Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning (Part 1) pdf

Chapter 122. Acute Infectious Diarrheal Diseases
and Bacterial Food Poisoning
(Part 1)

Harrison's Internal Medicine > Chapter 122. Acute Infectious Diarrheal
Diseases and Bacterial Food Poisoning
Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning:
Introduction
Ranging from mild annoyances during vacations to devastating dehydrating
illnesses that can kill within hours, acute gastrointestinal illnesses rank second
only to acute upper respiratory illnesses as the most common diseases worldwide.
In children <5 years old, attack rates range from 2–3 illnesses per child per year in
developed countries to as high as 10–18 illnesses per child per year in developing
countries. In Asia, Africa, and Latin America, acute diarrheal illnesses are not only
a leading cause of morbidity in children—with an estimated 1 billion cases per
year—but also a major cause of death. These illnesses are responsible for 4–6
million deaths per year, or a sobering total of 12,600 deaths per day. In some
areas, >50% of childhood deaths are directly attributable to acute diarrheal
illnesses. In addition, by contributing to malnutrition and thereby reducing
resistance to other infectious agents, gastrointestinal illnesses may be indirect
factors in a far greater burden of disease.
The wide range of clinical manifestations of acute gastrointestinal illnesses
is matched by the wide variety of infectious agents involved, including viruses,
bacteria, and parasitic pathogens (Table 122-1). This chapter discusses factors that
enable gastrointestinal pathogens to cause disease, reviews host defense
mechanisms, and delineates an approach to the evaluation and treatment of
patients presenting with acute diarrhea. Individual organisms causing acute
gastrointestinal illnesses are discussed in detail in subsequent chapters.
Table 122-1 Gastrointestinal Pathogens Causing Acute Diarrhea

Mechanism Locati

on
Illness

Stool
Findings
Exampl
es of
Pathogens
Involved
Noninflamma Proxi
mal small
Watery
No fecal
leukocytes;
Vibrio
cholerae,
tory (enterotoxin) bowel diarrhea
mild or no
increase in fecal
lactoferrin
enterotoxigenic
Escherichia
coli
(LT and/or
ST),
enteroaggregati
ve E. coli
,
Clostridium
perfringens

,
Bacillus
cereus,
Staphylococcus
aureus,
Aeromonas
hydrophila,
Plesiomonas
shigelloides,
rotavirus,
norovirus,
enteric
adenoviruses,
Giardia
lamblia,
Cryptosporidiu
m
spp.,
Cyclospora
spp.,
microsporidia
Inflammatory
(invasion or
cytotoxin)
Colon
or distal
small bowel
Dysent
ery or
inflammatory

diarrhea
Fecal
polymorphonuc
lear leukocytes;
substantial
increase in fecal
lactoferrin
Shigella
spp.,
Salmonella
spp.,
Campylobacter
jejuni
,
enterohemorrha
gic E. coli
,
enteroinvasive
E. coli
,
Yersinia
enterocolitica,
Vibrio
parahaemolytic
us,
Clostridium
difficile, ?
A.
hydrophila, ?
P.

shigelloides,
Entamoeba
histolytica
Penetrating Distal
small bowel
Enteric
fever
Fecal
mononuclear
leukocytes
Salmone
lla typhi,
Y.
enterocolitica,
?Campylobacte
r fetus

Abbreviations: LT, heat-labile enterotoxin; ST, heat-stable enterotoxin.
Source: After Guerrant and Steiner.