Smaller bites

Question 1

Why are NSAIDs a poor choice in asthmatics?

Answer 1

Can cause bronchoconstriction

Question 2

Why is methotrexate and trimethoprim a poor combo?

Answer 2

Both reduce folate which can lead to BM toxicity -> pancytopenia and neutropenic sepsis.

Question 3

Why is methotrexate and NSAIDs a poor combo?

Answer 3

Both nephrotoxic.

Question 4

What should you do with a patient with active infection on methotrexate?

Answer 4

Stop one dose of methotrexate.
Since methotrexate is usually taken once weekly, missing one dose should not affect control of the RA.

Question 5

Causes of hyponatraemia

Answer 5

Hypovolaemic - fluid loss (esp. diarrhoea/vomiting), diuretics (any type), addisons.
Euvolaemic - SIADH, psychogenic polydipsia
Hypervolaemic - heart failure, renal failure, liver failure.

Causes of SIADH remembered via SIADH (Small cell lung tumours, Infection, Abscess, Drugs (carbamazepine/antipsychotics), Head injury.

Question 6

Causes of hypokalaemia (DIRE) and Hyperkalaemia (DREAD)

Answer 6

Hypo (DIRE)
- Drugs (loop and thiazide diuretics esp.)
- Inadequate intake or Intestinal loss (diarrhoea/vomiting)
- Renal tubular acidosis
- Endocrine (Cushing’s and Conn’s)

Hyper (DREAD)
- Drugs (potassium-sparing direutics and ACEi)
- Renal failure
- Endocrine (Addisons)
- Artefact (very common due to clotted sample)
- DKA (when insulin given, K+ drops)

Question 7

Name 2 drugs which can cause low neutrophils

Answer 7

Clozapine (antipsychotic)
Carbimazole (antithyroid)

Question 8

Name 2 drugs which can cause low platelets

Answer 8

Penicillamine (used in RA treatment)
Heparin (increases destruction)

Question 9

Raised urea indicates which two conditions?

Answer 9

Kidney injury
Upper GI haemorrhage (Ur is a breakdown product of amino acids from globin in Hb - same happens if you eat a big, bloody steak).

Therefore, pt with raised Ur with normal Cr in a pt not dehydrated (i.e. does not have pre-renal failure) should prompt FBC to look at Hb (low -> upper GI bleed).

Question 10

Describe LFTs in:
- Prehepatic (haemolysis)
- Intrahepatic (hepatitis, cirrhosis, drugs, AID)
- Posthepatic (stone, cholestatic drugs, extrinsic)
Liver injury

Answer 10

Pre-hepatic - just raised bilirubin.
Intra-hepatic - raised bilirubin with raised AST/ALT.
Post-hepatic - raised bilirubin with raised ALP (NB raised ALP does not necessarily indicate post-hepatic jaundice)

Question 11

Name 3 hepatotoxic drugs

Answer 11

Paracetamol OD, statins, rifampicin

Question 12

Name 5 drugs which can cause cholestasis and a post-hepatic picture of LFTs

Answer 12

Flucloxacillin
Co-amoixclav
Nitrofurantoin
Steroids
Sulphonylureas

Question 13

What is the ALKPHOS mnemonic to remembering the causes of raised ALP?

Answer 13

Any fracture
Liver damage (post-hepatic)
Kancer
Paget’s disease of bone and pregnancy
Hyperparathyroidism
Osteomalacia
Surgery

Question 14

If a patient on warfarin has the following situations, what do you do?
- INR <6 (no signs of bleeding)
- INR >6 (no signs of bleeding)
- Active signs of bleeding (any INR)

Answer 14

INR <6 - reduce dose
INR >6 - omitted for 2 days (2 doses) then restarted at a lower dose. Also check INR.

Question 15

What are the two classic SE of vancomycin?

Answer 15

Ototoxicity
Nephrotoxicity

Question 16

Which tests need to be done before starting a statin?

Answer 16

LFTs - statins should be used with caution in liver disease as metabolised by the liver, hepatic impairment risks myopathy.
CK - only if at increased risk of myopathy.