General data interpretation (blood tests)

Question 1

Normal sodium range

Answer 1

135-145 mmol/L

Question 2

Causes of hypernatraemia

Answer 2

ALL BEGIN WITH d

• Dehydration
• Drips (i.e. too much IV saline)
• Drugs (e.g. effervescent tablet preparations or IV preps with high sodium content)
• Diabetes insipidus

Question 3

Causes of hyponatraemia

Answer 3

Question 4

Causes of SIADH

Answer 4

SIADH

• Small cell lung tumours
• Infection
• Abscess
• Drugs (carbamazepine, antipsychotics)
• Head injury

Question 5

Causes of microcytic anaemia (low MCV)

Answer 5

• IDA
• Thalassaemia
• Sideroblastic anaemia

Question 6

Causes of normocytic anaemia (normal MCV)

Answer 6

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

Question 7

Macrocytic anaemia (high MCV)

Answer 7

• B12/folate deficiency (megaloblastic anaemia)
• Excess alcohol
• Liver disease (including metabolic causes)
• Hypothyroidism
• Haematological disease beginning with M: myeloproliferative, myelodysplastic, multiple myeloma

Question 8

Normal range of potassium

Answer 8

3.5 - 5.0 mmol/L

Question 9

Causes of hypokalaemia

Answer 9

DIRE

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

Question 10

Causes of hyperkalaemia

Answer 10

DREAD

• Drugs (potassium sparing diuretics, ACE-inhibitors)
• Renal failure
• Endocrine (Addison’s disease)
• Artefact (very common, due to clotted sample)
• DKA (

Question 11

What does raised urea indicate

Answer 11

• Kidney injury
• Upper GI haemorrhage
  OR
• Upper GI bleed
  (pt with raised urea, normal creatinine, not dehydrated - look at hb, if this has dropped then its bleed)

Question 12

Main haematology to look at in FBC blood test

Answer 12

• Hb
• WCC
• Platelets

Question 13

Causes of high neutrophils (neutrophilia)

Answer 13

• Bacterial infection
• Tissues damage (inflammation/infarct/malignancy_
• Steroids

Question 14

Causes of low neutrophils (neutropenia)

Answer 14

• Viral infection
• Chemo or radiotherapy
• Clozapine (antipsychotic)

Patients undergoing chemotherapy or radiotherapy may become neutropenic (or even pancytopenic) in response to
infection (‘neutropenic sepsis’). This carries a much higher mortality rate so they must be given urgent IV broad-spectrum antibiotics (the choice is hospital specific).

Question 15

Cause of low platelets (thrombocytopenia)

Answer 15

Question 16

Causes of high platelets (thrombocytosis)

Answer 16

Question 17

Biochemical disturbances in the different types of AKI

Answer 17

Question 18

Causes of pre renal AKI

Answer 18

• Dehydration
• Shock (severe)
  due to sepsis, blood loss etc
• RAS
  Often triggered by drugs e.g. NSAIDs, ACEis

Question 19

Causes of intrinsic renal AKI

Answer 19

INTRINSIC

• Ischaemia (due to pre renal AKI -> acute tubular necrosis)
• Nephrotoxic antibiotics (gentamicin, vancomycin, tetracyclines)
• Tablets (ACEIs, NSAIDS)
• Radiological contrast
• Injury (rhabdomyolysis)
• Negatively birefringent crystals (gout)
• Syndrome (glomerulonephridites)
• Inflammation (vasculitis)
• Cholesterol emboli

Question 20

Causes of post renal (obstructive) AKI

Answer 20

Lumen
- Stone
- Sloughed papilla

Wall
- Tumour (renal cell, TCC)
- Fibrosis

External pressure
- BPD
- Prostate cancer
- Lymphadenopathy
- Aneurysm

Question 21

Markers of hepatocyte injury of cholestasis

Answer 21

• Bilirubin
• ALT (alanine aminotransferase) + less commonly measure AST (aspartate aminotransferase)
• ALP