Updated: 7/31/2018

Shigella dysenteriae

Topic
Review Topic
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Questions
3
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Evidence
2
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Snapshot
  • A 6-year-old girl is brought in to the emergency department for a 2-day history of fever and watery diarrhea.  This morning, the diarrhea contained some blood. She had just traveled to Bangladesh to visit relatives. According to her family, an uncle there recently had bloody diarrhea as well. On physical exam, she is febrile, has hyperactive bowel sounds, and abdominal tenderness to palpation. A stool culture and Gram stain reveals lactose-fermenting, gram - rods. She is admitted for immediate rehydration and treatment.
Introduction
  • Classification
    • Shigella spp.
      • a non-flagellated, non-lactose-fermenting gram - rod
      • oxidase - and does not produce H2S
      • produces endotoxin and Shiga toxin
    • transmission
      • fecal-oral transmission
    • organisms
      • S. dysenteriae (produces the most toxin)
      • S. flexneri
      • S. boydii
      • S. sonnei (most common in the United States and least severe)
  • Epidemiology
    • incidence
      • more common in developing countries
    • demographics
      • more common in children
    • risk factors
      • ingestion of contaminated or uncooked food/water
      • travel
      • poor hygiene
      • crowding
  • Pathogenesis
    • infects gastrointestinal track through invasion of Peyer patch M cells
      • resistant to gastric acid
    • does not spread hematogenously
    • Shiga toxin (enterotoxin)
      • "A" subunit inactivates 60S ribosome
        • kills intestinal cells by inhibiting protein synthesis
      • neurotoxic, cytotoxic, and enterotoxic
      • produced by S. dysenteriae
  • Associated conditions
    • shigellosis (bacillary dysentery)
    • reactive arthritis
  • Prognosis
    • symptoms occur a few days after exposure
Presentation
  • Symptoms
    • fatigue
    • malaise
    • anorexia
    • tenesmus
    • watery diarrhea precedes bloody diarrhea
      • bloody and mucoid stools
    • abdominal pain or cramping
  • Physical exam
    • fever
    • hyperactive bowel sounds
    • abdominal tenderness
    • signs of dehydration
Studies
  • Labs
    • stool culture
  • Making the diagnosis
    • based on clinical presentation and laboratory studies
Differential
  • Enteroin­vasive Escherichia coli (EIEC)
    • distinguishing factor
      • clinically very similar to shigellosis but typically less contagious and less severe
      • distinguish based on culture or polymerase chain reaction
Treatment
  • Management approach
    • antibiotics will shorten duration of dysentery 
    • choice of antibiotics ultimately depends on regional resistance patterns
    • anti-motility drugs should be avoided, as they may worsen symptoms
  • Conservative
    • rehydration
      • indication
        • all patients
      • modalities
        • oral
        • intravenous
  • Medical
    • antibiotics
      • indication
        • severe cases
      • drugs
        • ciprofloxacin
        • ceftriaxone
        • trimethoprim-sulfamethoxazole (TMP-SMX)
    • zinc
      • indication
        • young children
      • outcomes
        • shortens duration of disease in children
        • also improves weight gain
Complications
  • Reactive arthritis (Reiter syndrome)
    • classic triad of conjunctivitis, urethritis, and arthritis
  • Febrile seizures
 

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Questions (3)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
Calculator

(M1.MC.42) A 14-year-old boy presents with abdominal pain and diarrhea after returning from an East Asian vacation. Stool sample reveals the presence of red and white blood cells. Stool culture shows growth of immobile, non-lactose fermenting gram-negative rods. The attending physician explains to the medical students that the bacteria function by invading intestinal M-cells. The bacterium responsible for this patient's infection is: Review Topic

QID: 101099
1

Vibrio cholera

6%

(14/252)

2

Escherichia coli

8%

(20/252)

3

Salmonella enteritidis

14%

(35/252)

4

Shigella dysenteriae

69%

(174/252)

5

Helicobacter pylori

1%

(3/252)

M1

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