Tumour Lysis Syndrome

Question 1

Define Tumour Lysis Syndrome

Answer 1

Oncological emergency characterised by metabolic and electrolyte abnormalities that can occur after the initiation of any cancer treatment, but can also occur spontaneously

Question 2

Aetiology of Tumour Lysis Syndrome

Answer 2

Rapid breakdown of large numbers of cancer cells and subsequent release of large amounts of intracellular content (potassium, phosphate, nucleic acids) into the bloodstream, which overwhelms normal homeostatic mechanisms resulting in hyperuricaemia, hyperphosphataemia, hyperkalaemia, and/or hypocalcaemia.

Most commonly associated with highly proliferative, bulky, chemosensitive haematological malignancies:

• Non-Hodgkin’s lymphoma e.g. Burkitt’s lymphoma
• Acute lymphoblastic leukaemia
• Acute myeloid leukaemia

Cytotoxic chemotherapy, corticosteroids, hormonal therapy, radiotherapy, immunotherapy

Question 3

What are the renal complications of tumour lysis syndrome

Answer 3

Renal tubular obstruction, and a decline in renal function
= Hyperuricaemia + acidic urine and reduced urinary flow, may result in precipitation of uric acid crystals
Nephrocalcinosis and urinary obstruction = Hyperphosphataemia may lead to the formation of calcium phosphate crystals and precipitation

Question 4

Symptoms of Tumour Lysis Syndrome

Answer 4

Syncope/chest pain/dyspnoea (Cardiac arrhythmia from ↑ phosphate, potassium, ↓Ca )
Seizures (↓Ca ↑ phosphate)
Nausea and vomiting (chemotherapy or ↑ uric acid, phosphate, potassium)
Anorexia (↑ uric acid, phosphate)
Diarrhoea (↓Ca ↑ uric acid, phosphate, potassium)
Muscle weakness (↑ phosphate, potassium, ↓Ca)
Muscle cramps (↑ phosphate ↓Ca)
Lethargy
Paraesthaesia (↑potassium, ↓Ca)
Oliguria/anuria/haematuria (Renal failure)
Podagra (big toe gout)

Question 5

Signs of tumour lysis syndrome

Answer 5

Lymphadenopathy (malignancy)
Splenomegaly (malignancy)
Hypertension/hypotension (Renal failure)
Tetany (severe ↓Ca)
Trousseau sign (severe ↓Ca)
Chvostek sign (severe ↓Ca)
Laryngeal spasm (severe ↓Ca)
Peripheral oedema (Renal failure)

Question 6

Investigations for Tumour Lysis Syndrome

Answer 6

U+Es: ↑ Uric acid, ↑ Phosphate, ↑ Potassium, ↓ Calcium | U and Cr elevated

Urine pH: <5
ECG: arrhythmia due to hyperkalaemia (Tented T waves, PR prolongation, flat P waves, broad QRS -> sine wave)

FBC: Elevated WBC
LDH: elevated