Altered Immune Response –

A) Overview of Normal Immune System

• Innate Immunity (Non-specific): First line of defense (skin, mucous membranes, phagocytes).
• Adaptive Immunity (Specific): Long-term defense; includes B cells (antibodies: IgG, IgA, IgM, IgE, IgD) and T cells (CD4, CD8).
• Key Organs: Bone marrow, thymus, lymph nodes, spleen.

B) Altered Immune Response, Hypersensitivity, and Allergy

• Altered Immune Response: Overactive (hypersensitivity), underactive (immunodeficiency), or misguided (autoimmunity).
• Hypersensitivity Types (Gell & Coombs Classification):
  1. Type I (Immediate/IgE): Anaphylaxis, asthma, allergies.
  2. Type II (Cytotoxic/IgG, IgM): Hemolytic anemia, transfusion reactions.
  3. Type III (Immune Complex): Lupus, serum sickness.
  4. Type IV (Delayed/T-cell mediated): Contact dermatitis, TB test.
• Allergy: Exaggerated response to allergens like pollen, dust, foods.

C) Assessment of the Immune System

• History: Recurrent infections, autoimmune conditions, allergy history.
• Physical Exam: Rashes, swollen lymph nodes, respiratory issues, signs of infection.

D) Diagnostic Evaluation

• Blood Tests: CBC with differential, immunoglobulin levels (↑IgE = allergies), autoantibodies (ANA, RF).
• Skin Tests: Allergy skin prick, Mantoux (TB) test.
• Advanced Tests: Complement levels (C3, C4), Flow cytometry (HIV), ELISA (HIV antibodies).

🚨 Last-Minute Quick Facts (High-Yield for Exams):

• Type I Hypersensitivity → IgE-mediated → Anaphylaxis risk
• Autoimmune diseases → Positive ANA (SLE), RF (RA)
• IgE ↑ in allergies; IgG, IgM ↑ in infections
• ELISA → Used for HIV diagnosis
• Type IV hypersensitivity → Delayed reaction → TB test

Allergic Disorders for Competitive Nursing Exams

1. Anaphylaxis (Life-Threatening Emergency)

• Definition: A severe, rapid, systemic allergic reaction causing airway obstruction and shock.
• Causes: Food (nuts, shellfish), insect stings, drugs (penicillin), latex.
• Pathophysiology: IgE-mediated (Type I Hypersensitivity) → Mast cell degranulation → Histamine release → Vasodilation, bronchoconstriction.
• Symptoms:
  • Skin: Urticaria (hives), angioedema
  • Respiratory: Wheezing, stridor, dyspnea
  • Cardiovascular: Hypotension, tachycardia
  • Gastrointestinal: Nausea, vomiting
• Management:
  • First-line: Epinephrine IM (0.3–0.5 mg) immediately
  • Supportive care: Oxygen, IV fluids, antihistamines, corticosteroids
• Key Word: Epinephrine – Drug of Choice

2. Allergic Rhinitis (“Hay Fever”)

• Definition: Inflammation of nasal mucosa due to allergens (pollen, dust, pet dander).
• Pathophysiology: Type I Hypersensitivity → IgE-mediated histamine release.
• Symptoms: Sneezing, runny/stuffy nose, itchy eyes, postnasal drip.
• Management:
  • Avoid triggers
  • Antihistamines (Loratadine, Cetirizine)
  • Nasal corticosteroids (Fluticasone)
• Key Word: Seasonal or Perennial Allergy

3. Contact Dermatitis

• Definition: Inflammatory skin reaction due to contact with allergens or irritants.
• Types:
  • Irritant Contact Dermatitis: Non-immune reaction (e.g., chemicals, detergents).
  • Allergic Contact Dermatitis: Type IV Hypersensitivity (delayed) to allergens (e.g., nickel, poison ivy).
• Symptoms: Red, itchy rash, blisters, dry skin at contact site.
• Management:
  • Avoid irritants
  • Topical corticosteroids
  • Moisturizers
• Key Word: Delayed Reaction – Type IV

