From the Guidelines
Dysautonomia causes nausea by disrupting the autonomic nervous system's control over digestion, leading to gastroparesis, orthostatic hypotension, and vagus nerve dysfunction. The pathophysiological mechanism involves the autonomic nervous system's role in modulating gastrointestinal motor, sensory, and secretory functions, as described in the study by 1. When the autonomic nervous system malfunctions, it can slow gastric emptying, causing food to remain in the stomach longer than normal, leading to nausea and bloating. Additionally, dysautonomia often affects blood pressure regulation, causing sudden drops in blood pressure (orthostatic hypotension) that can trigger nausea, especially when changing positions. The vagus nerve, which helps regulate digestive processes, may become overactive or underactive in dysautonomia, further contributing to nausea symptoms. Key points to consider in the management of dysautonomia-related nausea include:
- Medications such as antiemetics like ondansetron, promethazine, or metoclopramide for gastroparesis
- Pyridostigmine to improve gut motility
- Non-pharmacological approaches like eating smaller, more frequent meals, staying well-hydrated, avoiding trigger foods, and using compression garments to help maintain blood pressure, as supported by the study 1. Understanding that nausea in dysautonomia stems from these autonomic regulatory problems helps explain why traditional nausea treatments may not always be effective and why a comprehensive approach addressing the underlying autonomic dysfunction is often necessary, as noted in the context of autonomic nervous system dysfunction 1.
From the Research
Pathophysiological Mechanism of Dysautonomia-Induced Nausea
The pathophysiological mechanism by which Dysautonomia causes nausea is complex and involves the interplay of multiple systems, including the autonomic nervous system, central nervous system, and gastrointestinal tract.
- The autonomic nervous system plays a crucial role in regulating various bodily functions, including digestion and gut motility 2.
- Dysautonomia, a disorder characterized by altered function of the autonomic nervous system, can disrupt these regulatory processes, leading to nausea and other gastrointestinal symptoms 3, 4.
- The central pathways of nausea and vomiting involve the nucleus tractus solitarius, which receives signals from the gastrointestinal tract via the vagus nerve and relays them to the central pattern generator, initiating downstream pathways that can lead to nausea 2.
- The autonomic nervous system modulates these central pathways, and dysfunction of the autonomic nervous system, as seen in Dysautonomia, can alter this modulation, contributing to the development of nausea 2, 5.
- Additionally, the extended autonomic system, which includes neuroendocrine, immune/inflammatory, and central components, may also play a role in the pathophysiology of Dysautonomia-induced nausea 5.
- The homeostat theory, which proposes the existence of comparators that receive information about regulated variables and sense discrepancies between the information and response algorithms, may also be relevant to understanding the pathophysiological mechanisms of Dysautonomia-induced nausea 5.