EMT CHAPTER 20 IMMUNOLOGIC
EMERGENCIES 2025 2026 COMPLETE
STUDY GUIDE KEY CONCEPTS PRACTICE
QUESTIONS and EXAM PREPARATION
EMT: Immunologic Emergencies (Questions 1–150)
1. What is the fundamental definition of an allergic
reaction?
A. A localized bacterial infection within the dermal layers of the
skin
B. An exaggerated immune system response to any
foreign substance (allergen)
C. Systemic failure of the pancreas to secrete adequate immune
proteins
D. Severe hypotension caused by rapid external volume loss
Correct Answer: B
Rationale: An allergic reaction is an immune response to a
foreign substance (allergen) that is normally harmless to most
people. The body misidentifies the substance as a threat and
launches an exaggerated defense [2].
2. How does anaphylaxis differ from a standard localized
allergic reaction?
A. Anaphylaxis is a delayed reaction that takes days to manifest.
B. Anaphylaxis is a systemic, life-threatening allergic
reaction involving multiple organ systems.
C. Anaphylaxis affects only the local skin site where the allergen
made contact.
D. Anaphylaxis causes a dangerous elevation in systemic blood
pressure.
, Correct Answer: B
Rationale: Anaphylaxis is a severe, systemic, immediate Type I
hypersensitivity reaction. Unlike localized reactions (e.g., a
simple rash), anaphylaxis involves multiple organ systems, most
critically causing airway swelling, severe bronchospasm, and
cardiovascular collapse (anaphylactic shock) [1, 2, 3].
3. Which of the following conditions must be present for
an immune response to be clinically classified as
anaphylactic shock?
A. A blood glucose reading above 200 mg/dL
B. Systemic vasodilation leading to hypotension and
signs of poor tissue perfusion
C. A localized cluster of hives limited strictly to the site of an
injection
D. Deep, rapid Kussmaul respirations with a fruity breath odor
Correct Answer: B
Rationale: Anaphylactic shock is a form of distributive shock. It
occurs when a massive release of histamines causes widespread
systemic vasodilation, dropping peripheral vascular resistance,
reducing blood pressure (hypotension), and impairing organ
perfusion [1, 3].
4. What chemical substance is released by mast cells and
basophils during an allergic reaction, driving
bronchoconstriction and vasodilation?
A. Glucagon
B. Insulin
C. Histamine
D. Acetylcholine
Correct Answer: C
Rationale: Histamine is the primary chemical mediator released
during degranulation of mast cells and basophils. It causes
smooth muscle contraction in the lungs (bronchoconstriction),
, widespread blood vessel relaxation (vasodilation), and increased
capillary permeability [1, 3].
5. What are the two primary life-threatening diagnostic
concerns when managing a patient in severe
anaphylaxis?
A. Hyperglycemia and profound dehydration
B. Spontaneous bleeding and joint destruction
C. Airway occlusion (laryngeal edema) and
cardiovascular collapse (hypotension)
D. Metabolic acidosis and elevated intracranial pressure
Correct Answer: C
Rationale: Anaphylaxis kills via two primary mechanisms:
swelling of the upper airway structures (laryngeal
edema/angioedema), which blocks ventilation, and profound
systemic vasodilation, which triggers fatal shock [1, 3].
6. What is the clinical term for the raised, red, intensely
itchy wheels or patches on the skin that commonly occur
during an allergic reaction?
A. Petechiae
B. Urticaria (Hives)
C. Purpura
D. Hematoma
Correct Answer: B
Rationale: Urticaria is the medical term for hives. They are
caused by localized histamine release, which dilates small
intradermal blood vessels and leaks fluid into the surrounding
skin tissue [1, 2].
7. A patient presents with dramatic swelling of the lips,
tongue, and eyelids during an allergic reaction. This
specific clinical presentation is termed:
A. Urticaria
B. Angioedema
, C. Pruritus
D. Erythema
Correct Answer: B
Rationale: Angioedema is the swelling of deeper subcutaneous
or submucosal tissues, most commonly affecting the face, lips,
tongue, and airway. It can rapidly cause a complete upper
airway obstruction [1, 2, 3].
8. During your assessment of an anaphylactic patient's
lung sounds, you note a high-pitched, whistling sound
during exhalation. This is documented as:
A. Stridor
B. Wheezing
C. Crackles
D. Rhonchi
Correct Answer: B
Rationale: Wheezing is a high-pitched, musical sound typically
heard on exhalation, caused by narrowing and
bronchoconstriction of the lower airways. Stridor, conversely, is
a harsh upper-airway sound heard on inhalation [1, 2].
9. What high-pitched, harsh inspiratory sound indicates
swelling of the upper airway structures (laryngeal
edema) and alerts the EMT to an imminent airway
closure?
