infection

what is a disease?

when microorganisms produce detectable alteration in normal tissue function

what is a communicable disease?

transmitted from one individual or animal to another

• directly: body fluids

• indirectly: contact with contaminated objects, airborne particles, or vectors

what is an infectious disease?

• disease caused by pathogens

• major cause of illness and death

what is a subclinical infection?

asymptomatic but can cause damage

what is sepsis?

whole body inflammatory response

what is bacteria?

• most commonly cause infection

• exist and interact with the body in a variety of relationships that are beneficial or are not harmful

what are viruses?

• acts on the cell nucleus

• takes over genetic material within the nucleus and replicates itself » pathogenic response

what is are fungal diseases?

• caused by fungi, yeasts, molds

• usually arise if individuals have a deficiency in immune system/response

what are parasites?

• protozoa, helminths, arthropods

• arise in underserved areas related to contamination of food and water

what is colonization?

• microorganisms grow, multiply

• do not cause disease

what is the chain of infection?

1. etiological (causative) agent

2. reservoir

3. portal of exit from reservoir

4. method of transmission

   • direct

   • indirect

   • vehicle-borne

   • vector-borne

   • airborne

5. portal of entry

   • skin is barrier to infectious agents

   • break in skin can serve as portal of entry

   • microorganisms may enter body by same route they left

   • mouth, throat, nose, eyes, urethral meatus, genitalia

   • open to outside exposure

6. susceptible host

   • individual who is at risk for infection

   • infants

   • young children

   • compromised host

   • individual more at risk for acquiring infection

how does medicine relate to infection?

• antibiotic resistant strains of microorganisms

• immunosuppressive therapy = more susceptible to infection

• prosthetic devices = potential colonization sites

what are the most common modes of transmission in children?

• fecal-oral

• respiratory routes

how can pathogens evolve to facilitate transmission?

• resistance to drying, environmental temperature variations

• producing toxins or enzymes that alter or destroy the normal function of host cells

• adhesion factors

what are exotoxins?

• soluble proteins secreted by pathogenic microorganisms into surrounding tissue

• highly poisonous

• causes cell death or dysfunction

what are endotoxins?

• in cell wall of gram negative bacteria

• released when the cell wall is disrupted

• can activate many human regulatory systems when released in large quantities: fever, inflammation, potentially clotting, bleeding, hypotension

what can pathogens produce?

• enzymes

  • enhance pathogen’s spread to local tissues

• chemicals

  • block specific immune processes or deplete neurophils, macrophages

• extracellular capsules

  • discourage phagocytosis

what is a chronic disease?

balance between organism and host, neither predominating

what is a carrier state?

• host defenses eliminate infectious disease

• organism continues to multiply

what are the common types of HAI?

• UTI

• surgical site infection

• pneumonia

what is an acute infection?

• appears suddenly

• has a short time span of few days to weeks

• ex: influenza, pneumonia

what is a chronic infection?

• lasts 12 weeks or longer

• cannot be treated or have intervals where the disease is dormant

• ex: tuberculosis

what is a localized infection?

has not spreads and remains close to the site of entry

• ex: otitis media, UTI

what is a disseminated infection?

• enters at a single point and then spreads throughout the body

• often affects numerous organ systems

what is a systemic infection?

• has spread throughout the entire body

• may arise from localized point of entry or spread through the bloodstream

• affects the entire body = sepsis, cellulitis

what is endogenous infection?

caused by infectious agents that are already present in the body, but have previously been dormant

what is endemic?

• restricted or peculiar to a locality or region

• in predictable occurrences

what is epidemic?

affecting or intending to affect a disproportionately large number of individuals within population, community, or region at the same time

what is a pandemic?

occurring over a wide geographic area and affecting an exceptionally high proportion of the population

what is pathogenicity?

speaks to the ability of a pathogen to cause disease

how can you assess infection?

• subjective history

• objective assessment and physical examination findings

• diagnostic tests

what would a subjective assessment include?

