Gastroenteritis, Salmonella

Key Features

Essentials of Diagnosis

• Nausea, vomiting, headache, meningismus

• Fever, diarrhea, abdominal pain

• Culture of organism from stool, blood, or other specimens

General Considerations

• Salmonella infections in childhood occur in two major forms

  • Gastroenteritis (including food poisoning)

  • Enteric fever (typhoid fever and paratyphoid fever)

• Transmission occurs by the fecal-oral route via contaminated food, water, fomites, and sometimes person-to-person

• Incubation period is 12–24 hours

• Numerous foods, especially milk and egg products, are associated with outbreaks

• Animal contact also can be a source for Salmonella

• Because salmonellae are susceptible to gastric acidity, the elderly, infants, and patients taking antacids or H₂-blocking drugs are at increased risk for infection.

• Most cases of Salmonella meningitis (80%) and bacteremia occur in infancy.

• Newborns may acquire the infection from their mothers during delivery and are at special risk for developing meningitis

Demographics

• Incidence of typhoid fever has decreased in the United States

• Incidence of Salmonella gastroenteritis has greatly increased in the past 15–20 years

  • Highest attack rates occur in children younger than age 6 years, with a peak in the age group from 6 months to 2 years

Clinical Findings

Symptoms and Signs

• Fever, vomiting, and diarrhea usually develop in infants

• Older children also may complain of headache, nausea, and abdominal pain

• In the usual case, diarrhea is moderate and subsides after 4–5 days, but it may be protracted

• Stools are often watery or may contain mucus and, in some instances, blood, suggesting shigellosis

• Drowsiness and disorientation may be associated with meningismus

• Splenomegaly occasionally occurs

• Convulsions occur less frequently than with shigellosis

Diagnosis

• Isolation of the organism from stool, blood or, in some cases, from urine, CSF, or pus from a suppurative lesion confirms diagnosis

• WBC count usually shows a polymorphonuclear leukocytosis but may show leukopenia

Treatment

• Careful attention must be given to maintaining fluid and electrolyte balance, especially in infants

• In uncomplicated Salmonella gastroenteritis, antibiotic treatment

  • Does not shorten the course of the clinical illness

  • May prolong convalescent carriage of the organism

• Colitis or secretory diarrhea due to Salmonella may improve with antibiotic therapy

• Because of the higher risk of sepsis and focal disease, antibiotic treatment is recommended in

  • Infants younger than age 3 months

  • Severely ill children

  • Children with sickle cell disease, liver disease, recent gastrointestinal surgery, cancer, depressed immunity, or chronic kidney or heart disease

• Infants younger than age 3 months with positive stool cultures or suspected salmonellosis sepsis should be

  • Admitted to the hospital

  • Evaluated for focal infection including cultures of blood and CSF

  • Given treatment intravenously

• A third-generation cephalosporin is usually recommended due to frequent resistance to ampicillin and TMP-SMX

• Older patients in whom bacteremia develops during the course of gastroenteritis

  ...