Free medical quiz
Type 1 Hypersensitivity Quiz
Focused SBA-style practice, followed by the answer and explanation for every question.
- Free now
- 5 questions
- Full bank
- 48 questions
- Answers
- Explained
Free question
Try one with the answer
A question from this quiz. Answer it to see the explanation students get.
Which treatment is first-line for a severe acute type 1 hypersensitivity reaction (anaphylaxis) causing airway, breathing or circulatory compromise?
- A Inhaled beta-agonist You picked ✕
- B Oral corticosteroid You picked ✕
- C Oral antihistamine You picked ✕
- D Intravenous antibiotic You picked ✕
- E Intramuscular adrenaline You picked ✓
Correct!
Incorrect
The answer is E: Intramuscular adrenaline
Explanation
Why E is correct
See Symptoms. Option E is correct. In anaphylaxis, mast cells release large amounts of histamine, leukotrienes and cytokines, which cause vasodilation (widening of blood vessels), leaky vessels, bronchoconstriction (narrowing of the airways) and swelling of the throat. Adrenaline (also called epinephrine) is the one drug that reverses all of these quickly. It acts on alpha receptors to constrict blood vessels and reduce swelling, and on beta receptors to open the airways, strengthen the heartbeat and damp down further release of histamine and leukotrienes. It is given by the intramuscular route, ideally into the anterolateral (front and outer) thigh, because this is safer than the intravenous route for most clinicians and is quick to absorb. The dose is repeated after five minutes if the response is poor. Alongside adrenaline, call for help, lie the patient flat with the legs raised if they are hypotensive, give oxygen and fluids, and monitor breathing and circulation continuously. Adrenaline should never wait for tests or for other drugs.
- Drug: intramuscular adrenaline is the one drug that quickly reverses all the effects of anaphylaxis.
- Actions: alpha receptors constrict vessels and reduce swelling, and beta receptors open the airways and strengthen the heartbeat.
- Route and repeat: give it into the anterolateral thigh and repeat after five minutes if the response is poor.
Why the other options are incorrect
- A. Inhaled beta-agonist: An inhaled beta-agonist such as salbutamol may be considered for wheeze after adrenaline, but it does not treat the swelling or low blood pressure of anaphylaxis. It is not the first-line drug. Your answer
- B. Oral corticosteroid: Corticosteroids take hours to work and routine use in the emergency treatment of anaphylaxis is not advised. They may be considered after resuscitation for ongoing symptoms and must never be given in place of adrenaline. Your answer
- C. Oral antihistamine: Antihistamines are a third-line treatment, because they do not treat airway or circulation problems and oral tablets act too slowly. They are used later for skin symptoms, once the patient is stable. Your answer
- D. Intravenous antibiotic: Anaphylaxis is an allergic reaction and not an infection, so an antibiotic has no role. Another antibiotic dose could also be the very trigger. Your answer
With Premium, questions you miss become Revision Coach flashcards, scheduled for review.
Question preview
What you will practise
More questions from this set. Start the quiz to answer them and see each explanation.
-
1
Which symptom most characteristically reflects a type 1 hypersensitivity reaction affecting the face?
-
2
A 19-year-old student with no previous allergy history eats a food containing peanuts for the first time she can recall and rapidly develops wheeze, hypotension and urticaria. Which statement best explains how this reaction can occur in type 1 hypersensitivity?
Revise before you test
Review SimpleMed's doctor-written article, then return here to check recall.
Read the topic articleNeed wider coverage?
Explore every Immunology topic set, or build a tailored mixed session.
Browse subject quizzes