Differential diagnosis and prognosis for longitudinally extensive myelitis in Buenos Aires, Argentina

Introduction: Longitudinally extensive myelitis (LETM) has classically been grouped with the full or limited neuromyelitis optica spectrum disorders (NMOSD). However, differential diagnosis reveals a wide range of aetiologies.

Objective: To report on differential diagnosis and prognosis for LETM observed in a group of patients in Buenos Aires, Argentina.

Patients and methods: Cross-sectional and retrospective multicentre study in two hospitals in Buenos Aires from June 2008 to June 2014.

Inclusion criteria: medullary syndrome associated with spinal cord lesion extending for 3 or more contiguous spinal segments in magnetic resonance imaging (MRI). Clinical, radiological, and biochemical data were collected and subjects were rated on the Hughes functional disability scale (WHFDS) at 3 months.

Results: We evaluated 27 patients, 74% of whom were women; mean age was 35.22 years. The NMO-IgG antibody test was performed in 66.6% and oligoclonal band testing in 71%. NMO-IgG seropositivity was found exclusively in NMOSD patients (75%). Brain MRI was normal in 59.2% and revealed a mean of 7.9 affected spinal segments. Differential diagnoses revealed NMOSD (37%), idiopathic LETM (22.2%), lupus (11.1%), tumour (11.1%), dural fistula (7.4%), acute disseminated encephalomyelitis (7.4%), and a single case of multiple sclerosis (3.7%). Patients with lesions to ≥ 7 spinal segments showed poor recovery at 3 months (P<.001); these cases were associated with neoplastic, vascular, idiopathic, and lupus-related aetiologies.

Conclusions: The most frequent causes of LETM in our cohort were NMOSD followed by idiopathic cases. Neoplastic, vascular, lupus-related, and idiopathic LETM may constitute a critical group with a distinct prognosis and other treatment needs.