A 14-year-old girl is brought to the emergency department due to 2 days of abdominal cramping, nausea, vomiting, and diarrhea. Today, she has developed fever and blood in the stool. The patient recently returned from a week-long summer camp and had no symptoms while she was away. She has common variable immunodeficiency that is managed with immunoglobulin replacement therapy. Prior to this illness, the patient had been generally well, except for an episode of sinusitis a month ago that was treated with amoxicillin-clavulanate. Temperature is 38.2 C (100.8 F) and pulse is 102/min. Abdominal examination shows mild, diffuse pain with palpation but no rebound tenderness or guarding. Stool ova and parasite testing is negative. Stool culture grows Salmonella species. Which of the following is the most likely underlying cause of this patient's current condition?

Question

A 14-year-old girl is brought to the emergency department due to 2 days of abdominal cramping, nausea, vomiting, and diarrhea.  Today, she has developed fever and blood in the stool.  The patient recently returned from a week-long summer camp and had no symptoms while she was away.  She has common variable immunodeficiency that is managed with immunoglobulin replacement therapy.  Prior to this illness, the patient had been generally well, except for an episode of sinusitis a month ago that was treated with amoxicillin-clavulanate.  Temperature is 38.2 C (100.8 F) and pulse is 102/min.  Abdominal examination shows mild, diffuse pain with palpation but no rebound tenderness or guarding.  Stool ova and parasite testing is negative.  Stool culture grows Salmonella species.  Which of the following is the most likely underlying cause of this patient's current condition?

Quizplus · Accepted Answer

11ec25c8_d6b1_8e5b_bc81_1dc307aa33ee_MD0003_00 Salmonella subspecies are categorized as nontyphoidal or typhoidal according to the causative strain and clinical manifestations. This patient likely has nontyphoidal Salmonella (eg, S Enteritidis), a common cause of bacterial food-borne illness. Most cases arise from ingestion of undercooked poultry or eggs. Inadequate refrigeration of prepared foods is also a common source because warm temperatures are ideal for Salmonella growth. Symptoms begin within 3 days of ingestion and usually include fever, vomiting, diarrhea, and abdominal pain. Bloody stools are uncommon in adults but may be seen in children. In contrast, typhoidal Salmonella (eg, S Typhi) causes typhoid fever, an invasive, potentially fatal illness characterized by bacteremia and high fever; diarrhea can occur. Typhoidal strains are largely endemic to resource-limited countries with poor sanitation, and fecal-oral transmission occurs via consumption of contaminated food or water. The typhoid vaccine, which is administered to patients prior to travel abroad, protects against typhoidal strains of Salmonella only (Choice E). Although patients with primary humoral immunodeficiency may have a deficient response to immunizations and may be at increased risk for vaccine-preventable diseases even if immunized, this child has symptoms consistent with nontyphoidal Salmonella, for which there is no vaccine. (Choice A) Bacteremia and sepsis can result from an infusion contaminated by gram-negative bacteria, such as Salmonella. However, infusate contamination is very rare, and patients are ill-appearing with high fever and chills. In addition, blood, not stool, culture would be expected to grow bacteria. (Choice B) Antibiotic use can disrupt the normal microbiota of the gastrointestinal tract and is associated with an increased risk of Clostridioides difficile infection. Symptoms include abdominal pain, fever, and diarrhea that is watery at onset. Salmonella infection is not associated with recent antibiotic use. (Choice D) Ingestion of raw or unrefrigerated seafood can lead to diarrhea with or without blood due to Vibrio parahaemolyticus, not Salmonella, gastroenteritis. Educational objective: Nontyphoidal Salmonella is a common cause of bacterial food-borne gastroenteritis, and most cases arise from the ingestion of undercooked poultry or eggs or improperly refrigerated food. Symptoms include fever, abdominal pain, vomiting, and diarrhea with or without blood. References: A review of temperature, pH, and other factors that influence the survival of Salmonella in mayonnaise and other raw egg products. (http://www.ncbi.nlm.nih.gov/pubmed/27869756)

A 14-Year-Old Girl Is Brought to the Emergency Department Due