J Neurol Neurosurg Psychiatry 1998;65:291–300 291 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.65.3.291 on 1 September 1998. Downloaded from NEUROLOGY AND MEDICINE Neurology and the gastrointestinal system G D Perkin, I Murray-Lyon The interrelation of neurology and the gas- that the two techniques are complementary, trointestinal system includes defects of gut acetylcholinesterase staining being particularly innervation, primary disorders of the nervous helpful when the biopsy material does not system (or muscle) which lead to gastrointesti- include submucosa, or in older infants or chil- nal symptoms—for example, dysphagia—and, dren in whom the population of distal submu- finally, certain gut disorders which include cosal ganglion cells may be less dense.6 neurological features in their clinical range. The first of this trio will be discussed only Gastrointestinal disorders due to briefly in this review, the second and third in neurological disease more detail. DYSPHAGIA A neurogenic mechanism for dysphagia, which Defects of innervation may have either sensory or motor components, ACHALASIA or both, can result from a disorder at the oral, Achalasia is characterised by an absence of pharyngeal, or oesophageal phase of swallow- peristalsis in the oesophageal body accompa- ing. In most patients, the neurological disorder nied by a failure of relaxation of the lower is evident, but in others, dysphagia is the oesophageal sphincter.1 Although the condi- presenting feature. Besides the dysphagia, tion can be secondary to other disease other symptoms suggesting a neurogenic copyright. processes—for example, Chagas’ disease—in mechanism include drooling of saliva, nasal Europeans it is usually a primary disorder. Dif- regurgitation, and episodes of coughing or fering opinions have been expressed as to choking during swallowing.7 Videofluoroscopy whether the problem of innervation rests in the has proved of particular value in the assessment dorsal motor vagal nucleus, the vagus itself, or of neurogenic dysphagia. The procedure allows in the intrinsic innervation of the oesophagus, identification of the site of maximal dysfunc- with most evidence favouring the last explana- tion, pinpoints areas of barium collection, and tion. By the time of oesophageal biopsy or indicates whether laryngeal penetration is resection, there is almost total loss of ganglion occurring.8 Neurogenic dysphagia may arise Department of cells with substantial destruction of myenteric from involvement of the cortical areas con- Neuroscience and nerves. The changes are accompanied by an cerned with swallowing, their eVerent pathway, http://jnnp.bmj.com/ Psychological Medicine, The inflammatory reaction both within and around the brain stem motor or sensory nuclei, the Hammersmith Trust the nerves. Neurochemical analysis has shown lower cranial nerves in their distal course, their Hospitals, Charing a reduction in the number of neurons in the neuromuscular junctions, or the striated mus- Cross Hospital, myenteric plexus containing immunoreactive cle components of the swallow pathway. London, UK vasoactive intestinal polypeptide.2 The way in G D Perkin which the disease evolves remains unclear. STROKE Department of Stroke is the commonest cause of neurogenic Gastroenterology, HIRSCHSPRUNG’S DISEASE dysphagia. Up to 50% of patients with stroke on September 24, 2021 by guest. Protected Chelsea and Hirschprung’s disease presents at, or soon have been estimated to have dysphagia, albeit Westminster after, birth. Constipation is accompanied by temporary in many. Dysphagia is a recognised Healthcare NHS Trust, gaseous abdominal distension. Typically a nar- feature of unilateral as well as bilateral Chelsea and rowed distal segment of bowel is demonstrable hemispheric stroke and is commonplace in Westminster Hospital, London, UK in which there is loss of parasympathetic brain stem stroke. Most studies of dysphagia in 3 I Murray-Lyon ganglion cells from the intramural plexus. The cases of unilateral hemispheric stroke have aganglionosis is the result of incomplete migra- been retrospective, but in one prospective Correspondence to: tion of neurenteric ganglion cells from the neu- study, swallow function was analysed with Dr GD Perkin, Department of Neuroscience and ral crest to the most distal part of the gut. respect to the size and distribution of ischaemic 9 Psychological Medicine, Increased acetylcholinesterase activity has been stroke in middle cerebral artery territory. Imperial College School of detected in the submucosal and myenteric Attempts to correlate swallow patterns with Medicine, Charing Cross Hospital, Fulham Palace plexus of the aVected bowel segment. Besides stroke site were hampered by the fact that Road,London, W6 8RF, UK. using