Immune System Dysfunction

Question 1

Immune system components

Alterations in WBC Formation and Immune Functioning

Answer 1

1. Primary lymphoid organs include the thymus and bone marrow.
2. Secondary lymphoid organs include the spleen, liver, lymph nodes, tonsils, skin and lymphoid tissues.

Question 2

Human leukocyte antigen (HLA)

Alterations in WBC Formation and Immune Functioning

Answer 2

1. Is a major histocompatibility complex (MHC) normally found on the cell surface of every nucleated cell
2. Allows the immune system to recognize self vs nonself. HLA consists of four main loci (HLA-A, HLA-B, HLA-C, HLA-D/DR)
   a. For organ transplants, markers are matched as closely as possible to decrease the odds of rejection; for bone marrow transplants, a near perfect match is required.
   b. The cornea is avascular and alyphatic in nature, thus does not require HLA matching.
3. Is genetically passed on chromosome 6, so the child gets markers from both parents
4. Contains a genetic predisposition or susceptibility to a disorder; does not pass the disorder itself
5. There is a 1-in-4 chance of a sibling match, 1-in-200 chance of a parent match, and 1-in-1,000,000 chance that two nonrelated people have the exact same HLA.

Question 3

Immune system functions

Alterations in WBC Formation and Immune Functioning

Answer 3

1. Hyperfunctioning results in allergy and autoimmunity
2. Hypofunctioning results in an immunodeficiency and cancer
3. Homeostasis involves the phagocytosis of debris from cellular warfare or of dead cells; this is nature’s way to clean out dead debris from the system.

Question 4

Natural first line of defense against infection

Answer 4

1. Skin (the body’s largest organ)
2. Body secretions (tears, saliva, sebum, mucus, acidic environments, normal body flora, and salt in sweat)
3. Nasal hairs and cilia
4. Controlled body temperature

Question 5

Neutrophil

Immune cells and their functions

Answer 5

(polymorphonuclear leukocyte): a short-lived phagocyte that is the first immune cell at the site of inflammation, infection or trauma

1. It attacks bacteria and fungi
2. A band is an immature cell; a segmented neutrophil (seg) is a mature cell.
3. Neutrophils make up 60% of the WBC count

Question 6

Eosinophil

Immune cells and their functions

Answer 6

effective in phagocytizing parasites

1. Also stimulates inflammation especially in response to mast cell degranulation, and increases with allergic attack (1%-3% of WBCs)

Question 7

Basophil

Answer 7

releases histamine, bradkykinin, serotonin, heparin, and other substances during an allergic attack (<3% of WBCs)

1. It is responsible for many symptoms of anaphylaxis.
2. In the tissues, it is known as mast cells; especially prevalent in the eyes, ears, nose, and throat and under the skin.

Question 8

Monocyte

Immune cells and their functions

Answer 8

phagocytizes antigens and presents antigenic markers to lymphocytes so that antibodies can be made (1-10% of WBCs)

1. It appears later than neutrophil but lasts longer.
2. It includes Kupffer cells (liver macrophages).
3. A macrophage is a monocyte that has left the circulation and entered the tissues after a few hours.
4. It releases cytokines to attract other immune cells to the site of attack.
5. An increase indicates chronic inflammation.

Question 9

B lymphocyte

Immune cells and their functions

Answer 9

a type of WBC that secretes antibodies

1. IgM is the first antibody made to protect against bacterial and viral infections. The largest immunoglobulin (Ig), it stays in the blood, activates complement, and is responsible for making antibodies against the ABO blood groups.
2. IgG is the most abundant type of antibody and protects against bacterial and viral infections. It is the smallest Ig and the only one that passes through the placenta, thus offering the newborn passive immune protection; it activates complement and has an excellent memory.
3. Action of IgD is not well understood
4. Secretory IgA is present in all body secretions, including breast milk, mucous membranes (respiratory and GI tract), saliva, and tears; it prevents viruses from entering through the mucous membranes.
5. IgE governs the allergic response by stimulating basophils to release their products after contact with the allergen.

Question 10

IgM antibody

Answer 10

is the first antibody made to protect against bacterial and viral infections. The largest immunoglobulin (Ig), it stays in the blood, activates complement, and is responsible for making antibodies against the ABO blood groups.

