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Medicine Year 3 > Academic Week 5 > Flashcards

Academic Week 5 Flashcards

1
Q

How does the influenza virus target humans?

A

Influenza targets the human respiratory epithelial cells via alpha 2,3 and alpha 2,6 silica acid receptors.

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2
Q

What is the definition of screening?

A

Screening is defined as the process of identifying apparently healthy people who are at increased risk of a condition. This provides information which informs further testing and appropriate treatment.

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3
Q

What is positive predictive value?

A

Percentage chance that a negative test result is a true negative for the disease

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4
Q

What is negative predictive value?

A

Percentage chance that a positive test result is a true positive result

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5
Q

What is test sensitivity?

A

Tests ability to detect a particular substance

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6
Q

What is test specificity?

A

Test result is wholly attributable to a particular substance

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7
Q

What does elevated Ca-99 indicate?

A

Pancreatic cancer

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8
Q

How is sensitivity calculated?

A

TP/ (TP+FN)

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9
Q

How is specificity calculated?

A

TN/ (TN+FP)

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10
Q

How is Positive Predictive Value calculated?

A

TP/ (TP+FP)

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11
Q

How is Negative Predicative Value calculated?

A

TN/ (TN+FN)

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12
Q

What are the three main categories screened for in antenatal testing?

A
  1. Sickle cell disease / Thalassaemia
  2. Foetal anomaly: USS at 20 weeks and Trisomy 13,18 and 21
  3. Infectious diseases: Hep B, Syphilis, Rubella and HIV
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13
Q

When is chorionic villus sampling or amniocentesis offered?

A

To parents whose child is deemed to have a risk of Trisomy 21 higher than 1/150

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14
Q

What are the three parts of newborn screening?

A

NIPE
Newborn hearing test
Bloodspot tests

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15
Q

What diseases are tested for in the newborn bloodspot test?

A

Sickle cell disease, congenital hypothyroidism, cystic fibrosis, PKU, homocystinuria, glutaric acuduria type 1, isovaleric aciduria, medical chain acyl coA dehydrogenase deficiency and maple syrup urine disease

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16
Q

When is the heal prick tired bloodspot taken?

A

Between 5-8 days

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17
Q

Describe congenital hypothyroidism

A

Congenital Hypothyroidism is treatable and is usually sporadic. Not treating this is serious. The majority of cases are primary with elevated TSH and low free T4. Classic symptoms of hypothyroidism. First line test is TSH and then T4 and finally thyroid imaging if needed.

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18
Q

Why is cystic fibrosis tested for?

A

Cystic fibrosis occurs in 1/2500. There is evidence to say life expectancy is improved with early detection. It is tested for with immunoreactive trypsinogen. If positive result then genetic testing for the four most common cystic fibrosis gene mutations is undergone.

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19
Q

Describe PKU (Phenylketonuria)

A

Phenylketonuria (PKU) is an autosomal recessive condition caused by a deficiency of the enzyme phenylalanine hydroxylase, so the phenylalanine is not metabolised to tyrosine. Symptoms can include mental retardation, seizures, limb spasticity, musty odour, microcephaly and hypopigmentation. If treated all these symptoms will be avoided. It occurs in 1/10,000. Greater than 240mmol/L of phenylalanine are investigated further after the bloodspot.

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20
Q

What is the definition of immunosuppression?

A

Immunosuppression is defined as suppression of the body’s immune system and its ability to fight infections and other diseases. This is done in patients with transplants and treatment of autoimmune disease. Immunosuppression may be intentionally caused by drugs or caused by disease such as AIDS, lymphoma and bone marrow disorders.

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21
Q

Why is immunosuppression dangerous?

A

Immunosuppresion is a problem because of the increased risk of infection, delayed wound healing, cancer risk due to poor immunological surveillance of host cells, interactions with other medications and use for unlicensed indications.

All patients should have screening before taking immunosuppression. This includes viral screen for HIV, Hep B and Hep C, quantiferon test to exclude TB, CXR and advise about specific side effects of the individual drug.

