A 16-year-old girl is brought to the clinic due to vomiting and abdominal pain. Since this morning, the patient has had multiple episodes of nonbilious, nonbloody emesis as well as intermittent nausea and abdominal pain. She has also had 3 episodes of watery diarrhea. The patient attended a school cookout approximately 36 hours prior to her first bout of emesis, and several of her friends who also attended have similar symptoms. Temperature is 37.4 C (99.1 F), blood pressure is 115/75 mm Hg, and pulse is 95/min. She appears uncomfortable but is alert and interactive. Mucous membranes are slightly dry. There is diffuse tenderness to deep palpation on abdominal examination but no masses or hepatosplenomegaly. The skin is well perfused, and no rashes are evident. Which of the following is the most likely etiology of this patient's illness?

Question

A 16-year-old girl is brought to the clinic due to vomiting and abdominal pain.  Since this morning, the patient has had multiple episodes of nonbilious, nonbloody emesis as well as intermittent nausea and abdominal pain.  She has also had 3 episodes of watery diarrhea.  The patient attended a school cookout approximately 36 hours prior to her first bout of emesis, and several of her friends who also attended have similar symptoms.  Temperature is 37.4 C (99.1 F), blood pressure is 115/75 mm Hg, and pulse is 95/min.  She appears uncomfortable but is alert and interactive.  Mucous membranes are slightly dry.  There is diffuse tenderness to deep palpation on abdominal examination but no masses or hepatosplenomegaly.  The skin is well perfused, and no rashes are evident.  Which of the following is the most likely etiology of this patient's illness?

Quizplus · Accepted Answer

11ec25c8_d6b3_b140_bc81_2fca3f531c4f_MD0003_00 Norovirus is the most common cause of gastroenteritis in the United States. Very few viral particles are necessary for infection to spread via fecal-oral route, leading to outbreaks (eg, schools, cruise ships, day care facilities). Although person-to-person transmission is most common, norovirus infection can also occur with ingestion of contaminated food, such as shellfish, salad, and fruit. Symptoms typically begin 1-2 days after viral exposure and include nonbloody, nonbilious emesis; watery diarrhea; and abdominal pain. Diarrhea is noninflammatory without blood or mucus in the stool. Fever, headache, and malaise are common. The diagnosis is generally clinical. However, confirmatory testing (ie, detection of norovirus in the stool) may be performed in outbreaks or atypical cases (eg, symptoms >7 days). Fecal leukocytes are not seen. Treatment is supportive with oral or intravenous rehydration therapy depending on severity, and symptom resolution is usually within 2-3 days. Because norovirus is not killed by alcohol-based sanitizer or standard cleaning solutions, prevention includes diligent hand hygiene using soap and water and cleansing of contaminated surfaces with bleach. (Choices A and E) Bacillus cereus and Staphylococcus aureus cause foodborne gastrointestinal illness via ingestion of preformed toxin. Vomiting is the predominant symptom and typically begins within 6 hours of eating the contaminated food. In contrast, this patient developed symptoms 36 hours after the cookout. (Choice C) Rotavirus causes severe vomiting and watery diarrhea in unvaccinated children age ≤2. Infection in adolescents and adults is typically mild or asymptomatic due to the presence of antibodies from prior exposure or vaccination. Rotavirus is less likely than norovirus in this symptomatic, teenage patient. (Choice D) Shigella sonnei presents with abrupt onset of high fever, abdominal cramping, and stools containing mucus and/or blood. This patient is afebrile with watery diarrhea, making norovirus more likely. Educational objective: Norovirus is the most common gastroenteritis in the United States and is often implicated in outbreaks on cruise ships and in schools. Patients develop vomiting, watery diarrhea, and abdominal pain 1-2 days after exposure. Treatment is supportive, and symptoms generally resolve within 2-3 days. References: Human norovirus transmission and evolution in a changing world. (http://www.ncbi.nlm.nih.gov/pubmed/27211790) Norovirus genotype profiles associated with foodborne transmission, 1999-2012. (http://www.ncbi.nlm.nih.gov/pubmed/25811368)

A 16-Year-Old Girl Is Brought to the Clinic Due to Vomiting