An 18-month-old boy is brought to the emergency department by his parents due to fever, vomiting, and lethargy. This morning, he developed a fever that initially responded to acetaminophen. Throughout the day, the patient developed a progressive rash on the lower extremities and became increasingly lethargic. He was treated with antibiotics for acute otitis media last month but is otherwise healthy. Immunizations are up to date. The patient lives with his parents and 3-year-old brother. Both he and his brother attend day care. Temperature is 40.2 C (104.4 F), and pulse is 124/min. On examination the patient is lethargic. He flexes his hips when his neck is flexed. There is an erythematous, nonblanching, pinpoint rash on the trunk and lower extremities. Which of the following is the most likely organism causing this patient's symptoms?

Question

An 18-month-old boy is brought to the emergency department by his parents due to fever, vomiting, and lethargy.  This morning, he developed a fever that initially responded to acetaminophen.  Throughout the day, the patient developed a progressive rash on the lower extremities and became increasingly lethargic.  He was treated with antibiotics for acute otitis media last month but is otherwise healthy.  Immunizations are up to date.  The patient lives with his parents and 3-year-old brother.  Both he and his brother attend day care.  Temperature is 40.2 C (104.4 F), and pulse is 124/min.  On examination the patient is lethargic.  He flexes his hips when his neck is flexed.  There is an erythematous, nonblanching, pinpoint rash on the trunk and lower extremities.  Which of the following is the most likely organism causing this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d282_8ab3_bc81_2bf352f3c832_MD0003_00 This patient has fever, lethargy, meningeal signs, and petechiae, which are findings concerning for Neisseria meningitidis meningitis. Meningococcal meningitis most commonly affects adolescents and young adults but is also a common pathogen in all children age >1 month. Young children often have acute onset of fever, vomiting, and a petechial rash on the extremities. Older children may also experience headache and severe myalgias (eg, leg pain). Symptoms progress rapidly (over 12-24 hours) to include a purpuric rash and altered mental status (eg, confusion, lethargy). Meningeal signs, such as this patient's positive Brudzinski sign, are common but often absent in patients age <1 year. Brudzinski sign Positive cerebrospinal fluid culture is diagnostic, but testing should not delay treatment (eg, ceftriaxone) in patients with suspected meningococcal meningitis. Empiric antibiotic regimens should also include vancomycin for coverage of penicillin-resistant Streptococcus pneumoniae, the most common pathogen in children age >1 month. Even with appropriate treatment, meningococcal meningitis is potentially fatal due to complications of shock, multiorgan failure, and disseminated intravascular coagulation. (Choice A) Enteroviruses (eg, coxsackievirus) can cause meningitis with fever, headache, and nuchal rigidity. However, symptoms typically develop over days (not hours), and additional findings of coxsackievirus infection (eg, posterior pharyngeal sores, maculopapular rash on palms/soles) would be expected. (Choices B and E) Meningitis in young infants is commonly caused by group B Streptococcus (in those age <3 months) and Listeria monocytogenes (in those age <1 month). These pathogens are extremely unlikely to cause meningitis in an immunocompetent 18-month-old. (Choice C) Haemophilus influenzae meningitis presents with symptoms similar to meningococcal meningitis; however, H influenzae is not associated with a petechial rash. In addition, the incidence of H influenzae has decreased dramatically since routine vaccination was implemented, making this diagnosis unlikely in a fully immunized child. (Choice D) Herpes simplex virus is typically associated with encephalitis and rarely causes meningitis beyond the neonatal period. In addition, it is associated with a vesicular, not petechial, rash. Educational objective: Meningococcal meningitis is a common cause of bacterial meningitis in children and classically presents with fever, lethargy, nuchal rigidity, and petechiae/purpura. Symptoms progress rapidly (over 12-24 hours), and the disease can be complicated by shock, multiorgan failure, disseminated intravascular coagulation, and death. References: Meningococcal disease in childhood: epidemiology, clinical features, and prevention. (http://www.ncbi.nlm.nih.gov/pubmed/26788732) Neisseria meningitidis. (http://www.ncbi.nlm.nih.gov/pubmed/31751039)

An 18-Month-Old Boy Is Brought to the Emergency Department by His