NR 507 2026 ADVANCED
PATHOPHYSIOLOGY ASSESSMENT STUDY
GUIDE
◉ Hypersensitivity: Type 2
Answer: Type 2: Cytotoxic reaction; tissue specific (ex: thyroid
tissue)
Macrophages are the primary effectors cells involved
Can cause tissue damage or alter function
Grave's disease (hyperthyroidism) - example of altering thyroid
function, but does not destroy thyroid tissue
Incompatible blood type- example of cell/tissue damage that occurs;
severe transfusion reaction occurs and the transfused erythrocytes
are destroyed by agglutination or complement-mediated lysis.
◉ Type 1 Hypersensitivity VS. Type 2 Hypersensitivity
,Answer: Type 1 Hypersensitivity
Organ Specific
Antibody binds to the antigen on the cell surface
Type 2 Hypersensitivity
Not Organ Specific
Antibody binds to the soluble antigen outside the cell surface that
was released into the blood or body fluids, and the complex is then
deposited in the tissues
◉ Hypersensitivity: Type 3 - Examples
Answer: Rheumatoid arthritis: Antigen/antibodies are deposited in
the joints
Systemic Lupus Erythematosus (SLE)- very closely related to
autoimmunity- antigen/antibodies deposit in organs that cause
tissue damage
◉ Hypersensitivity: Type 4
Answer: Delayed response
Does not involve antigen/antibody complexes like Types 1, 2 and 3
, Is T-cell mediated
◉ Differentiating Between the Rash of a Type 1 vs. Type 4 Reaction:
Answer: Type 1: Immediate hypersensitivity reactions, termed
atopic dermatitis, are usually characterized by widely distributed
lesions
Type 4: Contact dermatitis (delayed hypersensitivity) consists of
lesions only at the site of contact with the allergen
The key determinant is the timing of the rash:
-Type 1 = Immediate
-Type 4 = Delayed: Several days following contact, ex would be
poison ivy
◉ Treatment of Type 4 Rash
Answer: A non-severe case of contact dermatitis would be treated
with topical corticosteroid.
Why not epinephrine or antihistamines?
-Epinephrine is for emergent Type 1 anaphylactic reactions.
Antihistamines act on the H1 receptors. Type 4 does not involve
mast cells and H1 receptors.
PATHOPHYSIOLOGY ASSESSMENT STUDY
GUIDE
◉ Hypersensitivity: Type 2
Answer: Type 2: Cytotoxic reaction; tissue specific (ex: thyroid
tissue)
Macrophages are the primary effectors cells involved
Can cause tissue damage or alter function
Grave's disease (hyperthyroidism) - example of altering thyroid
function, but does not destroy thyroid tissue
Incompatible blood type- example of cell/tissue damage that occurs;
severe transfusion reaction occurs and the transfused erythrocytes
are destroyed by agglutination or complement-mediated lysis.
◉ Type 1 Hypersensitivity VS. Type 2 Hypersensitivity
,Answer: Type 1 Hypersensitivity
Organ Specific
Antibody binds to the antigen on the cell surface
Type 2 Hypersensitivity
Not Organ Specific
Antibody binds to the soluble antigen outside the cell surface that
was released into the blood or body fluids, and the complex is then
deposited in the tissues
◉ Hypersensitivity: Type 3 - Examples
Answer: Rheumatoid arthritis: Antigen/antibodies are deposited in
the joints
Systemic Lupus Erythematosus (SLE)- very closely related to
autoimmunity- antigen/antibodies deposit in organs that cause
tissue damage
◉ Hypersensitivity: Type 4
Answer: Delayed response
Does not involve antigen/antibody complexes like Types 1, 2 and 3
, Is T-cell mediated
◉ Differentiating Between the Rash of a Type 1 vs. Type 4 Reaction:
Answer: Type 1: Immediate hypersensitivity reactions, termed
atopic dermatitis, are usually characterized by widely distributed
lesions
Type 4: Contact dermatitis (delayed hypersensitivity) consists of
lesions only at the site of contact with the allergen
The key determinant is the timing of the rash:
-Type 1 = Immediate
-Type 4 = Delayed: Several days following contact, ex would be
poison ivy
◉ Treatment of Type 4 Rash
Answer: A non-severe case of contact dermatitis would be treated
with topical corticosteroid.
Why not epinephrine or antihistamines?
-Epinephrine is for emergent Type 1 anaphylactic reactions.
Antihistamines act on the H1 receptors. Type 4 does not involve
mast cells and H1 receptors.
