General Pathology 300 (Shock, & intro to infectious diseases) Flashcards
define shock
state of hypoperfusion to tissues (blood)
what are 3 possible mechanisms of shock
- Pump failure of heart
- Loss of circulating fluid
- Loss of peripheral vascular tone
features
collapse of circulation
disproportion of circulating blood volume & vascular space
result?
Tissue anoxia
multi-organ failure
cardiorespiratory failure
categories of shock (not including
- Cardiogenic shock = pump failure of heart
- Hypovolemic shock = not enough volume (blood)
- Hypotonic shock = not enough tone
how do categories of shock correspond to mechanisms of shock?
- # Pump failure of heartCARDIOGENIC SHOCK
- # Loss of circulating fluidHYPOVOLEMIC SHOCK
- # Loss of peripheral vascular toneHYPOTONIC SHOCK
what 3 categories of shock are sub-categories instead of main categories (in contrast to AP300 notes)
Obstructive shock
(categorized under cardiogenic shock?)
Septic shock
(under Hypotonic shock?)
Neurogenic shock
(hypotonic or cardiogenic??)
note about septic shock
“Septic shock is a mixed form of a variety of pathologies (hypovolemia, vasodilation, impaired cardiac function, and mitochondrial dysfunction)”
- Cardiogenic shock
via heart pump failure
via infarction (MI)
via destruction of large portion of myocardium
=
loss of contractile tissue
—> inability to pump
may also be via
—> myocarditis
—> valve disease
—> Arrythmias
—> conduction block (Obstructive shock?)
- Hypovolemic shock
Loss of circulatory volume
via
—> massive hemorrahge
via fluid loss
—> burns
—> vomiting
—> diarrhea
- Hypotonic shock
loss of vascular tone
blood pooling in peripheral vessels (note varicose veins?)
via
—> anaphylactic shock (allergy)
—> neurogenic
(trauma, pain, spinal cord injury)
—> bacterial infection (SEPTIC SHOCK)
anaphylaxis vs sepsis (anaphylactic shock vs septic shock)
Septic shock (from a bacterial infection).
Example: A serious infection complication called sepsis that gets so bad it leads to septic shock.
Anaphylactic shock (from an allergic reaction or asthma attack).
Example: An allergic reaction to peanuts that leads to anaphylactic shock.
Events of shock
series of events – act synergistically
cause viscious cycles
result in death if not treated
early vs late stages of shock
early stages are treatable and reversible
late stage
—> serious organ failure
—> @ this stage shock can be irreversible
(nervous tissue, myocardium = no regeneration
what can shock (late?) lead to
Acute Respiratory Distress Syndrome (ARDS)
Acute Respiratory Distress Syndrome
AKA “Shock Lung”
result of shock
lungs cannot function properly
pump failure, vasodilation —-> LOW BP
(cardiogenic/hypotonic)
LEADS TO
—> STAGNATION OF BLOOD IN PULMONARY CIRCUIT
—-> PULMONARY EDEMA
What can ARDS lead to?
COR PULMONALE
recall cor pulmonale
The definition of cor pulmonale (pulmonary heart) is when a lung issue causes your right ventricle (heart chamber) to get so big that your heart starts to fail.
It’s a type of right-sided heart failure. Normally, your right ventricle sends blood to your pulmonary artery to get oxygen from your lungs.
ARDS facts
break-down of alveolar-capillary units of lungs
loss of lung function
hypoxia/anoxia
dyspnea/tachypnea
what can anoxia lead to in tissues
anoxia of tissues can lead to release of cytokines
E.g.
—> TNF
—> IL-1
Leads to
—> increase permeability of vessels
—> vasodilation (hypotonic)
why hypoxia/anoxia lead to cytokine release (?)
(Hypoxia induced factor)
Hypoxia leads to the activation of HIF-1α, which is involved in several cellular processes (such as apoptosis, vasomotor control, energy metabolism and angiogenesis).
Additionally, hypoxia leads to the activation of HIF-2α, which is involved in the activation of pro-inflammatory cytokines.
Clinical correlations of shock (THREE STAGES)
- Early, or compensated shock
- Decompensated but reversible shock
- Irreversible shock
- Compensated (early) shock
adaptive characteristics to compensate for changes in homeostasis
E.g.
—> Tachycardia
—> Peripheral artery casoconstriction
(send blood to vital organs?)
