A 6-year-old boy with lymphoreticular malignancy has come for a cycle of chemotherapy. Which of the following investigations need to be done for next 4 hours to diagnose tumour lysis syndrome?
Correct Answer: Urea, Creatinine, Phosphate, Ca2+ and K+
Description: B i.e. Urea, Creatinine, Phosphate, Ca2+ and K+Ref: style="font-size: 1.04761904761905em; font-family: Times New Roman, Times, serif; margin: 0">Explanation:Tumour Lysis Syndrome (TLS):Oncologic emergency triggered by the rapid release of intracellular material from lysing malignant cells.AKI / acute uric acid nephropathy (rapid accumulation of uric acid derived from the breakdown of nucleic acids) is central to the development of TLS.Renal failure then limits the clearance of potassium, phosphorus, and uric acid leading to hyperkalemia, hyperphosphatemia, and secondary hypocalcemia (phosphate chelation with calcium).Hypocalcemia of TLS may persist even after phosphate levels normalize, presumably because of acute deficiencies of 1,25-vitamin D.Diagnosis by Cairo-Bishop CriteriaCairo-Bishop criteriaLaboratory TLS>= 2 amongClinical TLSUric acid>= 476 umol/LLaboratory TLSPotassium>= 6 mmol/L Phosphorus>=2.1 mmol/L (children)>= 1.5 mmol/L (adults)And >=1 amongCalcium<= 1.75 mmol/L* Acute kidney injury* Seizure* Arrhythmia* Sudden deathLaboratory alterations should be measured within the same 24 hours and must occur within 3 days before and 7 days after therapy. TLS = tumour lysis syndromeCancers Associated with TLSHigh - large-volume, highly metabolic malignancies such as B-cell ALL and Burkitt's lymphoma.Low risk - slow-growing hematologic malignancies (such as multiple myeloma).PreventionMethods to increase GFR and urine output are appropriate regardless of risk category.Prophylactic use of recombinant urate oxidase before chemotherapy.ManagementVolume Expansion and DiureticsAugmenting potassium, phosphate and uric acid excretion.A robust urine flow rate will decrease the calcium-phosphate product in the renal tubules.Decreasing the risk of crystal formation and micro-obstruction.AllopurinolStructural isomer of hypoxanthine.It is metabolized by xanthine oxidase to oxypurinol (inhibits the conversion of xanthine to uric acid).Treatment can elevate serum and urine xanthine levels.Allopurinol hypersensitivity syndrome--a constellation of rash, acute hepatitis and eosinophilia.Febuxostat is a novel xanthine oxidase inhibitor that does not have the hypersensitivity profile of allopurinol.Urinary AlkalinizationThe solubility of uric acid is highly pH dependent.At a typical acidic urine pH of 5.0, the solubility of uric acid is 15 mg/dL vs 200 mg/dL at a pH of 7.0.A neutral urine pH may be achievable via the administration of bicarbonate with or without a carbonic anhydrase inhibitor.RasburicaseApproved by the U.S. Food and Drug Administration in 2002 in children.It is an aspergillus-derived recombinant urate oxidase and catalyzes the conversion of uric acid to allantoin, carbon dioxide, and hydrogen peroxide.The latter can lead to devastating methemoglobinemia and hemolytic anemia in individuals with glucose- 6-phosphate dehydrogenase deficiency.
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