Clin Med 1 Infectious Disease 2

Bacteria Pathophysiology

Invasion of tissue, Release Exotoxins and Endotoxins

Exotoxins

Poisonous substances secreted by bacteria

What do exotoxins do?

Cell lysis, degradation of extracellular matrix, cell dysfunction

Endotoxins?

Inflammatory/immune response, Cellular and tissue destruction

Viruses pathophysiology direct pathway

Produces a protein that damages the cell membrane

Virus pathophysiology indirect pathway

Produces a protein that is incorporated into the cell membrane, Immune system mounts a response to this protein

True or False: Sepsis is a syndrome associated with severe infection?

True

Is sepsis a systemic response to infection?

Yes, it enters the bloodstream

How is sepsis caused?

The release of bacterial endotoxins and/or exotoxins

Sepsis triggers the activation of what?

Inflammation cascade, coagulation cascade, complement system

Sepsis cycle

Infection, Bacteremia, Sepsis, Septic Shock, Multi-organ failure

What is the bacteremia stage?

Bacteria in the bloodstream

What is the sepsis stage?

2 or more of:

Temp>100 degrees, <96 degrees

HR>90

RR>20

WBC >12k, <4k

septic shock stage

Hypotension, Perfusion abnormalities, Altered mental status

multi-organ failure stage?

Failure of the kidneys, lungs, heart, liver, clotting, and CNS

What are the treatments for sepsis?

Treat primary infection, Fluid resuscitation, Medications to vasoconstrict, improve heart function, Treat organ failure, Immune modulators

Pathogen

The parasite or microorganism responsible for arousing a pathologic response

Infectivity

Pathogen's ability to invade and replicate in a host; how likely is the pathogen to infect someone

Pathogenicity

Ability of organism to cause disease; certain conditions or some disease can happen at any time.

Virulence

Potency of pathogen and producing severe disease; how bad it will be

Antigenicity?

The pathogen's ability to stimulate an immune response

What is are the sequences of infection?

Transmission, Contact, Airborne, Enteric, Vector-borne

contact transmission

Host is in direct/indirect contact with infection

Airborne transmission

Pathogen is inhaled in through contaminated droplets

Enteric transmission

Fecal/oral route

Vector-borne transmission

Indirect, intermediate, insects transmit the disease

Sequence of infection

Inoculation/portal of entry, Incubation, Prodromal period, Clinical disease, Convalescence, Recovery

Inoculation/portal of entry period

Pathogen fights past 1st line of defense

Incubation period

The period of time from when the pathogen enters until symptoms occur

Replication

Host may/not be contagious

Prodromal period

Mild non-specific symptoms

Clinical disease period

Body's response - immune, inflammation

true symptoms

Convalescence period

Resolution - body defeats pathogen

Recovery

No longer having the pathogen

Symptoms of infection

Fever, chills, sweating, malaise (general fatigue and feeling ill), nausea, vomiting

Symptoms in elderly for infection

Confusion, memory loss, difficulty concentrating

Signs of infection

Fever, rash, lymphadenopathy (swelling of lymph), and lymphangitis

Lymphangitis

What is the ancillary testing for infection?

Direct visualization of the organism, Culture and sensitivity, Detection of microbial antigen or antibody, Clues that infection may be present, Detection of specific microbial nucleotide sequences

Direct visualization of the organism?

Gram staining - finding certain bacteria, Used by sputum or urinalysis

What is the difference between culture and sensitivity?

Culture is different because each bacteria grow differently. Cultures are 24 hours. Sensitivity is 48 hours. Sensitivity is different by seeing how long infected tissue grows, antibiotics are treatments.

What does the detection of microbial antigen or antibody help do?

Identify viral rapid strep test

What clues that infection may be present?

X-ray and WBC in urinalysis

What is the detection of specific microbial nucleotide sequences?

Viral and bacterial infections

How do we treat infection?

Local methods: Heat, incision and drain

Antibiotics - bacterial

Antivirals - viruses

Antifungals - fungals

What are the antibiotic mechanisms?

Destroy the cell wall

Inhibit protein synthesis

Inhibit DNA synthesis

Inhibit RNA synthesis

What does inhibiting the protein synthesis do?

Bacteria can't replicate

What does inhibiting DNA and RNA synthesis do?

Prevent function and replicate

Antiviral medications do what for the body?

Inhibit viral replication

Frequent resistance

Often use multiple medications

What are the preventions for infection?

Handwashing

Disinfecting tables/equipment

Personal protective equipment (PPE)

Vaccinate healthcare workers

Follow isolation procedures

If ill, avoid treating high-risk patients