Pediatric Salmonella Infection Clinical Presentation

Updated: Jun 10, 2016
  • Author: Archana Chatterjee, MD, PhD; Chief Editor: Russell W Steele, MD  more...
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Presentation

History

Carefully obtain the patient's history to determine any potential sources of Salmonella and to help determine if the correct diagnosis has been made.

  • General history

    • Inquire about any recent travel abroad.

    • Inquire about possible animal exposures, including contact with pet iguanas, turtles, tortoises, or other reptiles.

    • Inquire whether any family members have current or recent gastroenteritis.

    • Inquire whether any recent outbreaks have occurred in the community.

  • Salmonella gastroenteritis

    • The incubation period of Salmonella gastroenteritis is 6-72 hours.

    • In most cases, children have cramping abdominal pain, nausea, vomiting, and loose watery stools.

    • Stools may be bloody; however, this is not as common as in infection with Shigella.

    • Fever, which rarely exceeds 39°C, occurs in approximately one half of infected patients.

    • Symptoms usually resolve spontaneously in 2-7 days.

  • Enteric fever (typhoid fever)

    • Enteric fever is caused by S. typhi and several other Salmonella serotypes.

    • The incubation period for enteric fever is 3-60 days, but symptoms typically occur in 1-2 weeks.

    • Patients may present with high fever, which rises in a steplike fashion.

    • Other symptoms include anorexia, abdominal pain, malaise, myalgias, headache, cough, diarrhea or constipation, and delirium.

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Physical

Physical findings may include the following:

  • Salmonella gastroenteritis

    • Upon physical examination, patients may have signs of dehydration, such as delayed capillary refill, sunken eyes, dry mucous membranes, or tachycardia.

    • Patients may have tenderness to palpation on abdominal examination, which sometimes can be difficult to differentiate from appendicitis.

    • Rectal examination may reveal heme-positive stools, gross blood, or mucoid stools.

  • Enteric fever (typhoid fever)

    • A typical finding of enteric fever is relative bradycardia for the height of the fever.

    • Hepatosplenomegaly may be found on examination.

    • Patients with enteric fever may develop rose spots; these spots are blanching pink papules most commonly found on the anterior thorax. They usually fade about 3-4 days after appearance, are 2-4 mm in diameter, and occur in groups of 5-20.

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Causes

Salmonella organisms are gram-negative rod-shaped bacilli in the family Enterobacteriaceae. All Salmonella organisms are to be considered a single species (Salmonella enterica) because of their close relationship by DNA hybridization studies. [7]

Differences in lipopolysaccharide (LPS) and flagellar structure generate the antigenic variation that is reflected in the more than 2500 known serotypes that cause human disease.

Nontyphoidal Salmonella (NTS) serotypes are divided into O-antigen groups A through E. Since 1997, Salmonellaenteritidis (D), S. typhimurium (B), and Salmonella newport (C2) account for about half of the culture-confirmed Salmonella isolates. The principal reservoirs for NTS organisms are poultry, livestock, reptiles, and pets. The mode of transmission is ingestion of foods of animal origin, including poultry, red meats, unpasteurized dairy products, and eggs that have been contaminated by infected animals or an infected human. [5, 21]

Recent Salmonella outbreaks have been attributed to commercially produced items, such as peanut butter, frozen pot pies, puffed vegetable snacks, and dry dog food. [22, 23, 24, 25, 26] Contact with infected reptiles, such as iguanas, pet turtles and tortoises, and ingestion of contaminated water are other modes of transmission.

S. typhi (D) is the species known to cause enteric fever (typhoid fever). S. typhi is found only in humans. In the United States, typhoid fever is usually caused by foreign travel to countries with contaminated food and drinking water or by ingestion of food contaminated by a chronic carrier. [5] Travelers visiting friends and relatives in typhoid-endemic countries may be at more risk than tourists because of a lack of precautionary measures. [27] Historically, Salmonella paratyphi (A) has been the cause of a smaller proportion of the cases of enteric fever. [28] However, China and India have experienced a substantial increase in enteric fever caused by S.paratyphi (A). [29]

Excess antibiotic use in the prior year has been associated with a higher incidence of NTS. Disruption of the microflora of the gut has been offered as a possible cause; however, an alternate explanation may be that these individuals are a more medically fragile group, requiring more antibiotics and, in general, are more susceptible to illness. [30]

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