Data Interpretation

Question 1

Causes of hypernatraemia

Answer 1

Dehydration
Drips (too much saline)
Drugs
Diabetes insipidus

Question 2

Causes of microcytic anaemia

Answer 2

Iron deficiency anaemia
Thalassaemia
Sideroblastic anaemia

Question 3

Causes of normocytic anaemia

Answer 3

Anaemia of chronic disease
Acute blood loss
Haemolytic anaemia
Renal failure (chronic)

Question 4

Causes of macrocytic anaemia

Answer 4

B12*/folate deficiency
(‘megaloblastic anaemia’)
Excess alcohol
Liver disease (including
nonalcoholic causes)
Hypothyroidism
Haematological diseases beginning
with ‘M’: myeloproliferative,
myelodysplastic, multiple myeloma

Question 5

Causes of neutrophilia

Answer 5

Bacterial infection
Tissue damage (inflammation/infarct/
malignancy)
Steroids

Question 6

Causes of neutropenia

Answer 6

Viral infection
Chemotherapy or radiotherapy
Clozapine (antipsychotic)
Carbimazole (antithyroid)

Question 7

Causes of lymphocytosis (high lymphocytes)

Answer 7

Viral infection
Lymphoma
Chronic lymphocytic leukaemia

Question 8

Causes of thrombocytopenia (low platelets)
Reduced production

Answer 8

Infection (usually viral)
Drugs
Myelodysplasia, myelofibrosis, myeloma

Question 9

Causes of thrombocytopenia (low platelets)
Increased destruction

Answer 9

Heparin
Hypersplenism
DIC
Idiopathic thrombocytopenic purpura
HUS/thrombotic thrombocytopenic purpura

Question 10

Causes of thrombocytosis (high platelets)
Reactive

Answer 10

Bleeding
Tissue damage (infection/inflammation/malignancy)
Post-splenectomy

Question 11

Causes of thrombocytosis (high platelets)
Primary

Answer 11

Myeloproliferative disorders

Question 12

Causes of hyponatraemia (hypovolaemic)

Answer 12

Fluid loss (especially diarrhoea/vomiting)
Addison’s disease
Diuretics (any type)

Question 13

Causes of hyponatraemia (euvolaemia)

Answer 13

SIADH
Psychogenic polydipsia
Hypothyroidism

Question 14

Causes of hyponatraemia (hypervolaemic)

Answer 14

Heart failure
Renal failure
Liver failure (causing hypoalbuminaemia)
Nutritional failure (causing hypoalbuminaemia)
Thyroid failure (hypothyroidism; can be euvolaemic too)

Question 15

Causes of hypokalaemia (DIRE)

Answer 15

Drugs (loop and thiazide diuretics)
Inadequate intake or intestinal loss (diarrhoea/vomiting)
Renal tubular acidosis
Endocrine (Cushing’s and Conn’s syndromes)

Question 16

Causes of hyperkalaemia (DREAD)

Answer 16

Drugs (potassium-sparing diuretics and
ACE-inhibitors)
Renal failure
Endocrine (Addison’s disease)
Artefact (very common, due to clotted
sample)
DKA (note that when insulin is given to treat
DKA the potassium drops requiring regular
(hourly) monitoring +/− replacement)

Question 17

Causes of raised urea

Answer 17

AKI
Upper GI bleed (make sure to check Hb)

Question 18

Biochemical disturbance in pre-renal AKI

Answer 18

Urea rise > creatinine rise

Question 19

Biochemical disturbance in intrinsic renal AKI

Answer 19

Urea rise «
creatinine rise

bladder or
hydronephrosis not
palpable

Question 20

Biochemical disturbance in post-renal AKI

Answer 20

Urea rise «
creatinine rise

bladder or hydronephrosis may be palpable depending on level of obstruction

Question 21

Causes of pre-renal AKi

Answer 21

Dehydration (sepsis, blood loss)
Renal artery stenosis

Question 22

Causes of intrinsic renal AKI

Answer 22

Ischaemia (due to prenal AKI, causing acute
tubular necrosis)
Nephrotoxic antibiotics
Tablets (ACEI, NSAIDs)
Radiological contrast
Injury (rhabdomyolysis)
Negatively birefringent crystals (gout)
Syndromes (glomerulonephridites)
Inflammation (vasculitis)
Cholesterol emboli

Question 23

Causes of raised ALP

Answer 23

ALKPHOS

Any fracture
Liver damage
Kancer
Paget’s disease of bone and Pregnancy
Hyperparathyroidism
Osteomalacia
Surgery

Question 24

How do you roughly calculate a normal PaO2 for a patient on oxygen?

Answer 24

by subtracting 10 from the FiO2 and if the PaO2
exceeds this calculated number then the patient is not hypoxic;
if the PaO2 is lower, then the patient is hypoxic.

For example,
a patient on 60% oxygen with an FiO2 of 30kPa is actually hypoxic because one would expect a PaO2 of 50kPa or above (i.e. 60 minus 10).

Question 25

Signs of digoxin toxicity (4)

Answer 25

Confusion
Nausea
Visual halos
Arrhythmias

Question 26

Signs of lithium toxicity

Early, intermediate and late

Answer 26

Early: tremor
Intermediate: tiredness
Late: arrhythmias, seizures, coma, renal failure
and diabetes insipidus

Question 27

Signs of phenytoin toxicity (5)

Answer 27

Gum hypertrophy
Ataxia
Nystagmus,
Peripheral neuropathy
Teratogenicity

Question 28

Signs of gentamicin toxicity

Answer 28

Ototoxicity
Nephrotoxicity

Question 29

Signs of vancomycin toxicity

Answer 29

Ototoxicity
Nephrotoxicity

Question 30

Action if peak (1hr post dose) gentamicin is out of range

Answer 30

Adjust dose

Question 31

Action if trough (just before next dose) gentamicin is out of range

Answer 31

Adjust dose interval

Question 32

Normal target INR for someone on warfarin

Answer 32

2.5

Question 33

Target INR for someone on warfarin with recurrent VTE or metal heart valves

Answer 33

3.5

Question 34

What to do if a patient on warfarin is bleeding (or is bleeding into a confined space e.g. brain or eye)

Answer 34

Stop warfarin
Give 5-10mg IV vitamin K
Give prothombin complex

Question 35

If INR <6 on warfarin

Answer 35

Reduce warfarin dose

Question 36

If INR 6-8 on warfarin

Answer 36

Omit warfarin for 2 days then reduce dose

Question 37

If INR >8 on warfarin

Answer 37

Omit warfarin and give 1-5mg oral vitamin K

Question 38

Minor bleeding with INR > 5 on warfarin

Answer 38

Give IV vitamin K

Question 39

Myopathy and raised CK in patients on statin therapy

Answer 39

Stop the statin
If symptoms resolve and CK returns to normal, restart statin at lower dose