14 Non-communicable diseases Flashcards

1
Q

what is the definition of a non-communicable disease?

A

a disease which is non-infectious and non-transmissable among people

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2
Q

what are the four main types of non-communicable diseases?

A

cardiovascular

cancer

chronic respiratory diseases

diabetes

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3
Q

what is the definition of a risk factor?

A

a variable associated with an increased chance of developing a disease or infection

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4
Q

what are the three ways in which a risk factor can be expressed?

A

relative risk

fraction of incidences occurring in a group having been exposed to the risk factor

increase in incidence in the exposed group

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5
Q

how is the risk calculated?

A

number of people experiencing event / number of people exposed to risk factor

OR

A = p x (1 + r)^n

where:
A = number of global cases
p = initial number of cases
r = annual increase
n = number of years
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6
Q

what are the three main risk factors associated with developing non-communicable diseases?

A

preexisting conditions

behaviour/lifestyle choices

hereditary/genetic factors

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7
Q

give three of the Bradford-Hill criteria for establishing causal relationships

A

strength

temporality

consistency

theoretical plausibility

coherence

specificity

experimental evidence

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8
Q

what are the

  • preexisting conditions
  • behavioural/lifestyle choices
  • hereditary/genetic factors

associated with strokes?

A

conditions:

  • hypertension
  • high cholesterol

behaviour:

  • excessive salt
  • excess alcohol inactivity

hereditary
- sickle cell disease

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9
Q

what are the

  • preexisting conditions
  • behavioural/lifestyle choices
  • hereditary/genetic factors

associated with lung cancer?

A

conditions:

  • chronic lung diseases
  • radiation exposure

behaviour:

  • smoking
  • asbestos exposure

hereditary:

  • 1st degree family member with lung cancer
  • gender
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10
Q

what are the

  • preexisting conditions
  • behavioural/lifestyle choices
  • hereditary/genetic factors

associated with asthma?

A

conditions:
- another allergic condition

behaviour:

  • exposure to allergens
  • smoking

hereditary:
- blood relative with asthma

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11
Q

what are the

  • preexisting conditions
  • behavioural/lifestyle choices
  • hereditary/genetic factors

associated with type 2 diabetes?

A

conditions:

  • aged 45+
  • gestational diabetes

behaviour:

  • physical activity < 3 times a week
  • being overweight

hereditary:

  • blood relative with diabetes
  • certain ethnicities
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12
Q

what is the definition of a tumour?

A

a lump or growth of abnormal cells that divide uncontrollably

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13
Q

what is the definition of cancer?

A

a disease usually caused by a mutation that causes uncontrolled cell division and the subsequent formation of a tumour

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14
Q

what are the four types of cancer?

A

carcinomas (internal and external body surfaces)

sarcomas (supporting structures)

lymphomas (lymph nodes and immune system)

leukemias (immature blood cells)

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15
Q

what is metastasis?

A

the process in which cancer cells break from the primary tumour and spread to initiate a secondary tumour formation at a different location

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16
Q

what is the difference between a benign and malignant tumour?

A

benign:

  • slow growing
  • not normally life-threatening
  • do not normally grow back

malignant:

  • fast growing
  • metastatic
  • can be life-threatening
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17
Q

what is the function of proto-oncogenes?

A

to stimulate cell division after stimulation from a growth factor

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18
Q

how can mutated proto-oncogenes cause cancer?

A

the base sequence mutates –> oncogenes with different receptor proteins

∴ DNA replication is triggered without the extra-cellular growth factor

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19
Q

what is the function of tumour suppressor genes?

A

to code for proteins that prevent cell division

and initiate breakdown of damaged cells in apoptosis

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20
Q

how can mutated tumour suppressor genes cause cancer?

A

apoptotic stimulation is lost ∴ damaged DNA can be replicated

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21
Q

what is a mutagen?

A

a physical, biological or chemical agent that mutated the DNA of an organism and increases the frequency of mutations above the natural background level

22
Q

give an example of a

  • physical
  • biological
  • chemical

mutagen

A

physical: ionising radiation
- high energy breaks H bonds in DNA –> change in DNA base sequence
- DNA most susceptible at end of interphase and during mitosis

biological: viruses
- can interfere with p53 production –> prevention of apoptosis

chemical: benzene
- react with and alter structure of DNA
- can be counteracted with anti-oxidant

23
Q

outline the role of the Ras gene and explain [how its mutated form can cause cancer]

A

division stimulated by extra-cellular messengers

[division stimulated by Ras gene without hormone ∴ cell cycle inhibition removed]

24
Q

outline the role of the c-Myc gene and explain [how its mutated form can cause cancer]

A

regulator gene on chromosome 8 responsible for regulating 15% of gene expression

[Myc constantly expressed –> unregulated expression of genes –> cell proliferation and cancer formation]

25
Q

outline the role of p53

A

a transcription factor which plays a role in apoptosis, genomic stability and inhibition of uncontrolled cell division

temporarily stops cell cyle at G1/S checkpoint to allow reparation of damaged DNA

