WILSON'S DISEASE

WILSON'S DISEASE

Definition

• Wilson's disease is a rare autosomal recessive disorder caused by a deficiency of the plasma copper carrying protein caeruloplasmin.
• It is characterized by widespread deposition of copper in the tissues with particular impact on the liver and brain.
• Pathogenesis.: Wilson disease (hepatolenticular degeneration) is a rare condition caused by deficiency of caeruloplasmin resulting in widespread deposition of copper in the tissues.

Systemic features :

Presentation is with liver disease, basal ganglia dysfunction or psychiatric disturbances. 

∙ Wilson's disease becomes manifest in three main ways. 

1. Hepatic: this may present as acute hepatitis, cirrhosis or hepatosplenomegaly (e.g. on screening siblings).
2. Neurological: involvement of the basal ganglia may cause involuntary movements, rigidity, tremor or even a flap with dysarthria and dysphagia. There is also evidence of intellectual decline. 
3. Psychiatric: this may be manifest as manic- depression, bizarre behaviour disorders or even a schizophrenic-like illness. 

The only difficulty with diagnosing Wilson's disease is remembering to consider it as a possibility. 

Ocular features :

• Keratopathy is present in nearly all patients.
• It is characterized by a zone of copper granules in the peripheral part of Descemet membrane.
• Kayser-Fleischer ring is present in virtually all cases. 

• It consists of copper granules located deep in the cornea at the periphery of Descemet's membrane.
• The ring is more pronounced in the vertical meridians of the cornea and it may disappear when the patient is treated with penicillamine. 
  (The deposits are preferentially distributed in the vertical meridian and may disappear with penicillamine therapy.) 

Patients suspected to be suffering from Wilson's disease should be referred to an ophthalmologist because the Kayser-Fleischer ring is not usually evident to the naked eye but can be detected by slit lamp examination. (Kayser–Fleischer ring, best detected on gonioscopy when subtle) which change colour under different types of illumination.

• Green 'sunflower' cataract is less common. Anterior capsular ‘sunflower’ cataract is seen in some patients.

Diagnostic tests

• ∙ Serum ceruloplasmin assay is the definitive diagnostic test.
• ∙ Urinary copper excretion is high.
• ∙ Liver biopsy shows excess copper and evidence of cirrhosis.

Treatment

• Treatment with the chelating agent D-penicillamine is not without potential problems and patients require regular haematological and biochemical screening tests.
• In a minority of patients the drug causes nephritic syndrome, myasthenia or an SLE-like illness.