Is irritable bowel syndrome an infectious disease?

Irritable bowel syndrome (IBS) is the most common of all gastroenterological diseases. While many mechanisms have been postulated to explain its etiology, no single mechanism entirely explains the heterogeneity of symptoms seen with the various phenotypes of the disease. Recent data from both basic and clinical sciences suggest that underlying infectious disease may provide a unifying hypothesis that better explains the overall symptomatology. The presence of small intestinal bowel overgrowth (SIBO) has been documented in patients with IBS and reductions in SIBO as determined by breath testing correlate with IBS symptom improvement in clinical trials. The incidence of new onset IBS symptoms following acute infectious gastroenteritis also suggests an infectious cause. Alterations in microbiota-host interactions may compromise epithelial barrier integrity, immune function, and the development and function of both central and enteric nervous systems explaining alterations in the brain-gut axis. Clinical evidence from treatment trials with both probiotics and antibiotics also support this etiology. Probiotics appear to restore the imbalance in the microflora and improve IBS-specific quality of life. Antibiotic trials with both neomycin and rifaximin show improvement in global IBS symptoms that correlates with breath test normalization in diarrhea-predominant patients. The treatment response to two weeks of rifaximin is sustained for up to ten weeks and comparable results are seen in symptom reduction with retreatment in patients who develop recurrent symptoms.

Emerging therapeutic options for the management of hepatitis C infection

Until recently the traditional treatment for hepatitis C infection included pegylated interferon and ribavirin combination therapy. The sustained virological response (SVR) seen with this combination is poor and requires lengthy treatment to achieve. Additionally, significant side effects and numerous contraindications prevented many patients from being successfully treated with this therapy. In 2011, two new protease inhibitors, telaprevir and boceprevir, were approved for use with pegylated interferon and ribavirin in the United States by the United States Food and Drug Administration. These agents have significantly improved SVR rates; however significant problems with toxicity remain including severe skin rash and neutropenia. There are a wide range of compounds in late stage development for the future treatment of hepatitis C that exploit many different mechanisms of viral inhibition. Some of these compounds include additional protease inhibitors, like telaprevir and boceprevir, as well as inhibitors of other nonstructural proteins in the viral genome such as NS5A and NS5B, and compounds that target host proteins within the virus. Some of these agents are being developed for oral administration once daily and various combinations are being assessed for use without the need for pegylated interferon and ribavirin. This paper reviews agents in late phase development that may be commercially available within 1-2 years.

Treatment guidelines for hepatic encephalopathy

Practice guidelines for hepatic encephalopathy were developed and published in 2001 for overall management in adults. Hepatic encephalopathy is caused by nitrogenous substances from the gastrointestinal tract that adversely affect brain function. Hepatic encephalopathy is a diagnosis of exclusion. The West Haven criteria are recommended for staging the disease. Treatment goals are providing supportive care, identifying and removing precipitating factors, reducing nitrogenous load, and assessing long-term therapy needs. Data from some trials published before 2001 are not included in the guidelines. In addition, since the publication of the guidelines, new data have become available regarding treatment interventions and outcomes. Newer, nonabsorbed agents, such as rifaximin, alone or in conjunction with lactulose, may enhance compliance and adherence with therapy, and provide better treatment outcomes. New updated practice guidelines need to be developed for hepatic encephalopathy, along with treatment algorithms for patients with both minimal hepatic encephalopathy and overt hepatic encephalopathy.