A 34-year-old male, who was previously well, has been admitted to your ICU with vomiting, malaise and oliguria. He has a new diagnosis of diffuse large B cell lymphoma and received his first round of chemotherapy four days ago. The following blood results were obtained:
|Parameter||Patient Value||Adult Normal Range|
|Sodium||138 mmol/L -||135 - 145|
|Potassium||6.2 mmol/L*||3.5 - 5.0|
|Bicarbonate||17.0 mmol/L*||22.0 - 26 .0|
|Urea||21.0 mmol/L*||3.0 - 8.0|
|Creatinine||398 µmol/L*||45 - 90|
|Glucose||5.3 mmol/L||3.5 - 6.0|
|Magnesium||1.10 mmol/L* it-||0.75 - 0.95|
|Calcium corrected||1.78 mmol/L*||2.12 - 2.62|
|Phosphate||3.9 mmol/L* "t-||0.8 - 1.5|
|Urate||10 mmol/L||0.20 - 0.42|
a) List a differential diagnosis for the kidney injury. (20% marks)
b) Outline your assessment and management of this patient. (80% marks)
It is likely the patient has tumour lysis syndrome (10/20).
Other differentials of acute kidney injury should be considered turn into list
• pre-renal (e.g. hypovolaemia, reduced perfusion)
• renal (e.g. glomerulonephritis, interstitial nephritis, vasculitis, ATN, acute cortical necrosis, drugs, pyelonephritis)
• post-renal (e.g. obstruction for calculi, tumour, clot)
• Chronic kidney injury which would put the patient at greater risk of tumour lysis is possible, but not likely if he is previously well.
• Sepsis is possible although it would usually occur at a later stage
(Marking Guide: 1 Mark for TLS; 0.25 marks for each reasonable differential)
Resuscitation as needed to ensure adequate oxygenation and tissue perfusion.
Exclude differential diagnoses (history, examination and investigation including renal ultrasound).
• ECG, and if ECG changes consistent with hyperkalaemia, consider early intervention with (1) CaCl2 or Ca gluconate for temporary ECG stabilisation (new broad QRS or arrhythmia)
• (2) shift K intracellularly with either B2 agonist therapy (e.g. ventolin neb), insulin dextrose, or NaHCO3 if indicated
Specific management of tumour lysis syndrome
• IV fluids to encourage a diuresis
• Once well hydrated diuretics could be considered to encourage a diuresis (frusemide is most widely used, acetazolamide may alkalinise the urine which will increase the solubility of uric acid but reduce the solubility of CaPO4 and hence is less widely used)
• Rasburicase (to break down uric acid) o Urine alkalinisation not recommended if rasburicase has been given
o If rasburicase not available allopurinol maybe given (however, this is not as effective and will not breakdown uric acid, it merely reduces further uric acid formation)
Haemodialysis and/or filtration is generally instituted for standard indications, although it maybe instituted earlier in tumour lysis syndrome or if the patient remains oliguric.
Treat hypocalaemia only if symptomatic (cramps, paraesthesia) as excessive Ca replacement may precipitate CaPO4.
Hyperphosphataemia is most efficiently treated with haemodialysis and/or filtration, insulin dextrose and oral phosphate binders have a limited role.
Seek and treat sepsis.
Consider excluding renal obstruction with US.
Routine supportive care
Optimise oxygenation (if fluid overloaded maybe need supplemental oxygen)
Optimise perfusion and blood pressure
Withhold nephrotoxic medications drugs (NSAIDS, ACE-I, ARBs)
Consider dose modification of renally excreted drugs
Single room/ neutropenic precautions
The college certainly seems to love tumour lysis syndrome. This is the fourth time it has come up in the exam. It is certainly the top differential in this context. Nothing else could ever give rise to a urate level of 10mmol/L.
The list of other differentials might include:
And there is no reason why all of these might not co-exist simultaneously.
Assessment will consist of:
Specific management will consist of:
Tiu, Ramon V., et al. "Tumor lysis syndrome." Seminars in thrombosis and hemostasis. Vol. 33. No. 4. New York: Stratton Intercontinental Medical Book Corporation, c1974-, 2007.
Howard, Scott C., Deborah P. Jones, and Ching-Hon Pui. "The tumor lysis syndrome." New England Journal of Medicine 364.19 (2011): 1844-1854.
Cairo, Mitchell S., and Michael Bishop. "Tumour lysis syndrome: new therapeutic strategies and classification." British journal of haematology 127.1 (2004): 3-11.