-NOTE PALLOR (“paleness or a loss of color from your normal skin tone. Pallor affects your skin and mucous membranes”
—> reduced urine production to preserve volume of circulating blood
Compensated shock symptoms
BP is normal
no serious signs of organ ischemia
- Decompensated shock
compensatory mechanisms failing
Hypotension
—> BP & CO drop
Tachypnea
—> shortness of breath, increased respiratory rate
Decompensated shock symptoms
Oliguria (renal fluid output decreases)
Acidosis (build up of metabolic wastes, CO2)
—> renal excretory failure / retention of metabolites
—> note also possible congestion in lungs = CO2 build-up
- Irreversible shock
circulatory collapse
hypoperfusion of vital organs
loss of vital functions
great distress, unconsciousness, death
NOTE ALSO
—> DISSEMINATED INTRAVASCULAR COAGULATION
disseminated intravascular coagulation (irreversible shock)
“Disseminated intravascular coagulation, or DIC, is a complicated condition that can occur when someone has severe sepsis or septic shock.”
widespread clot formation
/
in small blood vessels (?)
via
—> hypercoagulability of blood
—> fluid loss
—> hemoconcentration
Infectious diseases
..
infection
disease caused by microorganisms (including viruses)
—> esp microorganisms that release toxins or invade body tissues
infection is
process where organism establishes parasitic relationship with host
can cause cellular damage
—> producing toxins
—> intracellular multiplication
—> competing with host metabolism
INFECTION vs COLONIZATION
colonization:
micro-organisms reside harmlessly on/in body,
&
Perform useful functions
—> gut bacteria/digestive health
—> adaptation of immune system
—> reproductive health
Microbes on/in body outnumber cells by 10-1
Colonies not harmful, but can become harmful if become infections
Colonies
do not cause detectable Sx /infection
However, they can be transmitted to others
CAN CAUSE INFECTION IF IMMUNE SYSTEM WEAKENED/COMPRIMISED — or if circumstances like going from one place to another (cut/break in skin)
—> some bacteria may thrive in some parts of body, but not in others
Normal flora
mix of organisms typically found @ a particular anatomical site
I.e.
In that part of the body, it would be typical to find a particular set of micro-organisms
what are benefits for normal flora
nutrients
stable environment
proection/transport from host
what are benefits for host
nutrition/digestion benefits
stimulation/development of immune system
protection against colonization/infection of pathogenic microbes
relatively, what is the proportion of micro-organisms that can cause infection?
only small proportion are capable of causing infection/disease
Clinical manifestations (infection)
vary based on pathogen type (etiology)
also vary based on system involved
clinical manifestations (SYSTEMIC Sx)
fever, chills, malaise, enlarged lymph nodes (lymphadenopathy)
consitutional symptoms (?)
Integumentary system Sx
pus, open wound, rash, red streaks, bleeding
CV system Sx
tachycardia,
hypotension
(RECALL cytokines —> vasodilation/hypotension E.g. TNF, IL-1)
also
increased pulse rate (?)
CNS Sx
altered consciousness, confusion, seizures, headache, memory loss
photophobia
Stiff neck (MENINGITIS)
I.e.
NUCHAL RIGIDITY
GI Sx
nausea, vomiting, diarrhea
Genitourinary Sx
dysuria, flank pain (kidneys?)
hematuria
oluguria
urgency, frequency, nocturia
URT Sx
tachypnea, dyspnea
cough, hoarseness, sore throat
nasal drainage, sputum production
decreased exercise tolerance
TYPE OF (MICRO)ORGANISMS
Viruses
BACTERIA
MYCROPLASMAS
RICKETTSIAE
CHLAMYDIAE
PROTOZOA
FUNGI
PRIONS
viruses
pathogen made of nucleic acid (DNA/RNA) inside protein shell
smallest known organism (only visibly through electron microscope)
depends on host cells for replication
how many virus types that infect humans
estimated 400 viruses that infect humans
how are viruses classified
Nucleic Material
Size
Shape
Means of transmission
BACTERIA
single-celled microorganism
without true nucleus
without membrane bound-organelles
have CELL WALLS
can grow INDEPENDENTLY without other cells
bacteria classified via
shape:
—> SPHERICAL (cocci)
—> ROD (bacilli)
—> SPIRAL (spirochetes)
response to staining:
—> gram positive
—> gram negative
—> acid fast
motility
capsulation
spore forming
MYCOPLASMAS
“mykes (fungus) and πλάσμα, plasma (formed)”
self-replicating, very small bacteria
LACK CELL WALL (cell membrane =/= cell wall)
unique/different from other bacteria in lacking cell wall
mycoplasmas usually associated with which diseases/systems
diseases of repiratory system
diseases of urinary system
E.g.
PNEUMONIA
RICKETTSIAE
“Obligate” Intracellular Bacteria
—> I.e. require host for replication (LIKE VIRUS)
“animal reservoire”
arthropod vector (insects?)
Obligate define
Capable of existing only in a particular environment or by assuming a particular role.
E.g.
