and/or the amplitude is reduced.

RESULTS

The RP group consisted of 19 women (95%) and one male (5%); three patients (15%) had primary Raynaud's phenomenon (PRP) and 17 patients (85%) had secondary Raynaud's phenomenon. The control group consisted of 16 women (80%) and four males (20%). The mean age of the RP group and control subjects was 43.1 ± 9 and 36.7 ± 8.6 years, respectively. The SSR to the electrical stimulus was absent in three patients with PRP. The total median nerve mean latencies in the upper limb were 1.90 ± 0.57 and 1.19 ± 0.52 seconds for the RP group and control groups, respectively (P <0.001). These findings revealed significantly prolonged SSR latencies in the RP group, while the mean amplitude showed no significant differences in both groups (P = 0.756).

CONCLUSION

Absence or prolonged latency of SSR was associated with the disorders of the unmyelinated axons in the sympathetic system. The findings of the present study suggested the disorders of unmyelinated axons in Raynaud's phenomenon.

Ganglionic Acetylcholine Receptor Antibodies and Autonomic Dysfunction in Autoimmune Rheumatic Diseases

Autonomic neuropathy has been reported in autoimmune rheumatic diseases (ARD) including Sjögren’s syndrome, systemic sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. However, the pathophysiological mechanism underlying autonomic dysfunction remains unknown to researchers. On the other hand, autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder, which causes dysautonomia that is mediated by autoantibodies against ganglionic acetylcholine receptors (gAChRs). The purpose of this review was to describe the characteristics of autonomic disturbance through previous case reports and the functional tests used in these studies and address the importance of anti-gAChR antibodies. We have established luciferase immunoprecipitation systems to detect antibodies against gAChR in the past and determined the prevalence of gAChR antibodies in various autoimmune diseases including AAG and rheumatic diseases. Autonomic dysfunction, which affects lower parasympathetic and higher sympathetic activity, is usually observed in ARD. The anti-gAChR antibodies may play a crucial role in autonomic dysfunction observed in ARD. Further studies are necessary to determine whether anti-gAChR antibody levels are correlated with the severity of autonomic dysfunction in ARD.