Dysautonomia (or autonomic dysfunction, autonomic neuropathy) is an umbrella term for various conditions in which the autonomic nervous system (ANS) does not work correctly.
Dysautonomia is a type of neuropathy affecting the nerves that carry information from the brain and spinal cord to the heart, bladder, intestines, sweat glands, pupils, and blood vessels. Dysautonomia may be experienced in a number of ways, depending on the organ system involved, for example difficulty adapting to changes in posture, or digestive symptoms.
Autonomic dysfunction is one of the predictors of poor outcome in patients with acute ischemic stroke.
The diagnosis is achieved through functional testing of the autonomic nervous system, focusing on the organ system affected. Investigations may be performed to identify underlying disease processes that may have led to the autonomic neuropathy that is causing the dysautonomia.
Symptomatic treatment is available for many symptoms associated with autonomic neuropathy, and some disease processes can be treated directly.
Results indicate the presence of sympathetic dysregulation and impairment of parasympathetic modulation of heart function in primary Raynaud's patients. The different cardiovascular and sudomotor functions are not affected to the same degree. These observations might support the theory of a central impairment of autonomic function in primary Raynaud's phenomenon. Peripheral nerve lesion as a coexisting cause of the observed dysautonomy remains uncertain 1).
Cerebral lesion due to different neurological conditions could be complicated by autonomic dysfunction, reported in the literature as a sympathetic hyperactivity. The mechanisms of dysautonomia still remains partial. The aim of a study was to assess the profile of autonomic dysfunction in patient with primary brain tumors, with attempt to estimate the additional factors in pathogenesis of dysautonomia.
Neurological examinations, the Low's autonomic disorder questionnaire, electrophysiological autonomic tests (Heart Rate Variability test at rest and during deep breathing, spectral analysis of R-R intervals, sympathetic skin response test), studies of peripheral nerves, blood sampling collection for antibodies were done in 33 patients with recognized primary brain tumors.
The averaged Low's Questionnaire score in the patients group was significantly higher than in the controls, systolic blood pressure was increased, heart rate tended to be higher without significance, but heart rate variability was severe low, LF/HF ratio also tended to be higher in the patients group. In SSR test the amplitude of responses from hand and foot was significantly lower without changes in their latencies. We found changes in the electrophysiological tests of peripheral nerves, and positive anti-neural antibodies in 5 patients.
The results of the study indicated to the sympathetic nervous system hyperactivity in patients with primary brain tumors. Local brain lesion with high intracranial pressure, additional peripheral nerve damage probably in the course of autoimmunity, and direct influence of autoimmunity to the central part of autonomic nervous system are possible in the pathogenesis of dysautonomia 2).