Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning (Part 5) pps

Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning Part 5 History The answers to questions with high discriminating value can quickly narrow the range of potential cause

Chapter 122 Acute Infectious Diarrheal Diseases

and Bacterial Food Poisoning

(Part 5)

History

The answers to questions with high discriminating value can quickly narrow the range of potential causes of diarrhea and help determine whether treatment is needed Important elements of the narrative history are detailed in Fig 122-1

Physical Examination

The examination of patients for signs of dehydration provides essential information about the severity of the diarrheal illness and the need for rapid therapy Mild dehydration is indicated by thirst, dry mouth, decreased axillary sweat, decreased urine output, and slight weight loss Signs of moderate dehydration include an orthostatic fall in blood pressure, skin tenting, and sunken eyes (or, in infants, a sunken fontanelle) Signs of severe dehydration range from hypotension and tachycardia to confusion and frank shock

Diagnostic Approach

After the severity of illness is assessed, the clinician must distinguish

between inflammatory and noninflammatory disease Using the history and

epidemiologic features of the case as guides, the clinician can then rapidly evaluate the need for further efforts to define a specific etiology and for therapeutic intervention Examination of a stool sample may supplement the narrative history Grossly bloody or mucoid stool suggests an inflammatory process A test for fecal leukocytes (preparation of a thin smear of stool on a glass slide, addition of a drop of methylene blue, and examination of the wet mount) can suggest inflammatory disease in patients with diarrhea, although the predictive value of this test is still debated A test for fecal lactoferrin, which is a marker of fecal leukocytes, is more sensitive and is available in latex agglutination and enzyme-linked immunosorbent assay formats Causes of acute infectious diarrhea, categorized as inflammatory and noninflammatory, are listed in Table 122-1

Post-Diarrhea Complications

Chronic complications may follow the resolution of an acute diarrheal episode The clinician should inquire about prior diarrheal illness if the conditions listed in Table 122-2 are observed

Table 122-2 Post-Diarrhea Complications of Acute Infectious

Diarrheal Illness

Chronic diarrhea

Lactase deficiency

Occurs in ~1% of travelers with acute diarrhea

Small-bowel bacterial

overgrowth

Malabsorption syndromes

(tropical and celiac sprue)

Protozoa account for ~⅓ of cases

Initial presentation or

exacerbation of inflammatory bowel

disease

May be precipitated by traveler's diarrhea

Irritable bowel syndrome Occurs in ~10% of travelers with

traveler's diarrhea

Reiter's syndrome (reactive

arthritis)

Particularly likely after infection with invasive organisms (Shigella,

Salmonella, Campylobacter)

Hemolytic-uremic syndrome

(hemolytic anemia,

thrombocytopenia, and renal failure)

Follows infection with Shiga toxin–

producing bacteria (Shigella dysenteriae type 1 and enterohemorrhagic Escherichia

coli)

Epidemiology

Travel History

Of the several million people who travel from temperate industrialized countries to tropical regions of Asia, Africa, and Central and South America each year, 20–50% experience a sudden onset of abdominal cramps, anorexia, and

watery diarrhea; thus traveler's diarrhea is the most common travel-related illness

(Chap 117) The time of onset is usually 3 days to 2 weeks after the traveler's arrival in a tropical area; most cases begin within the first 3–5 days The illness is generally self-limited, lasting 1–5 days The high rate of diarrhea among travelers

to underdeveloped areas is related to the ingestion of contaminated food or water

The organisms that cause traveler's diarrhea vary considerably with location

(Table 122-3) In all areas, enterotoxigenic and enteroaggregative E coli are the

most common isolates from persons with the classic secretory traveler's diarrhea syndrome