Chem Path Flashcards

1
Q

Demeclocycline

A

SIADH. Reduces responsiveness of collecting tubules to ADH

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2
Q

Tolvaptan

A

SIADH. V2r antagonist

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3
Q

DI treatment

A

Thiazide diuretic

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4
Q

Simple heam pathway

A

ALA –> (PBG synthase) PBG –> (HMB synthase) –> porphyrinogen

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5
Q

Acute intermittent porphyria enyzme deficiency and manifestations

A

HMB
Neuro visceral only.
NO cutaneous because absence of porphyrinogens
ALA + PBG in urine = initially coloureless (unlike porphyrinogens) but then oxidise to ‘port wine urine’

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6
Q

Acute intermittent poprphyria precipitating factors

A

ALA synthase inducer = steroids, ethanol, barbiturates
Stress = infection, surgery
Reduced caloric intake
Premenstrual

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7
Q

Hereditary coproporphyria and Variegate porphyria are…?

A

Acute porphyrias with skin lesions

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8
Q

Congenital erythopoietic porphyria
Erythropoietic protoporhyria
Porphyria cutanea tarda
are…?

A

Non-acute porphyrias
Skin lesions ONLY
Raised COLOURED (port wine) porphyrins in faeces or urine

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9
Q

Erythropoietic protoporphyria

A

Photosensitivity, burning, itching, oedema following sun exposure.
NO BLISTERS.

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10
Q

Porphyria cutanea tarda

A

Uroporphyrinogen decarboxylase deficiency
Vesicles on sun exposed sites
Raised uroporphyrins and coproporphyrics and ferritin

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11
Q

High uptake hyperthyroidism drug treatment

A

Carbimazole
Propylthiouracil - rarely used now because of risk of aplastic anaemia

(Also symptomatic beta blockade)

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12
Q

Osteopenia caused by hypo or hyperthyroidism

A

Hyper

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13
Q

Thyroid neoplasia

Psammoma bodies

A

Papillary

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14
Q

Thyroid neoplasia

Originate in parafollicular C cells

A

Medullary
Produce calcitonin
MEN2

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15
Q

MEN1

A

Pituitary
Pancreatic (insulinoma)
Parathyroid (hyperparathyroidism)

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16
Q

MEN2

A

Parathryoid
Phaeochromocytoma
Medullary thyroid

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17
Q

MEN3

A

Phaeochromocytoma
Medullary thyroid
Mucocutaneous neuromas
(+Marfanoid)

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18
Q

Cushings disease

A

Pituitary tumour secreting ACTH

HIGH dose dexamethasone (2mg) succeeds in suppressing pituitary cause of Cushings

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19
Q

Causes of Addison’s

A

AI, TB, tumour mets, adrenal haemorrhage, amyloidosis

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20
Q

Adrenal cortex zones from outside to inside

A

Glomerulosa, Fasciculata, Reticularis

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21
Q

Alfacalcidol

A

Vitamin D analogue for those with renal failure (can’t convert vit D to active form)
Can treat hypocalcaemia due to RF

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22
Q

Hypercalcaemia, high phosphate, with suppressed PTH

Rarer causes

A
Sarcoid (+other granulomatous disorders) - expresses renal 1alpha hydroxylase 
Vitamin D excess
Thyrotoxicosis
Milk-alkali syndrome
Thiazide diuretics (mild)
Hypoadrenalism
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23
Q

Alcoholic hep AST:ALT ratio

A

2:1

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24
Q

Colestyramine

A

Prevents bile acids from being reabsorbed, thus stimulates production of more BAs which uses up more cholesterol. Therefore lowers LDLs.

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25
Q

LDLR, apoB, PCSK9 dominate mutations in…

A

Familial hypercholesteraemia
PCSK9 binds LDLR and promotes its degredation. Gain of function mutation = Increased degredation of receptor –> higher circulating LDL levels.
Novel form of LDL lowering therapy is anti-PCSK9 MAb

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26
Q

LipoproteinA is a cardiovascular disease RF that should be treated with…

A

Nicotinic acid

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27
Q

Empagliflozin - SGLT2 inhibitor

A

Stops Na and glucose reabsorption from proximal tubule - pee out glucose and decreases BP. Good for patients with HF and diabetes

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28
Q

Liraglutide - GRP1 agonist

A

Stimulates release of insulin. Reduction in primary CV outcome in T2DM patients.

