Management and Prevention of Disease Flashcards
what is primary prevention?
prevent disease or injury before it occurs.
prevent exposures to hazards and altering unhealthy behaviours
what type of prevention is legislation and enforcement to ban or control use of hazardous products (asbestos) or to mandate safe and healthy practices (seatbelts)
primary
what type of prevention is education about healthy and safe habits?
primary prevention
what type of prevention is immunisation?
primary prevention
what is secondary prevention?
aim to reduce impact of disease or injury that has already occurred by detecting and treating disease or injury ASAP.
-encourage personal strategies to prevent reinjury or recurrence and implement programs to return people to original health
what type of prevention is regular exams and screening tests such as mammogram?
secondary prevention
what type of prevention is a daily, low dose aspirin or diet and exercise programmes to prevent further heart attack?
secondary prevention
what type of prevention is suitably modified work so injured or ill workers can return safely to jobs?
secondary prevention
what is tertiary prevention?
aim to soften the impact of an ongoing illness or injury that has lasting effects.
this is done by helping people manage long-term, complex health problems and injuries to improve quality of life and life expectancy
what kind of prevention is cardiac rehabilitation programs or chronic disease management programmes for conditions such as diabetes, arthritis, depression?
tertiary prevention
what type of prevention are support programmes that allow members to share strategies for living?
tertiary prevention
what type of prevention is vocational rehabilitation programmes to retain workers for new jobs?
tertiary prevention
what is screening?
the systematic application of a test or inquiry, to identify individuals at sufficient risk of a specific disorder to warrant further investigation or direct preventive action, amongst persons who have not sought medical attention on account of symptoms of that disorder
give examples of screening?
Using ultrasound to identify a wide abdominal aorta
Measuring serum AFP, hCG, oestriol during pregnancy for Down’s (before a amniocentesis)
Heel-prick tests for congenital hypothyroidism, PKU
what type of prevention is most screening?
secondary
what are the national screening programmes?
aortic aneurysm bowel cancer breast cancer cervical cancer diabetic eye fetal anomaly infectious diseases in pregnancy newborn and infant physical examination newborn blood spot newborn hearing sickle cell and thalassaemia
what are the reasons for screening?
Opportunities for primary prevention are limited
Opportunities for treatment are limited
Screening gives potential for early and more effective treatment
what is the criteria for appraising screening programmes?
viability
effectiveness
appropriateness of screening programme
what is the criteria for the condition to have a screening programme?
An important health problem
Epidemiology & natural history of the condition … should be adequately understood … there should be a detectable risk factor … and a latent period
Cost-effective primary prevention should have been implemented
what is the criteria for the test for a screening programme?
There should be a simple, safe, precise and validated screening test.
The distribution of test values … should be known and a suitable cut-off … agreed.
The test should be acceptable
There should be an agreed policy on further management.
what is the criteria for the treatment for the condition to have a screening programme?
There should be an effective treatment … with evidence of early treatment leading to better outcomes
There should be agreed policies covering who should be offered treatment
Clinical management of the condition should be optimised prior to … a screening programme
what is the criteria for the screening programme itself?
There must be RCT evidence that the programme is effective in reducing mortality or morbidity
There should be evidence that the whole programme is acceptable to professionals and public
The benefit from the programme should outweigh the harm
The opportunity cost of the programme should be economically balanced in relation to health care spending
There must be a plan for quality assurance and adequate staffing and facilities
what is sojourn time?
This is the time between the point at which a disease case becomes detectable by screening and the point at which it would become clinically apparent in the absence of screening.
how does the sojourn time of a disease effect prognosis?
‘sojourn time’ short – rapidly progressing disease – poorer prognosis
Long ‘sojourn time’– better prognosis
what is length bias?
“length bias” is used to refer to the phenomenon whereby slower-growing, less aggressive tumors have a longer preclinical screen-detectable period and are therefore more likely to be screen-detected than faster-growing, more aggressive cancers.
what is the consequence of length bias?
Diseases with a longer sojourn time are ‘easier to catch’ in the screening net.
On average, individuals with disease detected through screening ‘automatically’ have a better prognosis than people who present with symptoms/signs.