Question 11

IgG antibody

Answer 11

IgG is the most abundant type of antibody and protects against bacterial and viral infections. It is the smallest Ig and the only one that passes through the placenta, thus offering the newborn passive immune protection; it activates complement and has an excellent memory.

Question 12

IgA antibody

Answer 12

Secretory IgA is present in all body secretions, including breast milk, mucous membranes (respiratory and GI tract), saliva, and tears; it prevents viruses from entering through the mucous membranes.

Question 13

IgE antibody

Answer 13

IgE governs the allergic response by stimulating basophils to release their products after contact with the allergen.

Question 14

T lymphocyte

Immune cells and their functions

Answer 14

(T cell): matures in the thymus. T cells function directly or by their cell products; releases soluble factors (lymphokines) that stimulate the immune system and destroy antigens.
1. CD4 cells (helper T cells) tell the B cells when to make antibodies and how many to make to attack against infection.
2. CD8 cells (suppressor T, Ts, or cytotoxic T cells) tell the B cells to stop making antibodies.
3. Normally there are twice as many CD4 as CD8 cells, so the system is always in a state of readiness.
4. There are two subsets of CD4: Th1 and Th2.
a. Increased Th2 has an increased role in the allergic response.
b. Th1 cells are designed to attack intracellular threats. Those with high Th1 do not have allergy.

Question 15

Lymphocytes make up what percentage of WBCs?

Answer 15

20-40% of the WBCs

Question 16

The normal WBC count =

Answer 16

4,500 - 11,000 (normal may be up to 17,000 in infants up to age 2 and then drops to normal WBC).

1. On some written and verbal reports, WBCs are abbreviated as one thousandth of their value (e.g., a WBC of 5,000 is described as 5)

Question 17

Function of immune cells in the inflammatory reaction is as follows:

Answer 17

1. Histamine causes vasodilation, and granulocytes and monocytes are attracted to the site.
2. Cells leave the blood and enter the damaged site, resulting in redness, warmth, swelling, pain, and altered function.

Question 18

Fever

Answer 18

Introduction
1. Fever is a normal body response to assist the immune system in destroying foreign antigens.
2. Temperatures of less than 100.4 - 101° F (38 - 38.5° C) usually do not require treatment, unless a child is uncomfortable.
3. Treatment of fever may mask other signs that would help the diagnosis.

Intervention
1. Provide comfort measures and institute antipyretic actions for temperatures >101° F (38.5° C).
2. Due to the risk of neonatal sepsis, fever in this population should be evaluated by the healthcare provider
3. Give the child acetaminophen or ibuprofen.
4. Place the child in a cool room, dressed in light pajamas; cover the child only with a sheet (unless the child has chills).
5. Offer cool fluids, and provide cool, moist compresses to the skin.
a. Tepid sponge baths are recommended only for temperatures greater than 104° F (40° C).
b. Alcohol baths are not recommended for children.
c. Avoid cooling the child to the point of shivering, because this increases body temperature.

 **ALERT:** Children should not receive aspirin because of the risk of Reye syndrome, which is associated with the use of aspirin during a febrile viral infection. Since the cause of illness is often unknown in the early stages of fever, it is best to avoid using aspirin in children.

Question 19

Neutropenia

Answer 19

Introduction
1. Neutropenia is less than the normal ANC of >2500. [Note: this is the actual number rather than the percent.]
2. Results from decreased production of or increased destruction of neutrophils.
3. Increases susceptibility to opportunistic infection because the body cannot initiate the immune response.

Assessment
1. Be aware that signs of inflammation may be altered (no pus; limited redness and swelling).
2. Assess for irritability and anorexia, which may be the only sign.
3. The ANC indicates the degree of immune system functioning.
a. 500 to 1,000 indicates moderate risk for infection.
b. Less than 500 indicates a severe risk of life-threatening infection.
4. There are three methods to calculate the ANC:
a. (Bands + Segs)% x True WBC = ANC
b. ([Bands + Segs] x WBC)/100 = ANC
c. (Bands + Segs) x (Abbreviated WBC x 10) = ANC
5. Culture of all body orifices to help in early detection of baterial growth.