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22
Q

Give an example of a drug which causes general immunosuppression

A

Corticosteroids such as prednisolone.

These inhibit inflammatory response and cytokine expression via gene transcription

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23
Q

Give an example of a calcinuerin inhibitor and what is its mechanism of action?

A

Ciclosporin inhibits calcineurin phosphatase and T cell activation

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24
Q

Give an example of an anti-metabolite and what is its mechanism of action?

A

Azathioprine and methotrexate interfere with DNA synthesis to cause immunosuppression

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25
Q

Give an example of an mTOR inhibitor and how does it cause immunosuppression?

A

Sirolimus works by inhibiting IL-2 driven T cell proliferation

26
Q

Give an example of a purine synthesis inhibitor and how do these cause immunosuppression?

A

Mycophenolate mofetil cause immunosuppression by preventing the proliferation of B and T cells.

27
Q

How do glucocorticoids cause immunosuppression?

A

Glucocorticoids are immunosuppressive and anti-inflammatory. They reduce the proliferation of Th cells and reduce transcription of IL-2, TNF-A, IFN-G and IL-1 which are immune modulators. They also increase the synthesis and release of anti-inflammatory proteins. Examples include prednisolone, methylprednisolone, betamethasone and dexamethasone.

28
Q

What are the side effects and concerns when using glucocorticoids?

A

Glucocorticoids are generally used acutely but have many indications. They are not suitable for long term use because of side effects. Mineralocorticoid effects should be monitored. Switching steroid treatments can be difficult and equivalent doses should be checked.

C - Cataracts
U - Ulcers
S - Striae
H - Hypertension
I – Infection risk
N – Necrosis 
G – Growth Restriction
O - osteoporosis
I – Increased Intracranial Pressure
D – Diabetes Mellitus

M – Myopathy
A – Adipose tissue hypertrophy
P – Pancreatitis

If patients have had corticosteroids for more than three weeks they are at risk of adrenal suppression. They will need gradual withdrawal from treatment. Patients who require long term corticosteroids should also be prescribed a PPI (Reduce GI bleed risk) and bone protection (Calcium and Vitamin D supplementation or bisphosphonate).

29
Q

What is the mechanism of action for calcineurin inhibitors and what are their side effects and indications?

A

These include ciclosporin and Tacrolimus and are usually used for patients with organ transplants. They are pro-drugs which means they become active after binding with their immunophilin (calcineurin). Calcineurin normally receives the 2nd messenger and activates transcription of IL-2 resulting in TCR mediated T cell activation. This blocked by the non-competitive inhibition.

Ciclosporin is used orally and IV for ulcerative colitis, rheumatoid arthritis, atopic dermatitis, psoriasis, organ transplantation, bone marrow transplantation and nephrotic syndrome.

Side effects include nephrotoxicity and hypertension, and so blood pressure and renal function must be checked twice before initiation.

Tacrolimus is also available IV, Oral and topically for eczema and psoriasis. This has also be associated with cardiomyopathy but generally similar to ciclosporin.

30
Q

What is the mechanism of action for mTOR inhibitors and what are their side effects and indications?

A

(Mammalian target of Rapamycin): mTOR acts as a cell cycle checkpoint and regulates progress through G1 to S phase following chanced in local cytokine concentration. Sirolimus is an mTOR inhibitor which decouples the relationship between the cell cycle and cytokine concentrations. This prevents lymphocyte proliferation.

Sirolimus is only licensed for prophylaxis of kidney allograft rejection. It is initially used in conjunction with ciclosporin and corticosteroids after a transplant for three months, at this point ciclosporin is withdrawn.

31
Q

What is the mechanism of action for Purine Synthesis Inhibitors and what are their side effects and indications?

A

MMF (Mycophenolate mofetil) is a drug that is metabolised in the liver to mycophenolic acid. This inhibits inosine monophosphate dehydrogenase which normally controls the pathway of purine synthesis used by proliferating lymphocytes.