If we simply compare individuals who choose to be screened with those who don’t we will get a distorted picture
Basing our RCT on ‘intention to screen’ we will include the full range of outcomes and be able to assess the impact of the screening.
what is lead time bias?
Lead-time bias is the appearance that early diagnosis of a disease prolongs survival with that disease.
what is the consequence of lead time bias?
Survival is inevitably longer following diagnosis through screening because of the ‘extra’ Lead Time
Because of this the appropriate measure of effectiveness is deaths prevented, not survival.
describe the ethics of screening?
Issues of benefit and harm are at the heart of screening what are the harms/benefits Screening follows a utilitarian logic Autonomy – truly informed choice? What are our objectives? birth prevalence/information Screening infants and children
describe the benefits of a good screening programme?
early detection of disease means risk of death orillness can be reduced for some people
what are the disadvantages of a good screening programme?
some people get tests, diagnosis and treatment with no benefit
some people get ill or die despite negative screening test
what are the measures of test performance?
sensitivity
specificity
negative and positive predictive values
likelihood ratios
what are the different tests used in clinical practice?
Biological measure Hb, Ca2+, ALT Images CXR, mammogram, ultrasound scans Questions CAGE questions (Craving, Anger, Guilt, Eye-opener) Examination tactile vocal fremitus, liver edges
what is a true positive?
positive test result and disease present
what is a false positive?
positive test result with no disease
what is a false negative?
negative result with disease present
what is true negative?
negative result with no disease
how is sensitivity/ true positive rate calculated?
number of true positives / all those with disease
what does a test with high sensitivity indicate?
Tests with high sensitivity correctly classify a high proportion of people who really have disease
how is specificity/true negative rate calculated?
No. True Negatives / All those without disease
what do tests with high specificity indicate?
Tests with high specificity correctly classify a high proportion of people who really don’t have disease
what is positive predictive value and how is it calculated?
No. True Positives / All those test positive
Chance of having disease if your test is positive
what is negative predictive value and how is it calculated?
No. True Negatives / All those test negative
Chance of not having disease if your test is negative
describe the D-dimer test?
Degradation product of fibrin
Indicates plasma lysis of fibrin
If you’ve got D-Dimer about suggests that clotting has occurred
what test performance measures are affected by prevelance?
predicitve values
what happens to prevalence with changing predictive values?
The negative predictive value falls
The positive predictive value rises
And vice versa
what does a test with high sensitivity indicate?
Tests with high sensitivity correctly classify a high proportion of people who really have disease
what are likelihood ratios?
Another way of summarising the performance of tests
A test with two outcomes (positive/negative) has two likelihood ratios:
-Likelihood ratio for a positive test result (LR+)
-Likelihood ratio for a negative test result (LR-)
Likelihood ratios can help you assess how the chances of disease have changed after a test
what do tests with high specificity indicate?
Tests with high specificity correctly classify a high proportion of people who really don’t have disease
what is positive predictive value and how is it calculated?
No. True Positives / All those test positive
Chance of having disease if your test is positive
what is negative predictive value and how is it calculated?
No. True Negatives / All those test negative
Chance of not having disease if your test is negative
describe the D-dimer test?
Degradation product of fibrin
Indicates plasma lysis of fibrin
If you’ve got D-Dimer about suggests that clotting has occurred
what test performance measures are affected by prevelance?
predicitve values
what happens to prevalence with changing predictive values?
The negative predictive value falls
The positive predictive value rises
And vice versa
what situations alter prevelance?
Between primary care and secondary care
Across age groups
Between countries
what are likelihood ratios?
Another way of summarising the performance of tests
A test with two outcomes (positive/negative) has two likelihood ratios:
-Likelihood ratio for a positive test result (LR+)
-Likelihood ratio for a negative test result (LR-)
Likelihood ratios can help you assess how the chances of disease have changed after a test
what does a large LR+ve indicate?
The larger the LR+ve greater chance have disease if your test is positive
what does a small LR-ve indicate?
The smaller the LR-ve less chance have disease if your test is negative
what is a patient pathway?
The pathways are the route or path a patient will take if they are referred for treatment by their GP (or other health professional). From first contact with the GP, through referral, to the completion of their treatment; including the period the patient is in a hospital or a treatment centre, right up until they leave.
