Brainstem Stroke and Increased Anal Tone

Gastrointestinal Dysfunction in Multiple Sclerosis and Related Conditions

Nervous system disorders may be accompanied by gastrointestinal (GI) dysfunction. Brain lesions may be responsible for GI problems such as decreased peristalsis (e.g., lesions in the basal ganglia, pontine defecation center/Barrington's nucleus), decreased abdominal strain (e.g., lesions in the parabrachial nucleus), hiccupping and vomiting (e.g., lesions in the area postrema), and appetite loss (e.g., lesions in the hypothalamus). Decreased peristalsis also may be caused by lesions of the spinal long tracts or the intermediolateral nucleus projecting to the myenteric plexus. This review addresses GI dysfunction caused by multiple sclerosis, neuromyelitis optica spectrum disorder, and myelin oligodendrocyte glycoprotein-associated disorder. Neuro-associated GI dysfunction may develop concurrently with brain or spinal cord dysfunction or may predate it. Collaboration between gastroenterologists and neurologists is highly desirable when caring for patients with GI dysfunction related to nervous system disorders, particularly since patients with these symptoms may visit a gastroenterologist prior to the establishment of a neurological diagnosis.

Gastrointestinal dysfunction in neuroinflammatory diseases: Multiple sclerosis, neuromyelitis optica, acute autonomic ganglionopathy and related conditions

Disorders of the nervous system can produce a variety of gastrointestinal (GI) dysfunctions. Among these, lesions in various brain structures can cause appetite loss (hypothalamus), decreased peristalsis (presumably the basal ganglia, pontine defecation center/Barrington's nucleus), decreased abdominal strain (presumably parabrachial nucleus/Kolliker-Fuse nucleus) and hiccupping and vomiting (area postrema/dorsal vagal complex). In addition, decreased peristalsis with/without loss of bowel sensation can be caused by lesions of the spinal long tracts and the intermediolateral nucleus or of the peripheral nerves and myenteric plexus. Recently, neural diseases of inflammatory etiology, particularly those affecting the PNS, are being recognized to contribute to GI dysfunction. Here, we review neuroinflammatory diseases that potentially cause GI dysfunction. Among such CNS diseases are multiple sclerosis, neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein associated disorder, and autoimmune encephalitis. Peripheral nervous system diseases impacting the gut include Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, acute sensory-autonomic neuropathy/acute motor-sensory-autonomic neuropathy, acute autonomic ganglionopathy, myasthenia gravis and acute autonomic neuropathy with paraneoplastic syndrome. Finally, collagen diseases, such as Sjogren syndrome and systemic sclerosis, and celiac disease affect both CNS and PNS. These neuro-associated GI dysfunctions may predate or present concurrently with brain, spinal cord or peripheral nerve dysfunction. Such patients may visit gastroenterologists or physicians first, before the neurological diagnosis is made. Therefore, awareness of these phenomena among general practitioners and collaboration between gastroenterologists and neurologists are highly recommended in order for their early diagnosis and optimal management, as well as for systematic documentation of their presentations and treatment.

Gastrointestinal dysfunction in movement disorders

PURPOSE OF REVIEW

This article provides an overview of the clinical presentation, investigations, and treatment options for gastrointestinal tract (GIT) dysfunction in patients with Parkinson's disease (PD) and other movement disorders.

RECENT FINDINGS

GIT dysfunction commonly appears as constipation and fecal incontinence (mostly overflow, accompanied with sphincter failure in multiple system atrophy [MSA]). Bowel dysfunction (underactive) occurs irrespectively from the site of the neurologic lesion, which is in contrast to site-dependent bladder dysfunction (brain, overactive; periphery, underactive). GI emergencies may arise, including intestinal pseudo-obstruction, intussusception, volvulus, and stercoral ulcer (ulcer of the colon due to pressure and irritation resulting from severe, prolonged constipation). Bowel function tests in neurologic patients often show a combination of slow transit and anorectal dysfunction. Management for slow transit constipation includes bulking agents, softening agents, yogurt/probiotics, and prokinetic agents. Suppositories, botulinum toxin injections, and transanal irrigation are options for managing anorectal constipation.

CONCLUSIONS

Function of the bowel is commonly affected in PD and other movement disorders. Neurologists play an important role in assessing bowel symptoms in their patients and planning treatment strategies, often in collaboration with specialist teams.

Lower Urinary Tract and Bowel Dysfunction in Neurologic Disease

PURPOSE OF REVIEW

This article provides an overview of the clinical presentation, investigations, and treatment options for lower urinary tract and bowel dysfunction in patients with neurologic diseases.

RECENT FINDINGS

The site of the neurologic lesion influences the pattern of lower urinary tract dysfunction. Antimuscarinic agents are first-line management for urinary incontinence; however, the side effect profile should be considered when prescribing them. β3-Receptor agonists are a promising alternative oral medication. Botulinum toxin injections into the detrusor have revolutionized the management of neurogenic detrusor overactivity.Bowel dysfunction commonly presents as constipation and fecal incontinence. Gastrointestinal emergencies may arise, including intestinal pseudoobstruction, intussusception, volvulus, and stercoral ulcer (ulcer of the colon due to pressure and irritation resulting from severe, prolonged constipation). Bowel function tests in neurologic patients often show a combination of slow transit and anorectal dysfunction. Management for slow transit constipation includes bulking agents, softening agents, yogurt/probiotics, and prokinetic agents. Suppositories, botulinum toxin injections, and transanal irrigation are options for managing anorectal constipation.

SUMMARY

Functions of the lower urinary tract and bowel are commonly affected in neurologic disease. Neurologists play an important role in assessing lower urinary tract and bowel symptoms in their patients and planning treatment strategies, often in collaboration with specialist teams.

Central pattern generators in the brainstem and spinal cord: an overview of basic principles, similarities and differences

Central pattern generators (CPGs) are generally defined as networks of neurons capable of enabling the production of central commands, specifically controlling stereotyped, rhythmic motor behaviors. Several CPGs localized in brainstem and spinal cord areas have been shown to underlie the expression of complex behaviors such as deglutition, mastication, respiration, defecation, micturition, ejaculation, and locomotion. Their pivotal roles have clearly been demonstrated although their organization and cellular properties remain incompletely characterized. In recent years, insightful findings about CPGs have been made mainly because (1) several complementary animal models were developed; (2) these models enabled a wide variety of techniques to be used and, hence, a plethora of characteristics to be discovered; and (3) organizations, functions, and cell properties across all models and species studied thus far were generally found to be well-preserved phylogenetically. This article aims at providing an overview for non-experts of the most important findings made on CPGs in in vivo animal models, in vitro preparations from invertebrate and vertebrate species as well as in primates. Data about CPG functions, adaptation, organization, and cellular properties will be summarized with a special attention paid to the network for locomotion given its advanced level of characterization compared with some of the other CPGs. Similarities and differences between these networks will also be highlighted.