Infectious Diseases--Overview Flashcards
Infectious Disease
-consequences of microbial invasions
Host
-any organism capable of supporting another organism’s nutrition and growth
Infection
- presence and multiplication of living organisms on or within host
- -healthy infection vs pathogenic infection
Factors Influencing Severity of Infectious Diseases
- Virulence
- Pathogens
- Opportunistic Pathogens
Virulence
-disease-producing potential
Pathogens
-virulent organisms capable of causing disease
Opportunistic Pathogens
- attact vulnerable hosts
- (wakened immunity, illness, or medical therapy)
Incubation Period
-reproduction of pathogen without manifest symptoms
Prodromal Slide
-Initial appearance of symptoms
Acute Stage
- host experiences maximum impact from infectious process
- rapid proliferation and dissemination of pathogen
Convalescent Period
- containment of infection
- tissue repair
Resolution Stage
- resolution of symptoms
- elimination of pathogen
4 Factors of Virulence
- toxins
- adhesion factors
- evasive factors
- invasive factors
Common S/Sx
- fever, chills, malaise (early)
- enlarged and painful lymph nodes
- rash, skin lesion
- joint effusion
- diarrhea
- frequency, urgency
- cough, sore throat
- nausea, vomiting
- headache, stiff neck
- myalgia
- convulsions
- CONFUSION
- TACHYCARDIA
- HYPOTENSION
Lymph Nodes in Cancer
-large and painless
Confusion in elderly=
- very common 1st sign of infectious disease
- ex. from urinary tract infection
- (also tachycardia and hypotension)
Nosocomial Infection
-infections acquired during hospitalization
Eliminate Transmission of Pathogens
- hand washing
- antibiotics to prevent surgical site infections
- maximum barrier protections during central lines
- ensure pt with certain infections placed in isolation
Infectious Patients
- risk of transmitting infections FROM them to others
- protect self and other pts
Immunosuppressed Patients
- risk of transmitting infections from us or pts TO them
- protect pt
Chain of Infection Transmission
- Causative Agents, bacteria, pathogen, or virus
- Survival of pathogen in reservoir in human, animal, inanimate objects
- Portal of exit (how to leave reservoir)
- Transmission (airborne, contact, droplet, vehicle modes)
- Portal of Entry
- Transmission to susceptible host
Fomite
-contaminated inanimate object
Substance
- vehicle for transmission
- ex. feces, blood, urine
Portal of Exit
- pathogen’s method of leaving reservoir
- (secretions, excretions, blood, emesis)
Transmission Types
- airborne
- contact
- droplet
- vector
- vehicle modes
Vector
-anything that allows the transport and/or transmission of pathogen
Portal of Entry
- how pathogen gets in
- ex. through non-intact skin, blood, mucous membrane, inhalation, ingestion, percutaneous injection
Methods of entry
- penetration
- direct contact
- ingestion
- inhalation
Penetration
- disruption in integrity of body’s surface
- eg. abrasions, burns, lesions, bites
Direct Contact
- transmission directly from infected tissue or secretions to exposed, intact mucous membranes
- eg. sexual transmission via secretions
E. Coli
- from stool of infected persons
- spread by drinking or contact with sewage contaminated water, or contaminated food
Universal Precautions
-ALL PATIENTS, regardless of infectious status
List of Universal Precautions
- wash/sanitize hands before and after pt contact
- clean treatment area
- cover any open lesions on self
- use PPE as needed
- use medical aseptic technique (as needed)
- place biohazard materials in appropriate receptacle
PPE
-personal protective equipment
Transmission-Based Precautions for Preventing Infection
(pts with known or presumed infectious agent)
- hand wash/sanitize
- gloves
- mask
- gown
- pt care equipment
Diagnostic Measures
- Culture
- Serology
- CSF analysis
- Urinalysis
- body temperature
- plain films
- CT
Treatment goal
-rid body of pathogen and restore normal physiologic function to damaged tissue
Most infectious diseases are:
- self-limiting
- little to no medical therapy required
Treatment Choices
- antimicrobial agents
- immunologic agents (stim host immune system)
- surgical removal
Antimicrobial Drugs
- chemotherapeutic
- Bacteriocidal
- Bacteriostatic
- Antimicrobial Spectrum of Activity
Chemotheraputic Drugs
-selective toxicity to invading organisms with little effect on host
2 forms of bacteria
- rigid cell wall (gram-positive)
- alcohol-/acetone-labile cell membrane (gram-negative)
- type of cell wall determines best antibacterial agent
Gram Positive
-rigid cell wall
Gram Negative
-Alcohol- or acetone-labile cell membrane
Bacteriocidal
-at sufficient levels in host, will kill invading organisms
Bacteriostatic
- inhibit bacterial growth without killing organisms
- high failure rate in CNS, heart and other reservoirs in body
Antimicrobial Spectrum of Activity
- number/types of bacteria the drug is effective in treating
- broad vs narrow spectrum
Broad Spectrum Agent
effective against many different types of bacteria
Narrow Spectrum Agent
-effective against only a few or one strain of bacteria
Examples of Infectious Diseases in PT
- pneumonia
- tuberculosis
- hepatitis
- AIDS
- Leprosy (hansen’s)
- meningitis
- chicken pox
Suppurative
-pus forming
Antibiotic-Associated Colitis
long courses of antibiotic meds can decrease colonies of normal GI bacteria leading to colonization by spore-forming bacterium Clostridium Difficile
-voluminous diarrhea–>dehydration
Respiratory syncytial virus
- infants, young children, older adulta and immunocompromised
- transmit through droplets, eyes/nose
Infections with prosthetics and Implants
- prosthetic joint sepsis is characterized by INCREASING joint pain
- darkened areas on bone scan
Someone with droplet precautions also have
-contact precautions
b/c droplets contain infection and land on stuff
Innate resistance
-no transport mechanism to move drug across bacterial cell wall
Acquired resistance
- spontaneous genetic mutation
- communication with other bacteria through plasmids
Plasmids
- extrachromosomal genetic material in cytoplasm
- R plasmid=material for drug resistance