PHYSICAL EXAMINATION

VS: T 39.2°C, P 145/min, R 32/min, BP 90/44 mmHg

PE: The patient’s mucous membranes were dry, and she was listless and febrile. Her neck was supple. Her chest was clear, and heart sounds were normal. Her abdomen was nontender. Bowel sounds were normal.

LABORATORY STUDIES

Blood

Hematocrit: 38%

WBC: 5300/μL

Differential: Normal

Serum chemistries: BUN 22 mg/dL, creatinine 1.2 mg/dL

Table 43-1 lists the likely causes of illness (differential diagnosis). A clinical diagnosis of gastroenteritis was considered. Absence of fecal leukocytes (based on the examination of methylene blue-stained stool preparation) can rule out inflammatory diarrhea and bacterial causes. Investigational approach may include:

• Routine enteric bacterial cultures

• Stool viral antigen test

• In failed investigation, electron microscopy of enteric viruses and ova and parasite examination for protozoa

TABLE 43-1 Differential Diagnosis and Rationale for Inclusion (consideration)

Bacterial gastroenteritis

Dysentery: Shigella spp

Secretory diarrhea: enteropathogenic Escherichia coli

Protozoal diarrhea

Cryptosporidium parvum

Giardia lamblia

Viral gastroenteritis

Astrovirus