Unit 3 Case 3: Influenza Flashcards
virus of flu
influenza
virus of common cold
rhinoviruses
parainfluenza
seasonal coronaviruses
primary infection
first time body is exposed to and infected by a pathogen
secondary infection
when a primary infection has made a person more susceptible to disease
how can someone become more susceptible to disease
changes to immune system
comprised skin
consequences of treatment
changes to immune system
diseases can lower the immune systems ability to fight off harmful pathogens
comprised skin
skin infections can compromise the skins ability to act as a barrier especially when breaks or sores, can act as entry points for new infections
consequences of treatment
common with antibiotics
can kill good bacteria aswell as harmful bacteria
examples of secondary infections
pneumonia
symptoms of flu
sudden high temperature
aching
fatigue
dry cough
sore throat
headache
difficulty sleeping
loss of appetite
emergency flu symptoms
difficulty breathing
chest pain
dizziness
seizures
worsening of existing conditions
severe muscle pain
dehydration
pale grey or blue skin
sneezing mechanism
stimulation of trigeminal sensory nerves in the nasal epithelium
triggers sneeze centre in the medulla to trigger reflex activation of nasal and lacrimal glands
causes rhinorrhoea
facial muscles cause closure of eyes and grimace
respiratory muscles cause inspiration followed by explosive expiration
coughing mechanism
aspiration of food or fluid in the airway and stimulates sensory receptors supplied by vagus nerve
cough associated with URTIs caused by hyper-reactivity of the response and cough occurs spontaneously
cough can also be initiated and inhibited by voluntary control, indicating some control of cough from cerebral cortex
fever and chills mechanism
fever caused bycytokine released from macrophages and other immune cells
cytokines may act on vagal nerve endings or enter the brain to cause resetting of temperature control centre in hypothalamus
hypothalamus causes shivering and constriction of skin blood vessels and initiates sensation of chilliness perceived at level of cerebral cortex
lifestyle treatments of flu
rest and sleep
stay hydrated
pain relievers
keep warm
prescription treatments of flu
oseltamivir, orally
zanamivir, inhaled
peramivir, intravenous
baloxivir, orally
when are anti-viral drugs prescribed to patients with influenza
if hospitalised
severe/complicated/progressed illness
higher risk for flu
antigenic drift
consists of small mutations in the genes of influenza virus that can lead to changes of surface proteins HA and NA
HA and NA are antigens recognised by immune system
what is HA
hemagglutinin
what is NA
neuraminidase
antigenic shift
abrupt major change in flu A virus
resulting in new HA/ new HA and NA proteins
why do we need annual flu vaccines
due to antigenic drift and shift
new variants means older vaccines will be less effective
6 types of vaccines
live-attenuated
inactivated
subunit, recombinant, polisaccaride and conjugate
toxoid
mRNA
viral vector
live attenuated
use weakened form of germ that causes disease
life long immunity as they create strong and long-lasting immune response
chicken pox/small pox
inactivated vaccines
used to kill the version of the germ that causes the disease
don’t provide immunity like live vaccines so require several doses over a Long period of time
flu vaccine
subunit, recombinant, polysaccharide and conjugate
target specific pieces of the germ to create an immune response
such as capsid or proteins or sugars
provides long term immunity as it used specific part s
toxoid vaccines
target specific part of the germ which makes toxin with chemicals and inactivates the toxin
toxoid= inactivated toxin
mRNA vaccines
mRNA in vaccines make proteins to trigger immune response
covid-19
viral vector
use modified version of different virus as vector to deliver instructions for making antigens
different types of flu vaccines
standard dose flu shots
cell-based flu shots
recombinant flu shot
egg-based high dose flu shot
egg-based adjuvanted flu shot
egg-based live attenuated flu nasal spray vaccine
standard dose flu shot
given using virus grown in eggs
cell-based flu shot
given as virus grown in cell culture
recombinant flu shot
made using recombinant technology
egg-based high dose flu shot
contains 4x more antigens than standard dose
egg-based adjuvanted flu shot
made using adjuvant
egg-based live attenuated flu nasal spray vaccine q
made with weakened live flu viruses
what does adjuvant do
helps create stronger immune response
mechanism of action of the flu vaccine
administration
vaccine triggers immune system to create antibodies against surface portion on specific strain of flu
surface proteins such as HA
have two structural parts, head and the stalk and different vaccines target either the head or the stalk
what is asthma
common chronic lung disease in which the bronchial tubes are inflamed
causes the airways to become sensitive to environmental triggers
symptoms of asthma
shortness of breath
chest tightness or pain
wheezing when exhaling
types of asthma
intermittent
persistent
what is an asthma attack
when symptoms get much worse
signs of an asthma attack k
worsening of symptoms
reliever inhaler isn’t working
too breathless to speak, eat or sleep
peak flow score is lower than normal
what can occur during an asthma attack
bronchospasm
inflammation
mucus production
effect of flu on asthma
when you gave flu airways are more fin lamed and mucus production is increased
less room for air to get through
harder to breathe
triggers asthma symptoms
what is type 1 hypersensitivity
exaggerated response to an antigen or allergen
most widely known type of allergic reaction and includes anaphylaxis
what is anaphylaxis
where body reacts t stimulus or allergen
leading to swelling of airways and cardiovascular and other organ system effects
when does anaphylaxis occur
when IgE recognises foreign antigen and attaches itself to it
activates chain of reactions that result in the widespread release of chemicals, including histamine
drugs used in the case
oseltamivir and paracetamol
chemistry of oseltamivir
antiviral neuraminidase inhibitor (glycoprotein on virus surface)
pro drug of active metabolite oseltamivir carboxylate
clinical oseltamivir
used tot treat and prevent infection of influenza A and B
oseltamivir brand name
tamiflu
side effects oseltamivir
D&V
nausea
dizziness
dry/itchy eyes
dry skin
dry mouth
oseltamivir mechanism of action
virus infects host cells
tries to bud off from plasma membrane to infect other cells
virus remains on host cell by sialic acid receptors on host membranes as needs neuraminidase to cleave sialic acid receptors
oseltamivir mimics sialic acid binding site so binds to neuraminidase on virus
blocks neuraminidase from cleaving sialic acid receptors
prevents virus spreading to infect other cells
so it dies
oseltamivir physiology
viral neuraminidase enzyme activity is important for viral entry into unaffected cells for release of recently formed viral particles from infected cells
and for further spread of infectious virus in the body
decreases viral shedding and infectivity
chemistry of paracetamol
analgesic drug (pain management)
antipyretic agent (reduces fever)
clinical paracetamol
acetaminophen another name
no anti-inflammatory effects
overdose= liver failure due to NAPQI accumulation causes hepatocellular necrosis
side effects paracetamol
very few
allergic reaction
low blood pressure
mechanism of action of paracetamol
categorised alongside NSAIDS as it weakly inhibits cyclooxygenase pathways
increases pain threshold by inhibiting central COX1 and 2 enzymes involved in prostaglandin synthesis
reduces prostaglandin E2 concentrations in the thermoregulatory region of hypothalamus, controlling fever
has a specificity for COX2 rather than COX1
doesn’t inhibit COX in peripheral tissues so no peripheral anti-inflammatory effects
antipyretic actions due to drugs direct action on heat-regulating centres in brain result in peripheral vasodilation, sweating,losss of body heat
NSAIDS
non-steroid anti-inflammatory drugs
COX
cyclooxygenase
what does COX1 do
isoform involved in protecting gastric mucosa and regulating blood flow and clotting
what does COX 2 do
isoform induced in inflammation