MMF is licensed for use in transplantation and use of licence in psoriasis/eczema. It can be given orally or IV and side effects include genotoxicity and bone marrow suppression.

32
Q

What is the mechanism of action for Anti-metabolites and what are their side effects and indications?

A

Anti-metabolites including azathioprine and methotrexate. These are produgs which are activated in the liver. They work by inhibiting purine synthesis causing a reduction in the DNA/RNA produced by proliferating lymphocytes. Azathioprine and allopurinol are both metabolised via the Xanthine oxidase pathway. They should not be taken together as allopurinol will reduce the effect of azathioprine.

Another pathway which metabolises azathioprine is TPMT (Thiopurine methyltransferase). Patients should have their TPMT tested before initiation of treatment. Low TPMT may increase the risk of excessive myelosuppression and severe haematopoietic toxicity. TPMT deficiency is autosomal recessive affected 1/300. A patient with high TPMT activity may be able to take allopurinol as well.

Azathioprine is available orally or IV and is licensed for Crohn’s disease, Ulcerative colitis, rheumatoid arthritis, SLE, polymyositis, suppression of transplant rejection, severe refractory eczema and myasthenia gravis.

33
Q

Describe the indications and monitoring of methotrexate

A

Methotrexate was originally developed for cancer chemotherapy and is a folate antagonist. Folates are essential for synthesis of purine nucleotides and thymidylate which are essential for DNA synthesis and cell division.

Methotrexate is used for Crohn’s disease, Rheumatoid arthritis, psoriasis and certain cancers. It has weekly doses and side effects include nausea and vomiting with major concern about potential for hepatic toxicity so monitor LFTs and not given to patients with fatty liver or alcohol abuse. It can also cause bone marrow suppression. It is prescribed with folic acid to reduce GI side effects and contraception should be provided during and 6 months after treatment because it is not suitable for breast feeding and teratogenic.

34
Q

What are the two neonatal male genitalia surgical emergencies?

A

A hernia which cannot be reduced and is tender is a surgical emergency. A painful testicle in the absence of a blue dot sign in a child is a surgical emergency.

35
Q

Describe the pathophysiology of malrotation in children?

A

Babies with green vomiting are deemed to have malrotation until proven otherwise. The DJ flexure doesn’t extend to the LUQ which shortens the mesentery and leads to twisting. This twisting causes occlusion of the SMA which will cause lifelong nutritional damage. This is operated on with the Ladd’s procedure.

36
Q

What is the difference between the intrinsic and extrinsic clotting pathway?

A

The intrinsic pathway is achieved by platelets and collagen whereas the extrinsic pathway is activated by tissue factors released after damage to the endothelium.

37
Q

How does heparin cause anticoagulation?

A

Antithrombin is a natural anticoagulant which inactivates thrombin (IIa), factors Xa, XIA and IXA. Heparins bind to antithrombin and cause conformational change to enhance the rapid clearance of IIa and Xa. The effect of heparin is dependent on size of heparin molecule’s structure. Hence low molecular weight extra…

Unfractionated Heparin is larger, allows enhanced clearance of thrombin and Xa and is given intravenously. Low molecular weight heparins are smaller and are given subcutaneously in dalteparin/ enoxaparin or tinzaparin. They cause enhanced clearance of Xa but not thrombin. Fondaparinux is the smallest heparin which causes enhanced clearance of Xa only.

38
Q

How do DOACs work?

A

Direct oral anticoagulants are direct Xa inhibitors binding to factor Xa and prevent thrombin production such as apixaban, edoxaban and rivaroxaban or they are direct thrombin inhibitors which bind to the active site of thrombin and prevent fibrinogen crosslinking into a fibrin clot. Examples of anti-thrombin DOACs include Dabigatran and Argatroban.

39
Q

How does warfarin cause anticoagulation?

