Biochem

Question 1

X-linked adrenoleukodystrophy

Answer 1

a peroxisomal disorder (type of LSD)

Question 2

clinical features of LSD

Answer 2

coarse facial features
hepatosplenomegaly
neurological problems (learning difficulties, seizures, hearing loss)
claw hands

Question 3

acute type of toxic IMD

Answer 3

urea cycle defect

Question 4

OTC deficiency and what builds up

Answer 4

leads to an acute buildup of ammonia and carbomyl phosphate.
The latter is converted to orotic acid –> in urine
The former causes hyperammonaemia

Question 5

Symptoms of hyperammonaemia

Answer 5

Vomiting seizures
Tachypnoea
Lethargy
Encephalopathy

Question 6

OTC inheritance

Answer 6

X-linked

Question 7

Chronic form of toxic IMD

Answer 7

Phenyloketonuria

Question 8

PKU mutation

Answer 8

AR mutation of phenylalanine hydroxylase (so it doesn’t work/ can’t bind to cofactor BH4)

Question 9

PKU buildup and symptoms

Answer 9

Buildup of phenylalanine = neurotoxic –> learning difficulties and seizures
Decreased amounts of tyrosine –> less neurotrasmitter

Question 10

PKU treatment

Answer 10

low protein diet and phenylalanine-free protein supplements

Question 11

management of acute hyperammonaemia

Answer 11

stop protein intake
high glucose infusion to stop protein catabolism
give arginine to drive urea cycle
promote ammonia removal by giving sodium benzoate (chelation) and haemofiltration

Question 12

Long term management of child with urea cycle defect

Answer 12

low protein diet
long term benzoate
arginine and citrulline supplementation
Definitive treatment = transplant

Question 13

MCAD deficiency defect

Answer 13

AR mutation of enzyme that breaks down C6-C12 fatty acid chain lengths is broken

Question 14

buildup in MCADD

Answer 14

C8 is the most common which when bound to carnitine is called octanoyl carnitine

Question 15

test to confirm MCADD

Answer 15

urine sample for octanoyl carnitine

Question 16

management of MCADD crisis

Answer 16

high dose glucose and IV carnitine

Question 17

chronic management of MCADD

Answer 17

avoid fasting (prevents you going into fat oxidation)
low fat, high carb diet
oral carnitine if deficient

Question 18

how do we check if ovulation has occurred

Answer 18

progesterone rise

Question 19

how to know if you are anovulatory

Answer 19

2 tests in consecutive months with no progesterone rise after menses

Question 20

key test in primary ovarian failure

Answer 20

FSH

Question 21

what controls prolactin secretion from pituitary

Answer 21

inhibitory control of dopamine

TRH can also stimulate it in 1’ hypothyroidism

Question 22

prevalence of PCOS amongst anovulatory women

Answer 22

90%

Question 23

LH:FSH in PCOS

Answer 23

> 2.5

Question 24

when do we test for inhibin in the lab

Answer 24

when we suspect a granulosa cell tumour of the testes (very rare)

Question 25

% of glycosuria in pregnant women

Answer 25

15% because the renal glucose threshold changes

Question 26

gold standard test for gestational diabetes

Answer 26

OGTT

Question 27

physiological changes in GH excess

Answer 27

repro - loss of gonadotrophs cardio - megaly, hypertension GI - polyps and insulin resistance renal - calculi

Question 28

mecasermin + friend?

Answer 28

IGF1 analogue for laron type dwarfism | friend is a IGFBP3 analogue too which is sometimes given

Question 29

stages of AKI

Answer 29

``` 1 = 1.5-2x 2 = 2-3x 3 = 3+x ``` increase in creatinine from baseline

Question 30

fanconi syndrome

Answer 30

``` Fanconi syndrome describes a generalised disorder of renal tubular transport in the proximal convoluted tubule resulting in: type 2 (proximal) renal tubular acidosis polyuria aminoaciduria glycosuria phosphaturia osteomalacia ``` ``` Causes cystinosis (most common cause in children) Sjogren's syndrome multiple myeloma nephrotic syndrome Wilson's disease ```

Question 31

symptoms of hypercalcaemi

Answer 31

bones, stones, groans, moans | shortened QT

Question 32

symptoms of hypocalcaemia

Answer 32

paraesthesia prolonged QT cataracts brittle hair and nails

Question 33

FHH

Answer 33

familial hypocalciuric hypercalcamia looks like primary hyperparathyroidism mutation in Ca sensing receptor gene so the set point for calcium is just too high

Question 34

acute pancreatitis and calcium

Answer 34

can cause hypocalcaemia because calcium is used in the activation of the enzymes so it gets used up in all the autodigestion that occurs

Question 35

best enzyme for re-infarction

Answer 35

CKMB

Question 36

plasma osmolarity

Answer 36

2(Na) + glucose + urea

Question 37

urine osmolarity

Answer 37

most concentrated = 1200 mmol/kg | most dilute = 50 mmol/Kg

Question 38

treatment for cranial DI

Answer 38

nasal desmopressin

Question 39

gold standard test for looking at protein in urine

Answer 39

ACR

Question 40

what are the 3 negative acute phase proteins

Answer 40

albumin transferrin apolipoproteins (hence why your cholesterol drops by 30% after an MI)