Nursing: Communicable Diseases

Communicable Diseases and Nursing

• A communicable disease is an illness due to an infectious agent or its toxic products, transmitted directly or indirectly to a well person through an agent, vector, or inanimate object.

Infection and Contagious Diseases

• Infection is the implantation and successful replication of an organism in the tissue of the host, resulting in signs and symptoms as well as immunologic response.
• Not all infectious diseases are contagious, but all contagious diseases are infectious.

Overview of the Immune System

• The immune system is composed of bone marrow, WBC, and lymphoid tissue.
• Immunity is the ability of an organism to recognize and defend itself against agents that are "foreign" to it.
• Susceptibility is the vulnerability of the host to harm by infectious and other types of agents.

Immunoglobulins

• Antibodies are large proteins called immunoglobulins, found in the globulin fraction of plasma proteins.
• There are five classes of immunoglobulins:
  • IgG (75%): appears in serum and tissues, assumes a major role in bloodborne and tissue infections, activates the complement system, enhances phagocytosis, and crosses the placenta.
  • IgA (15%): appears in body fluids, protects against respiratory, gastrointestinal, and genitourinary infections, and prevents absorption of antigens from food.
  • IgM (10%): appears mostly in intravascular serum, appears as the first immunoglobulin produced in response to bacterial and viral infections, and activates the complement system.
  • IgD (0.2%): appears in small amounts in serum, possibly influences B-lymphocyte differentiation, but its role is unclear.
  • IgE (0.004%): appears in serum, takes part in allergic and some hypersensitivity reactions, and combats parasitic infections.

Immunity

• Immunity is a state of having sufficient biological defenses to avoid infection.
• There are two types of immunity: innate (natural) and acquired (through disease or vaccination).
• Herd immunity is the immunity of a large group of people through vaccination.

WBC and Immune Response

• WBCs are classified into granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (monocytes, lymphocytes).
• T cells are responsible for cell-mediated immunity and are classified into CD4+ (bacteria) and CD8+ (tumor and virus).

Acquired Immunity

• Active natural immunity: disease triggers the body to produce antibodies.
• Active artificial immunity: weakened bacteria is given to stimulate the body to produce antibodies (vaccines).
• Passive natural immunity: antibodies are given from the mother (colostrum).
• Passive artificial immunity: antibodies are given through immunization (TIG, HBIg).

Lines of Defense and Immune Response

• First line of defense: non-specific, physical barriers (skin, mucous membranes).
• Second line of defense: non-specific, inflammatory response (WBCs, chemical signals).
• Third line of defense: specific, immune response (antibodies, T cells).
• Stages of immune response: recognition, proliferation, response, and effector stages.

Normal and Abnormal Immune Responses

• Normal immune response: tissue inflammation, characterized by the five cardinal signs of inflammation (redness, heat, swelling, pain, and loss of function).
• Abnormal immune response: hypersensitivity reaction, allergic reaction, or anaphylaxis.

Tetanus and Its Management

• Tetanus is a disease caused by the bacterium Clostridium tetani.
• Manifestations of tetanus include muscle spasms, rigidity, and autonomic dysfunction.
• Diagnostic tests: history of punctured wound, clinical manifestations, CSF exam, blood exam.
• Modalities of treatment: specific (ATS, TAT, TIG, tetanus toxoid, Pen G) and non-specific (oxygen inhalation, NGT feeding, tracheostomy, fluid and electrolyte management).
• Interventions: provide adequate fluids and nutrition, administer prescribed medications, avoid unnecessary handling and stimulation, and provide wound care.

Meningitis and Its Management

• Meningitis is an inflammation of the meninges, caused by bacterial or viral infection.
• Classifications of meningitis: acute meningococcemia, aseptic meningitis, and meningococcal septicemia.
• Diagnostic tests: lumbar puncture, Gram staining, smear and blood culture, smear from petechiae, and urine culture.
• Modalities of treatment: IV antibiotics, digitalis glycoside for arrhythmias, and mannitol for cerebral edema.
• Complications: subdural effusion, hydrocephalus, deaf mutism, blindness, and otitis media.