Hypersensitivity reactions (types I-IV) — MCQs

A 25-year-old woman presents to an urgent care center following a bee sting while at a picnic with her friends. She immediately developed a skin rash and swelling over her arm and face. She endorses diffuse itching over her torso. Past medical history is significant for a mild allergy to pet dander and ragweed. She occasionally takes oral contraceptive pills and diphenhydramine for her allergies. Family history is noncontributory. Her blood pressure is 119/81 mm Hg, heart rate is 101/min, respiratory rate is 21/min, and temperature is 37°C (98.6°F). On physical examination, the patient has severe edema over her face and severe stridor with inspiration at the base of both lungs. Of the following options, this patient is likely experiencing which of the following hypersensitivity reactions?

A 60-year-old man who recently immigrated from South America schedules an appointment with a physician to complete his pre-employment health clearance form. According to company policy, a skin test for tuberculosis must be administered to all new employees. Thus, he received an intradermal injection of purified protein derivative (PPD) on his left forearm. After 48 hours, a 14-mm oval induration is noticed. The type of cells most likely present and responsible for the indurated area will have which of the following characteristic features?

A 55-year-old man with a history of fatigue and exertional dyspnea presents to the urgent care clinic following an acute upper respiratory illness. On physical examination, his pulses are bounding, his complexion is very pale, and scleral icterus is apparent. The spleen is moderately enlarged. Oxygen saturation is 79% at rest, with a new oxygen requirement of 9 L by a non-rebreather mask. Laboratory analysis results show a hemoglobin level of 6.8 g/dL. Of the following options, which hypersensitivity reaction does this condition represent?

A 31-year-old woman presents to her primary care provider to discuss the results from a previous urine analysis. She has no new complaints and feels well. Past medical history is significant for systemic lupus erythematosus. She was diagnosed 5 years ago and takes hydroxychloroquine every day and prednisone when her condition flares. Her previous urine analysis shows elevated protein levels (4+) and blood (3+). The urine sediment contained red blood cells (6 RBCs/high-power field). The treating physician would like to perform a renal biopsy to rule out lupus nephritis. What type of hypersensitivity is suggestive of lupus nephritis?

An 18-year-old man is known to be allergic to peanuts, and he mistakenly eats biscuits containing some traces of peanuts. Within 15 minutes, he develops generalized redness of the skin and urticaria, associated with shortness of breath and diffuse wheezing. His blood pressure is 80/55 mm Hg and heart rate is 124/min. He is given intramuscular epinephrine and transported emergently to the local hospital. This patient’s presentation is an example of which of the following hypersensitivity reactions?

A 7-year-old girl is brought to the physician with complaints of erythema and rashes over the bridge of her nose and on her forehead for the past 6 months. She also has vesiculobullous and erythematous scaly crusted lesions on the scalp and around the perioral areas. Her parents report a history of worsening symptoms during exposure to sunlight, along with a history of joint pain and oral ulcers. Her temperature is 38.6°C (101.4°F), pulse is 88/min, and respirations are 20/min. On physical examination, pallor and cervical lymphadenopathy are present. On cutaneous examination, diffuse hair loss and hyperpigmented scaly lesions are present. Her laboratory studies show: Hemoglobin 7.9 mg/dL Total leukocyte count 6,300/mm3 Platelet count 167,000/mm3 Erythrocyte sedimentation rate 30 mm/h ANA titer 1:520 (positive) Which of the following most likely explains the mechanism of this condition?

A 5-year-old African American female has experienced recurrent respiratory infections. To determine how well her cell-mediated immunity is performing, a Candida skin injection is administered. After 48 hours, there is no evidence of induration at the injection site. Of the following cell types, which one would normally mediate this type of immune reaction?

You are working in the emergency room of a children's hospital when a 4-year-old girl is brought in by ambulance due to "difficulty breathing." The patient had been eating lunch on a school field trip when she suddenly complained of abdominal pain. Shortly thereafter, she was noted to have swelling of the lips, a rapidly developing red rash and difficulty breathing. In the ambulance her blood pressure was persistently 80/50 mmHg despite intramuscular epinephrine. In the course of stabilization and work up of the patient, you note an elevated tryptase level. What is the mechanism behind this elevated tryptase level?

A 45-year-old woman presents to her primary care physician for knee pain. She states that she has been experiencing a discomfort and pain in her left knee that lasts for several hours but tends to improve with use. She takes ibuprofen occasionally which has been minimally helpful. She states that this pain is making it difficult for her to work as a cashier. Her temperature is 98.6°F (37.0°C), blood pressure is 117/58 mmHg, pulse is 90/min, respirations are 14/min, and oxygen saturation is 97% on room air. Physical exam reveals a stable gait that the patient claims causes her pain. The patient has a non-pulsatile, non-erythematous, palpable mass over the posterior aspect of her left knee that is roughly 3 to 4 cm in diameter and is hypoechoic on ultrasound. Which of the following is associated with this patient's condition?

A 55-year-old woman presents with pain in both hands and wrists for several years. It is associated with morning stiffness that lasts for almost an hour. She has a blood pressure of 124/76 mm Hg, heart rate of 71/min, and respiratory rate of 14/min. Physical examination reveals tenderness and swelling in both hands and wrists. Laboratory investigations reveal the presence of anti-cyclic citrullinated peptide. Which of the following immune-mediated processes is responsible for this patient’s condition?