Persistent spinal cord enhancement in longitudinal extensive transverse myelitis associated with α-1-antitrypisn deficiency: A case report

Background: Longitudinal extensive myelitis (LETM) is commonly seen as part of neuromyelitis optica spectrum disorder (NMOSD) and less frequently in other demyelinating or systemic autoimmune disorders. Case presentation: We present a case of LETM associated with α-1-antitrypsin (AAT) deficiency that we consider as a contributor to the pathophysiology and persistent MRI cord enhancement. A 58-year-old Caucasian male with no previous significant neurological history, presented with progressive worsening of bilateral lower limb paresthesia/numbness and ataxia for 6 months. On initial neurological examination, there was a bilateral decrease in pinprick sensation below the knees, impaired proprioception, decreased vibratory sensation at the level of the ankles, and balance difficulties. Laboratory cerebrospinal fluid testing showed mild increase in protein and negative for oligoclonal bands. Serum analyses were negative for aquaporin-4 (AQP4) antibody and systemic vasculitis biomarkers. The patient had heterozygous mutation (MZ) in the AAT gene and had low levels of AAT in serum. Magnetic resonance imaging of the cervical spine demonstrated a LETM with a T2 hyperintense lesion extending from C5 to T1 levels which was contrast-enhancing. Interestingly, the LETM lesion demonstrated persistent partial enhancement up to 4 years despite the clinical improvement after corticosteroid, intravenous immunoglobulins and rituximab treatment. Conclusion: Evaluating AAT status in patients with persistent enhancement may be considered in AQP4 and myelin oligodendrocyte glycoprotein (MOG)-negative demyelinating presentations. The role of AAT deficiency in demyelinating diseases still remains unknown and future studies are warranted.