Interventions
1. Decrease the child’s contact with pathogens.
a. Provide a private room or roommate without an infection.
b. Teach proper hand washing.
2. Initiate protective isolation if the ANC is less than 500/mm3.
3. Provide proper oral hygiene.
4. Provide antibiotics as ordered; granulocyte colony stimulating factor may be used to stimulate the bone marrow to make more white blood cells.
5. In the community, avoid large crowds.
6. Do not share food, drinks or other personal items.
7. Get a seasonal flu vaccine.

Question 20

Hypogammaglobulinemia

Answer 20

Introduction
1.Hypogammaglobulinemia is the absence or deficient production of B cells and antibodies, leaving the body’s ability to defend itself weakened; it may be congenital or acquired.
2. Passive IgG protection from the mother to the child decreases during the first year of life, so symptoms usually appear after age 6 months.
3. The child is susceptible to pyogenic bacterial infections.

Assessment
1. Review the child’s history for recurrent upper respiratory tract infections, otitis media, skin infections, meningitis, or pneumonia.
2. Assess for signs and symptoms of malabsorption, which may result in immunodeficiency.

Interventions
1. Administer monthly gamma globulin injections.
2. Be aware that immunizations may not result in protective antibodies.

Question 21

Acquired Immunodeficiency Syndrome (AIDS)/
Human Immunodeficiency Virus (HIV) Disease

Introduction

Answer 21

1. AIDS is an acquired immune deficiency that results from HIV attacking CD4/helper T cells. It is called HIV infection from the time of infection until the immune system is no longer able to mount an immune response; when the number of CD4 cells is less than 200 per uL of blood and/or the CD4 percentage is less than 20, it is called AIDS.
2. The majority of children in the U.S. who contract HIV do so in utero or perinatally by being born to an HIV-positive mother; others with HIV are teens in high-risk categories (sexual contact; sharing contaminated needles.)
3. AIDS is not spread by casual contact with an infected child.
4. It is spread only by an exchange of body fluid, including breast milk. (An untreated woman with HIV has a 25% chance of passing HIV to her baby during pregnancy or breastfeeding, while only a <5% of passing it to her baby with antiretroviral therapies.)
5. Early recognition and improved medical care have changed HIV disease from a rapidly fatal illness to a chronic disease.

Question 22

Acquired Immunodeficiency Syndrome (AIDS)/
Human Immunodeficiency Virus (HIV) Disease

Assessment

Answer 22

1. Check for mononucleosis-like prodromal symptoms (fatigue, malaise, and myalgia are common).
2. Ask about night sweats and recurring diarrhea.
3. Observe for weight loss and failure to thrive.
4. Assess for lymphadenopathy.
5. Note recurrent opportunistic infections (especially lymphoid interstitial pneumonia and Pneumocystis carinii pneumonia), autoimmune disorders, persistent oral and esophageal candidiasis, waisting syndrome, and HIV encephalopathy, all of which are common with AIDS.
6. Assess for neurologic impairment, such as loss of motor milestones.
7. For babies born to HIV+ mothers, ivral testing is done 3 times in the first 6 months of life.

Question 23

Acquired Immunodeficiency Syndrome (AIDS)/
Human Immunodeficiency Virus (HIV) Disease

Interventions

Answer 23

1. Prevent transmission of HIV.
   a. The course and type of Antiretroviral therapy (ART) are determined by whether mother was treated during pregnancy.
   b. Use standard precautions: wear gloves when handling any bodily secretions (mask and fluid-resistant gown when risk of splashing).
   c. Wash hands thoroughly.
   d. Use 10% solution of household bleach in water; applied over 1 minute to kill HIV outside the body. In the event of a large spill, a 1:10 ratio of bleach to water would be appropriate.
   e. Discourage the teenager from engaging in high-risk behaviors; teach safe sex behaviors.
   f. Teach HIV+ parents to prevent giving premasticated food to their child.
2. Prevent opportunistic and other infections.
   a. Administer routine childhood immunizations. All vaccines are recommended except the live vaccines or varicella and the intranasal influenza. MMR is given except in the severely immunocompromised child.
3. Provide adequate nutrition.
   a. Offer high-calorie, high-protein foods, including nutritional supplements.
   b. Monitor growth and potential for failure to thrive.
4. Provide child and family teaching.
   a. Be sure to include the following points in your teaching plan for the parents of a child with HIV:
   1. Hand washing procedures
   2. How and when to use protective equipment, whuch as gloves, gowns, and masks
   3. Household and laundry cleaning measures
   4. Care of patient’s eating utensils
   5. Spill cleanup
   6. Disposal of contaminated equipment and supplies
   7. Trash disposal

