Patients undergoing endoscopy are at risk of infection from the use of contaminated equipment. Dangers arise from the transmission of organisms from one patient to another and from the introduction of opportunist organisms which colonize endoscopic equipment on storage and can lead to sepsis and death in those who are immunocompromised and at ERCP. Staff are in danger from needle-stick injury and sensitivity to aldehyde disinfectants. These risks can be eliminated by careful attention to disinfection techniques. The most important part of endoscope disinfection is thorough mechanical cleaning first, followed by 5-10 min total immersion of the instrument and all channels in 2% glutaraldehyde (or the equivalent). At the end of the endoscopy list, following the disinfection protocol, all equipment should be dried internally and externally prior to storage. Staff must be fully aware of the risks of infection in endoscopy, be protected from hepatitis B by vaccination, and be fully trained in disinfection techniques. Glutaraldehyde should be used only in closed systems or in well-ventilated areas with the operator protected from direct contact from splashing and fumes. Institutions should designate an individual to be responsible for preparing, monitoring and overseeing disinfection procedures within the endoscopy room and for ensuring that regular microbiological testing of equipment (including automatic disinfecting machines) is undertaken.

Over 50% of the complications and 60% of the deaths associated with upper GI endoscopy are cardiopulmonary in type. Oxygen desaturation and cardiac arrhythmias at the time of endoscopy are common. Ways of trying to prevent hypoxia occurring are discussed. The most effective of these is the use of supplemental oxygen. Pulse oximeters are being used increasingly frequently by endoscopists. The way in which oximeters work is described in some depth, as are some of the potential errors that may result from their use. The author believes that, as in anaesthetic practice, pulse oximeters will be used ever more frequently by endoscopists and finally become standard equipment in all endoscopy units. The case for using continuous ECG monitoring and blood pressure measurement is briefly discussed. The ASGE have recently published their recommendations on monitoring patients undergoing GI endoscopic procedures. The BSG's own working party on safety and monitoring is in the process of finalizing its recommendations, and the final part of the chapter discusses the views of this working party and gives some insight into what its final recommendations are likely to be.

There is good evidence that colonoscopy, in expert hands, is the most accurate investigation for the diagnosis of colorectal disease, and it also allows histological confirmation and therapeutic procedures to be carried out. Furthermore, by screening high-risk groups together with regular follow-up of patients with known colorectal neoplasia and surveillance of long-standing ulcerative colitis patients, it may be possible to reduce the incidence of colorectal cancer. However, at the present time, the lack of widespread availability and the variability in the quality of examinations precludes the employment of colonoscopy as the first-line investigation in colorectal disease. Flexible sigmoidoscopy combined with good quality double contrast barium enema is a reasonable alternative in the majority of cases, reserving colonoscopy for investigation of the elderly and high-risk patients, together with surveillance of patients with premalignant conditions. Technologically, colonoscopy has probably reached its peak and it is now necessary to make provision for more widely available colonoscopy services, provided by adequately trained endoscopists who can guarantee total colonoscopy in more than 90% of cases safely and rapidly. This requires structured training programmes for gastrointestinal physicians and surgeons and ultimately changes in patterns of working practice if adequate numbers of colonoscopy sessions capable of dealing with a steadily increasing workload are to be achieved.

EUS unites two established imaging techniques and extends the range of observation into and beyond the wall of the GI tract. The close proximity of the sonographic probe to the region of interest combined with high ultrasonic frequencies of between 7.5 and 12 MHz yields images of high resolution. EUS is used in the staging of benign and malignant neoplastic disorders of the oesophagus, stomach, pancreas and extrahepatic bile ducts. It helps to establish operability, to plan surgical approach, to follow response to therapy and to search for recurrence. The predictive value in defining the T and N stages of oesophageal carcinoma lies between 80 and 90% and 65 and 85%, respectively. It is clearly superior to CT in tumour stages T1 and T2. In gastric cancer, resectability based on the TNM staging system can be correctly assessed by EUS in 85% of cases and EUS detection and staging of early gastric cancer reaches an accuracy of 90%. The EUS accuracy rate for resectability of pancreatic carcinoma is 83% and tumour infiltration into the portal and splenic vein can be correctly determined by EUS in 94% and 67%, respectively. A reliable EUS differentiation between chronic pancreatitis and pancreatic carcinoma based on the echo pattern and outer margins is not possible. The development of EUS-guided needle biopsy should improve the specificity of EUS in this regard. Experience to data suggests as well that EUS will assume an important place in the staging of bile duct tumours. EUS has expanded our endoscopic and sonographic capabilities and it is to be hoped that further technical improvement, e.g. the construction of forward-viewing endoscopes combined with radial scanning devices, will contribute to a widespread use of this technique by gastroenterologists.

