Haematological investigations

Question 1

Key enzyme for breakdown of purine

Answer 1

xanthine oxidase

Question 2

What is Lesch-Nyhan syndrome? (gene, inheritance, presentations)

Answer 2

HPRT1 (XR)
⨉ HGPRT –> ↓ salvage pathway –> ↑ de novo genesis –> ↑ uric aicd

hyperuricaemia
self mutilation

Question 3

How does alcohol lead to hyperuricaemia? (3)

Answer 3

↑ intake
↑ purine synthesis (ethanol oxidation –> ↑ ATP)
↓ excretion (↑ NADH –> inhibit gluconeogenesis –> ↑ lactic acid –> compete with uric acid breakdown)

Question 4

How to differentiate hyperuricaemia between overproducer and under-excretor?

Answer 4

24h urine urate after >=3d of purine-free diet

Question 5

Drugs for gout (4)

Answer 5

Anti-inflammatory: colchicine
Xanthine oxidase inhibitor: allopurinol, febuxostat
Uricolytics: Rasburicase
Uricosurics: Probenecid

Question 6

CEA role, DDx and RR

Answer 6

Role: detect recurrence of CRC

DDx:
- CRC, other CA
- IBD, cirrhosis, TB
- pregnancy, smoking

RR: <3 for non-smoker, <5 for smoker

Question 7

AFP DDx and RR

Answer 7

DDx:
- HCC, hepatoblastoma, NSGCT
- hepatitis, cirrhosis
- pregnancy, newborn

RR: <10
(CA: >1000)

Question 8

HCG DDx

Answer 8

NSGCT, trophoblastic disease, pregnancy

Question 9

PSA DDx and RR

Answer 9

BIG PROSTATE
BPH, infection, genetics , CA prostate, recent ejaculation, old, stricture, TURP, activities, Test (DRE), environment

<4

Question 10

CA125 DDx (5)

Answer 10

epithelial ovarian CA, primary peritoneal CA
endometriosis, pleural effusion
menstruation

Question 11

CA 15-3: which disease?

Answer 11

CA breast

Question 12

CA 19.9: which disease?

Answer 12

CA pancreas
prognostic marker + monitoring after treatment

Question 13

Which laboratory test is best for monitoring multiple myeloma progress? why?

Answer 13

serum FLC ratio

FLC has a short half life –> quick response