The pattern of urinary copper excretion and its response to treatment in patients with Wilson's disease

It is generally accepted that patients with Wilson's disease excrete excess copper in urine. However, there has been no study, on a large series of patients, as to whether there are differences in the rate of excretion at different stages of the disease or what changes may be expected after treatment.

The present study follows from an analysis of the results of urinary copper excretion of 192 patients with Wilson's disease seen between 1955 and 2000. These patients were divided into three groups, pre-symptomatic, hepatic and neurological Wilson's disease. Patients were studied for basal pre-treatment, 24-h urinary copper excretion and for 6 h after a test dose of 500 mg penicillamine. The tests were repeated after approximately 1 and 2 years of chelation therapy with either penicillamine, or in a small minority of cases, trientine.

The basal, pre-treatment copper excretion was the lowest in pre-symptomatic patients (207.93 µg/24 h) and the highest in the hepatic patients (465.75 µg/24 h). Those with neurological Wilson's disease gave an intermediate figure (305.58 µg/24 h). The response to penicillamine was the highest in the neurological patients and the lowest in the pre-symptomatic group. After 1 and 2 years of treatment all groups showed significant falls in both the basal and the after penicillamine rate of excretion of copper. The small subgroup treated with trientine, rather than penicillamine, showed similar results.

The rate of copper excretion in patients with Wilson's disease shows wide variation from patient to patient, but in general patients with pre-symptomatic disease excrete less copper than those with symptomatic disease. All groups show a great increase when challenged with penicillamine. After 1 and 2 years of treatment, there is significant decrease in copper excretion in both basal and after penicillamine challenge. This presumably indicates a reduction in the body load of copper.