The pathway gives an outline of what is likely to happen on the patient’s journey and can be used both for patient information and for planning services.
what are the factors that can cause barriers to accessing health care?
physical barriers psychological barriers financial barriers geographical barriers cultural and language barriers resource barrier
what are physical barriers to accessing health care?
These are objects that prevent an individual from getting where they must go e.g. a wheelchair user is unable to enter a building because the doorway is too narrow or there are steps so they can’t get to the entrance
what are psychological barriers to accessing health care?
This barrier affects the way an individual thinks about a service e.g. it may be they have a fear of the dentist. If an individual feels unwell but they are worried about finding out what is wrong . They may not seek help from their GP
what are the financial barriers to accessing healthcare?
This to do with how much it might cost to access a service. If the health, social care or early years service the individual is trying to access is some distance away they may not be able to afford the transport costs to get there. If a patient has to pay for medical prescriptions they may not be able to afford it so they do not get the medicine they need.
what are the geographical barriers to accessing healthcare?
Some individuals live near health, social care and early years services and others may live some distance away. For those individuals who do not live near the services they may find that the buses in the area do not run at a convenient time to get to an appointment. A patient may need to have specialist treatment which is many miles away and finds it difficult to get there. Finding it difficult to travel to the services because of distance is a geographical barrier. Some individuals may find that due to their mobility problem they cannot walk a short distance to the health, social care and early years services.
what are the cultural and language barriers to accessing healthcare?
If the information (signs, leaflets, posters) about health, social care and early years services is in English only then those with a different first language will not be able to find out about the service. If the information uses specialist language the individual may not understand it. They may become anxious or worried about the service.
what are the resource barriers to accessing healthcare?
Sometimes the health, social care and early years services an individual needs to access may not be available due staff shortages or a lack of money for the service. If there is a large demand for a service then people may have to wait until there is sufficient money to pay for all those that need the service. Also, there may be a high demand for vaccination against a disease and there is not enough vaccine available for all those that need it. So, people may have to wait until sufficient vaccine has been produced e.g. swine flu vaccine
give examples of ways to overcome barriers to healthcare?
- problem-irregular bus service, solution=voluntary organisations providing transport
- problem=unable to get to gp due to working, solution=morning or late surgeries
- problem=over reasons for not being able to attend GP, solution = mobile surgery
what are the common triggers of asthma?
tobacco exercise induced bronchoconstriction medications emotional anxiety and stress viral and bacterial infections exposure to cold, dry air or weather changes acid reflux
what agents can cause occupational asthma?
platinum, chrome, nickel, grain, bean, gum, latex, psyllium, antibiotics, cimetidine, isocyanates, anhydrides, laundry detergents, pancreatic enzymes, animal allergens
who should be considered for VTE prophylaxis?
- surgical patients (mechanical, pharmacological prophylaxis
- medical patients
- thromboprophylaxis in pregnancy
describe how VTE risk is screened for?
- assess patients admitted to hospital for mobility (all surgical and medical with reduced mobility should be considered)
- review factors on thrombosis risk sheet (any tick should prompt prophylaxis)
- review this against bleeding risk
what factors are used when assessing for VTE risk?
- cancer or cancer treatment
- > 60 years
- dehydration
- known thrombophilias
- obesity
- comorbidities
- history
- hormone replacement therapy
- oestrogen contraceptive
- varicose veins with phlebitis
- pregnancy (<6 weeks post partum)
- reduced mobility for 3 days
- hip or knee replacement
- hip fracture
- total anaesthetic +surgical time >90 mins
- surgery involving pelvis or lower limb with anaesthetic and surgery >60 min
- acute surgical admission with inflammatory or intra abdominal condition
- critical care admission
- surgery with reduction in mobility
what factors are used to assess bleeding risk when considering VTE prophylaxis?
- active bleeding
- acquired bleeding disorders
- concurrent use of anticoagulants increasing bleeding risk
- acute stroke
- thrombocytopaenia
- uncontrolled systolic hypertension
- untreated inherited bleeding disorders
- neurosurgery, spinal, eye surgery
- other procedure with high bleeding risk
- lumbar puncture/epidural/spinal anaesthesia either expected in next 12 hours or done within previous 4 hours
what methods can be used for VTE prophylaxis?
pharmacological (unfractionated heparin or LMWH)
non-pharmacological (stockings)
