Objective

The aetiologic diagnosis of non-traumatic acute myelopathies (AMs), and their differentiation from other mimicking conditions (i.e. ‘mimics’), are clinically challenging, especially in the emergency setting. Here, we sought to identify: (i) red flags suggesting diagnoses alternative to AMs and (ii) clinical signs and magnetic resonance imaging (MRI) features differentiating non-compressive from compressive AMs.

Materials and methods

We retrospectively retrieved MRI scans of spinal cord dictated at emergency room from January 2016 to December 2020 in the suspicion of AMs. Patients with traumatic myelopathies and those with subacute/chronic myelopathies (i.e. MRI scans acquired >48 h from symptom onset) were excluded from analysis.

Results

Our search retrieved 105 patients; after excluding 16 cases of traumatic myelopathies and 14 cases of subacute/chronic myelopathies, we identified 30 cases with non-compressive AMs, 30 cases with compressive AMs and 15 mimics. The presence of pyramidal signs (p = 0.012) and/or pain (p = 0.048) correctly identified 88% of cases with AMs. We failed to identify clinical indicators for distinguishing non-compressive and compressive AMs, although cases with inflammatory AMs were younger than cases with all the remaining conditions (p < 0.05). Different MRI patterns could be described according to the final diagnosis: among non-compressive AMs, inflammatory lesions were more often posterior or central; vascular malformation had a fairly widespread distribution; spine ischaemia was more often central. Anterior or lateral compression were more often associated with neoplasms and disc herniation , whereas hemorrhages and infections produced spine compression on all sides.

Conclusion

We propose a simple clinical indicator (i.e. pyramidal signs and/or pain) to distinguish AMs from their mimics in an emergency setting. Urgent spinal cord MRI remains essential to discriminate compressive and non-compressive aetiologies.