Download Inflammation, Infection, Immunity

Inflammation, Infection,
Immunity
Vocabulary
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Allergen
Antibodies
Antigen
Autoimmunity
Bacteria
Contamination
Colonization
Fungi
lysozyme
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Nosocomial
Immunity
Infection
Inflammation
Medical asepsis
Sebum
Surgical asepsis
Virus
Rickettsiae
Protection
• Natural barriers
– Skin and mucous membranes
– Sweat glands- lysozyme
– Sebaceous glands—sebum
– Immunoglobulin
– Phagocytes
– Cilia
– Acidic gastric secretions
– Normal bacterial flora
First line of Defense
• Intact skin provides
a physical barrier
against “foreign”
invaders
Second Line of Defense
• Phagocytosis
– Neutrophils
– Monocytes
• Inflammation
Circulating phagocytes move toward vessel walls and begin
to adhere to the vessel walls (pavementing). Through a
process called diapedesis, they squeeze through
intercellular junctions becoming part of the exudate and
migrate to inflammatory lesions.
4 steps of Phagocytosis
1. Recognition of the target and its
adherence to the phagocyte
2. Engulfment
3. Fusion with lysosomes within the
phagocyte
4. Destruction of the target by lysosomal
enzymes.
Leukocytes
– Three kinds of granulocytes
• neutrophils
• eosinophils
• basophils
– Two kinds of leukocytes without granules in their
cytoplasm
• lymphocytes
• monocytes
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Other important cells
• Basophils –act similarly to mast cells
• Platelets—stop bleeding if vascular injury
has occurred
• Mast cells– activate inflammatory
response through degranulation and
synthesis of mediators in response to
stimuli
The Inflammatory Process
• Series of cellular changes that signal the body’s
response to injury or infection.
• Most of the essential components of the process
are found in the circulation
• Most of the early mediators of inflammation
increase movement of plasma and blood cells
from the circulation into the tissues surrounding
the injury
• These substances are collectively called
“exudate.”
• Superficial hallmarks of inflammation are:
– Redness (rubor)
– Swelling (tumor)
– Heat (calor)
– Pain (dolor)
– Loss of function
Actions in the Inflammatory
Process
Cellular injury--Trauma, mechanical injury
Oxygen or nutrient deprevation
Chemical agent
Thermal injury
Radiation
• Hemodynamic changes
– Vascular changes are immediate
– Arterioles at injury site constrict briefly
– Followed by dilation, increasing blood flow to
the area
– Increased pressure in microcirculation causes
exudation of plasma and blood cells into the
tissues leading to edema and swelling.
– Blood remaining in circulation becomes more
sluggish and viscous
• WBC’s migrate to vessel walls and stick
there (pavementing).
• Biochemical mediators stimulate
endothelial cells lining the capillaries,
causing them to retract, leaving spaces
between cell junctions
• Leukocytes squeeze out
• Vascular permeability continues
throughout inflammatory process
Chemical Mediators
• Cytokines
– Secreted by cells participating in the immune
response
– Function as messengers
• Eicosanoids
• Prostaglandins
– Any of a large group of biologically active
unsaturated fatty acids produced by the
metabolism of arachidonic acids through the
cyclooxygenase pathway. Local short-range
hormones that are formed rapidly, act
immediately and they decay or are destroyed.
– Influence vasodilation, vascular permeability,
bronchoconstriction, inhibition of gastric
secretions, stimulation of neural receptors for
pain curing tissue damage.
– NSAIDS block the production of
prostaglandins
• Histamine
– Substance produced from the amino acid
histadine which causes dilation of blood
vessels, increased secretion of acid by the
stomach, smooth muscle constriction, mucus
production, and itching. The release of
histamine from the mast cells is a major
component of type I hypersensitivity
reactions, including asthma.
• Leukotrienes
– Any of a group of arachidonic acid
metabolites that functions as a chemical
mediator of inflammation. Synthesized in the
cells in response to inflammation or tissue
injury. Extremely powerful
bronchoconstrictors and vasodilators and
mediate the adverse vascular and broncial
effects of systemic anaphylaxis.
• Cortisol
– Hormone produced by the adrenal cortex.
– Anti-inflammatory
– Slows the release of histamine, stabilized
lysosomal membranes and prevents the influx
of leukocytes, thus impeding the inflammatory
process.
