Case Presentation: A 65 year-old man was admitted overnight from the Emergency Department to a hospitalist service with oliguric acute kidney injury and abdominal pain. Past medical history includes a recently diagnosed metastatic melanoma. He had a very large tumor burden throughout the liver and abdomen and had not undergone any treatment yet. Physical examination showed a slightly distended abdomen with mild generalized tenderness to deep palpation. Laboratory evaluation revealed a creatinine of 3.1, BUN 69, potassium 5.6, and calcium 8. He had no prior history of kidney disease. Urinalysis with urine electrolytes was ordered and IV hydration was started. He continued to be oliguric however. Labs 12 hours later showed a creatinine of 3.7, phosphorous 6.5, and uric acid 14.1. Rasburicase was started and nephrology was consulted. Unfortunately his urine output did not respond to diuresis and urgent hemodialysis was therefore begun. He was diagnosed with spontaneous tumor lysis syndrome secondary to widely metastatic melanoma. A week later he continued to require dialysis support. Chemotherapeutic options were discussed with the patient and his family, but overall prognosis was extremely poor. In this context, he chose to prioritize quality of life and declined further dialysis or cancer-directed treatment. He expired in the hospital a few days later
Discussion: Tumor lysis syndrome (TLS) is an oncologic emergency frequently encountered by hospitalists. It is most often seen with hematologic malignancies following cytotoxic chemotherapy initiation; however, more rarely it can be seen spontaneously as in this case. Thus, it should be suspected in patients with large tumor burden who develop acute renal failure. If TLS is not diagnosed within the first 12-24 hours, it may lead to permanent renal failure requiring dialysis or even death. It is very helpful to use the Cairo-Bishop laboratory and clinical criteria as a guide when diagnosing TLS. These include the presence of at least 2 relevant electrolyte disturbances (hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia) in addition to creatinine 1.5 times the upper limit of normal and/or arrhythmia/seizure/sudden death.
Conclusions: 1. For patients with AKI and aggressive solid malignancy, consider spontaneous tumor lysis syndrome.2. It is helpful to use the Cairo-Bishop combined lab and clinical criteria as a guide for diagnosis of TLS.
3. TLS in the setting of malignancy can precipitate sustained renal failure. Thus, prompt recognition and urgent treatment in the hospital setting are extremely important.