Term1 C7 Module 2 Infection, Immunity, Inflammation

NUR1023C

Infection

the presence and multiplication of a microorganism within another living organism, with subsequent injury to the host; the invasion and multiplication of microorganisms in body tissues, which may be unapparent or the result of a local cellular injury caused by competitive metabolism, toxins, and intracellular replication, or antigen-antibody response

Chain of Infection components

1. infectious agent

2. reservoir

3. portal of exit

4. mode of transmission

5. portal of entry

6. susceptible hose

Infectious agent

micro-organisms capable of causing disease or illness

-bacteria, fungi, parasites, prions

Reservoirs

place in which infectious agents live, grow, and reproduce

-people, water, food

Portals of exit

ways in which infectious agent leaves the reservoir

-blood, secretions, excretions, skin

Modes of transmission

ways in which the infectious agent is spread from the reservoir to the susceptible host

-physical contact, droplets, airborne

Portals of entry

ways in which infectious agent enters the susceptible host

-mucous membrane

-respiratory system

-digestive system

-broken skin

Susceptible host

individuals may have traits that affect their susceptibility and severity of disease

-immune deficiency, diabetes, burns, surgery, age

The single, most effective way of breaking the chain of infection

proper hand hygiene

-handwashing with soap and water, alcohol-based sanitizer, or surgical hand scrub

Systemic infection symptoms

fever, increases heart rate and respiratory rates, lethargy, anorexia, and tenderness or enlargement of lymph nodes

Localized infection symptoms

redness, swelling, warmth, pain, tenderness, drainage, numbness, or tingling, and loss of function in affected area

Bacteria

single-celled organisms without a true nucleus or cellular organelles. While they can reproduce independently, they need a host for a suitable environment for multiplication. Bacteria produce toxins that cause cell death. If enough cells die, the person can die as well.

-most significant and most prevalent in hospital settings

-ex: Clostridium difficile and Escherichia coli

Viruses

pathogens with a nucleic acid within a protein shell and requiring invasion of a host for replication, it uses the host cell’s DNA and RNA to reproduce

-primary method of transmission is sneezing & coughing (hand-to-mouth contact)

-smallest of all microorganisms

-ex: Covid-19, HIV, Hepatitis A, B, C, or E virus, Human papillomavirus

Fungi

microorganisms belonging to the kingdom of fungi, including yeasts, molds, and mushrooms. Like bacteria, they are single-cell organisms but can also grow as multicellular filamentous colonies (molds or mushrooms).

-plant-like organisms present in air, soil, and water

-ex: athletes foot, ringworm, thrush, vaginal yeast infections

Parasites

A subcategory termed parasitic protozoa and, with few exceptions, generally infect individuals with compromised immune responses.

-spread by the fecal-oral route by sexual contact, ingesting food or water contaminated with the parasitic spores or cysts from insects or animals.

-typically found in dead material in water and soil

-live on or in a host and rely on it for nourishment

-ex: Trichinosis, Toxoplasmosis, Malaria, Lyme Disease, and intestinal worm infestations

Nonpharmacological Interventions

• Adhering to basic hand hygiene and Standard Precautions

• Food hygiene- appropriate preparation and storage of food

• If high risk, staying away from known ill individuals

• Screening for early identification and treatment of infections (Pap smears, annual PPD tests

• Proper nutrition and fluid intake

• Comfort measures

• Rest

Pharmacological Interventions

• Staying current with immunizations

• Anti-infectives as ordered; Instructing the patient to take the entire prescription and not to stop when beginning to feel better

HIV

a retrovirus that cause gradual deterioration of the immune system by systematically destroying the CD4 “helper/inducer” T-cells. An affected person’s body cannot signal the immune system to fight of a pathogen when it enters. Found in all body fluids except sweat

Immunity

a physiological process that provides an individual with protection or defense from disease; originates in the bone marrow

Three processes necessary for immunity

-inflammation 

-antibody-mediated immunity, aka humoral immunity which generates antibodies produced by B-lymphocytes 

-cell-mediated immunity, produced by T-lymphocytes 

Innate immunity

(natural immunity) that's present at birth. This is a nonspecific defense mechanism that is not antigen-specific nonspecific and comes into play immediately or within hours of an antigen's appearance in the body.

ex: cough reflex, enzymes in tears and skin oil, mucus, which traps bacteria and small particles; skin, stomach acid 

Active (acquired) immunity

develops after introducing a foreign antigen resulting in the formation of antibodies or sensitized T lymphocytes. It can come from a vaccine or exposure to an infection or disease

-there are two types: humoral (antibody-mediated) and cellular (cell-mediated). 

Passive (acquired) immunity

occurs when a person receives an antibody produced in another body. Passive immunization provides immediate but short-term, temporary protection against antigens. 

ex: Infants acquire this type of immunity naturally through breast milk; this immunity can also provide 6–12 months of protection for the infant.  

also can be acquired artificially when antibodies are transferred via injection of an antibody-rich serum in the form of immunization. 

Suppressed Immune Response

denotes the inability to develop a normal immune response when necessary. This is also referred to as immunosuppressed or immunocompromised. 

Primary immunodeficiency

inherited genetic mutations present at birth that impair the immune system, often diagnosed in childhood 

Secondary immunodeficiency

 acquired later in life due to external factors like infections, malnutrition, or medical treatments

Exaggerated Immune Response

occurs when the immune system fails to recognize the difference between "self" and "non-self." The immune system may begin attacking host cells, and the individual may be harmed by a response that is supposed to be protective or curative. Frequently, this type of response leads to autoimmune disorders. 

Inflammation

a reaction to tissue injury caused by the release of chemical mediators causing a vascular response and migration of fluids/cells to the site.

Signs of inflammation

-redness

-swelling

-pain

-heat

-loss of function