Local vs Systemic Inflammation
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Heat
Swelling
Redness
Pain
Loss of function
• Systemic
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Fever
Headache
Muscle aches
Chills
Sweating
Leukocytosis
SIRS
• Systemic Inflammatory Response Syndrome
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Generalized inflammation occurs
Threatens vital organs
Damage endothelial lining of vessels
Increases capillary permeability
Hypotension
Microemboli
Blood shunting compromises organ perfusion
Hypermetabolic state
• Increased serum glucose
– Termed Sepsis when confirmed infection diagnosed
– MODS
Wound Healing
• End result of
inflammation
• Time dependent on
severity, presence of
infection, health of
patient
• Vitamin C, zinc protein
and other deficiencies
delay healing
Inflammatory Phase
• A) Immediate to 2-5 days
• B) Hemostasis
– Vasoconstriction
– Platelet aggregation
– Thromboplastin makes clot
• C) Inflammation
– Vasodilation
– Phagocytosis
Proliferative Phase
• A) 2 days to 3 weeks
• B) Granulation
– Fibroblasts lay bed of collagen
– Fills defect and produces new capillaries
• C) Contraction
– Wound edges pull together to reduce defect
• D) Epithelialization
– Crosses moist surface
– Cell travel about 3 cm from point of origin in all
directions
Remodeling Phase
• A) 3 weeks to 2 years
• B) New collagen forms which increases
tensile strength to wounds
• C) Scar tissue is only 80 percent as strong
as original tissue
Healing by Intention
• Primary
– Clean surgical wounds
• Secondary
– Contaminated or infected wounds
• Tertiary
– Delayed primary closure
Infection
• A process involving invasion of body by
micro-organisms that leads to tissue
damage
• Different from inflammation which is a nonspecific reaction to tissue injury
• Specific process that causes injury
• Infection leads to inflammation
Infectious Agents
Bacteria
• One celled organisms
• Rigid cell wall and gelatinous capsule
protect from phagocytosis
• Classified by shape, ability to take up
stain, need for oxygen
Bacteria
cocci
Bacilli
• Rod shaped
– Fusiform
– spirochetes
Bacteria
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Staphylococcus - normally found on the skin, but can cause boils and pimples.
Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for many
serious infections that are sometimes fatal.
Escherichia coli - normal inhabitant of the colon, hence called "coliform" bacteria
E. coli O157:H7 is a virulent strain that produces toxins that
can cause diarrhea, abdominal pain, and even kidney failure.
Chlamydia - a sexually transmitted disease (STD) caused by the bacterium
Chlamydia trachomatis.
Over one million cases of chlamydia were reported in the United States in 2006..
Salmonella - frequent cause of food poisoning
Vibrio cholerae - causes cholera, an infection of the small intestine characterized by
watery diarrhea
Treponema pallidum - a spiral-shaped (spirochete) bacteria that causes syphilis
Neisseria gonorrhoeae - a Gram-negative coccus that causes gonorrhea, one of the
most common sexually transmitted diseases
Borrelia - a spirochete transmitted by ticks that causes Lyme disease (borreliosis).
Mycobacterium tuberculosis - the cause of tuberculosis
Yersinia pestis - causes bubonic plague, transferred by flea bites
Bacillus anthracis - the organism that causes anthrax, characterized by black lesions.
Viruses
• Very small, cannot be seen with
microscope
• Cause significant disease in humans
• Needs the host cells to replicate
• Seldom possible to kill virus without
harming host
• Prevention via immunizations and hygiene
Viral Illnesses
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Common Cold is caused by a rhinovirus
Influenza (Flu)
Dengue fever is transmitted by bites from mosquitoes mainly in Southeast Asia and
South America
Acquired Immunodeficiency Syndrome (AIDS) is caused by the Human
Immunodeficiency Virus (HIV). It is transmitted by sexual contact with an infected
person or by sharing needles or syringes for drug injection.
Hepatitis (inflammation of the liver, jaundice)
Herpes (cold sores, and genital herpes)
Rabies (transmitted by bites from infected bats, raccoons, dogs)
Polio (may cause paralysis)
Smallpox (eradicated from the world in 1977 through vaccination)
Mumps
Yellow Fever is a viral hemorrhagic fever transmitted by infected mosquitoes.
