دانلود رایگان مقاله انگلیسی عفونت های شایع دستگاه گوارش - الزویر 2018

INTRODUCTION

Gastrointestinal infections account for a large burden of acute and chronic disease worldwide. Diarrhea is defined as 3 or more stools in 24 hours and is the most common manifestation. It is defined as acute if lasting less than 7 days, prolonged if lasting 7 to 13 days, persistent if lasting 14 to 29 days, and chronic if lasting 30 days or longer.1 Common bacterial, viral, and parasitic pathogens are spread via food, via contaminated water, or from person to person. According to the World Health Organization, diarrhea is the cause of 4% of deaths globally and kills approximately 2.2 million people each year.2 Those in developing countries, and particularly children, are most affected. In the United States, not all cases are actively reported, but it is approximated that 179 million cases of acute diarrhea in adults occur each year, resulting in 500,000 hospitalizations and more than 5000 deaths.3 Nationally, children less than 5 years old account for the largest portion of infections, but those older than 65 years old account for greatest number of hospitalizations and deaths.4 Despite modern advances in food preparation and delivery, gastrointestinal infections in the United States are commonly caused by food-borne pathogens.

Special Populations

Persons with HIV are at increased risk of acute and chronic diarrhea because of a combination of immunosuppression, direct HIV viral effects, adverse medication effects and behaviors that may increase exposure. HIV enteropathy can result from direct effects of HIV on gastrointestinal tract cells and gut-associated lymphoid tissue.51 After the introduction of highly active antiretroviral therapy in 1996, there was a reduction in opportunistic infections as the cause of chronic diarrhea from 53% to 13% in patients with AIDS, whereas the overall incidence of chronic diarrhea did not decrease.52 Lymphoma and Karposi sarcoma are other noninfectious causes of diarrhea. In those with HIV and bacterial diarrhea, C difficile was the most common cause in persons studied from 1992 to 2002.53 An acid-fast smear or immunofluorescent stain should be requested to look for Cryptosporidium, Isospora, and Cyclospora. In patients with CD4 counts less than 100 cells/mL, the possibility of Microsporidium should also be investigated via trichrome staining of a stool specimen. Biopsy may be required to confirm infection with Mycobacterium avium complex or cytomegalovirus.