Wilson disease (WD) is a rare autosomal recessive disorder characterized by abnormal copper accumulation in various organs, including the liver, brain, and kidneys. Its diverse clinical presentation, particularly in paediatric patients, poses a significant diagnostic challenge. We present a unique case of a 10-year-old boy initially misdiagnosed with immune thrombocytopenic purpura (ITP) and haemolytic anaemia, later diagnosed with WD after extensive evaluation. The patient's condition progressed to liver cirrhosis, spontaneous bacterial peritonitis, acute respiratory distress syndrome, and multisystem organ failure despite prompt initiation of copper-chelating therapy. This case underscores the importance of considering WD in paediatric patients with unexplained liver dysfunction, haemolysis, or hepatosplenomegaly, even in the absence of classic neurological symptoms or Kayser-Fleischer rings. The Wilson disease scoring system proved valuable in this atypical presentation, guiding diagnosis and management. This report highlights the need for heightened awareness, early diagnosis, and a multidisciplinary approach in managing WD, particularly in its advanced stages.