Measles or rubella
Warts caused by a virus may be treated at home with solutions and patches
containing salicylic acid over several weeks, or in the doctor's office by freezing
Fungi
• Fungi include one-celled yeasts slightly bigger
than bacteria, and multi-celled mushrooms and
molds. Fungi do not have chlorophyll to make
their own food, so they get their nutrition as
parasites or by breaking down remains of dead
plants or animals. Some fungi are poisonous
(e.g., Amanita mushrooms), but some have
beneficial uses. For example, Penicillium
notatum produces the antibiotic penicillin and
Saccharomyces cerevisiae is the yeast used to
make bread rise and to brew beer. Fungal
diseases are called mycoses
Mycoses
• Aspergillosis - infection of sinuses and lungs
• Blastomycosis - skin and pulmonary infections
• Candidiasis - cutaneous and vaginal infections.
Candida albicans is the most common cause of
vaginal yeast infections.
• Coccidioidomycosis - may cause cough, chest
pain, shortness of breath
• Cryptococcosis - may be transmitted in pigeon
droppings
Fungi
Protozoa
• One celled organisms
• More complex than bacteria
• May form cysts that can protect them from
harsh environments, allowing them to live
outside a host for prolonged periods
Protozoal diseases
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Malaria (transmitted by mosquitos) is
most prevalent in Sub-Saharan Africa
Leishmaniasis (transmitted by sandflies
which are about one-third the size of
mosquitoes)
African trypanosomiasis (sleeping
sickness transmitted by the tsetse fly)
Amoebic dysentery
Coccidiosis
Cryptosporidiosis
Giardial enteritis
Toxoplasmosis
Rickettsiae
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Between a virus and bacteria in size
May be rods, cocci or pleomorphic
Mulitply in the cells of host animals
Transmitted to humans through bites of
fleas and ticks
• Diseases more prevalent in areas of poor
sanitation and high rodent and insect
populations
Helminths
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Worms
Found in soil and water
Transmitted hand to mouth
Infections generally in GI tract
Pinworms most common, esp. in children
Tapeworms in GI tract lead to weight loss
and abdominal pain with bloating
• Hookworms enter through soles of feet
Pin worm
• Hook worm larvae
tracts
Transmission of Infection
6 requirements of transmission of infection
1) Infectious agent
2) Reservoir
3) Portal of exit
4) Mode of transfer
5) Portal of entry
6) Susceptible host
Signs and Symptoms of Infection
• Local: Local signs of inflammation
• Generalized: Pain, swollen lymph nodes,
fever, elevated WBC
• Infected individuals may be more
infectious before symptoms arise.
• Asymptomatic carriers may spread
disease
Types of Infection
• Community acquired–
– From day to day contact with society
– Increased incidence with poverty, poor
sanitation, overcrowding, resistant strains
– Food borne
• Salmonella, Hepatitis A,
– STDs
Community Acquired
• Prevention
– Hygiene
– Immunization
– Food handling laws
– Screening
– Cooking
– Isolation
– Vector control
Hospital Acquired
• Nosocomial– increased rates of morbidity
and mortality
• Prevention, prevention, prevention!
• At risk patients
– Anyone with non-intact skin
– Anyone with tubes or catheters
– Immune compromised
– Weakened or in poor health
– Poor nutritional status
Precautions
• Standard
– Used with all patients
– Wash hands before and after contact
– Wear gloves when handling any body fluid
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Table 2-1. Standard Precautions: Key Components
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Handwashing (or using an antiseptic handrub)
� After touching blood, body fluids, secretions, excretions and contaminated items
Immediately after removing gloves
Between patient contact
Gloves
� For contact with blood, body fluids, secretions and contaminated items
� For contact with mucous membranes and nonintact skin
Masks, goggles, face masks
� Protect mucous membranes of eyes, nose and mouth when contact with blood and
body fluids is likely
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Gowns
�Protect skin from blood or body fluid contact
Prevent soiling of clothing during procedures that may involve contact with blood
or body fluids
Linen
Handle soiled linen to prevent touching skin or mucous membranes
�� Do not pre-rinse soiled linens in patient care areas
Patient care equipment
�� Handle soiled equipment in a manner to prevent contact with skin or mucous
membranes and to prevent contamination of clothing or the environment
�� Clean reusable equipment prior to reuse
Environmental cleaning
�� Routinely care, clean and disinfect equipment and furnishings in patient care areas
Sharps
�� Avoid recapping used needles
�� Avoid removing used needles from disposable syringes
�� Avoid bending, breaking or manipulating used needles by hand
�� Place used sharps in puncture-resistant containers
Patient resuscitation
�� Use mouthpieces, resuscitation bags or other ventilation devices to avoid mouth-tomouth
resuscitation
Patient placement
�� Place patients who contaminate the environment or cannot maintain appropriate
hygiene in private rooms
Airborne Precautions
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Airborne precautions include:
Standard Precautions
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Personal respiratory protection
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N95 respirator
Prior fit-testing that must be repeated annually and fit-check / seal-check prior to each use.