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29
Q

Aggressive treatment of BP

A
Aspirin
High dose statin (atarvastatin 40-80mg) 
Optimal BP control
Thiazides
Assess for T2DM
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30
Q

Retinol

A

Vitamin A

Deficiency = colour blindness

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31
Q

Cholecalciferol

A

Vitamin D

Deficiency = osteomalacia/rickets

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32
Q

Tocopherol

A

Vitamin E

Deficiency = anaemia/neuropathy

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33
Q

Phytomenadione

A

Vitamin K
Deficiency = defective clotting
Test PTT time

34
Q

Thiamine

A

Vitamin B1
Deficiency = Beri Beri, neuropathy and Wernicke’s
Wet beri beri = fast HF, SOB and leg oedema
Dry beri beri = numbness of hands and feet, confusion, trouble moving legs, pain
Test RBC transketolase

35
Q

Riboflavin

A

Vitamin B2
Deficiency = glossitis
Test RBC glutathione reductase

36
Q

Pyridoxine

A

Vitamine B6
Deficiency = dermatitis/anaemia.
Test RBC AST activation

37
Q

Cobalamin

A

Vitamin B12

Deficiency = pernicious anaemia

38
Q

Ascorbate

A

Vitamin C

Defciency = scurvy

39
Q

Folate

A

Deficiency = megaloblastic aneamia, NT defect

40
Q

Niacin

A

Vitamin B3

Deficiency = Pellagra - dementia, dermatitis, diarrhoea

41
Q

Iodine

A

Deficiency = goitre/hypothyroid

42
Q

Copper

A

Deficiency = anaemia

43
Q

Flouride

A
Deficiency = dental caries 
Excess = flourosis, mottled enamel
44
Q

Zinc

A

Deficiency = dermatitis

45
Q

Cystic fibrosis

A

Mutation in CFTR. Failure of Cl ion movement from inside epithelial cell into lumen –> increased reabsorption of Na and water –> viscous secretions
Screening test - IMMUNE REACTIVE TRYPSIN (Trypsinogen produced by pancreas and transported to intestine, in CF mucus obstructs pancreatic ducts)

46
Q

PKU

A

Phenylalanice hydroxylase deficiency
Blue eyes, fair hair/skin
Retardation

47
Q

Medium chain AcylCoA dehydrogenase deficiency

A

Fatty acid oxidation disorder - impaired ability to break down medium chain fatty acids.
Hypoglycaemia and sudden death triggered by fasting or vomiting
LOW KETONES
Acylcarnitine levels by tandem mass spec
Treat with regular CHO

48
Q

Specificity

A

% probability that someone without the disease with correctly test negative

49
Q

Sensitivity

A

% probability that someone WITH the disease will correctly test positive

50
Q

PPV

A

Probability that someone who tests positive actually has the disease

51
Q

NPV

A

Probability that someone who tests negative doesn’t actually have the disease

52
Q

Urea cycle disorders

A

9 in total
High ammonia
Encephalopathy, developmental delay, respiratory alkalosis
Treat with low protein diet

53
Q

Organic acidurias

A

Involve the metabolism of branched chain amino acids (leucine, isoleucine, valine).
Truncal hypotonia, limb hypertonia, myoclonic jerks, UNUSUAL ODOUR
Metabolic acidosis with high anion gap (not lactate)
Neutropenia
Treat with low protein diet, acylcarnitine, haemofiltration
Invx: blood spot carnitine profile

54
Q

Maple syrup urine disease

A

Sweaty feet

55
Q

Galactosaemia

A

Conjugated hyperbilirubinaemia, hepatomegaly, sepsis, hypoglycaemia
Cataracts
Mx: Low lactose/galactose diet

56
Q

Glycogen storage disorder

A

Excessive glycogen storage, but also prevents glucose export from gluconeogenetic organs
Present at 3-6 months, hypoglycaemia with lactic acidosis
Treat with regular CHO

57
Q

Mitochondrial disorders

A

E.g. MELAS
Defective oxidative phosphorylation
Can present in ANY ORGAN at ANY TIME with ANY FORM OF INHERITANCE
Classic presentation is chronic muscle weakness with hyperlactataemia
Elevated lactate after periods of fasting (overnight)
Elevated CK
Invx: muscle biopsy/ragged red fibres

