Glutaric aciduria type I : MRI

Case Report: 4 month old female child  diagnosed as Glutaryl aciduria type 1  , displays correlative MRI findings in the form of  grossly expansile convexity subarachnoid spaces with possible arachnoid cysts in left presylvian  spaces ( aetiology of prominent space due to under opercularization or arachnoid cysts  per say ,not known) )  with symmetrical bright signal intensity lesions of basal ganglia  with reduced ADC values with rest normal for age 

Teaching points by Dr MGK Murthy, MRI technician Mr Sudhakar

1.  a variety of autosomal recessive  aetiology  leukodystrophy  with Glutaryl -CoA  dehydrogenase  deficiency , leading to accumulation of  glutaric acid and 3 hydroxy glutaric acid in brain and body fluids (  detected in urine for diagnosis either continuously or intermittently during  decompensation episodes)

2.MRI is described as typical with

(a) Basal ganglia  swelling (restricted diffusion)  initially and later necrosis/ atrophy 

(b) Substantia  nigra/ dentate nucleus may be affected 

(c) Expanded subarachnoid spaces  anterior to sylvian fissure  ( whether arachnid cysts or prominent spaces due to under opercularization not known)

(d) Tegmental tracts  along the 4 th ventricle floor may be bright  on DW

(e) Expanded subabrachnoid spaces put pressure on  bridging veins , may lead to hematomata/ hygromata

(f) Delayed myelination 

3. Though MRI is not diagnostic , extrapyramidal symptoms in macrocephalic child  with MRI findings as  above should warrant body fluids  examination for  glutaric acid ( can also present as  acute encephalopathy)

4. Slowly progressive and fatal in  1 st decade unless treated early(without metabolic crisis i.e.. basal ganglia lesions) unless  early treatment with  low protein diet,carnitine  and riboflavine supplements) started