Hypersensitivity Flashcards
What is the primary concept of hypersensitivities?
Hypersensitivities, also known as allergies, is an overactive immunity with excessive inflammation occurring in response to the presence of an antigen.
Define inflammation in the context of hypersensitivities.
Inflammation is a syndrome of normal tissue responses to cellular injury, allergy, or the invasion of pathogens, serving as an important protective mechanism.
What are the four types of hypersensitivity?
- Type I: Rapid or Immediate
- Type II: Cytotoxic
- Type III: Immune Complex-Mediated
- Type IV: Delayed
What is Type I hypersensitivity also known as?
Atopic allergy
What is the most common type of hypersensitivity?
Type I: Rapid or Immediate
What immunoglobulin is primarily involved in Type I hypersensitivity?
IgE
What are some examples of Type II hypersensitivity reactions?
- Immune hemolytic anemias
- Hemolytic transfusion reactions
- Drug-induced hemolytic anemia
What occurs during Type III immune complex reactions?
Excess antigens cause immune complexes to form in the blood and get lodged in small blood vessels of the kidneys, skin, and joints.
What autoimmune disorders are commonly associated with Type III hypersensitivity?
- Rheumatoid Arthritis (RA)
- Systemic Lupus Erythematosus (SLE)
What characterizes Type IV hypersensitivity?
T-cells are activated, and the response occurs hours to days after exposure.
What are examples of Type IV hypersensitivity?
- Poison ivy
- Insect stings
- PPD test
What is angioedema in relation to Type I hypersensitivity?
A severe reaction involving blood vessels, mucous membranes, and all layers of skin with deep-tissue IgE-mediated release of inflammatory proteins.
What assessments are prioritized for patients with hypersensitivities?
- Airway
- Lung sounds
- Respiratory rate
- Vital signs
- Psychosocial aspects
What are the signs of anaphylaxis?
- Widespread blood vessel dilation
- Decreased cardiac output
- Bronchoconstriction
What is the first-line medication for anaphylaxis?
Epinephrine
What is the mechanism of action of epinephrine?
It treats anaphylaxis symptoms.
How often should repeat doses of epinephrine be administered?
Every 5-15 minutes as needed.
True or False: Histamine antagonists like Benadryl are effective for Type IV hypersensitivities.
False
Fill in the blank: Anaphylaxis is the most life-threatening example of Type ___ hypersensitivity.
I
What should a nurse do if a client reports exposure to poison ivy and an itchy rash?
A. ‘Antihistamines do not help poison ivy.’