The perception of colour at endoscopy has been taken for granted since the discovery of the fibreoptic bundle and the advent of fibreoptic endoscopy. Fibreoptic and lens assemblies can distort the impression of colour by selectively absorbing some wavelengths of light. In the case of electronic endoscopes, the principal sensor is the charge-coupled device (CCD), a small microelectronic device that converts an image into a sequence of electronic signals which, after appropriate processing, are transformed into an image on the monitor screen. The image is therefore visualized as a mosaic of small images, one from each sensing element. Colour is synthesized by using sequential illumination using filters or by filters placed over the CCD. Fibre-endoscopes may alter colour by selectively transmitting certain portions of the visible spectrum, while electronic endoscopes are susceptible to errors due to poor calibration of the instrument and manipulation of the colour controls by endoscopists. Colour information provides the endoscopist with clues to the nature of the lesion and also a site for biopsy. In experimental situations, colour information has been used to determine blood flow and classify lesions. Much work needs to be done to define normal and abnormal colour in the gastrointestinal tract and to develop a standard terminology for colour nomenclature in endoscopy.

Since its introduction in 1968, ERCP has developed from being a purely diagnostic method, mostly used in the investigation of unexplained upper abdominal pain, to an invaluable tool for the management of patients with pancreatic disorders. In cases with severe gallstone pancreatitis, the biliary obstruction is disclosed and relieved by ERCP and ES. In patients with severe acute pancreatitis of other aetiologies, as well as in post-traumatic pancreatitis, ERCP is indispensable for revealing complications (e.g. pancreatic duct rupture) and/or for planning the treatment strategy. Furthermore, in cases of pancreatitis not related to alcohol or gallstones, it often demonstrates causes which may be treatable, and it is also useful for evaluation of the gland after massive pancreatic necrosis. Moreover, ERCP is helpful in establishing the diagnosis of chronic pancreatitis and its complications as well as in demonstrating morphological grounds for therapeutic intervention. Although the indications, limitations, and practicability of the different techniques of therapeutic ERCP in various pancreatic diseases still remain to be defined, the method appears to offer an alternative to surgery, particularly in cases in which operative treatment is technically difficult and the results are less favourable. Frequency and severity of complications associated with both diagnostic and therapeutic ERCP seem to be, at least in the hands of experts, reasonably low.

With the development and widespread use of flexible endoscopes, injection sclerotherapy of oesophageal varices has advanced beyond the early stages. Although slightly different techniques and different sclerosants are used, the results are not strikingly different. The cumulative rate of adverse effects is in the range of 20 to 40%, with a procedure-related mortality of around 1 to 2%. Sclerotherapy is the best available treatment for haemostasis of acute oesophageal variceal bleeding. However, as a long-term therapy it is less effective in the prevention of recurrent gastrointestinal bleeding events, since obliteration of all varices often takes several months. Furthermore, extra-oesophageal bleeding is not amenable to sclerotherapy. Thus, if repeated injections fail to prevent recurrent bleeding, other options such as shunt surgery, transection, chronic medical portal decompression with beta-blockers or even liver transplantation should be considered according to the needs of the individual patient. Prophylaxis of first variceal haemorrhage was beneficial in selected patients with a high bleeding risk. It cannot, however, be generally recommended at present.

Laparoscopic cholecystectomy has emerged in the last 2 years as a unique procedure that offers the long-term advantages of open cholecystectomy without much of the short-term morbidity. Importantly, when compared with non-surgical approaches to symptomatic gallstones, it is suitable for virtually all patients rather than a highly-selected group as in the case of oral bile salt dissolution therapy or extracorporeal lithotripsy. Furthermore, it obviates the high recurrence rate seen with these techniques. Complications including bleeding and ductal injury appear to occur at a slightly higher rate than with traditional open cholecystectomy, but most surgeons who have had experience with the procedure predict that these complications will become rarer as more experience is gained. We may indeed be witnessing the first major successful challenge to traditional surgical management of symptomatic gallstone disease in 100 years.

