Biochemistry

Question 1

What would cause an increase in urea?

Answer 1

UGIB and dehydration

Question 2

What would cause an increase in urea and creatinine?

Answer 2

AKI

Question 3

What biochemical changes are seen in reduced muscle mass?

Answer 3

low creatinine

Question 4

List causes of hyponatraemia.

Answer 4

nephrotic syndrome, cirrhosis, HF, SIADH, GI loss, diuretics

Question 5

List causes of hypernatraemia.

Answer 5

DI, primary aldosteronism, fluid loss without water replacement e.g. burns, D/V

Question 6

List causes of hypokalaemia.

Answer 6

diuretics, D/V, pyloric stenosis, Cushing’s syndrome, Conn’s syndrome

Question 7

List causes of hyperkalaemia.

Answer 7

drugs e.g. K+ sparing diuretics, ACEi, rhabdamyolysis, oliguric renal failure, Addison’s

Question 8

What causes an increase in bilirubin?

Answer 8

any acute or chronic Dx or Gilbert’s syndrome

Question 9

Describe the LFT changes in hepatocellular pattern.

Answer 9

high AST high ALT high bilirubin

Question 10

Describe the LFT changes seen in cholestasis.

Answer 10

high AlkPhos high GGT high bilirubin

Question 11

How can albumin levels be used to detect whether a disease is acute or chronic?

Answer 11

normal = acute
decreased = albumin

Question 12

Which LFT result is most closely related to alcohol excess?

Answer 12

elevated GGT (with normal AlkPhos)

Question 13

Name some bone diseases that can cause elevation of AlkPhos.

Answer 13

fractures, Paget’s disease, osteomalacia, bony metastasis

Question 14

Following LFTs, what other investigations could you carry out?

Answer 14

liver US, liver biopsy, tumour markers including AFP, autoantibodies

Question 15

Differentiate between TFTs of primary and secondary hyperthyroidism.

Answer 15

both have high T3/T4
primary = low TSH
secondary = high TSH

Question 16

Differentiate between TFTs of primary and secondary hypothyroidism.

Answer 16

both have low T3/T4
primary = high TSH
secondary = low TSH

Question 17

List some causes of hypocalcaemia.

Answer 17

vit D deficiency, osteomalacia, CKD, hypoparathyroidism, acute rhabdomyolysis

Question 18

List some causes of hypercalcaemia.

Answer 18

malignancy, sarcoidosis, thyrotoxicosis, lithium

Question 19

Rheumatoid factor and anti-CCP are elevated in which autoimmune disease?

Answer 19

rheumatoid arthritis

Question 20

Anti-Sm and anti-dsDNA antibodies are present in which autoimmune disease?

Answer 20

SLE

Question 21

Can you describe what each of the following virology results show?
HbsAg
anti-Hbs
anti-Hbc
HbeAg

Answer 21

HbsAg: acute (<6m) or chronic (>6m) infection
anti-Hbs: exposure or IMMUNISATION (-ve in chronic)
anti-Hbc: previous (or current) infection
- IgM anti-Hbc acute or <6m infection
- IgG anti-Hbc persists
HbeAg: marker of infectivity

Question 22

Which antibiotics are usually prescribed in uncomplicated lower UTI?

Answer 22

trimethoprim or nitrofurantoin 3 days oral

Question 23

Which antibiotics are usually prescribed in uncomplicated upper UTI?

Answer 23

ciprofloxacin or trimethoprim 7 days oral

Question 24

Which antibiotic is usually prescribed in urinary sepsis?

Answer 24

IV gentamicin (max 3 days)

Question 25

Which antibiotics is not resistant to C. diff?

Answer 25

oral vancomycin

Question 26

What are the three most common pathogens causing bacterial meningitis?

Answer 26

N. meningitis, strep. pneumoniae, listeria monocytogenes

Question 27

What are the NHSGGS guidelines for antibiotic prescription in bacterial meningitis?

Answer 27

IV ceftriaxone IV dexamethasone +/- IV amoxicillin if ?listeria or 60+ +/- IV benpen if ?meningococcal septicaemia

Question 28

Portal hypertension causes ascites with SAAG > 11g/L. What are the different causes of portal hypertension?

Answer 28

prehepatic: portal vein thrombosis hepatic: cirrhosis, chronic hepatitis post-hepatic: right HF

Question 29

What causes ascities with low SAAG <11g/L?

Answer 29

intraabdominal malignancy, peritonal dialysis, nephrotic syndrome, malnutrition, protein losing enteropathy

Question 30

What is spontaneous bacterial peritonitis?

Answer 30

ascitic tap neutrophils > 250 cells/ul

Question 31

Which pathogen most commonly causes SBP?

Answer 31

E. coli -> IV cefotaxime

Question 32

Describe the CSF fluid analysis results if bacteria is present in terms of appearance, glucose, protein and WCC.

Answer 32

appearance: cloudy glucose: low protein: high WCC: high neutrophil polymorphs

Question 33

Describe the CSF fluid analysis results if virus is present in terms of appearance, glucose, protein and WCC.

Answer 33

appearance: clear or cloudy glucose 60-80% plasma glucose protein: high WCC: high lymphocytes

Question 34

Differentiate between the crystals seen in gout and pseudogout.

Answer 34

gout: negatively birefringent needle crystals pseudogout: positively birefringent rhomboid crystals

Question 35

List some non-inflammatory causes of joint problems. What investigations would you want to carry out aside from joint aspirate?

Answer 35

OA, trauma bloods: WCC, CRP normal X-ray: LOSS in OA or # changes

Question 36

List some inflammatory causes of joint problems. What investigations would you want to carry out aside from joint aspirate?

Answer 36

RA, reactive arthritis, psoriatic arthritis, acute gout, pseudogout bloods: high ESR, high CRP, high urate in gout anti-CCP and RF in RA X-ray: SOLE in RA

Question 37

What changes are seen in the X-ray of a joint with psoriatic arthritis?

Answer 37

joint erosions, joint space narrowing, bony proliferation, osteolysis (pencil in cup deformity)

Question 38

What changes are seen in the X-ray of a joint with pseudogout?

Answer 38

chondrocalcinosis

Question 39

What pathogens commonly cause septic arthritis?

Answer 39

S. aureus, Strep, N. gonorrhoea in young sexually active, E. coli in elderly and IVDU

Question 40

What investigations would you want to carry out in septic arthritis aside from joint aspirate?

Answer 40

bloods: high WCC, high CRP blood and fluid cultures X-ray

Question 41

List some causes of haemarthritis and the investigations would want to carry out alongside joint aspirate.

Answer 41

trauma, tumour, bleeding disorders bloods: FBC (low Hb), coag studies X-ray: #changes

Question 42

How would you differentiate between transudate and exudate pleural effusion?

Answer 42

pleural fluid analysis protein < 30g/L = transudate protein > 30g/L = exudate

Question 43

Give some examples of causes of transudate pleural effusion.

Answer 43

congestive heart failure, liver cirrhosis, nephrotic syndrome, severe hypoalbuminaemia

Question 44

Give some examples of causes of exudate pleural effusion.

Answer 44

malignancy, infection e.g. empyema due to bacterial pneumonia, trauma, PE, pulmonary infarction

Question 45

Describe Light's criteria for the diagnosis of exudate pleural effusion.

Answer 45

- pleural fluid protein:serum protein > 0.5 - pleural fluid LDH:serum LDH > 0.6 - pleural fluid LDH > 2/3rd upper limit of normal for serum value