Sympathetic Hyperactivity and Sympathovagal Imbalance in Amyotrophic Lateral Sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder with progressive loss of upper and lower motor neurons. Autonomic nervous abnormalities, including sympathetic hyperactivity and sympathovagal imbalance, have been found in both early and advanced stages of ALS. In early stage, the dysfunction may be subclinical. Occasionally, elevated blood pressure or heart rate and increased sweating may be observed. In advanced stage when ventilators are required, the sympathetic hyperactivity may lead to hypertensive crisis without counter-regulation of heart rate, followed by the consecutive circulatory collapse, known as the 'autonomic storm'. The symptoms of 'autonomic storm' are similar to that of 'baroreflex failure', and 'autonomic storm' indicates poor prognosis and may result in sudden death. Careful evaluation and individual treatment are strongly suggested, although appropriate therapeutic approaches have not been established. Causative central nervous lesions remain to be elucidated, although the limbic system may be involved. The autonomic dysfunction further supports the concept that ALS is a multisystem-degenerative disease. KeywordsAmyotrophic lateral sclerosis, autonomic nervous system, sympathetic hyperactivity, sympathovagal imbalance, baroreflex Disclosure: The author has no conflicts of interest to declare. Clinical and Haemodynamic StudiesThe autonomic nervous system is divided into sympathetic and

A rare case of full neurological recovery from severe nonexertional heatstroke during a bedrock bath

“…Although Hannuksela et al have reported the risks of sauna bathing, only one case report in Japanese on nonexertional heatstroke during a bedrock bath exists . Our case demonstrated that falling asleep in a bedrock bath might cause central sympathetic hyperactivity, which sometimes results in sudden death as a result of circulatory collapse …”

“…Her vital signs showed hypertensive crisis without counter‐regulation of heart rate, followed by the consecutive circulatory collapse every 2 hours, shown in Figure B. It was similar to “autonomic storm” found in amyotrophic lateral sclerosis, suggesting that limbic system may have been involved . The fluctuating blood pressure probably due to central sympathetic hyperactivity quitted on hospital day 5 without life‐threatening events.…”

Non‐motor manifestations in ALS patients with tracheostomy and invasive ventilation

“…Unstable blood pressure occasionally results in circulatory collapse and sudden death . Particularly, paroxysmal hypertensive attacks and subsequent nocturnal hypotension have been reported in ALS patients with TIV, and disease‐specific central sympathetic hyperactivity, sympathovagal imbalance, and secondary down‐regulation of peripheral alpha‐noradrenergic receptors might play a key role in these vasomotor symptoms . These vasomotor features may be similar to autonomic dysreflexia and central sympathetic de‐efferentation signs in cervical spinal cord injuries, but those in ALS are of a different pathophysiology, in which the central sympathetic tone is hyperactive.…”

“…Patients with ALS living with TIV often display non‐motor clinical manifestations over a long disease course, including macroglossia, autonomic dysfunction, glucose intolerance or hyperglycemia, infection, gall bladder or urinary stones, and decubitus ulcers . These may affect the quality of life and survival time of patients; however, their prevalence is unknown.…”

Cardiac Failure as an Unusual Presentation in a Patient with History of Amyotrophic Lateral Sclerosis

“…Further studies may be required to show the pathognomonic importance of autonomic dysfunction in ALS [8]. …”