139 Influenza Flashcards
What is the phenotype model for frailty?
Five variables - 3 or more = frail W/L Self reported exhaustion Low energy Slow gait Weak grip strength
What is the cumulative deficit model of frailty?
92 variables of symptoms + signs + lab results.
Frailty index calculated
What is meant by the term ‘medical futility’?
Interventions that are unlikely to produce any significant benefit for the patient
What is meant by the term quantitative medical futility?
The consultant is the expert in balancing the benefits and burdens of the treatment
What is meant by the term qualitative medical futility?
The pt is the ‘expert’ in balancing the benefits and burdens of the treatment
What is the ‘error’ theory of ageing?
Accumulation of errors in the process of information flow from genes to proteins resulting in faulty proteins that do not function normally resulting in impaired cell function and death.
What is the ‘free-radical’ theory of ageing?
Ageing is due to cells accumulating damage from free radicals over time
What is the immune theory of ageing?
Gradual deterioration of the immune system brought about by natural age advancement.
What is meant by ‘neuroendocrine theory of ageing’?
That ageing is caused by a progressive loss of sensitivity by the hypothalamus and related structures in the brain to negative feedback inhibition
What does stiffening of the walls of the vessels along with increased vascular resistance in the elderly lead to?
Hypertension –> left ventricular hypertrophy
What could the reduction of atrial pacemaker cells in the elderly lead to?
AF
Why do the elderly often get postural hypotension?
Their veins are stiffer and so are less able to buffer the effect of pooling of the blood in the venous system - unable to shift the fluid back to the heart.
What percentage of brain mass is lost by age 80?
30%
What is the outcome of a loss of baroreceptor sensitivity in the elderly?
They are less able to cope with abrupt changes in physiology
What is presbyacusis?
Age related hearing loss - most marked at higher frequency
What is enophthalmos?
Posterior displacement of the eyeball
What change happens to the basement membrane in the glomerulus in the elderly? Leading to…?
Becomes more permeable –> albuminuria and proteinuria is a normal finding
What type of epithelium does the uroepithelium change into during ageing?
Stratified squamous
Which factors contribute to reduced food intake and impaired mastication in the elderly? (7 listed)
Reduced saliva production Masticatory muscle loss Tooth loss and poor dental hygiene Decrease in taste buds and therefore sensation Decrease in sense of smell Atrophy of jaw Tongue enlargement
What are the clinical features of delerium? (7 listed)
Impaired consciousness Disorientation Behaviour changes Slowed thinking Altered perceptions - visual hallucinations Mood disturbances Memory impairment
What can increased serum ADH in the elderly lead to?
Chronic hyponatraemia
Why are the elderly more likely to suffer from hypothermia?
Impaired shivering
Impaired cutaneous vasoconstriction
Impaired hepatic thermogenesis
Achlorhydria occurs in the elderly. What is it and why is it a problem?
Reduction in stomach acid production
Affects the absorption of drugs
Why is there a decrease in first pass metabolism in the elderly?
Partly due to decreased hepatic blood flow
What happens to the proportion of body fat with age?
Increases
What is the risk of an increased proportion of body fat with age? (pharmacokinetics)
Increased distribution of hydrophilic drugs
Why might elderly patients appear to have a normal serum creatinine when they have renal impairment?
They have a decreased muscle mass
What does the Cockroft- Gault equation calculate?
Creatinine clearance
What is xanthopsia?
Yellow vision
What is the principal infection caused by rotavirus? Enveloped/non-enveloped?
Gastroenteritis in children
Non- enveloped
Does influenza have DNA or RNA?
-ssRNA
Does HSV have RNA/DNA?
dsDNA
What are the stages in the life cycle of a virus?
Attachment Penetration and uncoating Replication Assembly Maturation Release
How are herpes and poxvirus able to infect more than one type of host cell?
They use more than one type of cell
What are the 3 methods of viral penetration?
- Viral translocation
- Surface fusion
- Receptor-mediated endocytosis
How and why does the virus containing endosome become more acidic?
Fusion with cellular lysosomes and H+ pumped into the endosome. Conformational change –> viral coat fuses with membrane of the endosome –>viral genome into the cytoplasm of the host cell
Which enzyme is needed for viral RNA replication (usually taken into host by the virus)?
RNA polymerase
Although -ssRNA viruses can act as mRNA –> RNA polymerases =first things to be made
Where in the host cell are the viral proteins necessary for capsid assembly anchored?
In the internal membranes of the organelles of the host cells
What causes lysis of a host cell infected with a virus?
Normal functions of a cell not met
Which virus has an RNA genome but replicates in the nucleus and not the cytoplasm of its host cell?
Influenza
Why does HSV make its own enzymes for DNA replication instead of using the hosts?
Allows a faster replication when the host cells are ‘resting’
What is the MOA of immunoglobulins when treating eg rabies/VSV/HepB?
Block the attachment of viruses to host cells by attaching to the viral structures which are necessary for this.
What is the MOA of the antiviral Palivizumab? What is it used to treat?
Blocks the attachment of the virus to host cell by binding to the fusion GP on RSV (Respiratory Syncytial Virus)
What is the MOA of the antiviral amantadine? What is it used to treat?
Prophylactic Tx of influenza - interferes with viral protein M2 (proton pump) –>acidification of the endosome doesn’t happen.
Which step in the lifecycle of a virus does aciclovir interfere with?
Replication
How does the antiviral aciclovir interfere with replication of HSV/VZV virus?
Structurally similar to guanisine so incorporated into the viral DNA and prevents replication downstream
What is the antviral gancyclovir used to treat?
CMV pneumonias in immunocompromised patients
What are the SE of the antiviral gancyclovir?
neutropaenia anaemia thrombocytopaenia leucopaenia pancytopaenia diarrhoea, dyspnoea, damage to liver/kideys tremor
Which step in the lifecycle of a virus does oseltamivir inhibit?
Release
What is the MOA of the antiviral oseltamivir?
Inhibits viral neuramindase - required for budding and release of the virus
What are the side effects of the antiviral oseltamivir?
nausea, headache, cough, abdo pain
When should oseltamivir be given?
Within 48 hours of symptoms only when high rates in the community