• history of risk factors

  • exposure to pathogens

  • travel

  • history of prior and/or chronic infections

  • current or past treatment that would cause immunosuppression

  • chronic disease that affects the immune system response

  • close contact within large groups where transmission of a pathogen is easier

• history of symptomatology

  • symptoms of inflammation (pain, redness, swelling)

  • symptoms associated with organ affected, as well as, fatigue or malaise, that are result of generalized stress to the host

  • assessment of onset, location, duration, characteristics, whether anything aggravates or alleviates, whether symptoms radiate, treatments used related to the symptoms, and severity of symptoms

what would an objective assessment include?

• fever/calor

• swelling/edema

• redness/rubor

• drainage/exudate: color, consistency, odor

• respiratory congestion (respiratory infection)

• diarrhea or constipation (gastrointestinal involvement)

• malaise

• lymphadenopathy

• ALOC

• skin, scalp

• eye assessment

• s/s pain

what diagnostic tests would you perform?

• CBC

• WBC count

• WBC differential

• C&S

• C-reactive protein

• erythrocyte sedimentation rate

• serologic test

• radiographic tests of chest, abdomen, urinary system

• direct antigen detection methods

• antibiotic peak, trough levels

• lumbar puncture

• echocardiogram

• renal ultrasonography

• urinalysis

• stool culture

what does a CBC test determine?

• critical to evaluate response of the immune system and determine effectiveness of treatment of infection

• WBC, specifically, levels of neutrophils, band T lymphocytes, monocytes, and basophils are elevated in presence of infection

• neutrophils = bacterial infection » release of immature neutrophils in response known as shift to left

• lymphocytes = viral infection

• basophils = parasitic and protozoan infections

what do C&S tests determine?

• causative agent

• culture and sensitivity can be performed on any body fluid, tissue, or exudate

what does a serologic test determine?

detection of specific virus (antigens) antibodies

what do radiographic tests determine?

used to visualize any area of possible infection

what precautions can you take to prevent infection?

• avoid injury from sharp instruments

• take measures in cases of exposure to bloodborne pathogens

• communicate to employees about biohazards

  • federal regulations require warning labels

what are the CDC HIPAC isolation precautions?

Hospital Infection-Control Practices Advisory Committee

• standard precautions

• transmission based precautions

  • used in addition to standard

  • airborne, droplet, contact

what are aseptic precautions

• strict aseptic technique

• change IV tubing, solution containers

• check all sterile supplies for expiration, intact packaging

• prevent UTIs

• measures to prevent impaired skin integrity

what is open method in sterile gloving?

• most used in operating room

• without a sterile gown

• only allowed to touch inside the cuff with bare hand

what is the closed method in sterile gloving?

• requires sterile gown

• surgeon’s hand remain inside the cuffs of their sterile gown while putting on gloves

what is the National Institute for Occupational Safety and Health?

• investigates potentially hazardous working conditions

• publishes recommendations for preventing workplace illness, injuries

what is OSHA?

publishes, enforces regulations to protect healthcare workers from occupational injuries

what is WHO?

• world health organization

• major regulatory agency at international level

what is the CDC?

• centers for disease control and prevention

• principal public health agency concerned with disease prevention and control at the national level

what is virulence?

severity of the disease microorganisms produce and their degree of communicability

what is septicemia?

• systemic infection

• systemic inflammatory response: vasodilation, increased capillary permeability, hyper-coagulability

what is bacteremia?

when a culture of individual’s blood reveals bacteria

what is the incubation period?

• initial stage

• pathogen begins active replication, but doesn’t cause symptoms

• depending on organism and host, can last from hours to years

what is the prodromal stage?

• symptoms begin to appear

• symptoms are nonspecific

• include general malaise, fever, myalgias, headache, fatigue

what is the illness stage?

• maximal impact of infectious process

• pathogen proliferates and disseminates rapidly

• tissue damage and inflammation

what is the convalescent stage?

• infection is contained and pathogen eliminated

• affected tissues are repaired and manifestations revolve

• resolution of infection is total elimination of pathogen from the body without residual manifestations