A 55-yr-old man was referred to the rheumatology
department by his GP with a 3-month history of right
shoulder pain. On examination, active and passive shoulder
movements were globally restricted by pain. Shoulder
capsulitis was diagnosed and treatment with an intracapsular
injection of steroid planned. The patient consented to take
part in a research study designed to determine the accuracy
of placement of intra-articular steroid injections. This
protocol involved the administration of depot methylprednisolone
acetate mixed with radiographic contrast medium
(iopamidol). During the injection, the patient began to
experience pain and the procedure was therefore abandoned
after 5 ml had been injected. It was then realized that 50%
dextrose had been mixed with the steroid instead of
iopamidol; both preparations were stored in the same
refrigerator. The mistake and its implications were clearly
explained to the patient. In view of the potentially caustic
nature of the injection, an urgent arthroscopy and lavage
were performed the same day. The patient made an excellent
recovery from his capsulitis, no doubt significantly aided by
the therapeutic lavage.