Section 8.4: Immunologic, Inflammatory, and Infectious Response Disorders

Why This Block Matters

Within Nursing Practice III (Medical-Surgical Nursing, Part A), disorders of the infectious, inflammatory, and immunologic response carry about 14% of the subject's items under the Enhanced Table of Specifications. These adult disorders are distinct from the pediatric infectious diseases and from the oncology/cellular-aberration block; here the focus is the immune system's overreaction, self-attack, or deficiency, plus systemic infection. Items emphasize prioritization (airway, isolation), pharmacology, and safety.

The Four Types of Hypersensitivity

A frequent exam scenario is anaphylaxis: sudden urticaria, wheezing, hypotension, and laryngeal edema after a bee sting or antibiotic. The priority is maintaining a patent airway and administering epinephrine intramuscularly into the vastus lateralis; antihistamines and corticosteroids are adjuncts, not first-line.

Autoimmune Disorders

Systemic Lupus Erythematosus (SLE) is a chronic type III/IV inflammatory disorder in which autoantibodies attack multiple organs. The hallmark is the butterfly (malar) rash across the cheeks and nose, plus photosensitivity, arthralgia, and lupus nephritis. Teach clients to avoid direct sunlight (use sunscreen and protective clothing), report signs of renal involvement (edema, decreased urine output), and adhere to corticosteroid/immunosuppressant therapy. Because immunosuppression raises infection risk, emphasize infection prevention.

Rheumatoid Arthritis (RA) is a symmetric inflammatory polyarthritis producing morning stiffness lasting more than 30–60 minutes, joint swelling, and eventual deformity (e.g., ulnar deviation). Nursing care balances rest during acute flares with range-of-motion exercise to preserve function, and teaches joint protection and DMARD/methotrexate adherence.

HIV and AIDS

Human immunodeficiency virus (HIV) destroys CD4+ T lymphocytes, progressively impairing cell-mediated immunity. Nurses must know the monitoring markers:

• CD4 count: normal 500–1,600 cells/mm3. A CD4 below 200 cells/mm3 or the appearance of an AIDS-defining illness (e.g., Pneumocystis jirovecii pneumonia, Kaposi sarcoma) defines AIDS.
• Viral load: goal of antiretroviral therapy (ART) is an undetectable viral load; adherence is critical to prevent resistance.

Apply standard precautions for all clients—HIV transmits through blood and body fluids, not casual contact. Teach ART adherence, opportunistic-infection prophylaxis, and safer-sex practices. Post-exposure prophylaxis (PEP) after a needlestick should begin as soon as possible, ideally within hours.

Sepsis: A Systemic Emergency

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Early recognition drives survival. Warning signs include fever or hypothermia, tachycardia, tachypnea, altered mental status, and hypotension. The nursing priority is to recognize early and intervene fast: obtain blood cultures before antibiotics, administer broad-spectrum antibiotics promptly, and give fluid resuscitation for hypotension. Untreated sepsis progresses to septic shock (persistent hypotension requiring vasopressors) and multi-organ failure. Hand hygiene and catheter/line care remain the strongest preventive measures.

Transfusion and Latex Reactions

Because hypersensitivity underlies many acute events, the exam links it to everyday nursing tasks. In a hemolytic transfusion reaction (type II), the client develops fever, chills, flank pain, and dark urine soon after a transfusion starts. The first action is to stop the transfusion, then keep the vein open with 0.9% normal saline through new tubing, and notify the provider and blood bank. Latex allergy is another recurring item: clients with spina bifida or repeated surgeries are high risk, and the nurse prepares a latex-free environment.

Autoimmune Care Priorities

With SLE, teach the client that fatigue and infection are constant threats and that flares are often triggered by sun exposure, stress, and infection. Monitor for lupus nephritis - the leading cause of morbidity - through urinalysis, blood pressure, and edema assessment. In rheumatoid arthritis, apply heat to relieve stiffness and cold to reduce acute joint inflammation, and schedule the heaviest activities for later in the day after morning stiffness eases. Both conditions commonly require corticosteroids, so teach clients never to stop steroids abruptly (risk of adrenal crisis) and to watch for signs of infection masked by the drug.

Infection Control and Isolation

The infectious-response block ties directly to transmission-based precautions, which build on standard precautions:

A classic prioritization question asks which client to place in a negative-pressure isolation room - the answer is the client with suspected pulmonary tuberculosis or measles (airborne), not one with a wound infection.

Sepsis Bundle Thinking

Beyond recognition, the nurse should understand the logic of early sepsis care: cultures before antibiotics, broad-spectrum antibiotics within the first hour, fluid resuscitation for hypotension or elevated lactate, and frequent reassessment of perfusion and mental status. Elderly and immunosuppressed clients (including those on the corticosteroids used for the autoimmune disorders above) may show atypical, subtle presentations - confusion or a falling temperature rather than a spiking fever - so vigilance is the safeguard.