An obligate aerobe, such as certain bacteria, can live only in the presence of oxygen.
An obligate parasite cannot survive independently of its host.
vector
BIOLOGY
an organism, typically a biting insect or tick, that transmits a pathogen, disease, or parasite from one animal or plant to another.
Example of conditions via RICKETTSIAE
ROCK MOUNTAIN SPOTTED FEVER
TYPHUS
CHLAMYDIAE
small “OBLIGATE” intracellular bacteria
“Obligate”
—> requires host cell for replicaiton
associated with
—> STDs
—> Respiratory infections
PROTOZOA
single-celled organisms
classification
—> INTRAINTESTINAL parasites
—> EXTRAINTESTINAL parasites
E.g. conditions (intraintestinal protozoa)
Amebiasis
Giardiasis
E.g. conditions (extraintestinal protozoa)
Malaria
Toxoplasmosis
FUNGI
unicellular / filamentous organisms
have hyphae
have CELL WALL
have NUCLEUS
Can occur as YEASTS (single-cell, oval shaped organisms)
Can occur as MOLDS (organisms with branching filaments)
Can be systemic or local
E.g.
Fungal skin infections (ringworm, athlete’s foot),
fungal mucosal infections (candida vaginitis)
hyphae
each of the branching filaments that make up the mycelium of a fungus.
mycelium
A mycelium is a network of fungal threads or hyphae. Mycelia often grow underground but can also thrive in other places such as rotting tree trunks. A single spore can develop into a mycelium.
The function of the mycelium is to provide a transportation network to pass nutrients along the fungal body.
presence of fungus or yeast in the blood
Fungemia
Fungal diseases in humans called
mycoses
“Fungal infections, or mycosis, are diseases caused by a fungus (yeast or mold).”
“most common on your skin or nails, but fungi can also cause infections in your mouth, throat, lungs, urinary tract and many other parts of your body.”
PRIONS
infectious particles
consist of proteins, WITHOUT NUCLEUS ACIDS
transmitted from animals to humans
E.g.
Creutzfeldt-Jakob disease
Bovine spongiform encephalopathy (Mad Cow disease)
Classification
endogenous (from within)
—> microorganism that was previously not pathogenic, but now pathogenic
E.g.
Yeast
exogenous (not from within)
—> from source outside body
E.g. Influenza virus
Nosocomial
—> acquired in health care setting
E.g. staphylococcus
nosokomos
from Greek nosokomos ‘person who tends the sick’
Tranmission
invading organism must be transported from the infected source to susceptible host
portals of exit from host
feces, urine, vomit, tears, semen, open lesions, blood
transmission routes
via several possible routes
contact
airborne
droplet
vehicle
vector
contact
direct or indirect
airborne
float
air currents
remain suspended
small particles
droplet
“fall out within 3 ft of source” (??)
large particles
vehicle
E.g.
food, water
vector
intermediate source
E.g.
insect (usually)
pathogen may enter new host via
ingestion
inhalation
bites
contact with mucosa
transplacentally
injections
other
skin to skin contact
contact with blood/fluids
contact with contaminated articles
variation (requirement for infection to take place)
number of organisms required to start infection
duration of exposure required to start infection (RECALL LYME)
pathogenecity:
“the property of causing disease.”
Susceptibility – depends on
vary from person to person
—>
Age?
Nutrition
hormonal balance
concurrent disease (immmune comprimised?)
drug use?
hygiene
chain of transmission
pathogen or agent: virus, mycobacteria, bacteria, fungi, prions
reservoire:
humans
portal of exit: GU, GI, oral cavity, open lesion, semen, tears, blood, feces, urine
Transmission: contact (direct/indirect), airborne, droplet, vehicle, vector
modes of entry: ingestion, inhalation, injeciton, transplacental
susceptible host
portal of exit
The Portal of Exit refers to any route that the pathogen can leave the reservoir
chain of transmission define
This describes how microorganisms are transmitted from one person or place to another.
This could be via someone’s hands, on an object, through the air or bodily fluid contact. portal of entry. This is how the infection enters another individual.
chain of transmission is
mode of transmission
portal of entry
susceptible host?
infectious agent
reservoir
portal of exit
defense
first, second, third line of defense
first = mechanical barriers
second = inflammation, nonspecific/innate immune response
third = acquired imune response
first line of defense e.g.
intact skin, mucous membranes
oil, perspiration
cilia (resp tract)
gag/cough
peristalsis (GI)
flushing of tears, saliva, mucus
normal flora
2nd/3rd line of defense
2
inflammatory process
NK cells, eosinophils, neutrophils, macrophage, basophil
3
lymphatic system
leukocytes/lymphocytes (B/T cells)
cehmical, proteins, enzymes
