Small cell lung cancer presenting with spontaneous tumor lysis syndrome

What happened, in summary

A man in his early 70s came to the emergency department after 2 weeks of worsening back spasms that reached 10/10 severity. Blood tests showed severe metabolic abnormalities, including potassium of 7.8 mmol/L, uric acid of 17.6 mg/dL and phosphorus of 7.1 mg/dL, together with acute kidney injury. CT showed abnormal tissue in the right paratracheal-suprahilar region suggesting a lung primary and marked enlargement of the liver with multiple metastatic lesions.

The combination of suspected cancer, hyperuricaemia, hyperkalaemia and hyperphosphataemia led clinicians to diagnose spontaneous tumor lysis syndrome before any cancer treatment had been given. He received intravenous fluids, a dose of rasburicase and daily allopurinol. When he became anuric and the high potassium level did not respond to medical treatment, emergency haemodialysis was started.

A liver biopsy confirmed metastatic small cell neuroendocrine carcinoma, consistent with Stage IV lung cancer. Carboplatin and etoposide chemotherapy was planned. Before chemotherapy could start, however, he developed encephalopathy with visual hallucinations, rectal bleeding, cyanosis and mottling. His condition deteriorated rapidly and he died.