Neurodegeneration with Brain Iron Accumulation (NBIA): MRI
32 yr old lady of non consanguineous parents with two decades history of seizures, altered behavior (no definite extrapyramidal symptoms) , shows on MRI , symmetrical regions of relative low signal foci on all sequences including SWI ,in basal ganglia (globus pallidi more than others), midbrain in the substantial nigra location (possible red nuclei ) with non age matched ex vacuo findings of ventricles, hippocampi, sulcal spaces , with focal band of differential signal in midbrain component and unremarkable cerebellar hemispheres, suggesting possible heavy metal accumulation including NBIA (Neuro degeneration with brain iron accumulation). Systemic work up including heart, liver and kidneys align with genetic profiling would help.
Discussion by Dr MGK Murthy, Dr A Satish & Dr GA prasad
Neurodegeneration with brain iron accumulation (NBIA) - NBIA disorders have typically symmetrical accumulation of Iron in parts of grey matter which normally are rich in Iron content , i. e. Basal ganglia (Globi pallidi /Putamen) / Thalamus / Midbrain (Substantia nigra / Red nuclei) cerebellum (Dentate nuclei) with each of the appx 10 varieties demonstrating relatively unique pattern , Permitting imaging classification
This group of inherited neurologic disorders in which iron accumulates in the basal ganglia resulting in progressive dystonia, spasticity, parkinsonism, neuropsychiatric abnormalities, and optic atrophy or retinal degeneration. At least ten types and their associated genes are recognized. The age of onset ranges from infancy to late adulthood; the rate of progression varies. Generalized cerebral atrophy and cerebellar atrophy are also frequently observed. The diagnosis is usually first suspected when brain MRI findings suggest abnormal brain iron accumulation.
An important initial distinction between NBIA and other conditions that lead to both extrapyramidal findings and abnormal basal ganglia signal is the nature of the T2 signal. NBIA disorders produce a characteristic hypointensity of the basal ganglia, while other disorders, such as mitochondrial encephalopathies, organic acidurias, and abnormalities of cofactor metabolism, feature T2 hyperintensity . Furthermore, NBIA typically leads to a symmetric, homogeneous hypointensity, in contrast to the pattern seen with extravasated blood products. Furthermore, iron deposition typically also appears hypointense on both DWI and ADC sequences, which can further confirm the diagnosis.
Other metal accumulation disorders -
Wilson disease can also be associated with T2 hypointensity of the deep gray nuclei, although typically the signal change associated with Wilson's is more heterogeneous and may feature prominent concurrent hyperintensities.
Calcium can also produce T2 hypointensity. In ambiguous cases, CT may be of great use in distinguishing calcium (hyperdense) from iron (isodense). Symmetric deposition of calcium may occur in inherited calcinoses (Fahr disease) or in hyper- or hypoparathyroidism and can be associated with extrapyramidal findings on examination.
Inherited disorder of manganese accumulation - leads to T1 hyperintensity of the caudate, putamen, and globus pallidus, similar to the pattern seen in environmental manganism.
- Treatment of manifestations: Intrathecal or oral baclofen, oral trihexyphenidyl, intramuscular botulinum toxin, and deep brain stimulation to treat dystonia; services for the blind, educational programs, assistive communication devices; adaptive aids (walkers, wheelchairs) for gait abnormalities.
- Prevention of secondary complications: Adequate nutrition through swallowing evaluation, dietary assessment, gastrostomy tube feeding as needed.
- Surveillance: Evaluation for treatable causes of pain during episodes of extreme dystonia; monitoring of height and weight; routine ophthalmologic assessment; regular assessments of ambulation and speech abilities
Neurodegeneration with Brain Iron Accumulation (NBIA): MRI Reviewed by Sumer Sethi on Friday, March 31, 2017 Rating: