Infectious Diseases Flashcards
infectious Disease
those that rapidly spread between hosts and are caused by organisms called pathogens
virus
- contains a hard protein shell, DNA or RNA and a protective outer covering (they inject the host and hijack cells)
- the simplest form of pathogen
- attack specific things
how do bacteria spread
- infect hosts by spreading indiscriminately
- bacteria are sometimes not what is dangerous, it is the toxin the bacteria creates
Direct vs Indirect
- droplet/ fluids/ airborne
- Physical contact: Shaking hands/Touching surface that is infected (indirect)
- Bodily fluids: Blood/ Saliva
Routes of Entry
- gross: airways, eyes, skin, urinary tract etc.
- microscopic: cell membrane component (transporters or proteins to allow entry into the cell)
- Target tissue can be specific for pathogenic oragnism
Zoonotic Disease
transfer between animals and humans
vector borne
- animals
- droplets of fluids
nosocomial
- hospital acquired disease
- ex. a common one is pneumonia, people are bed ridden and they are more susceptible
- ex. Urinary tract infections because of catheters
- ex. IV line is a classic one because it is a direct line to blood
latrogenic
transmission by medical treatment
epidemiology
the branch of medicine which deals with the incidence,
distribution, and possible control of diseases and other factors relating to health
incidence
number of new cases
prevalence
number of sick (infected)
endemic
disease prevalence in area
epidemic
rise in disease incidence in
a specific area (higher frequency then expected)
Pandemic
wide geographical spread of disease affecting large
population
Acute
- something that is happening right now but will be over in a couple of weeks
ex. cold/ influenza
chronic
- Something with you for a long time or for the rest of your live
ex. HIV
Virulent
level of pathogenicity that an organism has
prions
proteins that lead to cleavage cascades that lead to neurodegenerative lesions in CNS (sometimes not considered one but it is also sometimes considered)
ex. mad cow disease
infectious agents (4+1)
- prions
- virus
- bacteria
- fungi
- parasites
virus
-These are very small things
-Classification of viruses:
Based on if DNA/RNA is double or single stranded
-These need a host to reproduce, they take over the host machinery
-They need a mode of entry
-Lytic/Lysogenic life phases
-Treatment:
• Antiviral drugs
Lysogenic
virus integrates DNA into the host cells
-because of a stimulus, expression begins and can cause more viruses to be produced.
lytic
uncontrolled production of viruses that leads to cell membrane breaking up
Bacteria
- Prokaryotes (no nucleus)
- Main Types:
- Gram pos (ex. Staphylococcus sp.)
- Cell walls have huge peptidoglycans - Gram neg (ex. E.coli)
- Others
- Spirochetes -borrelia burgdorferi Lyme disease
- Mycoplasma tuberculosis
- Gram pos (ex. Staphylococcus sp.)
- Some species produce toxins and create spores
- Spores allow for them to wait for environment to be habitable and then can re rise again - Treatment:
- antibiotics
Fungi
- Eukaryotic (have a nucleus)
- These are more related to humans because of this
- Yeast/molds main human antagonists
- Rare infections indicative of immunosuppression
- Ex. HIV going to AIDS - Treatment:
- antifungal
Parasites
-Protozoans: unicellular eukaryotes
-Helminths: worms
-Arthropods: ex. Insects/mites
-Antiparasitic drugs
• Depends on the organism
Why is it important to be careful around parasites and curing them?
Great care due to eukaryotic nature because they are more similar to the human cells of the person taking it so we don’t want to cause issues in those cells
Things to look for with inflammation
- pain
- redness
- warmth
- swelling
- Loss of function
what you are looking for when checking for Signs and symptoms of Infection:
- physical examination: this will often be tip to toe
- general: fever, vitals (blood pressure, pulse, oxygen saturation, respiratory rate)
- focused: other organ systems, pus/discharge, malodorous material, lesions, pain tenderness, lymph nodes/swollen, signs of inflammation
what is a red flag for meningitis
neck rigidity or light sensitivity
why do you want a working diagnosis?
this is because some patients can be very complicated, for example the eldery
How do we measure the degree of infections?
ABCDE
- airway
- breathing
- circulation
- disability
- exposure
workup for infection:
- degree of infection (ABCDE)
- arterial blood gas(Can get a lot of interesting things and allows for a lot of information on patient)
- blood work (check for CRPs, WBC etc)
- visual aids (MRI, CT, ultrasound)
what do you need before giving antibiotics
Blood work because can look at what is going on and check for CRPs, WBC, thrombocytes
C reactive Proteins
- this rises when you have an infection
- these are produced by the liver
Principles of management/treatment of infectious disease
- degree of treatment: (conservative vs aggressive)
- timeframe: Short term vs Long term
- drugs: antibiotics, pain relief, organ specific treatment
treatment for infectious diseases
- Antibiotics - remember samples for lab work up!
- Hydration - IV fluids (hypovolemic patient)
- Vaccines
- IVIG (Intravenous immunoglobulin)
- Symptomatic/infectious agent treatment
Fever
- 38°C measured rectally (37,5 – 38,0°C subfebrile)
- Should not exceed 41,1 °C in infections
- > 42 °C is life threatening due to organ damage and dysfunction of e.g. proteins
Why does a fever happen?
- Maybe to kill the infection so its not in its natural habitat
- Could also be seen as an activator that turns things on
- Evolutionally it shows body to be on alert
Sepsis
- Life threatening condition characterized by organ dysfunction due to dysregulated host response to infections
- Can lead to septic shock (low blood pressure due to extravasation of liquids)
SIRS criteria
(systemic inflammatory response syndrome)
Assessment of possible severe systemic infection
-you need 2 of the following:
• >38C,<36C
• Pulse > 90
• RF (resp. freq.) > 20
• Leukocytes/WBC > 12E9/L, <4E9/L
SOFA
(Sepsis-related/sequential organ failure assessment)
• Assessment of organ (dys)function (CNS, lungs, circulation, liver, kidneys, coagulation)
Pneumonia
Infection involving alveola (distal part) of the lung
• Most common in children + elderly
• Highest freq. during Winter
• Incidents: ca. 5 per 1000 capita per year
what causes Pneumonia
- Bacteria, virus, funghi (immunodeficient pt.)
* Community acquired, hospital acquired (e.g. ventilation), aspiration, immunocompromised
predisposing factors for Pneumonia
- Smoking
- Old age
- Cough dysfunction
- Neurological dysfunction
- Alcohol dependence
- Heart disease
- COPD (chronic obstructive pulmonary disease/disorder)
- Cystic fibrosis
CURB-65
this is apredicting if death is going to happen for a patient with ammonia
differential diagnosis for pneumonia
COPD, asthma, bronkitis
typical presentation of pneumonia
-cough, exasperate, fever, pain, dyspnea
workup for pneumonia
- blood work
- chest x ray
- check microbiology for a culture of LUT
- check antibodies
treatment for pneumonia
- antibiotics
- fluids and oxygen
- symptomatic treatment (pain medications, enhancers of respiratory functions)
