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Morning Report: Thursday, January 12th
Epidemiology
Common cause of bacterial diarrhea
worldwide (especially in developing
countries)
 In the US:

 Third in frequency (after Salmonella and
Campylobacter)
 Primarily affects children
○ Peak incidence ages 1-4
The Details…
Gram-negative bacilli
 Four species:

 S. dysenteriae
Only Shiga toxinproducing species!
 S. boydii
 S. flexneri
 S. sonnei
Most common
subtypes in the US
Transmission

*Person-to-person via the fecal-oral
route
 Transmission in institutions
○ *Child care centers
 Grouping of susceptible children
 Lack of adherence to hand-washing procedures
 Small inoculum required for disease production
 Food borne transmission
○ Cold salads
○ Raw veggies
 Sexual transmission
Clinical Presentation
Incubation period 1-7 days, average 3
days
 Range of GI illness

 Mild diarrhea life-threatening dysentary
Clinical Presentation

Course
 Presentation: abrupt onset of high fever,
generalized toxicity, crampy abdominal pain*,
high-volume, watery stools
 24-48h later: Small-volume, bloody, mucoid
stools* with tenesmus

Neurologic manifestations (40%)





Severe HA
Seizures
Meningeal signs
Lethargy
Delirium/ hallucinations
Physical Exam
VS: high fever (>102F)
 Gen: toxic-appearing
 Abd: lower quadrant abdominal pain,
distension
 GU: tenderness on rectal exam


+/- signs of dehydration
Laboratory Findings
Bandemia
 Stool microscopy

 Large number of PMNs
 +/- RBCs

Stool culture
 Send stool specimen promptly to lab
 Can be grown on MacConkey or Hektoen-
Enteric agars
 Always want speciation and sensitivities
*Treatment

Mainstay= SUPPORTIVE CARE!
 Correction of fluid and electrolyte losses
○ Substantial volume depletion uncommon
○ Hyponatremia
 NO intestinal antimotility drugs
 Early restoration of oral intake
*Treatment

Antibiotics
 Lead to improvement in symptoms and
decreased spread of infection to contacts
 The problem…increasing antimicrobial
resistance!!
○ Ampicillin
○ TMP-SMX
 So, who do I treat and what do I use to treat
them?
*Treatment

Who to treat?
 Red Book
○ Severe disease
○ Underlying immunosuppressive conditions
○ Dysentery
○ In mild cases Rx to prevent spread of the
organism
*Treatment

What to use?
 Parenteral
○ Ceftriaxone
○ Cipro
 Oral
○ Azithromycin
 First-line oral Rx for children <18yo when Abx
susceptibility is unknown
○ Fluoroquinolones
 First-line oral Rx for children >17yo and adults
*Treatment

What to use?
 Oral
○ Cefixime
 Alternative to azithromycin in children <18yo
○ Ampicillin or TMP-SMX
 Only if sensitivities are known
Control Measures

Most importantly….
 METICULOUS HAND HYGIENE!!!
Control Measures

Hospital
 Contact precautions

*Day care
 Notify local health department
 Stool cultures should be performed on all
symptomatic attendees and staff
 Affected persons should be excluded until:
○ Initiation of appropriate ABx
○ ≥24 hours after diarrhea has resolved
○ Stool cultures are negative for Shigella
Complications

Intestinal
 Proctitis or rectal prolapse
 Toxic megacolon
 Intestinal obstruction
 Colonic perforation
Complications

Systemic





Bacteremia
Metabolic disturbances
Leukemoid reaction
Neurologic disease
Reactive arthritis
○ Alone or in association with conjunctivitis and
urethritis (Reiter syndrome)
 Hemolytic-uremic syndrome
○ Caused by EHEC (O157:H7), S. dysenteriae
A Question…

A previously healthy 3 ½ yo girl presents following 2 days
of diarrhea, vomiting, and low-grade fever. Her symptoms
began shortly after the family dined at a local fast-food
restaurant. She has had 4-6 watery, mucoid stools per
day. Her parents are very concerned because the have
started to see some blood in her stool. On PE, the alert,
somewhat irritable child has a T 38.6C, HR 100, RR 16.
Her oral MM are dry. CRT~2 secs. Her abdomen is
diffusely tender without distension. Labs show HgB 11.5,
WBC 14.5, Na 136, K 4.5, Bicarb 18. Of the following,
which is the most appropriate treatment?





A. A glucose-electrolyte solution
B. Cholestyramine
C. Loperamide
D. Metronidazole
E. TMP-SMX
A Question…

A 5yo girl presents after having a brief generalized
seizure. Her mother reports that the child has had a
3 day h/o fever, tenesmus, and bloody diarrhea. On
PE, you find a mildly toxic-appearing child who has a
T104F and diffuse abdominal tenderness. The rectal
exam produces significant pain. Stool from her
rectum is guaiac-positive. You tell the mother that
you believe the diarrhea has an infectious cause. Of
the following, the MOST likely pathogen is:





A. Cryptosporidium sp
B. Rotavirus
C. Salmonella sp
D. Shigella sp
E. Yersinia sp
A Question…

You are evaluating a 2 yo boy with a 10h history of a
temperature of 40.0C and progressively worsening diarrhea.
Yesterday he attended a birthday party at the petting zoo, but
he had no other history of ill contacts or unusual exposures.
His mother states that he has had 8 watery bowel movements
with mucus and streaks of blood in the last 10h. On PE, the
boy is irritable and has a temp of 39.5C. His MM are slightly
tacky, and his abdomen is diffusely TTP. The rest of the PE is
normal. Labs show WBC 16.0 with 65% neutrophils and 9%
bands. Microscopic exam of the stool shows fecal leukocytes,
blood and mucus. Of the following, the MOST likely etiologic
agent for this patient’s condition is





A. Campylobacter
B. E. Coli
C. Salmonella
D. Shigella
E. Yersinia enterocolitica
Infectious Diarrhea
Transmission
Symptoms
Labs
Treatment
Salmonella
Chicken, milk,
eggs; exotic pets
(reptiles)
Fever, diarrhea
with blood/ mucous
High WBC with left
shift, +stool WBC,
RBC (?+ BCx)
None with
uncomplicated GE;
at risk* Amoxil,
Bactrim
Shigella
Person-to person;
daycare! Fresh
fruits and veges
Fever, abd. pain,
watery diarrhea
that becomes
bloody, szs
High WBC and
band ct, +stool
WBC, RBC
Azithromycin,
quinolones
Campylobacter
jejuni
Undercooked
poultry or meat
Fever, abd pain,
diarrhea with
blood, vomiting
+stool WBC, RBC;
Cx with chocolate
agar
Erythromycin
E.Coli
O157:H7
Undercooked beef,
unpasturized milk
Fever, diarrhea
with blood/ mucous
+stool WBC, RBC;
look for signs of
HUS
Abx not
indicated!
(increases risk for
HUS)
Yersinia
enterocolitica
Pork (chitterlings)
Dysenteric
syndrome, can
mimic appy/
Crohns
+stool WBC, RBC
Bactrim,
aminoglycosides,
cephalosporins
(3rd), quinolones
Clostridium
difficile
ABx exposure
Mild diarrhea
dysentric
syndrome
Dx with toxin
assay
PO Flagyl (Vanc)
Noon Conference: JIA, Dr. Brown