Pediatric emergency medicine trisk 134

TABLE 23.1
CAUSES OF DIARRHEA
Infections
Enteral
Viruses: rotavirus, caliciviruses (norwalk and sapporo viruses), enteroviruses,
adenoviruses, astroviruses
Bacteria: Salmonella, Shigella, Yersinia, Campylobacter, pathogenic
Escherichia coli, Aeromonas hydrophila, Vibrio spp., Clostridium difficile,
tuberculosis
Parasites: Giardia lamblia, Entamoeba histolytica, Cryptosporidia
Nongastrointestinal (parenteral diarrhea): otitis media, pneumonia, urinary tract
infection
Dietary disturbances
Overfeeding, food allergy, starvation stools
Anatomic abnormalities
Intussusception, Hirschsprung disease, partial obstruction, appendicitis, blind
loop syndrome, intestinal lymphangiectasia, short bowel syndrome
Inflammatory bowel disease
Ulcerative colitis, Crohn disease
Malabsorption or increased secretion
Cystic fibrosis, celiac disease, disaccharidase deficiency, acrodermatitis
enteropathica, secretory neoplasms
Systemic illnesses
Immunodeficiency
Endocrinopathy: hyperthyroidism, hypoparathyroidism, congenital adrenal
hyperplasia
Psychogenic disturbances (irritable bowel syndrome)
Miscellaneous
Antibiotic-induced diarrhea, secondary lactase deficiency, neonatal drug
withdrawal, toxins (e.g., organophosphate ingestion), hemolytic uremic
syndrome

TABLE 23.2
LIFE-THREATENING CAUSES OF DIARRHEA
Intussusception
Hemolytic uremic syndrome
Pseudomembranous colitis
Appendicitis
Salmonella gastroenteritis (with bacteremia in the neonate or
immunocompromised host)
Hirschsprung disease (with toxic megacolon)
Inflammatory bowel disease (with toxic megacolon)
Appendicitis manifests primarily with abdominal pain. Common presentation
is periumbilical abdominal pain that migrates to the right lower quadrant,
followed by anorexia, vomiting, and/or fever. Less commonly, appendicitis may
cause diarrhea. The presumed mechanism for the diarrhea is irritation of the colon
by the inflamed appendix. Particularly in very young children or among patients
of any age who have a perforated appendix and a long duration of illness, the
diagnosis of appendicitis as the cause of diarrhea may be delayed because the
classic constellation of signs and symptoms is often absent. However, the
examiner will usually be able to elicit abdominal tenderness greater than would
be expected with gastroenteritis.
Toxic megacolon is a life-threatening condition that can occur as a
complication of a number of conditions including inflammatory bowel disease
(IBD), Shigella infection, pseudomembranous colitis, and Hirschsprung disease.
It is characterized by a dilated colon and abdominal distention with abdominal
pain and fever that may progress to shock.

EVALUATION AND DECISION
The history and physical examination are paramount in determining if the child

with diarrhea has a mild self-limiting illness or a condition that is potentially life
threatening. For patients with diarrhea, a comprehensive history, including
exposure history should be obtained. Further, the physician must also identify if
the diarrheal illness is acute or chronic as the etiologies can be different.
In evaluating a child with diarrhea, a rapid assessment is necessary to
determine the need for urgent or emergent fluid resuscitation. Historical
information that should be elicited include detailed questions about the onset of


illness, frequency (number of diarrheal stools per day), quantity (smear in the
diaper or stool fills and overflows the diaper in infants), and characteristics (e.g.,
bloody, mucoid, black) of stools, presence of concurrent vomiting, the amount of
liquid taken orally, and the frequency or volume of urination (number of wet
diaper changes in the infant).
A diagnostic approach to the pediatric patient with diarrhea is outlined in
Figure 23.1 . Inquiry about associated symptoms may be helpful in determining
possible causes and need for other acute interventions. The presence of vomiting
and fever may help determine infectious versus noninfectious causes. Vomiting in
association with diarrhea is very suggestive of viral gastroenteritis, whereas
bilious vomiting in isolation is more concerning for intestinal obstruction. Bloody
diarrhea points particularly to bacterial enteritis but occasionally occurs with viral
infections and may also herald the onset of HUS or pseudomembranous colitis.
The combination of episodic abdominal pain and blood in the stool characterizes
intussusception. The presence of abdominal pain should raise the index of
suspicion for appendicitis and intussusception. A history of ear pain, cough, or
dysuria should alert to the possibility of nonintestinal infections as the etiology of
the diarrhea.
A history of family members or close contacts with similar symptoms may
indicate a food-borne etiology. The use of recreational water facilities such as
pools and lakes may indicate a waterborne pathogen. Institutionalized children

