Colorectal responses to distension and feeding in patients with spinal cord injury

Editorial: The unquenchable thirst for drinks and diets as treatments for constipation

This article is linked to van der Schoot et al paper. To view this article, visit https://doi.org/10.1111/apt.17782

Changes in gut microbiota in the acute phase after spinal cord injury correlate with severity of the lesion

After spinal cord injury (SCI), patients face many physical and psychological issues including intestinal dysfunction and comorbidities, strongly affecting quality of life. The gut microbiota has recently been suggested to influence the course of the disease in these patients. However, to date only two studies have profiled the gut microbiota in SCI patients, months after a traumatic injury. Here we characterized the gut microbiota in a large Italian SCI population, within a short time from a not only traumatic injury. Feces were collected within the first week at the rehabilitation center (no later than 60 days after SCI), and profiled by 16S rRNA gene-based next-generation sequencing. Microbial profiles were compared to those publicly available of healthy age- and gender-matched Italians, and correlated to patient metadata, including type of SCI, spinal unit location, nutrition and concomitant antibiotic therapies. The gut microbiota of SCI patients shows distinct dysbiotic signatures, i.e. increase in potentially pathogenic, pro-inflammatory and mucus-degrading bacteria, and depletion of short-chain fatty acid producers. While robust to most host variables, such dysbiosis varies by lesion level and completeness, with the most neurologically impaired patients showing an even more unbalanced microbial profile. The SCI-related gut microbiome dysbiosis is very likely secondary to injury and closely related to the degree of completeness and severity of the lesion, regardless of etiology and time interval. This microbial layout could variously contribute to increased gut permeability and inflammation, potentially predisposing patients to the onset of severe comorbidities.

Bowel Dysfunction in Spinal Cord Injury

PURPOSE OF REVIEW

To evaluate and report current evidence regarding the management of bowel dysfunction in spinal cord injury. There is a paucity of high-quality large studies on which to base management advice.

RECENT FINDINGS

Recent research has focused on defining the nature of symptomatology of bowel dysfunction in SCI and describing the effects on quality of life and social interactions. Technical aspects of colonoscopy have received attention, and aspects of understanding the pathophysiology in relation to both neural and non-neural dysfunction have been studied. There has been refinement and expansion of the pharmacological and non-pharmacological treatment options for bowel dysfunction in SCI. Management of bowel dysfunction in SCI requires a comprehensive and individualized approach, encompassing lifestyle, toileting routine, stimulation, diet, medications, and surgery. Further high-quality research is required to inform best practice.

Colonic transit time and pressure based on Bernoulli's principle

PURPOSE

Variations in the caliber of human large intestinal tract causes changes in pressure and the velocity of its contents, depending on flow volume, gravity, and density, which are all variables of Bernoulli's principle. Therefore, it was hypothesized that constipation and diarrhea can occur due to changes in the colonic transit time (CTT), according to Bernoulli's principle. In addition, it was hypothesized that high amplitude peristaltic contractions (HAPC), which are considered to be involved in defecation in healthy subjects, occur because of cecum pressure based on Bernoulli's principle.

METHODS

A virtual healthy model (VHM), a virtual constipation model and a virtual diarrhea model were set up. For each model, the CTT was decided according to the length of each part of the colon, and then calculating the velocity due to the cecum inflow volume. In the VHM, the pressure change was calculated, then its consistency with HAPC was verified.

RESULTS

The CTT changed according to the difference between the cecum inflow volume and the caliber of the intestinal tract, and was inversely proportional to the cecum inflow volume. Compared with VHM, the CTT was prolonged in the virtual constipation model, and shortened in the virtual diarrhea model. The calculated pressure of the VHM and the gradient of the interlocked graph were similar to that of HAPC.

CONCLUSION

The CTT and HAPC can be explained by Bernoulli's principle, and constipation and diarrhea may be fundamentally influenced by flow dynamics.

Colonic content in health and its relation to functional gut symptoms

BACKGROUND

Gut content may be determinant in the generation of digestive symptoms, particularly in patients with impaired gut function and hypersensitivity. Since the relation of intraluminal gas to symptoms is only partial, we hypothesized that non-gaseous component may play a decisive role.