The argon ion and Nd: YAG lasers were used initially in the mid 1970s to produce haemostasis in acutely bleeding peptic ulcers. With the evolution of treatment techniques, the main area of use of the Nd: YAG laser has now become the palliation of upper and lower GI malignancies. Thermal ablation of tumours may be achieved endoscopically by non-contact laser application at high power, or in the contact mode using artificial sapphire probes at much lower energy levels. Still lower powers can be employed therapeutically using interstitial hyperthermia, and this is best applied endoscopically to exophytic tumour nodules in the gut lumen or to tumours localized ultrasonically in solid organs, such as the liver or pancreas. PDT involves destruction of previously photosensitized tumours by the cytotoxic action of singlet oxygen released on exposure of the neoplastic tissue to light of an appropriate wavelength. Although the theory is attractive, the available experimental and clinical information suggests that treatment should, for the present, be confined to small or early malignancies whose depth of invasion can be verified by endoscopic ultrasound or other imaging techniques. PDT carries the biological advantage of healing by regeneration with preservation of connective tissue stroma, while the Nd: YAG laser causes destruction by thermal coagulation or vaporization and subsequent healing by fibrosis. Laser therapy of GI tumours expands the range of therapeutic endoscopic procedures in a relatively safe and readily repeatable manner which achieves high patient tolerance. By reducing morbidity, mortality and time spent in hospital, it offers significant advantages in the palliative treatment of conditions previously managed by conventional surgery, and also offers opportunities for treatment of previously inoperable disorders. Developments in laser technology and diagnostic imaging techniques are likely to promote laser therapy in the future as a primary treatment modality.

Two cases of patients with Crohn's-like colitis and glycogen storage disease Ib have been reported previously. In the current report, chronic inflammatory bowel disease that developed in another adolescent with this glycogenosis is described, thereby corroborating the association. The neutrophil dysfunction observed in glycogen storage disease Ib is the most likely predisposing factor. Neutrophil function was investigated in our patient in an attempt to shed light on the pathogenesis of his intestinal inflammation. The patient displayed reduced neutrophil chemotaxis to zymosan-activated serum, N-formyl-methionine-phenylalanine, and Escherichia coli bacteria-derived factor and reduced intracellular killing of Staphylococcus aureus 502A. Others have found this defective bacteriocidal activity to be caused by impaired oxidative metabolism. The recent recognition of chronic inflammatory bowel disease in glycogen storage disease Ib, as well as in chronic granulomatous disease, suggests that further study of respiratory burst activity of neutrophils in Crohn's disease is warranted.

This report documents the disturbance in gastrointestinal motor function in a patient with selective cholinergic dysautonomia that occurred following acute infectious mononucleosis. Apart from the gut, other organs affected included the pupils, sweat glands, lacrimal and salivary glands, and urinary bladder. Autonomic function tests showed the preservation of sympathetic adrenergic functions in contrast to the generalized involvement of postganglionic parasympathetic and sympathetic cholinergic nerves, including denervation hypersensitivity of the pupil and urinary bladder to exogenous cholinergic agonists. Cardiac and abdominal vagal responses were abnormal. Colon myenteric plexus ganglion cells were normal by morphological and immunohistochemical studies, suggesting that the selective cholinergic dysautonomia was the most likely pathophysiologic process responsible for the observed motility disorder. This study documents the occurrence of selective cholinergic dysautonomia following a viral illness, the importance of the extrinsic neural control on the motor function of the gastrointestinal tract, and the usefulness of combined motility and autonomic function testing in the evaluation of patients with symptoms suggestive of gut dysmotility.

Two cases of herpes simplex virus hepatitis in pregnancy are presented. Each case was characterized by extremely high serum aminotransferase levels with minimal bilirubin elevation. In both cases, liver biopsy was instrumental in arriving at the diagnosis. In addition, computed tomography showed a radiographic appearance of the liver not characteristically seen in other hepatic disorders of pregnancy. A high index of suspicion in the second case led to early recognition and treatment. Despite the presence of fulminant liver failure and evidence of herpes encephalitis in the other case, institution of therapy with acyclovir was associated with complete recovery in both patients. The present cases are compared and contrasted with the literature. The incidence of two cases within a 6-month period suggests that herpes simplex virus hepatitis in pregnancy may occur more frequently than previously reported.

This report analyzes the clinical and physiological evidence supporting a role for altered visceral afferent mechanisms in the pathogenesis of two functional bowel syndromes: noncardiac chest pain and the irritable bowel syndrome. Considerable recent evidence indicates that increased contractility is present only in a minority of patients and that hypercontractile episodes are not temporally related to abdominal pain. In contrast, altered sensation and motor reflexes in response to physiological stimuli, such as mechanical distention or acid, is common when appropriately investigated. The vagal and spinal afferent innervation mediates visceral sensation and is involved in multiple reflex loops regulating gastrointestinal effector function, such as motility and secretion. Sensory input can be modulated peripherally at the afferent nerve terminal, at the level of prevertebral ganglia, the spinal cord, and the brainstem. An up-regulation of afferent mechanisms would result both in altered conscious perception of physiological stimuli and in altered motor reflexes. Current evidence is consistent with an alteration in the peripheral functioning of visceral afferents and/or in the central processing of afferent information in the etiology of altered somatovisceral sensation and motor function observed in patients with functional bowel disease.

