Saturday 27 August 2011

Hallervorden Spatz syndrome

A 19 y o male with extra pyramidal motor impairment.
Here is non contrast CT Brain
MRI Brain Axial T1, T2, FLAIR and Diffusion.
Axial CT study of brain normal.
Axial T1w images of brain are unremarkable.
T2 and FLAIR images show bilateral symmetrical T2 hyperintensity in the region of Globus pallidi with low signal intensity rim surrounding the T2 hyperintensity - 'Eye of tiger' appearance.

Imaging diagnosis : Hallervorden Spatz.

Hallervorden Spatz Syndrome

A rare condition.
Syn: HSS; Pantothenate Kinase- Associated Neurodegeneration (PKAN); neurodegeneration with
brain iron accumulation type 1 (NBIA type 1).
Neurodegeneration with brain iron accumulation (NBIA) is a new umbrella term for disorders of focal brain iron accumulation, includes former HSS, aceruloplasminemia, neuroferritinopathy and others.
HSS is a progressive neuro degenerative disorder characterized brain iron accumulation.

Imaging wise the diagnostic clue is "Eye-of-the-tiger" sign, a bilateral, symmetric T2 hyperintensity in globus pallidi surrounded by hypointensity. The ferritine bound iron deposition is responsible for T2 hypo intensity.

CT Findings: Normal or Hyperdense Globus Pallidi.
MRI (The best imaging tool) Findings:
• Tl WI: Variable (ferritin-bound iron has greater Tl shortening than hemosiderin-bound)
• T2WI and FLAIR : Eye-of the tiger appearance in Globus pallidi.
• T2* GRE: Low signal intensity "bloom" due to paramagnetic effect iron.
• T1 C+: No abnormal enhancement.
• MRS:  reduced NAA in GP implies to neuronal loss.

Lab findings: Normal serum and CSF iron levels.

o Autosomal recessive (50% sporadic)
o PKAN: PANK2 mutation on chromosome 20p12.3-p13.
Theory is PANK2 mutation > CoA deficiency > energy and lipid dyshomeostasis > production oxygen free radicals > phospholipid membrane destruction. Basal ganglia in that GB is esp more prone to oxidative damage because of high metabolic demands. Cysteine accumulation in GP secondary to decreased phosphopantothenate causes iron chelation and peroxidative cell membrane damage is a contributing factor.

Clinical presentation:
Dystonia (most common), other extrapyramidal signs/symptoms are dysarthria, rigidity, choreoathetosis.
Cognitive decline is frequent, dementia.
Pigmentary retinopathy 66%
Psychiatric and speech disturbances
Teenager with speech, psychiatric disturbance is classical. Majority present before age of 6 yrs.

Mean duration disease after symptom onset = 11 yrs

No curative treatment.
Iron chelation ineffective.
Palliative treatment with Baclofen, trihexyphenidyl, stereotactic pallidotomy, Pantothenate (vit B5).

Reference: Diagnostic Imaging Brain, Anne G. Osborn.

1 comment:

Anonymous said...

fantastic case i have seen once