4. Atopic Dermatitis (Eczema)

• Definition: Chronic, relapsing inflammatory skin condition with genetic predisposition.
• Pathophysiology: Associated with atopy (asthma, allergic rhinitis) and Type I Hypersensitivity.
• Symptoms: Dry, itchy, red skin, often in skin folds (elbows, knees).
• Management:
  • Emollients (moisturizers)
  • Topical steroids for inflammation
  • Antihistamines for itching
• Key Word: “Itch-Scratch Cycle”

5. Drug Reactions (Drug Hypersensitivity)

• Definition: Adverse immune response to medications.
• Types:
  • Type I (Immediate): Urticaria, anaphylaxis (common with penicillin).
  • Type II: Hemolytic anemia (e.g., methyldopa).
  • Type III: Serum sickness-like reaction.
  • Type IV: Stevens-Johnson syndrome, contact dermatitis.
• Management:
  • Stop the offending drug
  • Epinephrine for anaphylaxis
  • Antihistamines, corticosteroids
• Key Word: Stevens-Johnson Syndrome = Medical Emergency

6. Food Allergy

• Definition: Immune reaction to specific foods (nuts, shellfish, eggs, milk).
• Pathophysiology: Type I Hypersensitivity (IgE-mediated).
• Symptoms:
  • Mild: Hives, itching, GI upset
  • Severe: Anaphylaxis (breathing difficulty, hypotension)
• Management:
  • Avoid trigger foods
  • Epinephrine auto-injector (EpiPen) for emergencies
• Key Word: Peanuts – Most Common Trigger

7. Serum Sickness

• Definition: A Type III Hypersensitivity reaction to foreign proteins (e.g., antiserum, some drugs like penicillin).
• Pathophysiology: Immune complex formation → complement activation → inflammation.
• Symptoms: Fever, rash, joint pain, lymphadenopathy, occurring 1–2 weeks after exposure.
• Management:
  • Stop the triggering agent
  • Antihistamines, corticosteroids
• Key Word: “Immune Complex-Mediated Reaction”

8. Latex Allergy

• Definition: Allergic reaction to natural rubber latex.
• Pathophysiology:
  • Type I Hypersensitivity (IgE-mediated): Immediate reaction (anaphylaxis risk).
  • Type IV Hypersensitivity: Delayed skin reaction (contact dermatitis).
• Symptoms:
  • Mild: Rash, itching
  • Severe: Urticaria, angioedema, anaphylaxis
• Management:
  • Avoid latex products
  • Use latex-free gloves and equipment
  • Epinephrine for severe reactions
• Key Word: High Risk in Healthcare Workers

🚨 Quick Revision (High-Yield Points):

• Anaphylaxis = IgE-mediated → Treat with Epinephrine
• Allergic Rhinitis = Antihistamines + Avoid triggers
• Contact Dermatitis = Type IV Hypersensitivity (Delayed)
• Atopic Dermatitis = Itchy, Chronic, Eczema → Moisturizers + Steroids
• Drug Reactions = Stop drug immediately, treat symptoms
• Food Allergy = EpiPen for severe reactions
• Serum Sickness = Type III Reaction (Immune Complexes)
• Latex Allergy = Healthcare Workers at Risk → Latex-free products

Approaches to Treat Allergic Diseases, Nursing Management, and Autoimmune Diseases

(High-Yield for Competitive Nursing Exams)

F) Approaches to Treat Allergic Diseases

1. Allergen Avoidance:

• Identify and avoid triggers (dust, pollen, food, latex).
• Use air purifiers, dust-proof covers, hypoallergenic products.

2. Pharmacological Therapy:

• Antihistamines: For mild allergic reactions (e.g., loratadine, cetirizine).
• Corticosteroids: Reduce inflammation (e.g., nasal sprays for rhinitis, topical creams for dermatitis).
• Decongestants: For nasal congestion (e.g., pseudoephedrine).
• Leukotriene Modifiers: (e.g., montelukast) for asthma and allergic rhinitis.
• Epinephrine: First-line drug for anaphylaxis (IM route).

3. Immunotherapy (Allergy Shots):

• Gradual desensitization by exposing to small amounts of allergens over time.