A

Warfarin is an anticoagulant which works as a Vitamin K antagonist. It is specifically a vitamin K reductase inhibitor. Vitamin K is involved in the synthesis of clotting factors IIa, VIIa, IXa and Xa. Warfarin binds to Vitamin K reductase in the liver and prevents the activation of factors II, VII, IX and X.

40
Q

Why is INR only a measure of the effect of warfarin?

A

It is important to remember that INR and prothrombin time is far removed from normal physiology and does not account for C or S protein. Therefore, it should only be used to determine the effects of Warfarin. Normal INR is 1.0, therapeutic is 2.0-3.0 but higher targets are used for those who have continued to clot and those with metallic heart valves.

Anti Xa assay allows for measurement of unfractionated and LMW heparin activity. Can also be used to derive drug levels for Anti Xa DOACs. Targets are drug, dose and indication dependent.

41
Q

When should hypertension be treated with anti-hypertensives?

A

Stage 2 hypertension is a systolic pressure of 140 mm Hg or higher or a diastolic pressure of 90 mm Hg or higher.

This should also be commenced in patients over 80 with type 1 hypertension and diabetes, renal disease, cardiovascular disease or other end organ damage.

42
Q

How should an adult with type 2 diabetes and hypertension be treated with antihypertensives?

A
  1. ACE inhibitor or angiotensin II receptor blocker
  2. Calcium channel blocker or thiazide like diuretic
  3. Angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker + calcium-channel blocker + thiazide-like diuretic
  4. Resistant hypertension, consider referral and spironolactone
43
Q

How should someone with hypertension who is under 55 and not black African or afro-carribean be treated with antihypertensives?

A
  1. ACE inhibitor or angiotensin II receptor blocker
  2. Calcium channel blocker or thiazide like diuretic
  3. Angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker + calcium-channel blocker + thiazide-like diuretic
  4. Resistant hypertension, consider referral and spironolactone
44
Q

How should someone with hypertension and from a black African or afro-carribean heritage be treated with antihypertensives?

A
  1. Calcium channel blocker
  2. Angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker or thiazide-like diuretic
  3. Angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker + calcium-channel blocker + thiazide-like diuretic
  4. Resistant hypertension, consider referral and spironolactone
45
Q

How should someone with hypertension aged over 55 be treated with antihypertensives?

A
  1. Calcium channel blocker
  2. Angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker or thiazide-like diuretic
  3. Angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker + calcium-channel blocker + thiazide-like diuretic
  4. Resistant hypertension, consider referral and spironolactone
46
Q

What is the difference between the appearance of the discharge in bacterial vaginosis and thrush?

A

Smells like fish is bacterial vaginosis and thrush is like cottage cheese.

47
Q

How should bacterial vaginosis and trichomonas be distinguished between?

A

The symptoms of bacterial vaginosis are:

A thin white or gray vaginal discharge;

Pain, itching, or burning in the vagina;

A strong fish-like odor, especially after sex;

Burning when urinating;
Itching around the outside of the vagina.

The symptoms of trichomonas vaginalis are:
Abnormal vaginal discharge that may be thick, thin or frothy and yellow-green in colour.

Producing more discharge than normal, which may also have an unpleasant fishy smell.

Soreness, swelling and itching around the vagina – sometimes the inner thighs also become itchy.

48
Q

What are the differentials for heavy menstrual bleeding?

A

Hypothyroidism, diabetes, clotting disorders, endometriosis, fibroids, malignancy, PCOS and infection are all differentials for heavy menstrual bleeding. Always check if there is any chance they could be pregnant.

49
Q

What are the investigations of heavy menstrual bleeding?

A

Investigations of HMB are FBC (anaemia – often all that is needed for an investigation), pelvic USS if worried about a mass, TV USS is suspect adenomyosis, laparoscopy if endometriosis and referral for hysterectomy if submucosal fibroids, polyps or endometrial pathology.

50
Q

How is chronic pelvic pain defined and what are the differentials?

