NUR 951: Immune System and Anesthesia Quiz

Immune System and Anesthesia

• The immune system is a critical component of anatomy and physiology, with 20% of the NCE/SEE exam dedicated to it

Anatomy and Physiology of the Immune System

• Review of anatomy and physiology of the immune system is essential for anesthesia for surgical procedures and special populations

Angioedema

• Characterized by episodic, asymmetric subcutaneous and submucosal edema formation, involving the face, extremities, and gastrointestinal tract
• Two types:
  • Mast cell-mediated: release of mast cell mediators, causing urticaria, bronchospasm, flushing, and hypotension
  • Bradykinin-mediated: does not cause allergic symptoms
• Hereditary vs Acquired:
  • Hereditary: deficiency or dysfunction of C1 esterase inhibitor, triggered by menses, trauma, infection, stress, or estrogen-containing oral contraceptives
  • Acquired: patients with lymphoproliferative disorders have antibodies to C1 inhibitor, triggered by angiotensin-converting enzyme (ACE) inhibitors

Treatment of Angioedema

• Mast cell-mediated: epinephrine, antihistamines, glucocorticoids
• Bradykinin-mediated: C1 inhibitor concentrate, kallikrein inhibitor, or bradykinin-receptor antagonist
• ACE inhibitor-induced: stop the offending drug, administer supportive care, glucocorticoids, and C1 inhibitor concentrate, kallikrein, or bradykinin-receptor antagonist

Management of Angioedema

• Prophylactic management: before a stimulating procedure, availability of C1 inhibitor concentrate, androgens, and tranexamic acid to prevent attacks
• Emergent management: secure the airway, depending on the severity of swelling, using videolaryngoscope, awake fiberoptic, or surgical airway

Alloimmunity

• Response of the immune system towards nonself antigens of the same species, called alloantigens or isoantigens
• Two major types:
  • Blood group alloantigens: thrombocytopenia, transfusion reactions
  • Histocompatibility alloantigens: rejection of solid organ transplantations

Autoimmunity

• Abnormal response to self-antigens, resulting in production of self-antibodies or autoantibodies
• Damage to self-tissues due to dysfunction of the innate and/or adaptive immune systems
• Genetic predisposition towards developing an autoimmune disorder
• Over 80 different types of autoimmune disorders, including Graves disease, Hashimoto thyroiditis, multiple sclerosis (MS), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE)

Autoimmune Disorders

• Graves Disease:
  • Type V hypersensitivity caused by autoantibodies to the TSH receptor
  • Symptoms: tachycardia, palpitations, tremor, heat intolerance, anxiety, and ophthalmopathy changes
  • Diagnosis: elevated plasma levels of T3 and T4, low or absent TSH, radioactive iodine (RAI) uptake, and thyroid ultrasound
  • Treatment: antithyroid medications, thyroidectomy, and RAI destruction of the thyroid

Anesthetic Management of Graves Disease

• Euthyroidism should be established preoperatively
• Airway evaluation: evidence of tracheal compression or deviation caused by a goiter
• Intraoperative management: adequate anesthetic depth, avoiding drugs that stimulate the sympathetic nervous system
• Postoperative management: continue β-blocker therapy, monitoring for thyrotoxicosis

Hashimoto Thyroiditis

• Most common thyroid disorder
• Females are seven times more likely than males to develop the disorder
• Etiology: thyroglobulin (Tg) and thyroid peroxidase (TPO) antigens stimulate the production of Tg and TPO antibodies
• Symptoms: goiter and hypothyroidism
• Diagnostic tests: low plasma levels of total T4 and elevated TSH levels
• Treatment: thyroid hormone replacement (levothyroxine sodium)

Multiple Sclerosis

• Demyelinating disorder of the CNS
• Immune-mediated inflammatory disease that attacks the myelin, oligodendrocytes, and the underlying nerve fibers
• Symptoms: fatigue, tingling, numbness, muscle weakness, ataxia, vertigo, tremor, spasticity, bladder and bowel dysfunction, pain, and heat intoleranceHere are the study notes for the text:
• Multiple Sclerosis*
• Periods of relapse (new influx of immune cells) and remission (remyelination)
• Diagnosis:
  • MS lesions on MRI
  • Elevated IgG in CSF
  • Decreased conduction velocity on evoked response studies
• Treatment:
  • Disease-modifying agents (DMARDS)
  • Acute relapses: corticosteroids and plasma exchange
  • Severe progressive: antineoplastic agents (cyclophosphamide, mitoxantrone)
• Rheumatoid Arthritis*
• Autoimmune inflammatory disease with widespread effects
• Characterized by:
  • Synovial inflammation and hyperplasia
  • Cartilage and bone destruction
  • Systemic features (cardiovascular, pulmonary, renal, and skeletal disorders)
• Treatment:
  • Avoid triggers (viruses, sunlight, smoking)
  • NSAIDs, corticosteroids, or immunosuppressants (azathioprine, mycophenolate, MTX)
• Systemic Lupus Erythematosus (SLE)*
• Autoimmune inflammatory disease with widespread effects
• Characterized by:
  • Large variety of autoantibodies
  • Cardiovascular, hepatic, pulmonary, renal, and skin manifestations
• Diagnosis:
  • Antinuclear antibodies (ANA), anti-dsDNA, anti-Smith (anti-Sm), and antiphospholipid antibodies
  • Laboratory abnormalities (anemia, leukopenia, thrombocytopenia, and elevated ESR and/or CRP levels)
• Treatment:
  • Avoid triggers (sunlight, viral infections, smoking)
  • NSAIDs, corticosteroids, or immunosuppressants (azathioprine, mycophenolate, MTX)
• Immunodeficiency Disorders*
• Primary Immunodeficiency Disorders (PIDDs):
  • Result of genetic defect in cells of the immune system
  • Characterized by:
    • Low antibody levels, defective antibodies, or defective immune cells
    • Increased susceptibility to infections
  • Treatment:
    • Largely supportive
    • Bone marrow transplantation
    • Recent advances in immunobiology, genetics, and biologic modifiers
• Secondary deficiencies:
  • Acquired Immune Deficiency (AID) +[Causes:
    • Severe malnutrition
    • HTLV-1 infection
    • Lymphoid cancers
    • Autoimmune diseases
    • Splenectomy
    • Aging
    • Immunosuppressant drugs
  • Treatment:
    • Treatment of the primary condition usually results in improvement of the associated AID
• Acquired Immune Deficiency Syndrome (AIDS)*
• Result of HIV infection
• Mechanism:
  • Malignant lymphoblasts replace normal marrow elements
  • Abnormal lymphoblasts proliferate in lymphoid organs
  • HIV is capable of changing amino acid sequences of antigenic regions of their glycoproteins
• Symptoms: +