METHODS

Abdominal computed tomography scans were evaluated in healthy subjects during fasting and after a meal (n = 15) and in patients with functional gut disorders during basal conditions (when they were feeling well) and during an episode of abdominal distension (n = 15). Colonic content and distribution were measured by an original analysis program.

KEY RESULTS

In healthy subjects both gaseous (87 ± 24 mL) and non-gaseous colonic content (714 ± 34 mL) were uniformly distributed along the colon. In the early postprandial period gas volume increased (by 46 ± 23 mL), but non-gaseous content did not, although a partial caudad displacement from the descending to the pelvic colon was observed. No differences in colonic content were detected between patients and healthy subjects. Symptoms were associated with discrete increments in gas volume. However, no consistent differences in non-gaseous content were detected in patients between asymptomatic periods and during episodes of abdominal distension.

CONCLUSIONS & INFERENCES

In patients with functional gut disorders, abdominal distension is not related to changes in non-gaseous colonic content. Hence, other factors, such as intestinal hypersensitivity and poor tolerance of small increases in luminal gas may be involved.

Bowel dysfunction in spinal cord injury: current perspectives

Permanent disruptions of gastrointestinal function are very common sequel of spinal cord injury (SCI). When motor and sensory nervous integrity are severely affected, neurogenic gastrointestinal dysfunction is an inevitable consequence. Autonomic nervous system miss function has significantly diminished or lost sensory sensations followed with incomplete evacuation of stool from the rectal vault, immobility, and reduced anal sphincter tone all of those predisposing to increased risk of fecal incontinence (FI). The FI is, beside paralysis of extremities, one of the symptoms most profoundly affecting quality of life (QOL) in patients with SCI. We are reviewing current perspectives in management of SCI, discussing some pathophysiology mechanisms which could be addressed and pointing toward actual practical concepts in use for evaluation and improvements necessary to sustain SCI patients QOL.

Rectal hyposensitivity for non-noxious stimuli, postprandial hypersensitivity and its correlation with symptoms in complete spinal cord injury with neurogenic bowel dysfunction

STUDY DESIGN

Prospective clinical study.

OBJECTIVES

To assess fasting and postprandial (PP) perception of rectal distension and its correlation with symptoms in patients with spinal cord injury (SCI) and neurogenic bowel dysfunction compared to ten healthy subjects (HS).

SETTING

Experimental Medicine and Motility Unit, Mexico General Hospital and National Institute of Rehabilitation.

METHODS

Twenty patients with complete SCI at cervical, thoracic and lumbar levels [American Spinal Injury Association (ASIA) A] were studied. Rectal sensitivity was evaluated with a barostat.

RESULTS

In SCI patients, while lower the rectal tone more time was used for defecate (R=0.50, P=0.048) and more PP episodes of fecal incontinence occur (R=0.54, P=0.030). The thresholds for non-noxious stimuli of first (23.6 mmHg, CI 19.5-27.7) vs 14.0 (CI 10.9-17.1), P=0.004; gas (27.9 mmHg, CI 19.9-35.8) vs 17.9 mmHg (CI 14.25-21.69), P=0.02 and urge-to-defecate sensation (33.2 mmHg, CI 27.5-38.8) vs 22.4 mmHg (CI 17.9-26.9), P=0.01 were reported by SCI patients at higher pressure than HS, respectively. SCI patients reported PP pain sensation at a lower pressure than controls (27.8 mmHg, CI 21.5-34.2 vs 36.5 mmHg, CI 31.8-41.2), P=0.04.

CONCLUSION

SCI patients preserve rectal sensation, present rectal hyposensitivity for non-noxious stimuli and PP hypersensitivity. Lower rectal tone was related to the time used for defecate and with fecal incontinence. The results suggest that an intact neural transmission between the spinal cord and higher centres is indispensable for noxious stimulus, but not for non-noxious stimuli. Also, barostat sensitivity studies can complement ASIA criteria to verify a complete injury.

Acute effect of electrical stimulation of the dorsal genital nerve on rectal capacity in patients with spinal cord injury

BACKGROUND

Constipation and fecal incontinence are considerable problems for most individuals with spinal cord injury (SCI). Neurogenic bowel symptoms are caused by several factors including abnormal rectal wall properties. Stimulation of the dorsal genital nerve (DGN) can inhibit bladder contractions and because of common innervation inhibitory effects are anticipated in the rectum too. Therefore, DNG could have a future role in the treatment of neurogenic fecal incontinence.

