Infection Flashcards
Infection
Colonization of a host by a microbial species
- can be localized
- systemic: spread to several regions/areas of body
causes of infection
common: virus, bacteria
rare: fungi, protozoa, helminths, prions
modes of transmission
direct: kissing, sex, touching soils, droplet
indirect: airborne
vehicle: transmission through food, water, blood
vector: something else carries disease (mosquito)
reservior
habitat where microorg usually lives and grows
portal of entry
- oro/naso pharynx
- genitourinary tract
- skin (places w decrease integrity) and mucous membranes, largest vulnerability but also biggest barrier
translocation
movement of bacteria across intestinal lining
- frequently occurs in peritoneal cavity (leaky gut)
- bloodstream (infection can move from finger to leg)
blood as portal of entry
organism gets directly into blood
- needle sticks
- blood transfusion contamination
maternal-fetal transmission
some microorgs can cross barriers
- placental barrier directly to fetus
- occur during childbirth (vaginal canal)
stages of infection
incubation period
prodromal stage
acute stage
convalescent stage
resolution stage
incubation period
time org is in body before symptoms appear
prodromal stage
onset of unspecific symptoms
acute stage
onset of specific symptoms
convalescent stage
decrease in illness and begin to feel better
resolution stage
pathogen is eliminated from the body
infectious process
the body fighting something in the body
- injury
- increased permeability
- immigration of leukocytes
- phagocytosis
- exudate
- systemic symptoms
injury: infectious process
the initial insult to the area
- short period of vasoconstriction to stop bleeding and movement of invading organisms
- prolonged period of vasodilation which allows blood to bring immune cells to area and contributes to symptoms of inflammation
increased permeability: infectious process
fluid is pulled out of vascular space (blood vessel) and into the space of injury
- allows white blood cells to enter injury
immigration of leukocyte: infectious process
neutrophils from the fluid are attracted to site of injury and attach to endothelium of injured cells to move around injured tissue
phagocytosis: infectious process
phagocytosis occurs at site of injury by neutrophils and monocytes which recognize, engulf and destroy invaders
exudate: infectious process
- transports leukocytes to injured areas
- dilutes toxins
- transports nutrients for healing process
systemic symptoms: infectious process
occurs if the infection doesn’t remain localized resulting in a total body response stimulating the hypothalamic fever set point
what does a fever point set increase
- helps concern body heat
- stimulates defense mechanisms to help rid body of organisms
- some bacteria/virus less virulent in heat
- improves neutrophil and macrophage function
- improves antibody release and T-cell activation
colonization
pathogens inhabit a specific body site but not an active infection
- do not cause S/S
infection
invasion of micro orgs that cause tissue damage
- clinical s/s of illness and inflammation
indications of infection
vital signs increased, verify with labs (cultures, urinalysis)
gram stain
shows gram +/- (presence of thick cell wall or not), shape an arrangement
what does culture and sensitivity tell you?
tells exact bacteria and what antibiotics would work to treat it
- 24 hours for basic result
- 72 hours for full identification
what can you culture?
- sputum (coughing)
- urine (catheter)
- blood (septic) : high likelihood of skin contamination, need at least one peripheral stick, aerobic/anaerobic
Urinalysis Normal results
- Dip Stick: 5-9
- Nitrates: negative
- Leukocyte esterase: negative
- Blood, WBC, RBC: <5
- Bacteria: negative
- Epithelial cells: <5
nosocomial
Infections that occur while in healthcare facility
- more virulent (spread quickly, more disruptive)
Drug resistance infections
- MRSA: methicillin resistant Staph aureus
- CRE: carbapenem resistant enterobacteriaceae
- MDRO: multi drug resistance
Superinfection
New infections that occur during treatment for a different infection
- typically caused by resistant orgs
- antimicrobial used to treat primary infection inhibit or kill NORMAL helpful flora usually in the GI tract or skin or mucosal surfaces
C diff
Clostridium difficile
- normal intestine flora killed by antibiotics which allows c diff without control factor
- extreme diarrhea, ab cramping and tenderness
- can occur days to months after first antibiotic treatment
- identified with PCR
C diff precautions
Contact D: gown, gloves, wash hands
C diff treatment
PO/IV metronidazole
PO vancomycin
- never give anti diarrheal medications
Complications of c diff
Pseudomembranous colitis
- life threatening
- dilation of the colon
- may require surgery
Candidiasis
Yeast infection caused by over growth of fungus
- occurs in mucous membranes (oral/vaginal)
- occurs on moist skin surfaces
Candidiasis treatment and prevention
- mycostatin: swish and spit anti-fungal medication
- nystatin: anti fungal powder
Cellular adaptation
Changes that your bodies cell go through to permit survival and maintenance of cellular function
- cells can change size and form
- both normal and abnormal
Atrophy
Decreased or shrinking cell size
- cells have decreased protein synthesis and or increase protein catabolism
Types of atrophy
Physiologic: related to developmental issues
- organ doesn’t develop properly
Pathologic: related to decreased workload or changes environmental conditions
- nutritional deficiencies, blood supple decrease, hormonal problems, prolonged immobility, aging
Hypertrophy
Increased cell size and can increase function of cell
- typically a response to mechanical stimuli like repetitive stretching, chronic pressure, prolonged volume overload
- heart and kidney most prone to negative adaptations
- muscle/skeletal cells do naturally
Hyperplasia
Increased number of cells resulting from increase rate of cell division responding to prolonged/severe injury
- only cells that divide (epidermal, intestinal epithelial, glandular cells)
- normal w pregnancy changes, wound healing
- abnormal w cancers, abnormal hormone stimulation
Dysplasia
Abnormal changes in size/shape/organization of mature cells (related to atypical hyperplasia)
- associated w neoplastic growth (cancerous cells)
- doesn’t equal cancer
- reversible
- inflammation and chronic irritation
Metaplasia
Reversible replacement of one type of mature cells to another
- less differentiated
- pathologic response to chronic irritation and inflammation
* allows cells to survive better in a hostile environment and is reversible*
Neoplasia
Cellular growth not responding to normal regulator processes
- usually bc mutation
Anaplasia
Cells differentiate to immature form or embryonic form
- associated w neoplasms and malignant tumors
Cancer
Controlled cellular growth w rapid uncontrolled proliferation and loss of ability of cells to differentiate
Neoplasms-benign
- differentiated cells (less anapastic)
- reproduced more rapidly than normal cells
- unable to metastasize
- grow slowly
- frequently encapsulated
- do not usually cause problems unless cause compression like in brain
neoplasms-malignant
- undifferentiated cells (super immature)
- reproduce rapidly w atypical cells
- often metastasize
- sites near primary site or distant
- no capsule
Necrosis
Cellular injury that results in cell death
- irreversible
- leads to swelling
- bursting of cell
- inflammation
- can lead to gangrene or liquefaction necrosis
Ischemic necrosis
- infarction
- prolonged ischemia
Gangrene
Dead tissue is breeding ground for bacteria
- large massive tissue related to decrease blood supply and bacterial invasion
- bc decrease blood supply, no WBC that can fight off bacteria
Liquefactive necrosis
Occurs in tissues w lots of lipids or where there are numerous inflammatory cells
- release proteolytic enzymes which destroy tissue
Types of gangrene
Dry: minimal bacteria and inflammatory response
- blackened, dry, wrinkled
Wet: extensive damage from bacteria and WBC that produce liquid wound
- foul smelling, rapid spread, can be systemic
Gas: destroy connective tissue/cell membranes
- caused by clostridium perfringens
- gas bubbles that form spores, often found in soils
