Reduced brain blood flow linked to dizziness in hypermobile EDS
Researchers matched the medical records of 270 patients, 29 healthy people
Nearly every person with hypermobile Ehlers-Danlos syndrome (hEDS) had reduced blood flow in the brain when they stood up, a phenomenon linked with orthostatic intolerance, that is, symptoms such as dizziness on standing up from sitting or lying down, a study shows.
Hallmark features of hEDS, the most common type of EDS, include hypermobile joints that frequently dislocate, fragile skin that tends to bruise and bleed easily, and scoliosis. But hEDS patients generally also see mild, but widespread, dysfunction of their autonomic nervous system, which regulates involuntary processes like heart rate, blood pressure, breathing, and digestion.
Orthostatic intolerance is another indicator of autonomic problems and are thought to be due to reduced blood flow to the brain. Neuropathic pain, that is, nerve damage marked by a shooting or burning pain, has also been reported.
“[hEDS] affects multiple systems, however, a comprehensive analysis of cerebrovascular, autonomic, and neuropathic features in a larger sample is lacking,” wrote researchers who reviewed the medical records of 270 hEDS patients and compared them to 29 healthy people matched by age, sex, and body mass index. A measure of body fat, body mass index, or BMI, takes both weight and height into account. Their study, “Hypermobile Ehlers-Danlos Syndrome: Cerebrovascular, Autonomic and Neuropathic Features,” was published in the American Journal of Medicine Open.
Brain blood flow in hEDS
In the study, all the people with hEDS reported at least one autonomic symptom and they had significantly higher scores on the Survey of Autonomic Symptoms (SAS) than the controls, indicating worse symptoms. In fact, nearly all the hEDS patients (98.1%) had clinically significant abnormal SAS scores, whereas none in the healthy control group did. The most common symptom of orthostatic intolerance was lightheadedness.
All the hEDS patients also had neuropathic pain, mostly aching and prickling pain, which occurred more often and was more severe for them than the controls. Clinically significant Neuropathy Total Symptom Scores (NTSS) were observed in most hEDS patients (88.8%), but not in the controls.
In autonomic testing, blood pressure during a heartbeat while lying down and mean cerebral blood flow velocity were significantly lower in hEDS patients. At the same time, the supine cerebrovascular resistance index, or the resistance to blood flow in the brain while lying down, was higher.
A tilt-table test, which measures the reaction to changes in body position, induced a greater drop in cerebral blood flow velocity in hEDS than in controls. In an upright position, the cerebrovascular resistance index was higher in hEDS, and the levels of carbon dioxide measured at the end of each exhaled breath (end-tidal CO2) were lower. Most hEDS patients (79.3%) had reduced brain blood flow when standing, overall.
Lightheadedness or dizziness during the tilt-table test was more common in hEDS than controls (72.6% vs. 20.7%). About a third of the hEDS patients had postural orthostatic tachycardia syndrome (POTS), that is, a fast heart rate and dizziness when standing up. And about 1 in 5 had one of two types of reduced blood flow to the brain: hypocapnic cerebral hypoperfusion (21.5%) and orthostatic cerebral hypoperfusion syndrome (18.1%). Orthostatic hypotension, a drop in blood pressure after standing up, with normal cerebral blood flow, was found in 12.5% of the hEDS patients.
Small fiber neuropathy, or damage to the nerves involved in pain and temperature sensation and autonomic function, was detected in most (81.7%) hEDS patients, based on symptoms and abnormal skin biopsy findings or related tests.
In a measure that combined test results related to autonomic dysfunction, cerebral blood flow abnormalities, and neuropathic involvement, nearly all the hEDS patients (90%) had autonomic failure, most often mild.
In a statistical analysis, age and cerebral blood flow velocity while standing up predicted upright lightheadedness/dizziness, but not other autonomic features.
“The most significant finding of this study is the presence of cerebrovascular dysregulation associated with reduced cerebral blood flow that can result in cerebral hypoperfusion, orthostatic intolerance, and impaired well-being,” the researchers wrote.
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