47. Hypersensitivity

Question 1

A patient presents to your office with a cytotoxic Type II hypersensitivity disorder. Which of the following is a possible disorder for the patient?

A. Mysthesia Gravis
B. DM Type II
C. Pericious Anemia
D. Acute Rheumatic Fever
E. Graves Disease

SZ

Answer 1

Ans. D Acute Rheumatic Fever

Cytotoxic Type II Hypersensitivity reactions involve Classical Complement Pathway, Phagocytosis via FcR, ADCC via NK cells or eosinophils. Acute Rheumatic Fever involves antibodies cross-reacting with the myocardial antigens.

The remaining answer choices are non-cytotoxic. These disease are caused by antibodies directed against the cell surface receptors.

Question 2

A 16 y/o boy presents to the ED with a laceration to his right shin from a old rusty machete he was throwing up and down in the air. Your nurse administers a tetanus booster after you repair the wound. 6 hours later he develops a erythema and edemas at the injection site. This is an example of which of the following hypersensitivity reactions?

A. Type I
B. Type II Cytotoxic
C. Type II Noncytotoxic
D. Type III Generalized (Serum Sickness)
E. Type III Localized 
F. Type IV

SZ

Answer 2

Ans. E Type III Localized

Type III hypersensitivity is immune complex mediated. Localized reactions deposit in the skin near the site of antigen injection entry. This occurs in 4-10 hours. Serum sickness is generalized forming in the blood vessels, kidney or joints. This process takes much longer, 1-2 weeks.