Gastrointestinal dysfunction in neuroinflammatory diseases

Nervous system has ‘guts’ to produce a variety of gastrointestinal (GI) dysfunction. Among these, focal brain disease causes appetite loss (hypothalamus), decreased peristalsis (presumably the basal ganglia, pontine defecation center/ Barrington's nucleus), decreased abdominal strain (presumably parabrachial nucleus/ Kolliker-Fuse nucleus), hiccup and vomiting (area postrema/ dorsal vagal complex); spinal cord disease causes decreased peristalsis and anismus (tracts, the intermediolateral nucleus) (CNS); and disease affecting the peripheral nerve including the myenteric plexus causes decreased peristalsis with/without loss of bowel sensation (PNS). Recently inflammatory causes of the nervous diseases, particularly those affecting the PNS, are being recognized to contribute to GI dysfunction of previously-unknown etiology. We briefly review neuroinflammatory diseases that potentially cause GI dysfunction, e.g., multiple sclerosis, neuromyelitis optica spectrum disorder (anti-aquaporin 4 or MOG antibody), autoimmune acute myelitis, subacute disseminated encephalomyelitis, and autoimmune encephalitis (anti-NMDA glutamate receptor antibody etc.) (CNS); Guillain-Barre syndrome (anti-ganglioside antibody etc.), acute sensory-autonomic neuropathy/ acute pandysautonomia (anti-nicotinic ganglionic acetylcholine receptor [gAChR] antibody), pure autonomic failure (anti-gAChR antibody in some), paraneoplastic sensory-autonomic neuropathy (anti-Hu, CRPMP5, gAChR, VGKC antibody etc.), (selective organs) paraneoplastic/idiopathic intestinal pseudo-obstruction and achalasia (anti-gAChR antibody in some), and collagen diseases affecting both CNS and PNS (Sjogren syndrome, scleroderma, etc.). These GI dysfunctions may occur solely, predate, or occur concurrent with other nervous system symptoms. Such patients may visit gastroenterologists or physicians first before the correct diagnosis was made. Therefore, collaboration of gastroenterologists and neurologists are highly recommended in order for the early diagnosis and optimal management.