A 21-year-old girl, while attending college, was referred to our outpatient department with a 12-day history of gradual onset of quadriparesis. Weakness was present both proximally and distally, was initially asymmetric to start with but reached its nadir and became almost symmetric within 2 days. Along with her weakness she also experienced decreased sensation up to her lower chest and developed incontinence of urine. There was no history of any convulsions, loss of consciousness/altered sensorium, decreased vision, diplopia, facial weakness, or dysphagia. After review of the initial MRI and cerebrospinal fluid (CSF) profile, the patient had been prescribed anti-tubercular drugs along with steroids 1 week earlier by a local practitioner and associated with mild improvement in her symptoms.
On examination, she had a temperature of 37.2 C; no palpable lymph nodes were detected. The remainder of her general examination was unremarkable. On neurological examination, she was conscious, well-oriented but apprehensive. Tone was increased in both lower limbs; however, it was normal in the upper limbs. Strength was decreased in all four limbs (2/5 in both upper limbs and 1/5 in lower limbs), and muscle stretch reflexes were increased with Babinski sign bilaterally. On sensory examination, superficial and deep sensation to all modalities was diminished below the C7 dermatome.
Routine blood investigations, including complete blood count, erythrocyte sedimentation rate, blood sugar (BS), serum electrolytes, and liver and kidney function tests were normal. Serologies for human immunodeficiency virus, hepatitis C virus, hepatitis B surface antigen, and tuberculosis skin test were negative. Collagen vascular disease work up was also non-contributory. Chest X-ray and ultrasonography of the abdomen were also normal. MRI of the cervical spine, done prior to admission, had revealed long segment lesions with T2 hyperintensity in cervical and dorsal cord favoring demyelination (Figure 1). CSF study done prior to presentation at our hospital had shown 350 cells out of which 62% were neutrophils and 38% were mononuclear cells, protein was 180 mg/dL and sugar was 50 mg/dL (BS: 82).
On presentation at our center, we performed a MRI of the brain that revealed a single well-circumscribed T2 hyperintense lesion in the right subcortical frontal region (at gray white interface) (Figure 2) without any diffusion restriction or contrast enhancement. Accordingly, we repeated the CSF study in view of these lesions that showed 300 cells out of which 58% were neutrophils and 42% were mononuclear cells; however, there were no red blood cells. Protein was 203 mg/dL, sugar was 60 mg/dL (BS: 82), tuberculosis polymerase chain reaction was negative, and adenosine deaminase came out to be 3.2 U/L. Furthermore, oligoclonal band (OCB) was positive in the CSF. In view of the longitudinally extensive myelitis and a high CSF count, AQP4-Ab was also ordered. Although visual-evoked potentials (VEP) test was normal bilaterally, somatosensory evoked potentials (SSEPs) were suggestive of prolonged latency of N13 and N17 waveforms.
We made the provisional diagnosis of NMO spectrum disorder (NMOSD) in light of overall picture. She received a 5-day course of 500 mg daily intravenous methyl-prednisolone (IVMP) followed by oral prednisolone (OPN) at a dose of 1 mg/kg/day (60 mg). Significant improvement in power was noted (4/5 in upper limbs and 2/5 in lower limbs) at the seventh day from initiation of therapy. Meanwhile AQP4-Ab (done by indirect immunofluorescence) was positive (1:500 titer), so azathioprine therapy was initiated at a dose of 50 mg daily and subsequently increased to 100 mg/day over the next 4 weeks with monitoring of blood counts and liver function tests. Meanwhile, OPN was continued at the same dose.
The patient's neurological status remained unchanged over for next 5 weeks when she developed a left focal motor seizure, neck weakness, and bilateral facial and bulbar palsy along with increased weakness in all four limbs. A repeat MRI of the brain revealed bilateral frontal-parietal hyperintensities on T2 sequence with central hypointensity on FLAIR (Figures 3A,B). Furthermore, on contrast injection incomplete ring enhancement was noted (Figures 3C,D). Cervical MRI showed patchy enhancing long TR hyperintensities in cervical and dorsal cord favoring demyelination (Figures 4A,B). We decided to treat the patient with five cycles of therapeutic plasma exchange (TPE) along with IVMP. On the fourth day of TPE, she again started recovering with regard to extremity strength and with significant improvement in facial and bulbar weakness as well. She was discharged on azathioprine and continued physiotherapy at home. At her 4 months follow-up, she was ambulatory, had re-joined her college, and was doing fine otherwise. Subsequently, OPN was tapered off and azathioprine maintained at a dose of 125 mg/day.