A. Wheezing
B. Stridor
C. Crackles (Rales)
D. Pleural friction rub
Correct Answer: B
Rationale: Stridor is a rough, high-pitched crowing sound heard
on inspiration. It indicates a partial upper airway obstruction
EMERGENCIES 2025 2026 COMPLETE
STUDY GUIDE KEY CONCEPTS PRACTICE
QUESTIONS and EXAM PREPARATION
EMT: Immunologic Emergencies (Questions 1–150)
1. What is the fundamental definition of an allergic
reaction?
A. A localized bacterial infection within the dermal layers of the
skin
B. An exaggerated immune system response to any
foreign substance (allergen)
C. Systemic failure of the pancreas to secrete adequate immune
proteins
D. Severe hypotension caused by rapid external volume loss
Correct Answer: B
Rationale: An allergic reaction is an immune response to a
foreign substance (allergen) that is normally harmless to most
people. The body misidentifies the substance as a threat and
launches an exaggerated defense [2].
2. How does anaphylaxis differ from a standard localized
allergic reaction?
A. Anaphylaxis is a delayed reaction that takes days to manifest.
B. Anaphylaxis is a systemic, life-threatening allergic
reaction involving multiple organ systems.
C. Anaphylaxis affects only the local skin site where the allergen
made contact.
D. Anaphylaxis causes a dangerous elevation in systemic blood
pressure.
, Correct Answer: B
Rationale: Anaphylaxis is a severe, systemic, immediate Type I
hypersensitivity reaction. Unlike localized reactions (e.g., a
simple rash), anaphylaxis involves multiple organ systems, most
critically causing airway swelling, severe bronchospasm, and
cardiovascular collapse (anaphylactic shock) [1, 2, 3].
3. Which of the following conditions must be present for
an immune response to be clinically classified as
anaphylactic shock?
A. A blood glucose reading above 200 mg/dL
B. Systemic vasodilation leading to hypotension and
signs of poor tissue perfusion
C. A localized cluster of hives limited strictly to the site of an
injection
D. Deep, rapid Kussmaul respirations with a fruity breath odor
Correct Answer: B
Rationale: Anaphylactic shock is a form of distributive shock. It
occurs when a massive release of histamines causes widespread
systemic vasodilation, dropping peripheral vascular resistance,
reducing blood pressure (hypotension), and impairing organ
perfusion [1, 3].
4. What chemical substance is released by mast cells and
basophils during an allergic reaction, driving
bronchoconstriction and vasodilation?
A. Glucagon
B. Insulin
C. Histamine
D. Acetylcholine
Correct Answer: C
Rationale: Histamine is the primary chemical mediator released
during degranulation of mast cells and basophils. It causes
smooth muscle contraction in the lungs (bronchoconstriction),
, widespread blood vessel relaxation (vasodilation), and increased
capillary permeability [1, 3].
5. What are the two primary life-threatening diagnostic
concerns when managing a patient in severe
anaphylaxis?
A. Hyperglycemia and profound dehydration
B. Spontaneous bleeding and joint destruction
C. Airway occlusion (laryngeal edema) and
cardiovascular collapse (hypotension)
D. Metabolic acidosis and elevated intracranial pressure
Correct Answer: C
Rationale: Anaphylaxis kills via two primary mechanisms:
swelling of the upper airway structures (laryngeal
edema/angioedema), which blocks ventilation, and profound
systemic vasodilation, which triggers fatal shock [1, 3].
6. What is the clinical term for the raised, red, intensely
itchy wheels or patches on the skin that commonly occur
during an allergic reaction?
A. Petechiae
B. Urticaria (Hives)
C. Purpura
D. Hematoma
Correct Answer: B
Rationale: Urticaria is the medical term for hives. They are
caused by localized histamine release, which dilates small
intradermal blood vessels and leaks fluid into the surrounding
skin tissue [1, 2].
7. A patient presents with dramatic swelling of the lips,
tongue, and eyelids during an allergic reaction. This
specific clinical presentation is termed:
A. Urticaria
B. Angioedema
, C. Pruritus
D. Erythema
Correct Answer: B
Rationale: Angioedema is the swelling of deeper subcutaneous
or submucosal tissues, most commonly affecting the face, lips,
tongue, and airway. It can rapidly cause a complete upper
airway obstruction [1, 2, 3].
8. During your assessment of an anaphylactic patient's
lung sounds, you note a high-pitched, whistling sound
during exhalation. This is documented as:
A. Stridor
B. Wheezing
C. Crackles
D. Rhonchi
Correct Answer: B
Rationale: Wheezing is a high-pitched, musical sound typically
heard on exhalation, caused by narrowing and
bronchoconstriction of the lower airways. Stridor, conversely, is
a harsh upper-airway sound heard on inhalation [1, 2].
9. What high-pitched, harsh inspiratory sound indicates
swelling of the upper airway structures (laryngeal
edema) and alerts the EMT to an imminent airway
closure?
A. Wheezing
B. Stridor
C. Crackles (Rales)
D. Pleural friction rub
Correct Answer: B
Rationale: Stridor is a rough, high-pitched crowing sound heard
on inspiration. It indicates a partial upper airway obstruction