Powered Air-Purifying Respirator (PAPR)
Airborne Infection Isolation Room (AIIR)
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At a minimum, AIIR rooms must:
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Provide negative pressure room with a minimum of 6 air exchanges per hour
Exhaust directly to the outside or through HEPA (High Efficiency Particulate Air) filtration
Airborne precautions apply to patients known or suspected to be infected with
microorganisms transmitted by airborne droplet nuclei.
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• Airborne Precautions
• Airborne precautions are required to protect against airborne
transmission of infectious agents.
• Diseases requiring airborne precautions include, but are not limited
to: Measles, Severe Acute Respiratory Syndrome (SARS), Varicella
(chickenpox), and Mycobacterium tuberculosis.
• Preventing airborne transmission requires personal respiratory
protection and special ventilation and air handling.
• How airborne transmission occurs:
• Airborne transmission occurs through the dissemination of either:
• airborne droplet nuclei (small-particles [5 micrograms or smaller] of
evaporated droplets containing microorganisms that remain
suspended in the air for long periods of time) or
• dust particles that contain an infectious agent
• Microorganisms carried by the airborne route can be widely
dispersed by air currents and may become inhaled by a susceptible
host in the same room or over a long distance form the source
patient – depending on environmental factors such as temperature
and ventilation
• In addition to Standard Precautions, Droplet Precautions
are required for patients known or suspected to have the
following illnesses transmitted by large particle droplets.
Common organisms/diseases which require Droplet
Precautions include:
Bacterial:
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Invasive Hemophilus influenzae disease:
meningitis, pneumonia (in infants and small children),
epiglottitis. Invasive Neisseria meningitidis disease:
meningitis, pneumonia, and bacteremia. Mycoplasma
pneumonia Group A Streptococcal pharyngitis,
pneumonia, or scarlet fever in infants and young children
Viral
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Influenza Adenovirus
(requires Contact Precautions in addition) Mumps
Parvovirus B19 Rubella
Droplet precautions
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Private room
Mask when less than 3 feet from patient
Door may be open
No special ventilation required
Contact Precautions
• Direct contact transmission involves skin
to skin contact and physical transfer of
microorganisms to a susceptible host from
an infected or colonized person, such as
occurs when personnel turn patients,
bathe patients or perform other patient
care activities that require physical
contact. Direct contact can also occur
between patients that may have physical
contact with each other.
• Contact Precautions are required if:
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A patient is colonized and/or infected with
multidrug-resistant organism. A multidrugresistant organism is an organism that is
resistant to treatment with standard firstline antibiotics. A particular organism is
identified as being potentially hazardous to
others and/or to the ecology of the hospital
environment because of its antibiogram,
pathogenicity, virulence, or epidemiologic
characteristics (i.e., VRE, MRSA).
Contact precautions
• Private room
• Strict barrier precautions
Asepsis
• Medical
– Clean technique
– Hand hygiene
• Surgical
– Sterile technique
Immunocompromised Patients
• Decreased immunity to infection
– AIDS
– Transplant
– Chemotherapy
– Leukemia and aplastic anemia
Immunity
• Immune system body’s defense network
• Provides adequate protection from most
infections and diseases
• Factors that compromise immunity:
– Aging
– Stress
– Congenital defects
– Therapeutic interventions
– Malnourishment
Innate vs Acquired Immunity
• Innate
– Present at birth
– Not dependant on
previous exposure
– Non-specific defense
mechanisms
– Inflammatory response
• Acquired
– Develops after birth
– Response to specific
antigens
– Depends on proper
development and
functioning of B and T
lymphocytes
Non-specific defenses
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Innate
Physical and chemical
Inflammation and phagocytosis
Complement
– A series of proteins that inhance inflammation
and immunity
• Pyrogen—released in inflammation and
causes fever
• Interferon—produced in viral infections
Active Immunity
• Acquired after direct contact with antigen
– May be through illness or vaccination
• Antibodies develop to the specific antigen
• Antibodies retain memory
• Quickly react when exposed later to same
antigen
Passive Immunity
• From injection with immunglobulin or
antiserum
• Antibodies were produced by another
individual
• Temporary
• Newborns have passive acquired
immunity via breastmilk
Organs of Immunity
Antibody Mediated Immunity
• Immediate
• Initiated when antigen binds and interacts
with antibody receptors on the surface of
a mature B cell
• B-cell is triggered into a sequence of cell
division and differentiation steps
• Result is the production of
– Immunglobulin secreting plasma cells
– Long-lived memory cells
Antigens
• Almost any biochemical
• React with antibody or T-cell
• Diverse ability to induce an immune
response
• Proteins and complex carbohydrates are
very immunogenic
• Nucleic acids and lipids poor immunogens
• Some very small molecules are are not
immunogenic—called haptens
Antibodies
Immunglobulins are serum glycproteins
produced by plasma cells in response to a
challenge by antigens.
