Exam 3 - Infections/Inflammation/Immune Disorders Flashcards
Autoimmune disease - basic definition
- An individual’s immune system recognizes its own cells as foreign and mounts an immune response that injures self tissues
- Breakdown of self tolerance
- No single theory explains self tolerance of autoimmune diseases (polygenic = more than 1 gene; multifactorial = more than 1 factor)
Hypersensitivity - basic definition
- Altered immunologic response to an antigen; results in disease/damage to host
- An allergy is an abnormal, individual response to certain substances that normally do not trigger such an exaggerated reaction
Pathophysiology (detailed) & clinical manifestations of type I hypersensitivity reaction
- AKA immediate; anaphylactic
- Allergens activate T cells, which bind to mast cells
- Repeated exposure to relatively large doses of the allergens is usually necessary to cause this response
- When enough IgE has been produced, the person is sensitized to the allergen
- At the next exposure of the same antigen, the antigen binds with the surface IgE, releasing mediators (e.g., histamines, cytokines, and prostaglandins) and triggering the complement system
- Examples: hay fever, food allergies, anaphylaxis
- C/M: mild (hives, seasonal allergic rhinitis, eczema or other skin reactions), throat constriction, localized edema, atopic disease, wheezing, tachycardia, anaphylaxis
Pathophysiology of type II hypersensitivity reactions
- AKA tissue-specific, cytotoxic, or cytolytic hypersensitivity
- Causative: IgG, IgM, complement
- Involves the destruction of a target cell by an antibody-directed, cell-surface antigen
- IgG or IgM reacts with an antigen on the cell, activating the complement system
- Often immediate reaction, but some occur over time
- Effects of type II reactions include cell lysis and phagocytosis
- Examples include blood transfusion reactions and erythroblastosis fetalis, drug-induced hemolytic anemia
Pathophysiology of type III hypersensitivity reactions
- AKA immune complex
- Causative: Antigen-antibody complexes
- Circulating antigen-antibody complexes accumulate and are deposited in the tissue
- Common tissues include kidneys, joints, skin, and blood vessels
- Accumulation triggers the complement system causing local inflammation and increased vascular permeability, so more complexes accumulate
- Examples include autoimmune disorders (e.g. systemic lupus erythematosus and glomerulonephritis).
- Treatments are disease specific
Examples of type IV hypersensitivity
- AKA cell-mediated, delayed
- Causative: Sensitized T cells
- Involves a delayed processing of the antigen by macrophages
- Once processed, the antigen is presented to the T cells, resulting in the release of lymphokines that cause inflammation and antigen destruction
- Examples include tuberculin skin testing, transplant reactions, and contact dermatitis
Clinical manifestations of systemic lupus erythematosus (SLE)
- (Chronic, progressive, systemic inflammatory disease that can cause major organs and systems to fail)
- Erythema butterfly or rash of the face
- Dry, scaly raised rash on the face or upper body
- Fever
- Weakness, malaise, and fatigue
- Anorexia
- Weight loss
- Photosensitivity
- Joint pain
- Erythema of the palms
- Anemia
- Positive antinuclear body (ANA) test and lupus erythematosus (LE) preparation
- Elevated erythrocyte sedimentation rate (ESR) and C-reactive protein level
- Arthritis
- Lupus nephritis
- Pleural effusions
- Raynaud’s phenomenon
A client is suspected of having systemic lupus erythematosus. The nurse monitors the client, knowing that which of the following is one of the initial characteristic signs of systemic lupus erythematosus?
- Weight gain
- Subnormal temperature
- Elevated red blood cell count
- Rash on the face across the bridge of the nose and on the cheeks
4
Skin lesions or rash on the face across the bridge of the nose and on the cheeks is an initial characteristic sign of systemic lupus erythematosus (SLE). Fever and weight loss may also occur. Anemia is most likely to occur later in SLE.
To elevate the progress of the client’s systemic lupus erythematosus (SLE), the nurse evaluates which data?
- Increased serum complement fixation, which correlates with reduction of “butterfly” rash
- Increasing levels of C-reactive protein (CRP) and erythocyte sedimentation rate (ESR)
- Overall bone marrow proliferation, which correlates with symptoms of inflammation
- Presence of antinuclear antibodies (ANA), which correlates with a diminishing immune process.
2
The ESR and the CRP are indicators of inflammation in the body. Neither is diagnostic of SLE; however, the level of inflammation is an index to the progress of the condition. Presence of ANA is a characteristic of SLE, but it does not indicate progression. Complement fixation does not indicate progression, nor does absence or presence of the butterfly rash.
A client returns to the clinic to receive evaluation of his routine purified derivative (PPD) test for tuberculosis screening. The test result is positive. What is the best nursing interpretation of this information?
- This is a serious type II reaction and could indicate that he has active tuberculosis; he will need further evaluation immediately.
- The positive results indicate the client has been exposed to the tuberculosis bacilli and has had a delayed type IV response.
- The client’s immune system has been compromised, which allows the immune system to build up antibodies against the pathogen.
- An autoimmune response has occurred and the client will need further evaluation to determine appropriate treatment.
2
Type IV (cell-mediated; delayed hypersensivity) reaction is a delayed response that occurs 24 to 72 hours after exposure to the allergen (e.g., PPD). The client has been sensitized to tuberculosis. There is no indication of active TB, and it is not a type II reaction. The client’s immune system has not been compromised; rather, it has responded normally with the production of antibodies after exposure to the allergen. This does not represent an autoimmune response.
A client has systemic lupus erythematosus (SLE). What statement best describes this client’s immune response?
- A delayed hypersensivity that is cell-mediated
- An immediate reaction to prior exposure
- An immune complex that forms with antibody production
- An immune response that no longer recognizes normal body tissue
4
Systemic lupus erythematosus is characterized as an autoimmune disorder in which the body begins to invade and destroy normal tissue. A delayed hypersensitivity is a type IV response that is characteristic of a transplant rejection or reaction to tuberculin skin testing. An immediate reaction describes a type I reaction characterized by prior exposure to antigen. This occurs with atopic reactions and anaphylaxis. An immune complex that forms with antibody production is a type III response, which occurs with acute glomerulonephritis.
What is an allergic reaction that can quickly deteriorate into shock and death?
- Anaphylaxis
- Graft-versus-host disease
- Type III immune complex formation
- Delayed sensitivity
1
Anaphylaxis is a massive antigen-antibody response, causing a physiologic system shutdown and possible death. Graft-versus-host disease (GVHD) occurs when antibodies in the transplanted organ attacks the host’s antigens. An immune complex formation occurs when antigen-antibody complex is deposited in body tissue. A delayed sensitivity is a reaction that occurs after cells are sensitized to an antigen, as seen in the tuberculosis skin testing.
Pathophysiology of how a Tb skin test works
- Type IV, delayed type hypersensitivity
- Perivascular accumulation of TH1 and macrophages secretion of cytokines redness, swelling
- TH1 memory cells in circulation results in the DTH response
Be able to identify patients that need and do not need RhoGAM
Know mom’s Rh type and fetus/baby’s Rh type
- Administer RhoGAM to the mother during the first 72 hours after delivery if the Rh-negative mother delivers an Rh-positive fetus but remains unsensitized
- Also if baby’s type is unknown