AIM

To study the effect of acute DGN stimulation on the rectal cross sectional area (CSA) in SCI patients.

METHODS

Seven patients with complete supraconal SCI (median age 50 years) were included. Stimulation was applied via plaster-electrodes using an amplitude of twice the genito-anal reflex threshold (pulse width: 200 μs; pulse rate: 20 Hz). A pressure controlled phasic (10, 20 and 30 cmH(2)O) rectal distension protocol was repeated four times with subjects randomized to stimulation during 1st and 3rd distension series or 2nd and 4th distension series. The rectal CSA and pressure were measured using impedance planimetry and manometry.

RESULTS

All patients completed the investigation. Median stimulation amplitude was 51 mA (range 30-64). CSA was smaller during stimulation and differences reached statistical significance at distension pressures of 20 cmH(2)O (average decrease 9%; P = 0.02) and 30 cmH(2)O (average decrease 4%; P = 0.03) above resting rectal pressure. Accordingly, rectal pressure-CSA relation was significantly reduced during stimulation at 20 (P=0.03) and 30 cmH(2)O distension (P=0.02).

CONCLUSION

DGN Stimulation in patients with supraconal SCI results in an acute decrease of rectal CSA and the rectal pressure-CSA relation.

Neurogenic bowel dysfunction in patients with spinal cord injury, myelomeningocele, multiple sclerosis and Parkinson’s disease

Exciting new features have been described concerning neurogenic bowel dysfunction, including interactions between the central nervous system, the enteric nervous system, axonal injury, neuronal loss, neurotransmission of noxious and non-noxious stimuli, and the fields of gastroenterology and neurology. Patients with spinal cord injury, myelomeningocele, multiple sclerosis and Parkinson’s disease present with serious upper and lower bowel dysfunctions characterized by constipation, incontinence, gastrointestinal motor dysfunction and altered visceral sensitivity. Spinal cord injury is associated with severe autonomic dysfunction, and bowel dysfunction is a major physical and psychological burden for these patients. An adult myelomeningocele patient commonly has multiple problems reflecting the multisystemic nature of the disease. Multiple sclerosis is a neurodegenerative disorder in which axonal injury, neuronal loss, and atrophy of the central nervous system can lead to permanent neurological damage and clinical disability. Parkinson's disease is a multisystem disorder involving dopaminergic, noradrenergic, serotoninergic and cholinergic systems, characterized by motor and non-motor symptoms. Parkinson's disease affects several neuronal structures outside the substantia nigra, among which is the enteric nervous system. Recent reports have shown that the lesions in the enteric nervous system occur in very early stages of the disease, even before the involvement of the central nervous system. This has led to the postulation that the enteric nervous system could be critical in the pathophysiology of Parkinson's disease, as it could represent the point of entry for a putative environmental factor to initiate the pathological process. This review covers the data related to the etiology, epidemiology, clinical expression, pathophysiology, genetic aspects, gastrointestinal motor dysfunction, visceral sensitivity, management, prevention and prognosis of neurogenic bowel dysfunction patients with these neurological diseases. Embryological, morphological and experimental studies on animal models and humans are also taken into account.

What we have learned about colonic motility: normal and disturbed

PURPOSE OF REVIEW

Disorders of colonic motor and sensory function are common among children and adults and pose significant diagnostic and therapeutic challenges; the purpose of this review, therefore, was to critically assess the recent literature on this topic.

RECENT FINDINGS

Considerable progress has been made at the ultrastructural, molecular and electrophysiological level in understanding the normal functions of the muscles, nerves and interstitial cells that generate and control colonic motility. Furthermore, abnormalities in these cell types and in the interstitial cells of Cajal, in particular, have been identified in a number of disease states. Testing of colonic motor and sensory function in clinical practice continues to be a challenge due, in part, not only to the technical issues presented by accessing the organ but also to the intrinsic variability of its physiology. These have not been auspicious times for advances in the therapy of disturbed colonic motility; new agents or new applications for 'old' agents continue to be explored as are more innovative approaches such as those based on neural stimulation and cell therapy.

SUMMARY

Considerable progress has been made in understanding the basic pathophysiology of colonic dysmotility; clinical diagnostics and therapeutics continue to lag behind.