Antibodies—immunglobulins with specificity
for a particular antigen
Classes of Immunoglobulins
• IgA—predominant antibody in normal body
secretions
• IgG—most abundant, crosses placental barrier
to provide passive immunity to infant
• IgM—largest immunoglobulin; first antibody
produced during initial response to antigen
• IgE—allergic reactions and parasitic infections;
least common
• IgD—located on surfaces of developing B
lymphocytes.
Antibodies
• Neutralize bacterial toxins
• Neutralize viruses
• Opsonize bacteria to promote
phagocytosis
• Activate components of the inflammatory
response
Cell Mediated Immunity
• Varieties of mature T cells
– Memory cells- induce secondary immune response
– Lymphokine-producing cells- transfer delayed
hypersensitivity and secrete proteins that activate
other cells such as macrophages
– Cytotoxic cells- attack antigens directly and destroy
cells that bear foreign antigens
– Regulatory cells, primarily helper T—control cell
mediated and humoral immune response
– Suppressor cells- turn off the immune response when
danger is past
Cellular Immunity
• Fights most viral and bacterial infections
• Hinders growth of malignant cells
• Responsible for rejection of transplanted
organs
Immunodefciency
• Can be congenital or acquired
• Result from problems with any phase of
immunity: humoral, cell-mediated, vital
mediators, problems with phagocytosis
• Causes of Acquired Immune Deficiency:
– Infection
– Malignancy
– Autoimmunity (e.g. SLE, RA)
– Chronic disease (DM, renal dz)
– Drugs
– Aging
– Stress
– Malnutrition
Nursing Care of the Immunocompromised Patient
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Prevent infection
Small changes in body temp may be significant
Avoid rectal thermometers
Encourage adequate nutrition/hydration
Hygiene
TC&DB
Protective Isolation when needed
Patient and family education
Allergies
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Hypersensitivity
Atypical immune response
Causative antigen called an allergen
Inflammatory cascade
Release of histamine
Local manifestations vary according to
allergen: urticaria, pruritus, conjuctivitis,
rhinitis, laryngeal edema, GI cramps and
malabsorption, angioedema.
Nursing Care of the Patient with
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Know the allergies
Know allergic response
Know current medications
Pt education
Avoid allergens
Anaphylaxis
• Life threatening
• Histamine release
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Bronchospasm
Vasodilation
Increased capillary permeability
Hypovolemic shock
• Signs and symptoms
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Increased anxiety
Wheezing, dyspnea, cyanosis
Hives, facial edema
Arthralgia
Hypotension
Autoimmune Diseases
• Poorly understood etiology
• Ability to distinguish self from non-self
hampered
• Immune system attacks own tissue
• Cause injury by
– Effect of antibodies on cell surfaces
– Deposition of antigen-antibody complexes
– Action of sensitized T cells
• Multiple Sclerosis—myelin sheath
destruction
• Rheumatoid arthritis– lining of joints
• Diabetes type I—insulin secreting cells of
pancreas
• Grave’s disease—Thyroid
• Systemic lupus erythematosus—multiple
tissues
Nursing Care
• Medical interventions depend on the specific
disease
• Steroids and NSAIDS
• Nursing Diagnoses
– Risk for activity intolerance
– Impaired skin integrity
– Knowledge deficit
– Chronic pain
– Imbalanced nutrition
risk