From the Guidelines
Yes, autonomic neuropathy is a major cause of gastroparesis, as it damages the vagus nerve, leading to impaired gastric emptying, particularly in diabetes mellitus. According to the most recent evidence from 1, gastroparesis should be suspected in individuals with erratic glycemic management or with upper gastrointestinal symptoms without another identified cause. The damage to the vagus nerve disrupts the normal coordinated muscle contractions (peristalsis) that move food through the digestive tract, causing food to remain in the stomach longer than normal.
Causes and Risk Factors
The causes of autonomic neuropathy that can lead to gastroparesis include diabetes mellitus, Parkinson's disease, multiple sclerosis, amyloidosis, and certain autoimmune conditions. As noted in 1, gastroparesis is arguably the most important manifestation of gastrointestinal autonomic neuropathy, affecting about 30–50% of outpatients with longstanding type 1 or type 2 diabetes.
Symptoms and Diagnosis
Patients typically experience symptoms such as nausea, vomiting, early satiety, bloating, and abdominal pain. The diagnostic gold standard for gastroparesis is the measurement of gastric emptying with scintigraphy of digestible solids at 15-min intervals for 4 h after food intake, as stated in 1. The use of 13 C octanoic acid breath test is an approved alternative.
Management and Treatment
Management includes dietary modifications (small, frequent, low-fat, low-fiber meals), glycemic control in diabetic patients, and medications such as metoclopramide, domperidone (where available), or erythromycin to enhance gastric motility. In severe cases, interventions like gastric electrical stimulation or surgical options may be considered. As mentioned in 1, the etiology of gastroparesis is multifactorial, and diabetic gastroparesis is believed to represent a form of neuropathy involving the vagus nerve.
Key Considerations
It is essential to exclude reversible/iatrogenic causes such as medications or organic causes of gastric outlet obstruction or peptic ulcer disease before considering a diagnosis of or specialized testing for gastroparesis, as noted in 1. The relationships among symptoms, disordered gastrointestinal motility, and autonomic neuropathy are relatively weak, as stated in 1. However, the most recent and highest quality study 1 prioritizes the diagnosis and management of gastroparesis in the context of autonomic neuropathy, emphasizing the importance of early detection and treatment to improve patient outcomes.
From the Research
Autonomic Neuropathy and Gastroparesis
- Autonomic neuropathy can affect the function of any gut segment from the esophagus to the anus, and is a manifestation of diabetic autonomic neuropathy that impacts negatively on quality of life 2.
- Diabetic gastroparesis, or abnormally delayed gastric emptying, occurs frequently and is the best characterized manifestation of gastrointestinal autonomic neuropathy 2.
- Autonomic dysfunction may play an important role in the pathophysiology of gastroparesis, and altered central processing and autonomic dysfunction may be important factors in the pathogenesis of gastroparesis 3.
Relationship between Autonomic Neuropathy and Gastroparesis
- Autonomic dysfunction can be present in patients with idiopathic and diabetic gastroparesis, and parasympathetic dysfunction was associated with delayed gastric emptying and more severe upper gastrointestinal symptoms 4.
- Sympathetic hypofunction was associated with milder symptoms, and gastroparesis and chronic unexplained nausea and vomiting may be a manifestation of GI autonomic dysfunction or imbalance 4.
- Autonomic neuropathy can cause gastroparesis, as evidenced by the fact that diabetic autonomic neuropathy can lead to gastrointestinal autonomic neuropathy, which in turn can cause gastroparesis 2, 5.
Treatment of Gastroparesis
- Current management options for gastrointestinal autonomic neuropathy are, for the main part, empirical and sub-optimal, but treatments such as dietary modifications, medication adjustments, glucose control, antiemetic agents, and prokinetic agents are available 2, 6.
- New, highly selective 5-hydroxytryptamine 4 (5-HT4) agonists appear safe and may be effective in improving symptoms of gastric emptying, and gastric peroral endoscopic myotomy (G-POEM) may be a durable treatment option for refractory gastroparesis 3, 6.