Description

A previously healthy 28-year-old woman presented 4 days after sudden onset of neck pain radiated to both arms with progressive tetraparesis and bladder dysfunction. On neurological examination, we found normal mental status and higher functions and no meningismus; on cranial nerve examination, we found right ptosis and myosis with preserved pupillary reflexes and mild anhydrosis of the left hemiface, consistent with Horner syndrome (figure 1); we did not find any other cranial nerve dysfunction. On limb examination, we found an asymmetrical disproportionate tetraparesis, worse on right hemibody with lower limb predominance and hyperactive deep tendon reflexes.

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Figure 1

Horner syndrome. We observe right ptosis with an interpalpebral fissure 8 mm versus 12 mm and myosis, pupillary size 2.5 mm versus 4 mm.

MRI of the cervical spine revealed a longitudinally extensive myelopathy (figure 2) and a brain MRI was normal. Cerebrospinal fluid (CSF) analysis revealed a lymphocytic pleocytosis, with elevated protein and normal glucose levels. Infectious causes were discarded with negative PCRs for common bacterial, viral and fungal agents. Oligoclonal bands were negative in both CSF and serum. Anti-AQP4 antibodies were present in both CSF and serum, confirming the diagnosis of neuromyelitis optica spectrum disorder (NMOSD).1 2 Normal visual evoked potentials ruled out subclinical optic neuritis. The patient received high-dose pulse methylprednisolone during 5 days with minor improvement; so the five sessions of therapeutic plasmatic exchange were performed. After which, the patient gradually recovered movement against gravity in four limbs, without changes in autonomic dysfunction (Horner syndrome and incontinence). On discharge, the patient was bound to a wheelchair and dependant on a urinary catheter, with a Modified Rankin Scale (mRS) of 5; on follow-up 2 months later, the patient was able to stand and walk unaided, although she was still dependant on a urinary catheter (mRS of 1).

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Figure 2

Longitudinally extensive transverse myelitis. On a sagittal T2-weighted MR of the cervical spinal cord, we recognise a longitudinally extensive increase in the signal intensity from the craniocervical junction to T2, with an expansion of the spinal cord. Incidentally, we observe the rectification of cervical lordosis.

Horner syndrome (or oculosympathetic dysfunction) is caused by interruption of the oculosympathetic pathway. In our patient, it was caused by involvement of the second-order neuron in the ciliospinal centre of budge located on the lower cervical–upper thoracic spinal cord,3 as demonstrated by the lesion in C7–T1 (figure 2). In NMOSD, the presence of Horner syndrome is uncommon, with only two cases reported in the literature,4 5 ours being the first without overt or silent optic neuritis.

Despite the absence of a clinically overt optic neuritis, the presence of a longitudinally extensive transverse myelitis led us to rule out NMOSD.6 Since the discovery of the anti-AQP4 antibody, diagnosis of NMOSD can now be established in the absence of optic neuritis, with one of the other core clinical features: acute myelitis, area postrema, brainstem or diencephalic syndrome, or symptomatic cerebral syndrome with typical brain lesions; and a positive anti-AQP4 antibody assay, with reasonable exclusion of alternative causes.1 2 The current standard of care is based on high-dose steroids, therapeutic plasma exchange or intravenous immune globulin in the acute phase, and immunosuppressor agents for prevention of relapses.7