Paediatrics (RCH) - Theses
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ItemChronic constipation in children and the roles of nuclear transit scintigraphy (NTS) and transcutaneous electrical stimulation (TES) therapy( 2012)Chronic constipation in children is a challenging and difficult problem to manage for clinicians. It has huge psycho-socio-economic impact on the child, parents and the health care system. If left untreated, 1/3 of children will have their symptoms persisting into adulthood, contributing to poor quality of life. There is no standard therapy for the treatment of chronic constipation despite the numerous laxatives available in the market. Various conservative strategies like behavioural therapy, dietary modifications and biofeedback therapy have reported short-term success. Surgery is reserved as the last option for patients with intractable symptoms. Since the introduction of antegrade continence enema (ACE) by Malone in the 1990s, it was considered a less invasive surgical option to treat children with intractable constipation with faecal soiling. Various investigations have been used to characterize the underlying colonic dysmotility in patients suffering from intractable chronic constipation, with the hope of identifying a treatable cause. Ultrasound has a limited role for faecal matter and volume assessment in the rectum. Colonic transit study using scintigraphy (radioisotopes with gamma camera images) has replaced radio-opaque sitz markers (with x-rays) in our hospital, providing better characterization of segmental colonic transit. Wireless capsule motility studies and colonic manometry provide useful information on the underlying colonic dysmotility but are only available at certain centres with research interests. Electrical stimulation is available in two forms: the invasive form involving surgical implantation of electrodes, as in sacral nerve stimulation (SNS), and the noninvasive form involving the use of adhesive electrodes applied over the skin of the abdomen and paraspinal region, as in transcutaneous electrical stimulation (TES). Slow-transit constipation (STC) is a well-recognized cause of chronic constipation in women. The diagnosis of slow-transit constipation [by nuclear transit scintigraphy (NTS)] in children, by contrast, is a new diagnosis and the use of TES to treat STC in children is a novel therapy. However, little was known about 1) the various colonic dysmotility patterns contributing to chronic constipation in childhood, 2) an optimal diagnostic algorithm in children with intractable constipation, 3) targeted therapy for children with chronic constipation if underlying colonic dysmotility is revealed, 4) whether TES is effective in the treatment of childhood STC and its long-term effects, 5) whether TES at home is possible when a clinician is supervising the treatment, and finally 6) whether home TES is effective in the treatment of the commonest form of chronic constipation in children – anorectal retention/functional faecal retention. The aims of this thesis were: (1) to address these questions using clinical information from a database in a tertiary institution, and (2) perform prospective clinical studies using TES to treat children with chronic constipation, and (3) to perform a follow-up study of children treated with TES in a previous randomised controlled trial. In Chapter 1, I provide an overview of the literature on the diagnosis and various medical and surgical treatments of children suffering from chronic constipation. Chapters 2-8 are the clinical studies comprising the thesis. In Chapter 2, there is a detailed description on the use of nuclear transit scintigraphy (NTS) to diagnose colonic dysmotility in children with chronic constipation at a tertiary institution. A database of children with chronic constipation investigated by NTS has led to the development of a standardised protocol. The identification of different types of colonic dysmotlity as the potential underlying pathological cause of chronic constipation has changed the management algorithm in these children. This has enabled the treatment to target the likely cause of the chronic constipation in children. I aimed to provide the diagnostic criteria of different colonic transit patterns using the standardised gastro-intestinal transit protocol. Interestingly, in Chapter 3a, the potential use of NTS to identify a new subgroup of children with rapid proximal colonic transit has led to a new treatment strategy in a subgroup of children with chronic constipation. In addition, Chapter 3b illustrates how we can gather useful anatomical information from a physiological study like NTS as it provides information on colonic length. In Chapter 4, I show that NTS has potential monitoring values in children with chronic constipation with NTS produces no change in gastrointestinal transit if the patient symptoms did not improve after treatment. Therefore, any physiological changes identify at the repeat study will indicate the effects of treatment. It has great potential to monitor progression of disease and also to monitor response to treatments. Chapter 5a described the key elements for a successful administration of TES at home. Close regular contacts and appropriate supervision are essential elements for positive outcome of TES. Chapter 5b is a prospective study of home STC to treat children with STC. This study shows that home TES is effective to overcome symptoms in STC children and to improve their quality of life with a small but demonstrable increase in colonic transit measured objectively by NTS. Chapter 6a is a prospective study conducted to establish the long-term effects of TES in STC children previously treated in a separate randomised, controlled trial. This study showed variable responses with long-term effect lasting as long as 3 years in some children. In contrast, Chapter 6b is a retrospective study to assess how the use of TES at a single tertiary institution has affected the role of surgery as a treatment in children with slow-transit constipation. Chapter 7 is a pilot study to examine the role of home TES to treat the commonest form of chronic constipation in children – anorectal retention (AR) or functional faecal retention (FFR). Chapter 8a is a study to examine the effect of upper gastrointestinal dysmotility in children with slow-transit constipation and whether this will affect their response to TES. Excitingly, chapter 8b describes the effect of TES on gastric motility and its possible implications as a non-invasive treatment for delayed gastric emptying or gastroparesis. In chapter 9, I discuss the major conclusions from this study and the implications of this work. The studies comprising this thesis provide the first detailed description of the use of a standardised NTS protocol to diagnose colonic dysmotility in children, changing the algorithm of investigation and management of children with chronic constipation at a tertiary institute. The use of home TES to overcome chronic constipation in children offers a promising and non-invasive treatment option without surgery in treatment-resistant cases. Moreover, the exciting finding of TES affecting gastric motility will form the ground for future studies in investigating its role as a non-invasive treatment option for patients with intractable upper gastrointestinal tract symptoms.