and those recently returning from underdeveloped countries are more likely to
harbor bacterial or parasitic pathogens. A history of daycare exposure suggests a
viral infection whereas recent antibiotic use may suggest antibiotic-associated
diarrhea or pseudomembranous colitis.
Pre-existing conditions in the child may account for the diarrhea or predispose
him or her to unusual causes; in particular, the emergency physician should
search for a history of gastrointestinal surgery or chronic illnesses, such as
ulcerative colitis or regional enteritis. Immunodeficiency syndromes, neoplasms,
and immunosuppressive therapy all lead to an increased susceptibility to
infection. A child who presents with chronic diarrhea (more than 14 days) may
suggest other etiologies such as IBD, irritable bowel disease, bacterial infections,
Hirschsprung disease, human immunodeficiency infection (HIV), and assorted
malabsorptive and secretory disorders. With the possible exception of bacterial
enteritis in a febrile or toxic-appearing patient, such conditions, if uncomplicated,
do not require a definitive diagnosis emergently, but rather an evaluation over
time.


A complete physical examination is essential for determining the severity of
the dehydration in the child with diarrheal illness as well as for determination of
potential etiologies for the diarrhea (see Chapters 22 Dehydration and 100 Renal
and Electrolyte Emergencies ). Various clinical scales have been developed and
validated to determine the degree of dehydration. Scales that are commonly used
in the acute care setting include the Gorelick scale, the Clinical Dehydration
Scale (CDS), and the World Health Organization (WHO) scale. See Figure 23.2
for these scales.
Altered mental status may be seen in children with severe dehydration,
hypovolemic shock, and intussusception. Pallor and petechiae may denote HUS
or malignancy. On abdominal examination, the findings of a mass (IBD,
intussusception, malignancy) or evidence of obstruction (abdominal distention,

pain, and paucity of bowel sounds) is important. A rectal examination should be
performed in the child who has chronic diarrhea. With overflow stools secondary
to prolonged constipation, the rectal ampulla often contains a large amount of
hard stool, but it is usually empty in the patient with Hirschsprung disease.
Routine diagnostic testing is not necessary in pediatric patients with suspected
self-limiting diarrheal disease. Patients with fever, bloody diarrhea, mucoid
stools, severe abdominal pain, and/or signs of sepsis should have stool samples
evaluated for bacterial and other pathogens. Blood cultures are indicated for ill or
toxic-appearing patients of any age with diarrhea, children under 3 months,
immunocompromised hosts, and those being evaluated for fever of unknown
origin who have traveled to or had contact with travelers from enteric fever
endemic areas. If a history of significant stool output accompanied by poor oral
intake is obtained, bedside point of care glucose check should be performed to
evaluate for possible hypoglycemia, especially in infants and toddlers.
Electrolytes, BUN, and creatinine should be obtained only if the history and/or
physical examination are concerning for potential electrolyte abnormalities or
impaired renal function. Plain abdominal films should be performed in patients
with suspected gastrointestinal obstruction but are frequently normal in children
with intussusception and gastroenteritis. Because of its high diagnostic sensitivity
and lack of ionizing radiation, ultrasound (US) has replaced contrast enema as the
diagnostic test of choice in children with suspected intussusception. US may also
be helpful in the diagnosis of the patient with appendicitis. When HUS is
suspected, a complete blood count, renal function studies including serum
creatinine, urinalysis, coagulation studies, and peripheral smear should be
performed. The peripheral blood smear, in addition to reduced numbers of
platelets, may show evidence of intravascular hemolysis, including helmet cells