Neuromyelitis optica preceded by hyperCKemia episode

NEUROMYELITIS OPTICA PRECEDED BY HYPERCKEMIA EPISODE To the Editor: Suzuki et al.1 described 3 patients with neuromyelitis optica (NMO) preceded by hyperCKemia episode. I have cared for 2 patients with relapsing-remitting multiple sclerosis (MS) who presented with hyperCKemia. In August 1997, a 35-year-old man had transverse myelitis. He subsequently had a month of diplopia in April 2000. He presented to me in August 2000 with a 3to 4-week history of tingling in both hands. His examination had normal results except for impaired tandem gait. Laboratory tests were significant for CK of 3,000 IU/L (normal range 26–170). Repeat CK 3 days later was 1,250 IU/L. Brain MRI showed moderate plaque load. Spine MRI showed plaques at C2 and T11. Lumbar puncture revealed elevated immunoglobulin G of 9.5 mg/dL (normal 0.5–6.1) and no oligoclonal bands. EMG/NCV was performed twice and did not demonstrate myopathy. He was started on glatiramer acetate and since CK normalized by October 2000, muscle biopsy was deferred. In 2002, he had clinical and radiologic worsening and was switched to interferon -1b. Except for fatigue and subtle cognitive complaints, he is asymptomatic. My second patient was a 37-year-old man. In May 1999, he presented with worsening dexterity in his hands, impaired balance, and tingling in both feet for 1–2 years. Examination was significant for obesity, hyporeflexia in the arms, extensor plantar responses, vibratory loss in the toes, and slightly spastic gait. Laboratory tests were significant for CK of 645 IU/L. Brain MRI showed mild plaque load. Spine MRI showed a C2-C6 plaque and lumbar puncture revealed 3 oligoclonal bands. EMG/NCV was performed twice and did not demonstrate myopathy. He was started on glatiramer acetate. In December 2000, CK rose to 1,054 IU/L. Muscle biopsy in March 2001 was negative. In August 2002, CK remained mildly elevated; he had a clinical attack treated with IV steroids and glatiramer acetate was switched to interferon -1b. He had a worsening course despite stable neuroimaging. In 2004, CK was repeatedly in the 3,000–3,700 IU/L range. In April 2005, repeat muscle biopsy was negative. By June 2005, CK had reached 4,545 IU/L. Examination showed quadriparesis, which was most prominent for hip flexion weakness. Empiric prednisone was started with only mild clinical improvement, although CK declined to 516 IU/L in August 2005 and 70 IU/L in January 2006. His condition has continued to decline ostensibly due to secondary progression of MS. Serum CK is normal. Muscle biopsy for hyperCKemia yields a diagnosis in 55% of cases, more likely in children.2 The patients of Suzuki et al. and my first patient did not undergo muscle biopsy. In my second case, 2 muscle biopsies were not helpful. The 3 patients described by Suzuki et al. had transient hyperCKemia that did not recur, similar to my first patient. It is possible that a transient and underlying systemic autoimmune process involving the CNS and muscle is responsible and needs to be identified. Further studies are required to know the frequency of hyperCKemia in NMO and MS.