116 infection 1

physical barriers

skin (keratin) and mucous membranes (nose, GI tract)

body defenses

phagocytosis, inflammatory mediators, interferons and interleukins, specific (memory) response, fever

interferons and IL

immunogenic proteins (cytokines) secreted by WBCs, stimulate immune responses

WBCs

eosinophil, basophil, monocyte, neutrophils, T, B and NK cells

secrete ILs

naive t cells and Th2 cells

th2

aid in immune response, communicates via IL

allergy first responders

T reg, cytotoxic, Th2 -secrete IL

neutrophils

up to 70% of WBCs -1st to site of damage -live up to 1 week -immature = band

lymphocytes

innate and adaptive (memory) -NK, B cells, T cells

monocytes

in blood, and macrophages in tissues -specific to tissues

eosinophils

allergy response -release enzymes/ chem mediators to destroy allergens and parasites

basophils

allergy response -pro inflammatory and anti-coagulating

boosters

boost memory, promoting active immunity

passive immunity

transferred from one person to another -fetus, meds

B cells

antigen presents itself and b cells clone (millions of copies, aka plasma cells) -antibodies secreted which circulate: immunoglobulins

immunoglobulins

most common IgG, secreted from B cells

antibodies fx

neutralize or mark for destruction (by phagocytic cells)

the next exposure

memory b cells always remember antigen and response is immediate and very fast during

t cell types

helper, cytotoxic, memory

t cells

t helper activates B cells, secrete cytokines -t memory cells develop post exposure and recognize antigen next time to respond fast

cytokines

interleukins, interferon, tumor necrosis factor, perforin

causes of decreased WBC

autoimmune disease, drug therapy, chronic infection/inflammation, immunodeficiencies, cancer

autoimmune disease

like IBD -systemic inflammation decreases synthesis and proliferation -depletion due to chronic inflammatory requirements

drug therapy

glucocorticoids (lower inflammatory process) -immunosuppressant drugs (biologics)

chronic infection/inflammation

mononucleosis, HIV -longterm infections = depletion due to chronic requirements

immunodeficiencies

look up during patient research -inborn errors

cancer

lymphomas, leukemias -destruction of production organs -interference with maturation of normal WBCs

causes an infection

host susceptibility, pathogenicity, port of entry

pathogenicity

organisms ability evade or overcome body defenses

pathogens

bacteria, viruses, fungi, parasites

virulence

the power to produce disease (covid 19 has high virulence)(potency) -even low numbers of pathogen are able to produce disease

port of entry

into the body past endogenous defenses

mechanisms of infection

strength in numbers and toxin production (raises ability to live in host environment)

prevention by decreasing numbers

80% of infections spread by hands (WASH) -streptococcus septicemia common in early 1990s

microflora

microorganisms present on/in human body -commensalism, mutualism (intestinal flora), parasitic relationship

intestinal flora

vitamin K and B formation -balance of good and bad

infectious disease

pathogens -host is negatively affected -parasitic relationship

opportunistic

affects one person but not another -any microorganism causing disease -eg. intestinal infection in an immuno suppressed host -common in high risk patients: chronic illness, elderly, newborn, drug tx, malnutrition

parasites

animals -3 main groups: protozoa (malaria), helmiths (tapeworm), arthropods (lice, ticks, mites, fleas) -not high numbers, not often in hospitals

fungi

eukaryotic (organized nucleus), freely reproduce -yeast and mold (candida albicans) -like dark, moist environments -severe disease is rare in a non compromised host

fungi disease

superficial: superficial mycoses (athletes foot, thrush, ringworm) -systemic: (lung, GI) rare serious and difficult to treat -prevention is key

viruses

no cell structure: protein coat and nuleic acid only (DNA or RNA) -retroviruses like HIV

