Seminars in gastrointestinal disease最新文献

Clinically significant drug interactions are common in the liver transplant recipient. In addition to the immunosuppressive agents, these patients simultaneously receive many other medications. This review focuses on the clinically significant drug interactions of commonly prescribed immunosuppressives in the liver transplant recipient. Most reported drug interactions involve cyclosporin A.

Most liver diseases for which liver transplantation is performed recur after liver transplantation. The clinical impact of recurrence varies. For autoimmune liver diseases, such as primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune hepatitis, clinically significant recurrence appears to be relatively rare. Whether these diseases recur in any meaningful way after liver transplantation is still controversial. For the chronic viral diseases, hepatitis B and C, the issue is not whether they recur--they clearly do--but whether the recurrence affects prognosis and how best to manage recurrent disease. For hepatitis B virus (HBV), reinfection can lead to accelerated liver injury, graft loss, and dramatically worse patient and graft survival rates, whereas the prognosis of recurrent hepatitis C virus (HCV), at least in the short-term, appears to be more benign. Major advances have been made in preventing liver allograft reinfection with HBV. Before these advances, chronic hepatitis B was considered a relative contraindication to liver transplantation because the allografts almost always became reinfected. With the current strategies for preventing HBV reinfection, however, the graft and patient survival rates after transplantation for chronic hepatitis B approach those for nonviral diseases. The development of resistance to antiviral therapy is likely to represent the major problem in the future and mandate the use of combination therapy. There is currently no effective therapy available for recurrent hepatitis C. Until such therapy is developed, recurrent hepatitis C remains the most challenging problem facing liver transplant physicians and surgeons.

Although the transplanted human liver is susceptible to rejection with a similar incidence of rejection as seen with renal allografts, the liver enjoys many immunological benefits relative to other transplanted organs. These include relative resistance to antibody-mediated injury, low frequency of chronic rejection, relatively easy reversibility of acute rejection, and even reversibility of chronic rejection. The reasons for the liver's favored status from an immunological perspective are unclear but are perhaps multifactorial. Currently used clinical protocols of immunosuppression for liver transplantation rely principally on the calcineurin inhibitors, cyclosporine and FK-506. Steroid withdrawal at variable periods after liver transplantation is becoming increasingly common. Compared with other organ transplants, relatively few human liver transplants are lost because of rejection. The transplanted liver may be an appropriate target for tolerance studies.

Liver transplantation is now routinely used as a definitive treatment for patients with advanced cirrhosis. As survival after transplantation in most centers is at or above 70% to 80% at 1 year, an increasing number of liver transplant recipients requires further medical care. Several medical complications may develop during the immediate or long-term postoperative periods, including renal dysfunction, arterial hypertension, neurological complications, and psychiatric complications. In addition, other metabolic complications often develop in a more insidious manner, such as obesity, hyperlipidemia, diabetes mellitus, and posttransplant bone disease. Because the liver allograft function is frequently normal in many recipients experiencing the above-mentioned complications, the gastroenterologist, internist, or family practitioner frequently has a role in the diagnosis and management of these complications. In this review, we discuss the basic pathophysiological concepts and suggest guidelines for the diagnosis and management of frequent medical problems encountered after liver transplantation.

Pancreatitis may be acute or chronic, mild or severe. Acute necrotizing pancreatitis remains the most serious form of acute pancreatitis and accounts for the majority of complications. Although there is an established nomenclature for pancreatitis and pancreatic fluid collections, such as pancreatic pseudocysts, it is not widely understood or recognized by gastroenterologists. Because the management options for the treatment of pancreatic fluid collections continues to evolve with an increased use of endoscopic therapy, gastroenterologists will be increasingly called on to treat patients with pancreatitis and its complications. This article addresses and summarizes pancreatic fluid collections and their management, with an emphasis on endoscopic drainage.

The ability to place endoscopic stents into the pancreatic duct has led to a dramatic increase in stent therapy for benign pancreatic diseases, particularly chronic pancreatitis and pancreas divisum. The overall effectiveness of this therapy remains unknown. This article critically reviews the available literature with a focus on patient selection, efficacy, and risk. The risk of pancreatic duct stenting is only now beginning to be appreciated, and clinicians must understand not only the potential effectiveness of pancreatic duct stenting but also the magnitude of the potential risk when considering this therapy.

Chronic pancreatitis is a lifelong illness for patients and a persistent medical challenge for the gastrointestinal physician. Most cases are induced by alcohol abuse. This leads to a process of recurrent injury, chronic fibrosis and subsequent pain, pancreatic ductal scarring, and dilatation. The surgical management of these associated complications as seen in the patient presented in this report will be discussed in the context of the current surgical literature.

Endoscopic ultrasound has emerged as an important modality for management of pancreatic disease because of its ability to provide high frequency images of the pancreatic ducts and the parenchyma. Development of interventional techniques under endosonographic guidance has further advanced the potential use of this technique in pancreatic disorders. This paper shows and reviews the current knowledge on endoscopic ultrasound in pancreatic imaging.

Pancreatitis may be acute or chronic, mild or severe. In patients with acute pancreatitis the optimal imaging test is dynamic intravenous and oral contrast enhanced computed tomography (CECT). Serial CECTs are useful to monitor disease progression and to assess intraabdominal complications in patients with severe acute pancreatitis. CECT is helpful in planning the approach (endoscopic transmural versus percutaneous) for pancreatic drainage. Computed tomography or ultrasound-guided aspiration of pancreatic collections is safe, sensitive, and specific and has become a routine procedure used to screen for infected necrosis. When pancreatic drainage is contemplated, magnetic resonance imaging is useful for identifying residual necrotic debris within the collection. Patients with mild acute pancreatitis usually require no cross-sectional imaging study other than ultrasound screening for gallstones, if gallstone pancreatitis is suspected clinically. In patients with chronic pancreatitis, screening for complications such as superimposed acute pancreatitis or development of pancreatic pseudocysts may be performed with CECT or ultrasound.

Perianal disease is a frequent complication necessitating both medical and surgical management in Crohn's disease. Fissures, fistulae, or abscesses are found in approximately 36% of patients; occur more often in the ileocolonic and colonic disease; and may precede the onset of intestinal symptoms (Farmer et al, Gastroenterology 68:627-635, 1975; Rankin et al, Gastroenterology 77:914-920, 1979; Gray et al, Gut 6:515-524, 1965; and Homan et al, Arch Surg 111:1333-1335, 1976). To approach perianal manifestations, the physician must identify the anatomic location of the disease, treat the suppurative complications, and consider a long-term approach to palliation of chronic inflammatory sequelae. This article will review the medical management of perianal Crohn's disease and indications for surgery.