Med-Surg: Chapter 19: Type III Hypersensitivity Reaction: Immune Complex

Question 1

Type III Hypersensitivity Reactions

Answer 1

immune complex-mediated reactions

• mediated by the formation of antigen-antibody complexes
• can be systemic and local
• ex: systemic lupus erythematosus (SLE), rheumatoid arthritis, and serum sickness
• local reaction = Arthus reaction (rare)

Question 2

Epidemiology: Systemic Lupus Erythematosus

Answer 2

may be caused by genetic, environmental, or unknown factors

-more common in females

Question 3

Epidemiology: Rheumatoid Arthritis

Answer 3

• effects all ethnic groups

- women more affected

Question 4

Pathophysiology and Clinical Manifestations

Answer 4

involves the formation of an antigen-antibody immune complex

• immunoglobulin G is the immunoglobulin involved
• these immune complexes are large molecules of antibody combined with antigen and, due to their size, are difficult for the body to remove
• disease results when they are not removed but lodge in the tissues

Question 5

Systemic Immune Complex Disorders: Rheumatoid Arthritis

Answer 5

-manifestations of RA are caused by the immune complexes that are lodged in joint spaces
-when there are too many immune complexes, too much complement is activated, and an acute inflammatory response develops
-complement attracts neutrophils to the area of inflammation and stimulates the release of lysosomal enzymes; this release causes tissue damage, especially in small blood vessels where the immune complexes tend to lodge and the lack of blood supply causes tissue necrosis
>this is followed by destruction of tissue, scarring, and fibrous changes

Question 6

Systemic Immune Complex Disorders: Systemic Lupus Erythematosus

Answer 6

produces antibodies against any organ or tissue in the body

• it forms immune complexes that lodge in the vessels, causing vasculitis; in the glomeruli, causing nephritis; and in the joints, causing arthralgia (joint pain) and arthritis
• it affects the connective tissues and multiple organs, resulting in cardiovascular, renal, or neurological complications

Question 7

Systemic Immune Complex Disorders: Serum Sickness

Answer 7

an immune system reaction to certain kinds of medications, most commonly penicillin and other antibiotics or injected proteins (antiserum) used to treat immune conditions
-antiserum is given to enhance immunity, most commonly after a snake bite
-serum sickness occurs when the body mistakenly identifies a protein from the antiserum or medication as harmful and activates the immune system to fight it off; results in the collection of immune complexes in blood vessel walls of the skin, joints, and kidney; the deposited complexes activate complement; this increases vascular permeability, and phagocytic cells are recruited to the area that cause tissue damage and edema
>develops within 7 to 12 days after initial exposure but can take up to 3 weeks
>if exposed to a substance a second time, it develops faster (within 1 to 4 days); and a small amount can cause an intense response
>clinical manifestations: fever, arthralgia, lymphadenopathy (swollen lymph nodes), malaise, and possibly polyarthritis (arthritis in multiple joints), nephritis (inflammation of the nephrons in the kidney), urticaria (hives), a patchy or generalized rash, or extensive edema involving the face (angioedema), neck, and joints
-symptoms may last only a few days, and damage is temporary
-prolong exposure can lead to irreversible damage

Question 8

Clinical Manifestations of Serum Sickness

Answer 8

-fever
-arthralgia
-lymphadenopathy (swollen lymph nodes)
-malaise
-polyarthritis (arthritis in multiple joints)
-nephritis (inflammation of the nephrons in the kidney)
-urticaria (hives)
-patchy or generalized rash
-extensive edema involving the face (angioedema), neck, and joints
>symptoms may last only a few days, and damage is temporary
>prolonged exposure can lead to irreversible damage

Question 9

Local Immune Complex Reactions

Answer 9

Arthus Reaction

• localized vasculitis (inflammation of blood vessel) due to the deposit of immune complexes in dermal vessels after intradermal or subcutaneous injections, typically vaccinations
• within 4 to 10 hours, a red raised lesion develops at the site of the injection; an ulcer forms in the center; this is due to the in situ formation of antigen-antibody complexes

Question 10

Medical Management

Answer 10

-removal of the offending agent is the first treatment
-symptom treatment for systemic immune complex reactions includes:
>aspirin for joint pain
>antihistamines for the pruritis
-for sever reactions, epinephrine or systemic corticosteroids may be used
-epinephrine used for symptomatic relief of serum sickness, urticaria, and angioedema
-corticosteroids (prednisone) have been used to reduce the inflammation associated with serum sickness

Question 11

Epinephrine is used for what

Answer 11

• for severe reactions

- used for symptomatic relief of serum sickness, urticaria, and angioedema

Question 12

Corticosteroids (prednisone) have been used for what

Answer 12

reduce the inflammation associated with serum sickness

Question 13

Aspirin is used for what?

Answer 13

joint pain