Question 24

Hypersensitivity Reactions: Allergies

Introduction

Answer 24

1. An allergy is activation of the immune response to normal environmental antigens.
2. Common allergens include inhalents (e.g., dust, animal dander, dust mites and mold), insect bites (e.g., bee or wasp), foods, and contactants.
3. Allergic reactions can be immediate or delayed, genetic or acquired.
4. Allergy shots (desensitization) consist of doses of an allergen at levels low enough so that the body does not respond.
   a. Weekly shots of increasing doses can build tolerance.
   b. Not all allergies can be treated in this way.
5. Early contact with potential allergens decreases the possibility of developing allergies (e.g., children on farms have fewer allergies; early introduction to diluted peanut may decrease the incidence of peanut allergy.)
6. It is the nurse’s responsibility to ask about potential allergies at every health encounter.

Question 25

Type I allergic reaction (immediate hypersensitivity) | Classification of allergies

Answer 25

**an IgE-mediated response against the allergen; it is the most common type of allergy.** 1. IgE attaches to the mast cell, causing it to release histamine. 2. **Histamine dilates and increases the permeability of vessels resulting in erythema, swelling, and irritatino; it also constricts smooth muscles in vascular and bronchiolar tissue resulting in wheezing; it can cause urticaria (hives) and angioedema.** 3. **Anaphylaxis can result: hypotension (dizziness, fainting)m respiratory distress (tightness of the throat), hives "itch all over," rapid heartbeat and/or cardiac arrest.** 4. Examples include a reaction to penicillin, hay fever, respiratory allergies, and bee stings.

Question 26

Type II allergic reaction (cytolytic-cytotoxic) | Classification of allergies

Answer 26

the antigen is blood-cell bound 1. IgM and IgG activate complement. 2. Examples include transfusionreaction, Rh incompatibility, idiopathic thrombocytopenia purpura, and autoimmune hemolytic anemia. 3. Treatment involves anti-inflammatory and immunosuppressive agents.

Question 27

Type III allergic reaction (immune complex-Arthus reaction)

Answer 27

antigen circulates freely 1. IgG and IgM respond, and complement damage of the body organs can result. 2. Examples include systemic lupus erythematosus, rheumatic fever, glomerulonephritis, type 1 diabetes, and rheumatoid arthritis. 3. Reaction can occur within 3-10 hours after exposure to antigen. Treatment includes anti-inflammatory agents.

Question 28

**Type IV allergic reaction (cell mediated or delayed type hypersensitivity)**

Answer 28

1. **The reaction occurs in 48 to 72 hours.** 2. Examples include contact dermatitis, poison ivy, PPD/TST reaction, and graft rejection. 3. Corticosteroids and other immunosuppressive agents are used for treatment.

Question 29

Respiratory allergies

Answer 29

Introduction 1. Respiratory allergies are type I allergies that release histamine into the eyes, ears, nose, and throat, resulting in increased vessel permeability and discomfort. 2. They usually occur in reaction to inhalants (pollen, animal dander, smoke, strong odors, chemicals, dust, latex), insect bites (bee stings), and ingestants. Assessment 1. Obtain a hx of allergies and how and when symptoms occur. 2. Conduct allergy skin tests to identify the cause. 3. Note profuse rhinorrhea, nasal obstruction, and bouts of sneezing. 4. Note allergic shiners (dark circles under the eyes from venous dilation and edema). 5. Note the allergic salute, which will produce a crease across the bridge of th nose. 6. Note open-mouth breathing, leading to a dry mouth and increasing the risk of respiratory infections. 7. Check for structural change of the oral cavity and malocclusion. 8. Note itchy, watery eyes and itching in the back of the throat. 9. Assess for wheezing. Intervention to relieve attacks 1. Admin antihistamines, bronchodilators (if ordered), and anti-inflammatory agents (if ordered). 2. Apply cool compresses to the eyes. 3. Administer vasoconstricting nasal spray. 4. **For anaphylaxis, administer epinephrine via an EpiPen; this constricts blood vessels and relaxes smooth muscles of the respiratory tract; administer right through the clothing into the anterolateral thigh. Intervention to prevent attacks 1. **Use environmental controls (avoid allergen; keep the child in an air-conditioned room during grass-cutting or when the pollen count his high).** 2. **Permit only damp dusting.** 3. **Prevent mold development.** 4. **Restrict rugs, stuffed animals, drapes, and natural fibers; use a plastic-wrapped mattress; decrease clutter.** 5. **Avoid smoking in the child's environment.** 6. Administer allergy shots (immunotherapy), if appropriate.