26
Q

outline the use of x-rays in detecting cancer

give one strength and one weakness of this method

A

high energy radiation and photographic film plate create a black and white image, depending on the absorbency of the tissues

+ quick; non-invasive
- can’t distinguish without further tests

27
Q

outline the use of mammograms in detecting cancer

give one strength and one weakness of this method

A

low energy x-rays of the breast

+ quick; non-invasive
- can’t distinguish without further tests

28
Q

outline the use of computerised axial tomography (CAT) scans in detecting cancer

give one strength and one weakness of this method

A

x-ray tube rotates around patient and sends x-rays through their body to a photographic plate which captures a black and white image

+ non-invasive; produces a 3D image
- uses x-rays; can’t distinguish without further tests

29
Q

outline the use of ultrasound in detecting cancer

give one strength and one weakness of this method

A

high frequency sound waves are picked up by a handheld transducer and converted to an image by a computer

+ non-invasive; no x-rays
- can’t distinguish without further tests

30
Q

outline the use of magnetic resonance imagery (MRI) scans in detecting cancer

give one strength and one weakness of this method

A

creates a magnetic field, which causes protons in H atoms to line up; radio waves then ‘spin’ the protons - the resulting signal is converted into a 3D image

+ non-invasive; good for soft tissues
- costly; can’t distinguish without further tests

31
Q

outline the use of positron emission tomography (PET scans) in detecting cancer

give one strength and one weakness of this method

A

a radioactive tracer (e.g. fluorodeoxyglucose) is injected and used as a marker for glucose uptake; scanner detects gamma radiation given off by the tracer to produce coloured images

+ accurate; fine detail; 3D coloured images
- can’t distinguish without further tests

32
Q

outline the use of biopsies in detecting cancer

give one strength and one weakness of this method

A

cell/tissue sample is removed from the body and analysed in a lab for definitive diagnosis

+ can distinguish
- invasive

33
Q

outline the use of blood tests in detecting cancer

give one strength and one weakness of this method

A

diagnosis given concentration of certain compounds in the blood; indication of response to treatment

+ effective diagnostic tool
- invasive

34
Q

what is screening?

A

testing people who are known to be at risk of a certain condition before symptoms develop

35
Q

what four cancers are routinely screened for in England?

A

breast

bowel

cervical

prostate

36
Q

who is offered screening?

A

healthy individuals who have an elevated risk

37
Q

why might a false negative be diagnosed?

A

cancer doesn’t show up on x-ray

cancer cannot always be detected immediately

cancer can develop rapidly between scans

38
Q

why might a false positive be diagnosed?

A

after lots of mammograms, the chances of a false positive increases

human error (corrected by follow up tests)

39
Q

what are the disadvantages of screening?

A

distress from false positives

unnecessary treatment of benign tumour

most are false negatives - targeted screening would be more cost effective

40
Q

what are the two genes most commonly associated with breast cancer?

A

BRCA1 (c.17)

BRCA2 (c.13)

41
Q

name two other genes associated with and describe their effect in causing breast cancer

A

TP53 + PTEN

produce tumour-supressor proteins ∴ mutations in these genes –> DNA damage not properly repaired

42
Q

what is the risk of developing breast cancer?

A

1 in 8 women (increases with age)

~ 1% risk for BRCA1 male carriers aged 70+

43
Q

why and how do we test for breast cancer?

A

only if strong family risk

required a living relative with breast cancer

mutation search (takes weeks/months)

i.e. predictive testing

44
Q

what condition makes bowel cancer more likely? what percentage of cases is it associated with?

A

hereditary non-polyposis colorectal cancer (HNCC)

2-5%

45
Q

what other organs can HNCC increase the chances of cancer in?

A

uterus

urinary system

gastrointestinal tract

46
Q

what are the two ways of treating breast cancer by surgery?

A

lumpectomy - removing the tumour and barrier tissue

mastectomy - removing the whole breast and lymph nodes

47
Q

how can colon cancer be treated by surgery?

A

colectomy - tumorous section removed and colon rejoined by anastomosis

48
Q

what is chemotherapy? what are some potential side effects?

A

the use of chemicals that are toxic to dividing/cancerous cells

  • loss of appetite
  • nausea
  • increased risk of infection
  • fatigue (due to low RBC count)
49
Q

what is radiotherapy?

A

ionising radiation is accurately targeted to destroy actively growing cells

50
Q

what is immunotherapy?

A

monoclonal antibodies can be tagged with an enzyme that converts an inactive form of a cytotoxic drug into an active form that targets cancerous cells

51
Q

what is hormone therapy in relation to cancer treatment?

A

oestrogen - stimulates transcription of genetic material if cells have ER+ receptors

aromatase inhibitors - can be given to post-menopausal, early-stage breast cancer sufferers

LH blockers - prevent oestrogen synthesis