The use of antibiotics causes diarrhea by three mechanisms. Mild diarrhea is a side effect of many antibiotics, more often seen with broad-spectrum antibiotics and when multiple antibiotics are used simultaneously. Antibiotic-associated hemorrhagic colitis may rarely occur following the use…
Food poisoning is characterized chiefly by acute gastroenteritis developing within hours or days of ingesting contaminated food. The food may contain either live organisms that grow within the host and can be designated infectious, or more often, preformed toxins produced…
Salmonella typhi (S. typhi) causes classic typhoid fever, and serotypes paratyphi A, B, or C cause the less severe, paratyphoid fever. Transmission of the organism occurs from human feces or urine, but flies or shellfish such as oysters and clams…
Infectious esophagitis may be caused by fungal, bacterial, or viral agents. The three most common causes are Candia albicans, herpes simplex virus (HSV 1 and HSV 2), and cytomegalovirus (CMV). The most common predisposing factor for infective esophagitis caused by…
Acquired immunodeficiency syndrome (AIDS) has been a devastating pandemic since the late 20th century, caused by the human immunodeficiency virus (HIV). HIV-1 is the most prevalent type worldwide. HIV-2 is less prevalent and less pathogenic, found principally in western Africa.…
Fecal incontinence is the involuntary passage of fecal material. It may be a single occurrence, but when recurrent, incontinence can be devastating. Several surveys indicate that fecal incontinence may occur in 7% to 15% of the population. It is more…
Lymphogranuloma venereum (LGV) and sexually transmitted proctitis are relatively uncommon in the general population, occurring more often in male homosexuals and promiscuous heterosexuals. Certain infections are typically seen when proctitis is identified in a patient with a history of promiscuous…
Localized infection with a collection of pus in the anorectal area is designated an anorectal abscess. Usually, it results from the invasion of the normal rectal flora into the perirectal or perianal tissues. The pathologic process seems to start with…
Anal Fissure Anal fissure is a tear of the skin in the distal anal canal, usually in the posterior midline ( Fig. 104.1 ). Occasionally, it is in the anterior midline. When not in the midline, anal fissure is often…
Prolapse of the rectum is a condition in which one or more layers of the rectum or anal canal protrudes through the anal orifice ( Fig. 103.1 ). It can be partial or complete. Partial prolapse involves only the mucosa,…