Complete recovery after complement factor I deficiency associated fulminant acute hemorrhagic leukoencephalitis: a...

Area of Science:

• Neuroimmunology
• Complement System Biology

Background:

• Acute hemorrhagic leukoencephalitis (AHLE) is a rare, severe neuroinflammatory condition with a high mortality rate, often triggered by infections but with an unclear etiology.
• Complement factor I (FI) deficiency is a rare genetic disorder affecting immune system regulation.

Observation:

• A 9-year-old patient presented with symptoms including fever, headache, ataxia, and diplopia, rapidly progressing to neurological decline and increased intracranial pressure.
• AHLE was diagnosed based on clinical presentation, laboratory results, and MRI findings.

Findings:

• The patient received therapeutic plasma exchange (PEX) and underwent early decompressive craniectomy, resulting in complete recovery at one-year follow-up.
• Complement testing revealed complete FI deficiency, and genetic analysis identified a pathogenic variant in the CFI gene, linking FI deficiency to AHLE.
• This case highlights AHLE as an emerging phenotype of complement FI deficiency.

Implications:

• High clinical suspicion for complement FI deficiency is crucial in cases of AHLE, especially with unknown etiology.
• Prompt intervention with complement factor I substitution (via PEX) and decompressive craniectomy may be life-saving.
• Complement testing should be considered in neuroinflammatory diseases of unknown origin to identify potential complement system defects.