Tumour lysis syndrome
Massive tumour cell lysis
> release of potassium, phosphate, and nucleic acids into circulation
> nucleic acids catabolised to uric acid
- uric acid triggers renal vasoconstriction
- uric acid precipitates in renal tubules
- PO4 binds Ca and precipitates in tubules and causes hypocalcaemia
Can happen spontaneously or with initiation of chemotherapy
Rx
Monitoring of bloods
Hydration: dilutes solutes to prevent precipitation
Allopurinol (xanthine oxidase inhibitor) (IF pretreatment uric acid not high): reduced formation
Rasburicase: promotes degradation (recombinant urate oxidase)
Urinary alkalinisation: NaHCO3/acetozolamide to reduce likelihood of uric acid crystals (controversial as increases risk of CaPO4 crystals)
NB uric acid also involved in:
Urate crystals
Gout
Lesch–Nyhan syndrome