What is the workup for Senile Ferrocalcinosis (Fahr's disease)?

Workup for Senile Ferrocalcinosis (Fahr's Disease)

The diagnostic workup for senile ferrocalcinosis (Fahr's disease) should include brain CT scan as the primary imaging modality, followed by laboratory tests to exclude secondary causes of basal ganglia calcification, and neuropsychological assessment to evaluate cognitive and behavioral function.

Imaging Studies

• Brain CT scan: The gold standard for diagnosis, which will show characteristic bilateral calcifications in:

  • Basal ganglia
  • Dentate nuclei of the cerebellum
  • Thalamus
  • Cerebral cortex (subcortical regions)
  • Centrum semiovale 1, 2

• Brain MRI: May be used as a complementary study, though less sensitive than CT for detecting calcifications 3

Laboratory Investigations

To rule out secondary causes of basal ganglia calcification:

• Calcium metabolism assessment:

  • Serum calcium
  • Serum phosphorus
  • Serum alkaline phosphatase
  • Parathyroid hormone (PTH) levels 4, 2

• Other essential blood tests:

  • Complete blood count
  • Renal function tests (BUN, creatinine)
  • Liver function tests
  • Thyroid function tests (TSH, free T4) 5

• Additional tests to exclude other causes:

  • Ceruloplasmin and copper levels (to rule out Wilson's disease)
  • Heavy metal screening if exposure suspected
  • Infectious disease markers if clinically indicated 2

Neuropsychological and Neurological Assessment

• Cognitive evaluation using standardized tests:

  • Assessment of verbal and visual-spatial memory
  • Executive function testing (planning, attention, concentration)
  • Visual constructive skills 6

• Neurological examination focusing on:

  • Extrapyramidal signs (parkinsonism, dystonia, chorea)
  • Cerebellar function (ataxia, dysmetria)
  • Motor function and muscle tone 1, 3

Electrophysiological Studies

• Electroencephalogram (EEG): To evaluate for seizure activity if clinically indicated
• Cognitive evoked potentials (P300): May show abnormalities in information processing 6

Family History and Genetic Evaluation

• Detailed family history: Fahr's disease can be sporadic or familial (often autosomal dominant)
• Genetic testing: Consider if family history is positive 2

Diagnostic Criteria

The diagnosis of Fahr's disease requires:

1. Bilateral calcification of basal ganglia
2. Progressive neurologic dysfunction
3. Absence of biochemical abnormalities
4. Absence of infectious, traumatic, or toxic causes
5. Significant family history (when present) 2

Common Pitfalls and Caveats

• Fahr's disease can present with purely cognitive or psychiatric symptoms without motor manifestations, leading to misdiagnosis as primary psychiatric disorders 3
• Secondary causes of basal ganglia calcification must be excluded before diagnosing idiopathic Fahr's disease, particularly hypoparathyroidism 4, 6
• Late-onset cases may be mistaken for neurodegenerative disorders like Alzheimer's or Parkinson's disease 1
• The extent of calcification on imaging does not always correlate with clinical severity 2

Early diagnosis is crucial as some evidence suggests that early intervention may slow or reverse the calcification process and improve cognitive function in certain cases 2.