Question 30

Gastrointestinal allergies

Answer 30

Introduction 1. **The most common allergens include cow's milk, shellfish, nuts (especially peanuts), wheat, citrus, eggs, shellfish and soy.** (In most cases, the food must be consumed in order to elicit a reaction; however in rare cases with highly sensitized people, simply touching the food or being in the area of preparation can cause problems). 2. **Food allergy differs from food intolerance conditions, such as celiac disease and lactose intolerance.** Assessment 1. Review the child's history for food types and amounts that cause symptoms. 2. Ask how soon symptoms occur after ingestion. 3. Determine which symptoms occur (vomiting, diarrhea, colic, oral skin irritation, respiratory distress). 4. Observe for failure to thrive. Interventions 1. **Identify the cause, and eliminate it from the child's diet.** 2. **A food challenge can be performed under provider supervision by having the child eat the suspected food again after symptoms disappear to see if they reappear (uness the initial reaction caused anaphylaxis).** 3. Be aware that skin tests and allergy shots are not usually beneficial. 4. **Teach family to read labels carefully.** 5. **Check environment to make sure that there is no mixing of offending allergen with other products (silverware, cutting surfaces).**

Question 31

Dermatologic allergies: Eczema

Answer 31

Introduction 1. A type I reaction, common in infants, is chronic, with exacerbation and remissions. 2. Eczema can be caused or aggravated by foods, contactants (especially latex and wool), temperature changes, emotional factors, frequent bathing, and sweating. Assessment 1. Observe for red, oozing, highly pruritic vesicles that crust. 2. **Assess for secondary infections and skin thickening from scratching the lesions.** 3. **Check for lesions on the cheeks, scalp, wrists, ankles, and antecubital and popliteal areas.** 4. Assess for irritability, fretfulness, and insomnia. 5. **Observe for dry and scaly skin; hard skin cannot trap water.** Interventions to decrease dryness, inflammation, and pruritus 1. Avoid wool; use lightweight cotton. 2. **Avoid heat and sweating; keep the child dry.** 3. **Bathe the child with gentle cleaner or body wash as prescribed; apply topical emollient to the skin immediately after the bath; pat dry.** 4. **To prevent complications from scratching, keep the nails short; use hand mitts if necessary, and cover affected areas with light clothing.** 5. Rinse laundry thoroughly, and use a mild detergent. 6. Administer antihistamines and antibiotics, if ordered. Immunomodulators may also be ordered. 7. Apply a cortisone cream to decrease inflammation; use a topical lubricating cream on top (moisturizers and barriers provide relief). 8. Avoid allergy-triggering foods. 9. Encourage parents to humidify the home during the winter.

Question 32

Autoimmune Conditions

Answer 32

Introduction 1. The immune cells identify self-tissues as foreign antigens and attack almost any part of the body, however most target connective tissues. 2. This produces a loss of self-tolerance. 3. Antibodies attack a self-organ and activate complement, with resulting organ damage. 4. A predisposition to autoimmune conditions may be genetically based in HLA. Examples of autoimmune disease and organs attacked by self-antibodies 1. Acute glomerulonephritis attacks the glomerulus of the kidney. 2. Juvenile idiopathic arthritis attacks the synovial lining of joints. 3. Rhumatic fever affects the cardiac muscles and valves. 4. Type I juvenile diabetes affects the islet cells of the pancreas. 5. Multiple sclerosis attacks the myelin in the brain. 6. Systemic lupus erythematosus occurs in the DNA of the connective tissue; can result in arthritis, altered kidney function leading to failure, butterfly rash and sun sensitivity, and hematologic and central nervous system disorders. Interventions 1. Administer immunosuppressant medications, such as cortisone, to decrease the attack of the immune system against the self. 2. Implement other interventions specific to each condition to reduce or eliminate symptoms.