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

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.

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

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

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.

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.

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.