COVID-19 Flashcards
What is SARS-COV2?
Severe Acute Respiratory Syndrome from the Coronavirus 2
Is the virus that causes the COVID-19 disease
What is the ethology of COVID-19? (3)
- Started in Wuhan, China - traced back to a fish/meat market
- Believed to have come from bats - 96.2% genetic similarity to bat coronavirus
- Underwent antigenic shift from bat to human, unknown if intermediate carrier was involved
What is the name of the spike protein on coronavirus?
Glycoprotein-S
*spike proteins, membrane proteins, and envelope proteins essential for virus binding to host cell
What are the current variants of concern (VOC)?
None at present
What are the current variants under monitoring (VUM)?
Anything containing the F456L spike mutation
What are the current variants being monitored (VBM)?
Omicron
Beta
Alpha
Gamma
What is the reproductive rate (R0)?
How many individuals a virus can be passed on to from 1 infected individual
What is the series interval (Si)?
The time it takes (in days) to pass on a virus to another individual
What are the 4 modes of transmission for influenza?
- Respiratory droplet
- Fomite - depends on surface
- Fecal-oral
- Vertical transmission
How long can COVID last on surfaces (as fomites)?
Copper + latex = 8 hours
Wood + glass = 5 days
How long can COVID respiratory droplets stay in the air?
Up to 3 hours
What percent of COVID transmission occurs through vertical transmission?
~3% occurs during later stages of pregnancy and in breastfeeding
What are the 3 phases of COVIDs disease course?
Stage 1 - viral response
Stage 2 - pulmonary phase
Stage 3 - hyper inflammatory phase
Explain the viral response of COVIDs disease course.
The viral response includes the incubation and infectious periods
- person shows mild symptoms
- is contagious
Explain the pulmonary phase of COVIDs disease course.
- when the adaptive immune response occurs
- person experiences hypoxia and dyspnea
Explain the events of the hyper inflammation phase in COVIDs disease course.
DIC, cytokine storm, ARDS, multi-system organ failure
What are the target cells and target tissue of COVID?
Target cells: any cells that have an ACE2 receptor
Lungs are the main target area - alveoli have type 2 pneumocytes with ACE2 receptors
**other cells also have ACE2 receptors, which is why COVID produces a variety of symptoms
What is the co-receptor that COVID uses?
Transmembrane protease serine 2 (TMPRSS2)
List factors that increase risk of mortality with COVID infection.
CV disease, lung disease, diabetes, cancer/immunosuppressed, age > 60yr
Elevated: D-dimer, ferritin, CK-MB, troponin
labwork hint: clotting problems, heart problems
Explain the cytokine storm.
aka cytokine release syndrome – occurs when a large number of WBCs are activated via the AIR response, they release inflammatory cytokines, activates more immunity cells
– creates positive feedback loop
List the WBCs involved in the cytokine storm.
Monocytes
Lymphocytes
Macrophages
Dendritic cells
MLMs are dicks
What are the 4 effects of the cytokine storm?
- Act on vascular endothelium (VCAMS)
- Activate neutrophils
- Impaired coagulation
- Increase in chemical mediators
Explain how cytokines act on VCAMs.
Cytokines:
interleukin-1, 6, 8
tumor necrosis factor A (TNFA)
interferon gamma
Increase function of vascular cellular adhesion molecules to pull WBCs out of vasculature and into lungs
Explain the activated neutrophil step of the cytokine storm.
Increased neutrophil activity results in increased release of reactive oxygen species (ROS) and proteases = damages surrounding cells
Explain the effects of damaged alveolar cells as a result of increased neutrophil activity.
Damage to type 1 alveolar cells = impaired gas exchange
Damage to type 2 alveolar cells = decreases surfactant = increases surface tension = alveolar collapse
*further impairs gas exchange
Explain how coagulation activity is impaired due to the cytokine storm.
Increased pro-coagulant activity
Decreased anti-coagulant activity
= results in clot formation = possible pulmonary emboli
What is the result of the increased chemical mediators?
Damaged alveolar cells release chemical mediators (leukotrienes, prostaglandins, bradykinins) which activate the vagus nerve and stimulates CNS
Triggers cough reflex and bronchial smooth muscle constriction
chemical mediator hint: licensed practical bitch
What other body systems are affected by COVID?
Olfactory - loss of sense of taste + smell
Heart - damaged myocardial tissue
GI tract - N+V, diarrhea, abdominal pain
Kidneys - decreased function = decreased urine production
Liver - decreased function = metabolic disorders
What are pulmonary complications that can occur due to COVID?
- pneumonia
- pulmonary edema
- pulmonary emboli
- ARDS
What occurs with the lysis of cells with ACE2 receptors?
Increased angiotensin 2 production = affects blood pressure
Causes: pulm HTN, increased inflammation, increased vascular permeability
= results in acute lung injury
What are two methods of diagnosing COVID?
- Nasopharyngeal swab
- Serology
How does nasopharyngeal swabbing diagnose COVID?
Reverse Transcriptase Polymerase Chain Reaction Test (RT-PCR)
Tests for presence of viral RNA
**gold standard - 70% sensitivity
How does serology diagnose COVID?
Tests for presence of antibodies in blood.
- IgM present = actively infected
- IgG present = recovered from infection
** 95% sensitivity when combines with RT-PCR test
What are the treatments for mild-moderate COVID infection?
- inhaled corticosteroids
- antiretrovirals
What are the treatments for severe COVID infection?
- dexamethasone
- antiretrovirals
+/- supplemental O2
What are treatments for critically ill COVID infection?
- dexamethasone
- LMW heparin
- high-flow O2 or mechanical ventilation
+/- immunosuppressants to prevent or lessen cytokine storm effects
What is the preventative treatment for COVID?
VACCINE