-host needs to survive and replicate -more common and contagious than other pathogens

retroviruses

RNA only, requires reverse transcription into DNA (enzyme reverse trascriptase) -HIV (cause of aids)

virus host

must replicate and survive -must access host cell -may lyse host cell -eg HIV lyses host cell during replication -HPV alters host cell = oncogenic

common viral infections

covid 19, influenza, common cold, laryngitis

virus tx

symptom management: antivirals -immune system support: IVIG (boost immune response like interferons) -prevention: immunizations

bacteria

prokaryotes -no organized nucleus -contain DNA (small DNA bodies: plasmids) and RNA -reproduce autonomously -colonize affected areas: biofilms -like specific conditions -less contagious than viruses -commonly secrete toxin (exogenous pyrogens) = contribute to inflammation and disease process -gram negative or positive

bacteria tx

antibiotics -resistance is increasing

port of entry examples

direct content, inhalation, ingestion

direct contact

with the infected host -STIs, diseases causing a wound/rash (chickenpox)

inhalation

of airborne pathogens -resp diseases, colds, pathogens causing meningitis, childhood disease -chicken pox

ingestion

of contaminated foods -food poisoning -parasites (eggs) -food borne viruses (Hep A)

source of infection

nosocomial: acquired in hospital -community acquired: outside of hospital

emia suffix

for pathogen presence in blood -bacter____ = bacteria in blood

incubation

pathogen present and replicating -no symptoms -can infect others

prodromal stage

initial symptoms: malaise, mild fever, headache, myalgia -generic in nature (hard to differentiate)

acute stage

maximum presence of pathogen, maximum response by host -maximum impact of infection -more specific and consistent symptoms

convalescent period

pathogen decreasing in numbers -progressive host repair of damages -recovery

resolution

no signs of disease

1st step

where is the illness -based on health hx, and focused health assessment

immunization sched canada

part of assessing for something rare, should they already be protected against this?

common imunizations

DTaP, IPV, HPV

DTaP immunization

diptheria, tetanus, pertussis

IPV

polio virus immunization

HPV

human papillomavirus vaccine

botulism

less common due to prevention -gram + and anaerobic, neurotoxin (Ach block) -prevention with preservatives (potassium nitrate)

antitoxin HBAT

botulism tx -lowers binding of neurotoxin to ach receptors -need to treat in time

neurotoxin

Ach block -botulism does this -need for para, symp, and somatic NS fx -muscle paralysis

potassium nitrate salt

a way to prevent botulism -its a preservative

2nd step

identify what is causing illness -bacterial vs viral? CBC & diff, s&s, hx, culture from source

cbc

wbc, rbc, hemoglobin (HGB), hematocrit (HCT), PLT

diff

neutrophils, band neuts, lymphocytes

cbc and diff

to determine if bacterial or viral -part of identifying whats causing illness -24hrs

neutrophils

highest in bacterial infection -band _____ high in severe overwhelming infection

lymphocytes

T, B, NK? usually higher in viruses

culture tests

up to 72hrs -want to identify infection -blood culture, swaps, etc -on wounds -also sensitivity

sensitivity test

is it sensitive to this antibiotic or not

gram negative

thinner peptidoglycan, and has an outer membrane -ecoli, klebsiella, pseudomonas, salmonella, hib, cholera, syphillis, gonorrhea, nisseria M.

gram positive

thick peptidoglycan layer -staphylococci, streptococci (pneumococci), enterococci, listeria, c dif

tuberculosis

neither gram positive or negative

3rd step

antibacterial tx process -empiric or focal

abx empiric tx

based on suspected bacteria -evidence decision -broad spectrum may be used -starts ASAP -drug must reach target (ADME, patient compliance)

broad spectrum abx

effective at killing anything -both G + and -

abx focal tx

culture and sensitivity results used -tx initiated once results known -empiric tx maybe switched to focal -narrow spectrum abx better choice for that pathogen

streptococcus pyogenes

group A strep -bacterial pathogen -pharyngitis (sore throat) -incubation 2-4 days; highly infectious -post strep disease risk: glomerulonephritis, endocarditis (caused rheumatic fever)

streptococcus pyogenes symptoms

fever, sore throat, headache, malaise

variety of pathogens

an illness can be caused by