Management of Bilateral Putamen Necrosis with Reversible Optic Neuropathy and Dystonia
This clinical presentation strongly suggests infantile bilateral striatal necrosis (IBSN), likely due to a mitochondrial disorder or thiamine metabolism defect, and requires immediate thiamine supplementation while pursuing genetic testing for SLC25A19 mutations and mitochondrial DNA analysis.
Immediate Therapeutic Intervention
Initiate high-dose thiamine (100-300 mg/day orally or parenterally) immediately while awaiting genetic confirmation, as this is a potentially treatable metabolic disorder with documented clinical improvement 1. The combination of bilateral putaminal necrosis, reversible optic neuropathy, and dystonia in a child is pathognomonic for thiamine metabolism disorders, particularly SLC25A19 gene mutations causing bilateral striatal necrosis with polyneuropathy 1.
- Start thiamine before genetic results return, as delay can result in irreversible neurological damage 1
- Both reported cases with SLC25A19 mutations showed clinical improvement with thiamine supplementation 1
- The "reversible" nature of the optic neuropathy suggests early intervention may prevent permanent visual loss 2
Diagnostic Workup
Order next-generation sequencing for SLC25A19 gene mutations as the primary genetic test, followed by mitochondrial DNA analysis for Leber's hereditary optic neuropathy (LHON) mutations if SLC25A19 is negative 1, 3.
- SLC25A19 mutations (mitochondrial thiamine pyrophosphate carrier) cause bilateral striatal necrosis with polyneuropathy and are treatable 1
- The combination of dystonia and optic atrophy suggests mitochondrial encephalopathy, with documented overlap between IBSN, Leigh's disease, and LHON 2, 3
- Parental consanguinity increases likelihood of autosomal recessive inheritance 2, 4
Obtain nerve conduction studies to assess for axonal polyneuropathy, which is present in SLC25A19-related disease and helps confirm the diagnosis 1.
Perform serial brain MRI to monitor putaminal changes and assess for progression, as bilateral putaminal lesions appearing hypointense on T1 and hyperintense on T2 are characteristic 5, 2.
Dopaminergic Therapy Considerations
If dystonia persists despite thiamine supplementation, trial levodopa at standard doses (10 mg/kg/day) rather than low doses, as hemidystonia in putaminal necrosis responds to dopamine system modulation 5.
- Low-dose levodopa (0.5 mg/kg/day) worsened clinical signs in one documented case, while standard doses (10 mg/kg/day) produced improvement 5
- PET scanning with F-DOPA can demonstrate asymmetric putaminal uptake and guide levodopa dosing if available 5
- The dystonia reflects disturbance of the dopamine system secondary to putaminal damage 5
Ophthalmologic Management
Refer urgently to pediatric ophthalmology for comprehensive evaluation including cycloplegic refraction, visual acuity assessment, and optic nerve examination 6.
- Monitor for development of amblyopia, which can occur with optic neuropathy in children under age 8 during critical visual development 6
- Repeat pupillary examination to assess for afferent pupillary defect indicating optic neuropathy progression 6
- If vision worsens despite treatment, consider alternative diagnoses including optic nerve hypoplasia or maculopathy 6
Critical Pitfalls to Avoid
Do not delay thiamine supplementation while awaiting genetic confirmation, as this is a treatable disorder where early intervention prevents irreversible damage 1. The recurrent encephalopathy pattern with flaccid paralysis, dystonia, and neuropathy following febrile illness is characteristic of SLC25A19 mutations 1.
Do not start with low-dose levodopa if dopaminergic therapy is needed, as subtherapeutic dosing can worsen symptoms 5.
Do not attribute visual symptoms solely to amblyopia without ruling out progressive optic neuropathy, as compressive or metabolic optic neuropathy requires different management 6.
Genetic Counseling
Provide genetic counseling to parents regarding autosomal recessive inheritance pattern, as both SLC25A19 mutations and other causes of IBSN show this pattern 2, 1, 4. Parental carrier testing should be offered once the mutation is identified 1.
Long-term Monitoring
Continue thiamine supplementation indefinitely if SLC25A19 mutation is confirmed, with monitoring for recurrent encephalopathy episodes during febrile illnesses 1. Patients require lifelong treatment to prevent metabolic decompensation 1.