A

Chronic pelvic pain is defined as longer than 6 months or constant lower abdominal pain not occurring exclusively with menstruation or intercourse and not associated with pregnancy. It is a symptom with a heavy social, psychological and economic burden. This is caused by endometriosis/adenomyosis, adhesions, IBS, interstitial cystitis, MSK, pelvic organ prolapse, nerve entrapment and psychological problems.

51
Q

What are the red flags in chronic pelvic pain?

A

Red flags for chronic pelvic pain include bleeding from the rectum, new bowel symptoms over 50, new pain after the menopause, pelvic mass, suicidal ideation, excessive weight loss, irregular vaginal bleeding over 40 and post coital bleeding.

52
Q

What are the signs and symptoms of pelvic inflammatory disease?

A

The symptoms of PID include lower abdominal pain typically bilateral. There will be deep dysparenuria, abnormal vaginal bleeding (including post coital, intermenstrual and menorrhagia), secondary dysmennorhoea and abnormal vaginal or cervical discharge which is often purulent.

Signs of PID include lower abdominal tenderness, adnexal tenderness, cervical motion tenderness and fever greater than 38.

53
Q

How does endometriosis present?

A

Endometriosis presents with chronic pelvic pain, dysmenorrhoea, deep dysparenuria, cyclical GI symptoms, cyclical urinary symptoms and subfertility. On examination they are usually normal although they can have adnexal masses, pelvic tenderness and fixed retroverted uterus.

54
Q

What are the risk factors for ovarian cysts?

A

Ovarian cyst risk factors include early menarche, pre-menopause, PCOS, tamoxifen use and personal history or family endometriosis.

55
Q

When should ovarian cysts be investigated with Ca-125?

A

Ca-125 should be measured in women with cysts suspicious for malignancy and all postmenopausal women. Greater than 35 U/mL in post-menopausal women is a concern for ovarian cancer. In the peri-menopausal patient this serum marker yields little because elevated levels are associated with many benign conditions such as uterine fibroids, PID, endometriosis, adenomyosis, pregnancy and menstruation. Levels greater than 200 in perimenopausal women warrant a referral to a gynaecological oncologist for further evaluation.

56
Q

Give a brief overview of the menstrual cycle

A

The menstrual cycle is 21-35 days and is driven by changes in the HPO axis. The ovarian cycle has follicular and luteal phases whereas the uterine cycle has proliferative and secretory phases. Day 0 of the cycle in Menstruation as all progesterone has been lost causing positive feedback initiation of LH and FSH. This is the proliferative/Follicular phase.

The follicle ruptures on day 12 which is the beginning of the luteal and secretory phase. The follicle uses its theca and granuloma cells to produce progesterone which thickens the lining of the womb. At implantation the LH falls and hCG maintains the pregnancy.

57
Q

What is the difference between gravidity and parity?

A

Gravidity – Number of times been pregnant

Parity – number of pregnancies beyond 20 weeks

58
Q

When does labour start?

A

Labour starts when there is an onset of regular painful uterine contractions more than 1 in 10 minutes. There may be descent of the presenting part of the foetus, cervical effacement and dilatation, release of the mucus plug and rupture of membranes.

Contractions are when the oxytocin receptors receive oxytocin and an influx of calcium causes smooth muscle to contract.

59
Q

What are the stages of labour?

A
  1. From onset of labour until full dilatation. There is a latent phase (up to 3cm) and an active phase (3-10cm)
  2. From full dilatation to delivery of the foetus
  3. From birth of the foetus to delivery of the placenta.
60
Q

What is the bishop score?

A

The bishop score is a quantitative score used to assess the favourability of labour and is used to determine if induction of labour should occur.

This includes:
How dilated your cervix is.

How far down in your pelvis your baby’s head or bottom is.

The consistency of your cervix, whether it is firm or soft

Bishop score of less than 5 means induction is unlikely to help. Bishop score of 9 or above then spontaneous labour is likely to occur.

Medicine Year 3 (22 decks)

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