Transient diplopia after parathyroidectomy for hyperparathyroidism in chronic haemodialysed patients.

An increase in serum levels of the parathyroid hormone (PTH) and hyperplasia of the parathyroid glands have been observed to occur in the early stages of chronic kidney disease with decreased renal function, in an attempt to maintain serum calcium within the normal range [1]. However, this secondary hyperparathyroidism becomes maladaptive when chronic renal failure progresses to end-stage renal failure, leading to severe hyperparathyroidism, which is refractory to medical therapy. When severe hyperparathyroidism is associated with hypercalcaemia and/or hyperphosphataemia, parathyroidectomy (PTX) should be considered. However, PTX in such cases can often result in an acute decrease of serum calcium and is one of the leading causes of acute hypocalcaemia. Hypocalcaemia is associated with a wide spectrum of symptoms and signs, mostly related to acute changes in serum calcium, rather than constantly low levels [2]. Among them, neuromuscular dysfunction, including tetany and seizure, is the hallmark of the clinical manifestations of acute hypocalcaemia. On the other hand, transient diplopia has been reported only rarely. To illustrate this association, we report on three patients who, following PTX for severe hyperparathyroidism, experienced acute hypocalcaemia and thereafter transient diplopia, a rare complication of hypocalcaemia. Cases