New approaches to supporting the failing liver.
Cao S. Esquivel CO. Keeffe EB.
Department of Surgery, Stanford University School of Medicine, California 94305, USA.
With the continued, growing disparity between the numbers of organ donations and patients waiting for liver transplantation, various efforts have been made to optimize the allocation of organs, as well as to devise means to support the failing liver. Over the years, the development of bioartificial liver-assist devices has aimed at replacing the three main functions of hepatocytes, which are synthetic, metabolic, and excretory. The application of porcine hepatocytes in humans to carry out biotransformation, as well as other metabolic functions and refinement of the membrane separator, have yielded some promising results in supporting patients with acute liver failure. Further advances will need to be made before these bioartificial devices can be considered for routine application in clinical settings.
Assessing risks, costs, and benefits of laparoscopic hernia repair.
Memon MA. Fitzgibbons RJ Jr.
Department of Surgery, Creighton University School of Medicine, Omaha, Nebraska 68131, USA. firstname.lastname@example.org
Laparoscopic inguinal herniorrhaphy (LIHR) was introduced with the following potential advantages: less postoperative discomfort and pain, reduced recovery time that allows earlier return to full activity, easier repair of a recurrent hernia, the ability to treat bilateral hernias concurrently, the performance of a simultaneous diagnostic laparoscopy, ligation of the hernia sac at the highest possible site, improved cosmesis, and decreased incidence of recurrence. Potential disadvantages include complications, such as bowel, bladder, and vascular injuries; potential adhesive complications at sites where the peritoneum has been breached or prosthetic material has been placed; the apparent need, at least at the present, for a general anesthetic; and the increased cost because of expensive equipment needs. Most surgeons agree that LIHR has a role in the management of patients with a recurrent hernia after a conventional inguinal herniorrhaphy (CIHR), bilateral inguinal hernia, or a need for laparoscopy for another procedure, such as laparoscopic cholecystectomy. The routine use of LIHR for the unilateral, uncomplicated hernia is a more contentious issue.
How to screen for colon cancer.
Gastroenterology Section, Portland Veterans Administration Medical Center, Oregon 97207, USA.
The biology of colorectal cancer provides a unique opportunity for early detection and prevention. There is now evidence that screening of asymptomatic average-risk individuals over 50 years of age can reduce mortality resulting from colorectal cancer. New recommendations from the US Preventive Services Task Force endorse screening with fecal occult blood tests or sigmoidoscopy. The best method for population screening remains uncertain. The cost of screening is an important issue in the development of public policy. This review discusses the various screening options, examines the "downstream" effects of screening, and reviews the anticipated costs and effectiveness. Ultimately, the effectiveness of any screening program depends on patient compliance. Further research is needed to determine the best methods of enhancing patient adherence to a screening program.
Evaluation of the patient with recurrent bacterial infections.
Holland SM. Gallin JI.
Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. email@example.com
Recurrent bacterial infection is a complaint encountered regularly in the course of both adult and pediatric care. Defects of neutrophils and monocytes are most commonly associated with recurrent infection, but abnormalities of immunoglobulins and complement must be considered. Defensins, small antibacterial peptides, have been implicated recently in some of the infectious diathesis of cystic fibrosis. A thorough history and physical examination focused on severity, sequelae, and microbiology of infections can usually determine whether a patient needs further evaluation. The diseases and syndromes most frequently associated with recurrent infection are presented, along with discriminating clinical, pathologic, and microbiologic features.
Gastric lymphoma of mucosa-associated lymphoid tissue and Helicobacter pylori.
Department of Histopathology, Royal Marsden Hospital, London, United Kingdom.
Although the majority of primary gastric lymphomas are of high-grade non-Hodgkin's type, a significant number are low-grade B cell lymphomas. The recognition that the majority of the latter have characteristic clinicopathological features that are different from those of their nodal counterparts has led to the suggestion that these lymphomas arise specifically from within organized extranodal lymphoid tissue; this tissue resembles that seen constitutively in the intestine (mostly located in the terminal ileum as Peyer's patches) and is termed mucosa-associated lymphoid tissue (MALT). The paradox of this proposal is that there is no MALT in the gastric mucosa in normal individuals from which a primary lymphoma can arise. However, it has been shown that organized lymphoid tissue with all the features of MALT can be acquired in the gastric mucosa, and this is seen most frequently, but not exclusively, in association with infection by Helicobacter pylori (H. pylori). Subsequent studies have confirmed a close association between H. pylori infection and gastric MALT lymphoma with the infection preceding the development of the lymphoma. In vitro studies have demonstrated that there is an immunologically based drive to tumor cell proliferation in low-grade gastric MALT lymphomas associated with the presence of H. pylori. Clinical studies have shown that, at least in early lesions, eradication of the organism can result in tumor regression in 60 to 92% of cases.
Clostridium difficile infection.
Kelly CP. LaMont JT.
Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA. firstname.lastname@example.org
Clostridium difficile infection is associated with broad-spectrum antibiotic therapy and is the most common cause of infectious diarrhea in hospital patients. Pathogenic strains of C. difficile produce two protein exotoxins, toxin A and toxin B, which cause colonic mucosal injury and inflammation. Infection may be asymptomatic, cause mild diarrhea, or result in severe pseudomembranous colitis. Diagnosis depends on the demonstration of C. difficile toxins in the stool. The first step in management is to discontinue the antibiotic that caused diarrhea. If diarrhea and colitis are severe or persistent, oral metronidazole is the treatment of choice. Oral vancomycin is also effective, but it is more expensive than metronidazole and its widespread use may encourage the proliferation of vancomycin-resistant nosocomial bacteria. Diarrhea and colitis usually improve within three days after a patient starts taking metronidazole or vancomycin, but 20% suffer a relapse of diarrhea when these agents are discontinued.
Dyspepsia: current understanding and management.
Agreus L. Talley NJ.
Department of Family Medicine, Uppsala University, Akademiska Sjukhuset, Sweden.
Dyspepsia, defined as "pain or discomfort centered in the upper abdomen" is reported by one in four adults in Western societies. The most important causes are non-ulcer (functional) dyspepsia, peptic ulcer, gastroesophageal reflux, and, rarely, gastric cancer. Persons with heartburn alone are not considered to have dyspepsia. The division of dyspepsia into symptom-based subgroups (ulcer-like, dysmotility-like, reflux-like, and unspecified dyspepsia) has proven to be of doubtful value for the clinician, as it has a low predictive value for identifying the causes of dyspepsia. Upper endoscopy remains the "gold standard" test; ultrasound and blood tests have a low yield. The role of Helicobacter pylori in peptic ulcer disease is well known, but the clinical role of the infection in non-ulcer dyspepsia remains very controversial. In uninvestigated dyspeptic patients who are H. pylori infected based on a non-invasive test, empiric anti-H. pylori therapy is a reasonable and probably cost-effective option. In documented non-ulcer dyspepsia, prokinetics are superior to placebo while antisecretory therapy is of less certain efficacy.