Penicillamine challenge test in the diagnosis of Wilson's disease

Wilson's disease (WD) is one of the most common metabolic liver diseases encountered in children. Early diagnosis of the disease is essential because specific treatment can be offered, that will prevent further hepatocellular injury and neurologic complications. There is no single diagnostic test that can exclude or confirm the disease with certainty. Penicillamine challenge has proved itself to be a useful diagnostic test in the detection of WD. The main purpose of this study was to observe the reliability of penicillamine challenge test, in the diagnosis of WD. The cross sectional study was done with a case control design in the department of paediatric gastroenterology & Nutrition, BSMMU, Dhaka. The study was carried out on 60 patients of CLD. Along with other physical findings and laboratory investigations, 24 hours urinary copper excretions were estimated before and after penicillamine challenge. Study results were analyzed statistically. Thirty CLD patients who fulfilled the inclusion and exclusion criteria of WD were considered as cases (Group I) and remaining 30 CLD patients were considered as non-Wilsonian CLD and was labeled as control (Group II). Among the control group, 12 CLD patients were found to be HBsAg positive, 1 had hepatitis-C virus infection, 1 had autoimmune hepatitis and the remaining 16 CLD patients were Cryptogenic. The (mean±SD) age of WD patients was 9.90±28 years; male female ratio was 1.5:1. Most common presentation was ascites (70%). K-F ring was found in 86.7% cases. Serum ceruloplasmin level was found significantly lower in WD patients (mean±SD, 0.1197±23g/L, p<0.001). Baseline urinary copper excretion of WD patients differed significantly from controls (Median 219.0μg/24hour, range 35-2018μg/24hour, versus median 44μg/24hour, range 20-238μg/24hour, p<0.001). Baseline urinary copper excretion above 100μg/24hour was observed in 80% WD patients whereas it was 10% in controls. post penicillamine urinary copper excretion was significantly greater in WD patients than controls (Median 2635μg/24hour, range 648-6222μg/24hour, versus median 423μg/24hour, range 91-1250μg/24hour, p<0.001). Post penicillamine urinary copper above 1600μg/24hour observed in 70% of WD patients whereas not a single patient reached the value in control group. Twenty four hours urinary copper estimation after penicillamine challenge was found to be a valuable test in the diagnosis of WD.