histological criteria for diagnosis— stroke volumes for lesions in the anterior terri- namely, the presence or absence of ganglion tory of the middle cerebral artery were Received 11 February 1998 cells in rectal biopsy4—acetylcholinesterase substantially larger than those in the posterior and in revised form 15 May 1998 Accepted 15 activity can be measured in the same territory of the artery. Pharyngeal transit time May 1998 specimen.5 Further experience has established was prolonged, compared with controls, with 292 Perkin, Murray-Lyon J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.65.3.291 on 1 September 1998. Downloaded from lesions in either hemisphere. Laryngeal pen- movements, a delayed swallowing reflex, aspi- etration and aspiration were much more ration, and reduced pharyngeal peristalsis. common in the right hemisphere group. In Videofluoroscopy has allowed a more detailed general, however, attempts to correlate charac- analysis, particularly necessary as patients’ teristics of unilateral lesions with impairment symptoms correlate poorly with the type of of swallowing have not produced consistent swallow problem.16 Silent laryngeal aspiration findings. Data from experimental animals has is commonly found. Alhough opinions diVer, suggested that stimulation of either cortex can recent studies indicate that, for some patients, initiate swallowing.10 Transcranial magneto- significant improvement in swallow function electric stimulation has been used to study the occurs with medication. Patients with Parkin- projections of the corticofugal fibres involved. son’s disease who deny swallowing diYculties The oral muscles are represented symmetri- have also been studied.17 In such a group of 16 cally between the two hemispheres, whereas patients, all had some abnormality and three muscles of the pharynx and oesophagus tend to had silent aspiration. Their mean Webster be represented asymmetrically, but without score (used as an assessment of their disability) regard to speech dominance.11 The technique was 11, indicating relatively mild disease, and has been applied to the analysis of patients with assessments were performed at the time of the unilateral hemispheric stroke, with or without midday meal. dysphagia.12 In patients with dysphagia, pha- Dysphagia is a prominent feature of progres- ryngeal responses from the unaVected hemi- sive supranuclear palsy18 and is a recognised sphere are smaller than those in non-dysphagic finding in both Huntington’s and Wilson’s dis- patients, irrespective of the side of the lesion, or ease. Dysphagia in patients with spasmodic whether it is cortical or subcortical. The mylo- torticollis partly relates to the variable head and hyoid responses (taken as representative of oral neck posture but, in addition, delay in reflex swallowing musculature) do not display such initiation and the finding of pharyngeal residue asymmetry. It has been suggested that this on videofluoroscopy suggests a neurogenic implies that pharyngeal function is represented component.19 asymmetrically in the cortex, and that with damage to the hemisphere containing the pre- dominant pharyngeal centre, swallowing func- OTHER NEUROGENIC DISORDERS tion cannot be maintained by the “non- Besides stroke and multiple sclerosis, other dominant” hemisphere. Clearly, if this brain stem pathologies are associated with dys- hypothesis is correct, an alternative mechanism phagia. In the Chiari type 1 malformation, her- copyright. for dysphagia must exist in the small niation of the cerebellar tonsils through the proportion of patients with a predominant oral foramen magnum results in traction of the phase disorder of swallowing after hemispheric lower cranial nerves, secondary compression of stroke. the brain stem, and, in some patients, hydro- Some degree of swallow diYculty is remark- cephalus. Dysphagia is common in such ably common after unilateral hemispheric patients and is associated with a global impair- stroke. It was reported in nearly 30% of one ment of all phases of swallowing on series, based on the bedside assessment of videofluoroscopy.20 In some patients, dysphagia swallowing liquid.13 Some evidence was found has been the presenting feature. Palatal hypo- for an adverse eVect on functional outcome if aesthesia has usually been the norm, however, dysphagia was present. By one month after when such patients have been carefully 21 22 onset of stroke, only 2% of patients with assessed. http://jnnp.bmj.com/ unilateral stroke are still dysphagic. Clearly any Disorders of the lower motor neuron or neu- hypothesis regarding the pathogenesis of dys- romuscular junction that often result in dys- phagia after unilateral stroke needs to explain phagia include the Guillain-Barré syndrome, the transient nature