A 22-year-old woman is brought to the emergency department due to a day of fever, headaches, nausea, vomiting, and myalgias that began suddenly last night. This morning, the patient was lethargic, difficult to arouse, and confused. She is an exchange student who came to the United States 3 months ago, and her medical history is unknown. Temperature is 39.4 C (102.9 F), blood pressure is 100/60 mm Hg, pulse is 112/min, and respirations are 18/min. Physical examination shows nuchal rigidity. Skin examination findings are shown in the image. Leukocyte count is elevated, and lumbar puncture with cerebrospinal fluid Gram stain establishes the diagnosis. Which of the following is the primary component of the vaccine that could have prevented this patient's current condition?

Question

A 22-year-old woman is brought to the emergency department due to a day of fever, headaches, nausea, vomiting, and myalgias that began suddenly last night.  This morning, the patient was lethargic, difficult to arouse, and confused.  She is an exchange student who came to the United States 3 months ago, and her medical history is unknown.  Temperature is 39.4 C (102.9 F), blood pressure is 100/60 mm Hg, pulse is 112/min, and respirations are 18/min.  Physical examination shows nuchal rigidity.  Skin examination findings are shown in the image.  Leukocyte count is elevated, and lumbar puncture with cerebrospinal fluid Gram stain establishes the diagnosis.  Which of the following is the primary component of the vaccine that could have prevented this patient's current condition?

Quizplus · Accepted Answer

11ec160b_3883_4198_9249_d15f65f9fd96_MD0001_00 This patient's rapid-onset headache, fever, altered mental status, nuchal rigidity, and purpuric rash raise strong suspicion for meningococcal meningitis. Neisseria meningitidis is a gram-negative diplococcus transmitted via aerosolized respiratory droplets. Close living conditions (eg, college dormitories, prisons, military barracks) promote its spread. N meningitidis has several virulence factors, including a polysaccharide capsule (impairs phagocytosis of the bacteria), lipo-oligosaccharide (induces cytokine production, leading to circulatory collapse), pili (permit bacterial attachment to the respiratory mucosa), and IgA protease (cleaves secretory IgA that would otherwise inactivate the pili). Antibodies against the polysaccharide capsule confer immunity to N meningitidis. The meningococcal vaccines available in the United States are as follows: Quadrivalent conjugate vaccine: Capsular polysaccharide antigens (serogroups A, C, Y, and W) are fused to a diphtheroid toxin carrier, which allows the polysaccharides to be displayed on the major histocompatibility complex of antigen-presenting cells. This results in the stimulation of T-cells and provides a stronger, more lasting immunologic response. Serogroup B vaccine: Capsular polysaccharides from serogroup B are very similar to human neural cell adhesion molecules. This molecular mimicry prevented a polysaccharide vaccine due to difficulty in generating an immune response without increasing the risk of autoimmunity. A vaccine against this serogroup is now available that uses recombinant proteins instead of capsular polysaccharides. In the United States, the quadrivalent vaccine is part of routine immunizations; the serogroup B vaccine is recommended for specific high-risk populations (eg, those with asplenia or complement deficiency). (Choice B) The influenza vaccination typically contains three or four strains of inactivated virus. Although influenza is often associated with rapid-onset malaise, headache, myalgia, and fever, the presence of nuchal rigidity and purpuric skin rash make meningococcemia more likely. (Choice C) The diphtheria toxoid is used as protein carrier in conjugate vaccines because it allows the polysaccharide antigen to be displayed on the major histocompatibility complex of antigen presenting cells. The toxoid is not the primary component of conjugate vaccines. (Choice D) The measles-mumps-rubella vaccination contains live attenuated versions of these viruses. Measles is associated with the 3 C's (coryza, conjunctivitis, cough) and a maculopapular rash, mumps is associated with salivary gland swelling, and rubella is associated with a diffuse maculopapular rash. A purpuric rash and nuchal rigidity would be atypical. (Choice E) Virus-like particles are multiprotein structures that illicit a strong B- and T-cell response but contain no viral genetic material, so they are not infectious. Virus-like particles are used in the hepatitis B and human papillomavirus vaccines. Educational objective: Antibodies against the polysaccharide capsule of Neisseria meningitidis provide immunity against this pathogen. Quadrivalent meningococcal vaccines contain capsular polysaccharides from major serotypes (A, C, Y, and W) of N meningitidis. Serotype B vaccinations use recombinant proteins. __________ References: Meningococcal vaccinations. (http://www.ncbi.nlm.nih.gov/pubmed/27086142)

A 22-Year-Old Woman Is Brought to the Emergency Department Due