COVID-19-induced gastrointestinal autonomic dysfunction: A systematic review

Table 1 Factors affecting gastrointestinal autonomic nervous function

1 Psychological factors: Vigilance, stress, anxiety, and depression

2 Diet: A high-fat or protein diet slows digestion, while a high-fiber diet stimulates peristalsis

3 Exercise training: Moderate exercise can increase the motility and blood flow of the gastrointestinal tract. In contrast, prolonged or intense exercise can reduce blood flow to the gastrointestinal tract and shift blood flow to the muscles

4 Hormones: Cholecystokinin, gastrin, and secretin

5 Toxins: Such as toxic heavy metals (e.g., mercury or lead), alcohol, and industrial chemicals

6 Aging: Age-related neuronal loss in both intestinal myenteric and submucosal plexuses

7 Neurological disorders: Parkinson's disease, multiple sclerosis, amyloidosis, autonomic neuropathy, multiple system atrophy, amyotrophic lateral sclerosis, and autonomic dysreflexia such as in spinal cord injuries

8 Chronic metabolic disorders: Such as diabetes mellitus, hypothyroidism (hypothyroid gastroparesis and constipation), Addison's Disease (constipation, bloating, and abdominal discomfort), chronic kidney disease, chronic liver disease, Celiac disease, and inflammatory bowel disease

9 Infections: Viral gastroenteritis, bacterial infections (diphtheritic polyneuropathy, tetanus, and botulism), COVID-19, acute tick-borne encephalitis virus infections, Lyme disease, Chagas disease, human rabies, Guillain-Barre syndrome, and HIV/AIDS

COVID-19: Coronavirus disease 2019; HIV: Human immunodeficiency virus; AIDS: Acquired immunodeficiency syndrome.