Polio and Haemophilus influenzae — MCQs

A 2-year-old boy is brought in by his parents to his pediatrician. The boy was born by spontaneous vaginal delivery at 39 weeks and 5 days after a normal pregnancy. The boy has received all age-appropriate vaccinations as of his last visit at 18 months of age. Of note, the boy has confirmed sickle cell disease and the only medication he takes is penicillin prophylaxis. The parents state that they plan on enrolling their son in a daycare, which requires documentation of up-to-date vaccinations. The pediatrician states that their son needs an additional vaccination at this visit, which is a polysaccharide vaccine that is not conjugated to protein. Which of the following matches this description?

An investigator studying patients with symptoms of arthritis detects a nonenveloped virus with a single-stranded DNA genome in the serum of a pregnant patient. Fetal infection with this pathogen is most likely to cause which of the following manifestations?

A previously healthy 17-year-old boy is brought to the emergency department because of fever, nausea, and myalgia for the past day. His temperature is 39.5°C (103.1°F), pulse is 112/min, and blood pressure is 77/55 mm Hg. Physical examination shows scattered petechiae over the anterior chest and abdomen. Blood culture grows an organism on Thayer-Martin agar. Which of the following virulence factors of the causal organism is most likely responsible for the high mortality rate associated with it?

A 2-year-old girl who emigrated from Pakistan 2 weeks ago is brought to the emergency department because of lower limb weakness for one-day. One week ago, she had a 3-day episode of flu-like symptoms that resolved without treatment. She has not yet received any routine childhood vaccinations. Deep tendon reflexes are 1+ in the right lower extremity and absent in the left lower extremity. Analysis of cerebrospinal fluid shows a leukocyte count of 38 cells/mm3 (68% lymphocytes), a protein concentration of 49 mg/dL, and a glucose concentration of 60 mg/dL. Which of the following is the most likely diagnosis in this patient?

A 15-month-old boy presents to his family physician after being brought in by his mother. She is concerned that her son has been sick for more than 5 days, and he is not getting better with home remedies and acetaminophen. On examination, the child has a sore throat and obvious congestion in the maxillary sinuses. His temperature is 37.6°C (99.6°F). An infection with Haemophilus influenzae is suspected, and a throat sample is taken and sent to the laboratory for testing. The child is at the lower weight-for-length percentile. His history indicates he previously had an infection with Streptococcus pneumoniae in the last 4 months, which was treated effectively with antibiotics. While waiting for the laboratory results, and assuming the child’s B and T cell levels are normal, which of the following diagnoses is the physician likely considering at this time?

A 9-month-old boy is brought to a pediatrician by his parents for routine immunization. The parents say they have recently immigrated to the United States from a developing country, where the infant was receiving immunizations as per the national immunization schedule for that country. The pediatrician prepares a plan for the infant’s immunizations as per standard US guidelines. Looking at the plan, the parents ask why the infant needs to be vaccinated with injectable polio vaccine, as he had already received an oral polio vaccine back in their home country. The pediatrician explains to them that, as per the recommended immunization schedule for children and adolescents in the United States, it is important to complete the schedule of immunizations using the injectable polio vaccine (IPV). He also mentions that IPV is considered safer than OPV, and IPV has some distinct advantages over OPV. Which of the following statements best explains the advantage of IPV over OPV to which the pediatrician is referring?

A 1-year-old girl is brought to the physician for a well-child examination. She has no history of serious illness. She receives a vaccine in which a polysaccharide is conjugated to a carrier protein. Which of the following pathogens is the most likely target of this vaccine?

A 35-year-old man is brought to the emergency department by his wife because of a 1-week history of progressive confusion, myalgia, and nausea. His wife says that he first reported headaches and fatigue 10 days ago, and since then “he has not been himself”. He has refused to drink any liquids for the last day. Two months ago, he helped his neighbor remove a raccoon's den from her backyard. He appears agitated. His temperature is 100.8°F (38.2°C). Examination shows excessive drooling. Muscle tone and deep tendon reflexes are increased bilaterally. Administration of which of the following is most likely to have prevented this patient's condition?

A 4-year-old boy is brought to the emergency department with difficulty breathing. His mother reports that he developed a fever last night and began to have trouble breathing this morning. The boy was born at 39 weeks gestation via spontaneous vaginal delivery. He is unvaccinated (conscientious objection by the family) and is meeting all developmental milestones. At the hospital, his vitals are temperature 39.8°C (103.6°F), pulse 122/min, respiration rate 33/min, blood pressure 110/66 mm Hg, and SpO2 93% on room air. On physical examination, he appears ill with his neck hyperextended and chin protruding. His voice is muffled and is drooling. The pediatrician explains that there is one particular bacteria that commonly causes these symptoms. At what age should the patient have first received vaccination to prevent this condition from this particular bacteria?

A 43-year-old woman comes to the physician because of a fever, nausea, and a nonproductive cough for 7 days. During this period, she has had headaches, generalized fatigue, and muscle and joint pain. She has also had increasing shortness of breath for 2 days. She has type 2 diabetes mellitus and osteoarthritis of her left knee. Current medications include insulin and ibuprofen. She had smoked two packs of cigarettes daily for 20 years but stopped 10 years ago. Her temperature is 38.1°C (100.6°F), pulse is 94/min, respirations are 18/min, and blood pressure is 132/86 mm Hg. The lungs are clear to auscultation. There are multiple skin lesions with a blue livid center, pale intermediate zone, and a dark red peripheral rim on the upper and lower extremities. Laboratory studies show: Hemoglobin 14.6 g/dL Leukocyte count 11,100/mm3 Serum Na+ 137 mEq/L K+ 4.1 mEq/L Cl- 99 mEq/L Urea nitrogen 17 mg/dL Glucose 123 mg/dL Creatinine 0.9 mg/dL Which of the following is the most likely causal organism?