4. Biologic Therapies:

• Monoclonal antibodies (e.g., omalizumab) for severe asthma and chronic urticaria.

5. Emergency Measures (Anaphylaxis):

• Epinephrine auto-injector (EpiPen)
• Oxygen therapy, IV fluids, and airway management if needed.

G) Nursing Management of Clients with Altered Immune Response

1. Assessment:

• Detailed history (allergies, autoimmune conditions, recurrent infections).
• Physical exam: Skin changes, respiratory status, lymph node enlargement.

2. Diagnosis:

• Risk for anaphylaxis, impaired skin integrity, ineffective airway clearance, activity intolerance.

3. Planning and Implementation:

• Ensure Airway, Breathing, Circulation (ABCs) in emergencies.
• Administer prescribed medications (epinephrine, antihistamines, corticosteroids).
• Monitor for signs of anaphylaxis: wheezing, hypotension, urticaria.
• Educate patient on allergen avoidance and use of EpiPen.
• Infection prevention measures for immunocompromised patients (hand hygiene, avoid crowds).

4. Evaluation:

• Improved breathing, reduced allergic symptoms, no recurrence of severe reactions.

H) Autoimmune Diseases

Autoimmune diseases occur when the immune system attacks the body’s own cells.

1. Rheumatoid Arthritis (RA):

• Definition: Chronic systemic autoimmune disease causing joint inflammation.
• Pathophysiology: Type III Hypersensitivity reaction; immune complexes deposit in joints.
• Symptoms: Joint pain, stiffness (especially morning), swelling, fatigue.
• Diagnosis: Positive Rheumatoid Factor (RF), anti-CCP antibodies, elevated ESR, CRP.
• Management:
  • Medications: NSAIDs, corticosteroids, DMARDs (methotrexate), biologics (infliximab).
  • Physical therapy: To maintain joint mobility.
  • Nursing Care: Pain management, joint protection techniques.

2. Systemic Lupus Erythematosus (SLE):

• Definition: Chronic autoimmune disease affecting skin, joints, kidneys, brain.
• Symptoms: Butterfly-shaped rash, joint pain, fatigue, photosensitivity, kidney involvement.
• Diagnosis: Positive ANA (Antinuclear Antibody) test, low complement levels, elevated ESR.
• Management:
  • Medications: NSAIDs, corticosteroids, immunosuppressants (azathioprine), antimalarials (hydroxychloroquine).
  • Avoid sunlight, manage stress, regular follow-ups.
• Nursing Care: Skin care, infection prevention, fatigue management.

3. Ankylosing Spondylitis:

• Definition: Chronic inflammatory disease affecting the spine and sacroiliac joints.
• Symptoms: Lower back pain, stiffness, reduced spinal mobility, “bamboo spine” on X-ray.
• Diagnosis: HLA-B27 antigen positive, X-ray changes.
• Management:
  • Medications: NSAIDs, TNF inhibitors (etanercept), physical therapy.
  • Exercise: Posture correction, back-strengthening exercises.
• Nursing Care: Pain relief, mobility exercises, posture education.

4. Graft Versus Host Disease (GVHD):

• Definition: A complication after bone marrow or stem cell transplant where donor immune cells attack the recipient’s body.
• Types:
  • Acute GVHD: Occurs within 100 days post-transplant (skin rash, liver dysfunction, GI issues).
  • Chronic GVHD: Occurs later, affecting multiple organs.
• Symptoms: Skin rash, diarrhea, jaundice, dry eyes/mouth.
• Management:
  • Immunosuppressive drugs: Corticosteroids, cyclosporine.
  • Supportive care: Skin moisturizers, nutritional support.
• Nursing Care: Infection prevention, monitoring for signs of organ involvement, medication adherence.

🚨 High-Yield Quick Facts:

• Anaphylaxis = Epinephrine IM is the first-line treatment.
• Rheumatoid Arthritis = Positive RF and anti-CCP antibodies.
• SLE = Butterfly rash + Positive ANA test.
• GVHD = Complication after bone marrow transplant → Managed with immunosuppressants.
• Ankylosing Spondylitis = Bamboo spine on X-ray, HLA-B27 positive.