Familial amyloid polyneuropathy (FAP) is linked to important alterations of the autonomic nervous system, which regulates certain body processes such as breathing, heart rate, and digestion, according to researchers.
This finding resulted from a study led by Alejandra Gonzalez‑Duarte, a neurologist at the Salvador Zubirán National Institute of Medical Sciences and Nutrition in Mexico City, which evaluated autonomic dysfunction in FAP patients at early stages of the disease.
The results of the study will be presented at the 2018 American Academy of Neurology (AAN) Annual Meeting April 21-27 in Los Angeles.
The poster presentation is titled “Autonomic description in patients with very early TTR amyloidosis (Familial Amyloid Polyneuropathy)” and will be presented on April 24 in a session tiled Autonomic Disorders: Autonomic Neuropathies.
Dysfunction of the autonomic nervous system is commonly overlooked. In most cases, it consists of low blood pressure in a resting position (called orthostatic hypotension), but it can also manifest as sexual impotence, erectile dysfunction, altered gastrointestinal motility, skin blistering in the hands and feet (dyshidrosis), and abnormal bladder control.
All these symptoms can severely affect patients’ quality of life, and loss of control of the cardiovascular system can lead to a life-threatening event such as arrhythmia, or even sudden death.
The research team evaluated 33 patients diagnosed with FAP who were in the early stages of the disease. They had reduced peripheral nerve damage as determined by low mean neuropathic impairment score (NIS), neuropathic total symptom scores (NTSS-6), and UTAH early neuropathic scale.
An analysis of the patients’ heart rates showed they were below the levels expected for their age.
Patients older than 40 were found to have significantly more heartbeat impairments than younger patients, as demonstrated by several tests. Approximately 42% of these patients showed abnormal heart rate response to blood pressure changes.
In addition, patients older than 40 were also found to have reduced heart rate variability, which is known to be associated with a higher risk of mortality.
Collectively, these findings demonstrate that “even at a very early stage of somatic neuropathy the patients showed important alterations in all autonomic tests,” the researchers wrote.
The results are also in line with a study published earlier this year by neurologist Alejandra Gonzalez‑Duarte in which she emphasized the need for guidelines and standardized protocols to evaluate the autonomic nervous system in FAP patients.