Complications: Tumour Lysis Syndrome

Question 1

What is tumour lysis syndrome?

Answer 1

Massive tumour cell breakdown leading to release of large amounts of potassium, phosphate and uric acid into the circulation.

Question 2

What metabolic disturbances can occur?

Answer 2

Hyperkalaemia
Hyperphosphatemia
Hyperuricemia
Hypocalcaemia

AKI - from uric acid/ calcium phosphate crystals in kidney tubules

Question 3

What tumour types are more susceptible to TLS?

Answer 3

Haematological malignancies - especially high grade lymphomas and leukaemias
Bulky chemotherapy responsive malignancies

Question 4

Why does TLS cause hypocalcaemia?

Answer 4

It binds with the release of large amounts of phosphate - causing calcium phosphate precipitates

Question 5

When is TLS generally seen?

Answer 5

Following cytotoxic therapy

Question 6

What are patient specific risk factors for TLS?

Answer 6

Pre existing renal dysfunction
Pre treatment hyperuricaemia 
Hypovolemia e.g due to diuretic use 
High LDH 
Urinary tract obstruction

Question 7

Describe the presentation for TLS

Answer 7

Usually 3-7 days post chemotherapy 
Nausea and vomiting 
Diarrhoea 
Muscle cramps 
Weakness
Numbness and tingling 
Confusion 
Haematuria 
Reduced UO 
Arrhythmias 
HF

Question 8

How do you prevent /treat TLS?

Answer 8

Keep well hydrated
Monitor electrolytes
Allopurinol - xanthine oxidase inhibitor (reduces uric acid)
Rasbucase - synthetic uricase (degrades uric acid to allentoin, which is water soluble)

Question 9

What are the signs and symptoms of hypocalcaemia?

Answer 9

CATS go numb 
Convulsions
Arrhythmias 
Tetany
Spasms and stridor 
Numbness and tingling in extremities and around mouth
Positive Trousseau’s or Chvostek’s

Question 10

What are the signs and symptoms of hyperkalaemia?

Answer 10

MURDER
Muscle weakness and fatigue
Urine abnormalities - oliguria
Respiratory distress - SOB
Decreased cardiac contractility - irregular HR, palpitations, can lead to asystole
ECG changes
Reflexes - hyperreflexia or areflexia (flaccid)

Also - nausea

Question 11

What ECG changes can occur with hyperkalaemia?

Answer 11

Repolarisation abnormalities - tall tented T waves (usually earliest sign) 
Paralysis of atria 
- PR wave widens and flattens 
- PR segment lengthens 
- P wave eventually disappears 
Conduction abnormalities 
- wide QRS
- any kind of conduction block
- sine wave pattern = pre terminal leading to VF 
- asystole