Renal Unit,Leeds General Infirmary, Great George Street, Leeds, UK
Sir,
Haas et al. [1] give a lucid and informative account of the metabolic aberrations that constitute the acute tumour lysis syndrome (ATLS), emphasising the key role of hyperuricaemia and/or hyperphosphataemia in progression to oligo-anuric renal failure. With adequate pre-hydration, provision of the xanthine oxidase inhibitor, allopurinol, and perhaps an oral phosphate binder as well, this syndrome can be prevented in the majority of patients receiving chemotherapy for tumours associated with rapid cell-turnover. It is less widely known that corticosteroids alone can sometimes precipitate ATLS in patients suffering from lymphoproliferative disorders [25]. Other more unusual causes of ATLS include radiotherapy [6], interferon [7], hyperthermia [8] and, very infrequently, the syndrome occurs spontaneously [9,10]. Here, we report a case in which a single, moderately small dose of prednisolone unmasked malignancy by precipitating ATLS.
A 54-year-old man was extensively investigated for progressive polyneuropathy. Electromyography and a sural nerve biopsy had shown a mixed axonal and demyelinating neuropathy. A paraneoplastic process was thought likely but the site of the primary malignancy proved elusive. Fourteen months later, he presented to another hospital with a short history of anorexia and dysphagia, weight loss, abdominal distension, poor bladder control, and worsening neurological signs. Physical examination revealed a large mass in the left flank, ascites and a left pleural effusion. The small muscles of the hands were wasted with evidence of bilateral median nerve palsy. The legs were similarly affected with generalized atrophy of all muscle groups, diminished power and absent ankle tendon reflexes. Sensory testing was abnormal throughout with reduced perception of light touch, pinprick and vibration in all limbs but more pronounced in the left leg. Sacral sensation was intact. CT imaging confirmed a large retroperitoneal tumour occupying much of the left side of the abdomen and pelvis. Involvement of the pericardium by tumour was also noted but with an absence of mediastinal or hilar lymphadenopathy. Gastroscopy showed oesophageal dysmotility but no obstructing lesion.
The patient was given an oral dose of prednisolone 40 mg because of concerns about the speed of progression of the tumour and possible spinal cord compression, pending transfer to the specialist Oncology service at our hospital. Within a few hours of taking the steroid he began to vomit profusely and became anuric. Serum electrolytes were normal prior to treatment with blood urea 3.8 mmol/l and serum creatinine 110 µmol/l. Further tests now showed sodium 150 mmol/l, potassium 8.3 mmol/l, urea 58.4 mmol/l, creatinine 523 µmol/l, phosphate greater than 8 mmol/l, calcium 2.05 mmol/l and urate 2.88 mmol/l. Haemodialysis was performed on four consecutive days, for 3 h each on the first 2 days and 4 h sessions subsequently. By then, the serum urate and grossly elevated phosphate levels had normalized. He started producing urine on the fourth day and required only one further session of dialysis before total recovery of kidney function 10 days later.
Subsequent investigations revealed a high grade B cell non-Hodgkin's lymphoma which responded well to chemotherapy comprising cyclophosphamide, adriamycin, vincristine and prednisolone. Appropriate prophylactic measures were taken to prevent any recurrence of ATLS. That the patient should develop such a florid ATLS was most unusual given that the steroid dose was small, but some lymphoproliferative malignancies can be exquisitely steroid-sensitive. This is not an isolated case and a similar experience of others [25] suggests that standard precautions to prevent ATLS should be implemented when corticosteroids are used in these circumstances.
We wish to increase awareness of factors other than cytoreductive agents in the causation of ATLS. In the future, rarer causes of ATLS are likely to be encountered more often because of the stringent preventative measures that are routinely employed when treating patients suffering from lymphoproliferative disorders with cytotoxic agents.
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