Which part of the basal ganglia is primarily affected in Wilson's disease?

Basal Ganglia Involvement in Wilson's Disease

In Wilson's disease, the primary basal ganglia structures affected are the putamen, caudate nucleus, and globus pallidus, with the lenticular nucleus (putamen and globus pallidus) being the most consistently involved region. 1

Neuroimaging Evidence of Basal Ganglia Involvement

• MRI is the preferred imaging modality for detecting basal ganglia abnormalities in Wilson's disease, showing:

  • Increased density on CT or hyperintensity on T2-weighted MRI in the basal ganglia region 1
  • Susceptibility changes in the globus pallidus, putamen, and thalamus due to copper deposition 2
  • Abnormalities in the basal ganglia in approximately 77.7% of patients with Wilson's disease 3

• Susceptibility-weighted MRI sequences are particularly sensitive for detecting copper and iron deposition in the basal ganglia, even when conventional T1 and T2-weighted images appear normal 4, 2

Clinical Manifestations Related to Basal Ganglia Involvement

The neurological manifestations of Wilson's disease directly correlate with the basal ganglia structures affected:

1. Putamen and Globus Pallidus Involvement:

   • Dystonia (focal, segmental, or generalized) 1, 5
   • Parkinsonian features (rigidity, bradykinesia) 1

2. Caudate Nucleus Involvement:

   • Choreoathetosis due to increased activity of the direct pathway 5

3. Lenticular Nucleus (Putamen + Globus Pallidus) Involvement:

   • Tremor (both resting and action tremors) 1, 5
   • Dysarthria and speech changes 1

Diagnostic Considerations

• Neurologic evaluation should be performed on all patients with Wilson's disease, even those with predominantly hepatic presentations 1
• Brain MRI should be considered prior to treatment in all patients with neurologic Wilson's disease 1
• The characteristic "face of the giant panda" sign on MRI, though found only in a minority of patients, is virtually pathognomonic of Wilson's disease 1
• Hyperintensities in tectal-plate, central pons, and simultaneous involvement of basal ganglia, thalamus, and brainstem are highly specific for Wilson's disease 1

Clinical Implications

• Early recognition of basal ganglia involvement is critical as neurological symptoms may be irreversible if treatment is delayed 6
• Patients with neurological presentations almost invariably have Kayser-Fleischer rings and elevated urinary copper excretion 6
• Penicillamine should be avoided as initial treatment in patients with neurological manifestations due to risk of neurological deterioration 6

Common Pitfalls

• Misdiagnosing neurological symptoms as hepatic encephalopathy in patients with advanced liver disease 1
• Failing to perform slit-lamp examination for Kayser-Fleischer rings, which are present in approximately 95% of patients with neurological Wilson's disease 1
• Relying solely on CT imaging, which has limited sensitivity for detecting basal ganglia pathology compared to MRI 4

Understanding the specific basal ganglia structures affected in Wilson's disease is essential for early diagnosis and appropriate management to prevent irreversible neurological damage.