58
Q

Peroxisomal disorders

A

Cannot catabolise very long fatty acids or make bile acids

59
Q

Lysosomal disorders

A

e.g. Tay Sachs
Neuroregression
Slow progressing

60
Q

Diabetes diagnosis

A

Fasting glucose >7
Glucose tolerance test >11.1
Random glucose >11.1
HbA1c >48

61
Q

Impaired glucose tolerance

A

Oral glucose tolerance test >7.8 but <11.1

62
Q

Impaired fasting glucose

A

> 6.1 but <7

63
Q

Low glucose

A

Increase in ACTH, cortisol and GH

64
Q

Causes of increased insulin with low glucose

A
Insulinoma
Qunine (malaria treatment ) 
Pentamidin - antimicrobial for PCP, toxo, leishmania 
Sulphonylureas 
Beckwith Weidemam syndrome
65
Q

Low glucose, low insulin

A

Liver failure
Starvation
Anorexia
Adrenal failure - lack of adrenaline, NA and cortisol to raise glucose

66
Q

Paediatric renal function

A

Low GFR
Less reabsorption
Reduced concentrating ability
Persistant Na loss due to relatively ALD insensitive distal tubules

67
Q

Normal GFR

A

120ml/hr

68
Q

Measures of GFR

A

Inulin - research purposes

Creatinine - look for CHANGE OVER TIME to ESTIMATE GRF

69
Q

AKI

A

Rise in serum creatinine over 26.5 in 48 hrs, or 1x5 baseline in 48 hrs (over 3x is severe)
OR
Urine output <0.5mls/kg/hr

70
Q

Indications for dialysis

A
Pulmonary oedema
Hyperkalaemia 
Metabolic acidosis 
Uraemic encephalopathy
Drug toxicity (e.g. lithium)
71
Q

CKD stages

A
Stage 1 = GFR>90
2 = 60-89
3 = 30-59
4 = 15-29
5 = <15
72
Q

CKD common causes

A

Diabetes
Atherosclerotic renal disease
HTN

73
Q

CKD consequences

A
Acidosis
Hyperkalaemia
Anaemia (EPO)
Renal Bone disease (vitamin D) 
CVD disease: vascular calcification and subsequent atherosclerosis (biggest morality), uraemic cardiomyopathy
Uraemia and death
74
Q

Gout and purine metabolism

A

Purines –> hypo-xanthine –> oxidised by xanthine oxidase to xanthine then urate
Purine: adenosine, guanosine and inosine

75
Q

Rate limiting step of de novo purine synthesis

A

PAT enzyme
Only predominates in organs with high cell turnover, ie bone marrow, because purine synthesis is metabolically very hard work

76
Q

Main enzyme in salvage pathway

A

HPRT

Dominate pathway in purine synthesis (salvages purine from purine catabolism)

77
Q

Lesch Nyhan syndrome

A

Can’t do salvage pathway - massively removes feedback inhibition of PAT –> high urate levels
Developmental delay apparent at 6 months
Choreiform movements at 1 year
Spasticity, mental retardation
SELF MUTILATION - bites lips and digits
Hyperuricaemia - gouty arthropathy

78
Q

Secondary causes of hyperuricaemia

A

Any condition with increased cell turnover, e.g. myeloproliferative disorder, chronic haemolytic anaemia, sever psoriasis…
Decreased urate excretion - CRF

79
Q

Gout most commonly in…

A

1st metatarsal phalangeal joint

MONOSODIUM URATE CRYSTALS

80
Q

Gout managment

A

Reduce inflammation: NSAIDs, colchicine, glucocorticoids
ALLOPURINOL - inhibits xanthine oxidase, hence inhibits production of uric acid
Increase renal excretion with PROBENECID

81
Q

Gout investigations

A

Tap effusion
View sample from joint with POLARISED LIGHT MICROSCOPE THROUGH RED FILTER
Urate cyrstals are NEGATIVELY BIREFRINGENT - they appear BLUE PERPENDICULAR to red compensator filter. Also NEEDLE SHAPED.
Pyrophosphate crystals are positively birefringent in the same axis to red compensator (pseudogout)