Rhabdomyolysis after withdrawal of thyroid hormone in a patient with papillary thyroid cancer.

OBJECTIVE

To report a case of rhabdomyolysis presenting with severe hyperkalemia after withdrawal of thyroid hormone in a patient with differentiated thyroid cancer.

METHODS

We describe the clinical and laboratory findings of the study patient and review the relevant literature.

RESULTS

A 54-year-old man with progressive generalized weakness and myalgias presented with acute renal failure and hyperkalemia. He had undergone total thyroidectomy for papillary thyroid cancer 6 weeks earlier and had discontinued thyroid hormone 2 weeks before his current presentation in preparation for thyroid remnant ablation. He had a history of multiple colon and small-bowel resections for familial adenomatous polyposis and desmoid tumor. He was severely dehydrated on examination. Laboratory tests results included the following values: creatine phosphokinase, 5265 U/L (reference range, 52-336 U/L); creatinine, 2.1 mg/dL; potassium, >8.0 mEq/L; and thyrotropin, 92.2 mIU/L. His condition was diagnosed as rhabdomyolysis, and his fluid deficit and hyperkalemia were treated aggressively. Cardiac status remained stable, and both acute renal failure and hyperkalemia improved. He then received remnant ablation, and thyroid hormone was restarted. His muscle complaints resolved over the following 3 months.

CONCLUSIONS

Hypothyroidism-induced rhabdomyolysis can occur during thyroid hormone withdrawal and can present with life-threatening hyperkalemia. Patients under-going thyroid hormone withdrawal should be assessed for risk of rhabdomyolysis, and preventive strategies should be implemented, including prevention of dehydration. The use of recombinant thyrotropin, rather than thyroid hormone withdrawal, should be considered in those who are at high risk for such complications.