To date, no satisfactory treatment has been developed for treatment of patients with advanced pancreatic carcinoma. The median survival of these patients is only three to six months. Of more than 30 agents evaluated over the past three decades, only 5-FU results in a response rate with 95% confidence intervals greater than 20%. Most responses are partial, of short duration, and of questionable clinical benefit. To date, efforts to improve response rates by biochemical modulation of 5-FU have been unsuccessful but additional studies are warranted and are ongoing. Although improved response rates have been reported with some drug combinations, such as streptozotocin, mitomycin and 5-FU (SMF), median survival for combination therapy is no better than that attained with single-agent therapy. Current therapeutic options for patients with advanced disease include 5-FU, supportive care, or investigational treatment in a clinical trial. In three out of four studies, patients with locally advanced pancreatic carcinoma who received combined modality therapy (radiation in combination with 5-FU) survived significantly longer than those treated with either radiation or chemotherapy alone. The brief survival advantage, however, must be considered in the context of the additional toxicity and treatment time required for the combined modality treatment. Radiotherapy in combination with 5-FU should be considered standard adjuvant therapy for patients with completely resected disease. The median survival of treated patients was 20 months and significantly longer than the surgery alone control group (11 months) (Kalser and Ellenberg, 1985; GITSG, 1987). Of greatest significance is the tail-end plateau on the survival curve suggesting that approximately 18% of patients who received combined modality therapy were cured. The results with currently available treatment for all stages of disease are poor; therefore, patients should be informed about ongoing clinical trials which may someday improve the prognosis for pancreatic cancer.

Pylorus-preserving pancreaticoduodenectomy represents an important advance in the history of pancreatic surgery. The operation can be performed with a low operative mortality and morbidity, is technically easier than the standard Whipple resection, and it minimizes the long-term physiological disturbance to the patient. Clinical and experimental evidence has substantiated the view that preservation of the pylorus reduces the incidence of marginal anastomotic ulceration following pancreatectomy. Although gastric emptying may be prolonged transiently in the immediate postoperative period, this complication is easily managed, and is hardly a frequent long-term problem. PPPD is associated with a lower incidence of enterogastric reflux, dumping and diarrhoea than the classical Whipple operation, and patients who have had PPPD are more likely to regain their preoperative and preillness weight. Initial concerns about the use of PPPD in malignant disease have not been borne out, and should now be considered for curative or palliative resections of lesions in the periampullary region including the head of the pancreas. Present data suggest that PPPD does not compromise the long-term survival in patients with periampullary cancers. There is little doubt that the excellent results reported with this procedure as with other forms of major pancreatic surgery, are not simply related to improvements in surgical technique but to establishment of specialist pancreatic surgery.

For pancreatic cancer, endosonography is at present the most accurate method of imaging, especially for detecting small lesions and assessing the extent of locoregional tumour spread. Although the overall accuracy of tumour detection is nearly 100%, differentiation between cancer and pseudotumours of inflammatory origin may sometimes present a problem. Clinical history, symptoms and other imaging techniques, particularly ERCP, should therefore always be considered. On the other hand, endosonography is indicated when the other imaging techniques are negative or doubtful in the presence of a high index of clinical suspicion. In cases with proven malignant tumours, it should be performed for proper staging. The overall accuracy of staging the primary tumour is 80-90%, whereas for detecting lymph nodes it is around 75%. In contrast to angiography, endosonography gives more detailed information of major vessel involvement, an important factor in deciding whether the tumour is resectable. Endosonography is, however, not suitable for the detection of distant metastasis due to the limited penetration of ultrasound. The newly developed echoduodenoscopes, equipped with a working channel and an elevator, provide the possibility for improved accuracy of biopsy under endosonographic guidance, and under clinical evaluation. This should further improve the differentiation between pancreatic cancer and inflammatory pseudotumours, which continues to be a significant clinical problem. So far no procedure-related complications of endosonography have been reported. An adequate experience in conventional ultrasound and endoscopy is essential, however, in order to achieve reliable results.