Non-typhoidal Salmonella

Snapshot

• A 20-year-old student presents to the college health clinic for evaluation of vomiting and diarrhea. He had recently seen an ad for a new fad diet – the raw egg diet for body-building purposes. For the past 2 days, he has had a raw egg with each meal. However, today he started having abdominal cramping, nonbloody and nonbilious vomiting, and diarrhea with some blood in it. On physical exam, his abdomen is soft and nondistended and somewhat tender to palpation. His mucous membranes are dry.

Introduction

• Classification 
  • non-typhoidal Salmonella spp.
    • most commonly S. enteritidis
    • motile, non-lactose fermenting gram-negative rods
    • an endotoxin-producing bacteria
    • transmission via consumption of contaminated foods
    • causes enterocolitis
• Epidemiology
  • incidence
    • a common cause of diarrhea in the US
  • demographics
    • all ages
  • risk factors
    • eating poultry, particularly if undercooked or raw
    • reptile pets (turtles)
• Pathogenesis
  • inactivated by gastric acids, so a large inoculum is required
  • Vi antigen blocks antibody attack on O antigen 
  • invades mucosa in the ileocecum
• Prognosis
• typically self-limited

Presentation

• Symptoms
  • nausea and vomiting
  • diarrhea
    • may be bloody
  • abdominal pain
  • myalgia
• Physical exam
• fever

Studies

• Labs
  • culture of blood or stool
• Making the diagnosis
• based on clinical presentation and laboratory studies

Differential

• Salmonella typhi infection 
  • distinguishing factors
    • patients typically present with a pink macular rash
• associated with typhoid fever

Treatment

• Management approach
  • antibiotics are typically not indicated
    • have actually been shown to prolong the duration of disease
• Conservative
  • supportive care
    • indication
      • all patients
    • modalities
      • hydration
• correction of any electrolyte imbalances

Complications

• Shock