The Prognostic Value Of Features Of Spinal Cord Lesions In Acute Transverse Myelitis

Objective: to evaluate the prognostic value of the length of spinal cord lesions and severity of disease in patients with acute transverse myelitis (ATM),and explore the predictive factors relating to the rate of relapse and the rate of convertion into clinically definite multiple sclerosis (CDMS) or neuromyelitis optica(NMO).Methods: The clinical and neuroimaging data of 59 patients with first-ever ATM admitted to the third hospital, the second hospital of HeBei Medical University and HeBei province people's hospital between January 1996 and October 2008 were retrospectively reviewed.The mean follow-up time was 33 months(5 to 180 months).The residual disability status after treatment and recurrent during follow-up were analysed.The patients were divided into the long spinal cord segments group (spinal cord lesions involved at least 3 vertebral segments) and short spinal cord segments group (spinal cord lesions≤2 vertebral segments) according to the length of the lesions involved vertebral segments,acute complete transverse myelitis(ACTM) group and acute partial transverse myelitis(APTM) group according to the severity of disease and the symptoms is symmetrical or not.We compared the patient demographics,clinical impairment at onset and after treatment , CSF parameters,the risk of recurrent and convertion into CDMS or NMO between groups.The diagnosis of ATM was based on the criteria proposed by Transverse Myelitis Consortium Working Group.APTM and ACTM were based on the criteria proposed by Scott et al.The diagnosis of MS was made according to Poser criteria or McDonald criteria and NMO fulfilled the diagnostic criteria of Wingerchuk et al. Disability was measured with the use of Kurtzke's Expanded Disability Status Scale (EDSS). Relapses were defined as the appearance or worsening of symptoms of neurologic dysfunction lasting more than 24 hours.The comparisons between the two groups were by means of x2 statistic or Fisher's exact test and the t-test or the Mann–Whitney test.Results: A total of 59 patients with ATM were enrolled in the study. The mean follow-up time was 33 months(5 to 180 months).Among 44 patients of the long spinal cord segments group,relapses occurred in 13 patients(30%),conversion to CDMS occurred in 7 patients, to NMO in 6 patients . Of the 15 patients of the short spinal cord segments group,relapses occurred in 4 patients (27%),CDMS developed in 3 patients, NMO in 1 patients. The mean EDSS scores of patients in the long spinal cord segments group and the short spinal cord segments group were 6.34±2.00 and 5.97±1.87 respectively during the peak of the illness(p=0.320). The mean EDSS score after therapy was 6.02±2.98 and 4.64±3.35 respectively (p=0.238).There were no significantly different in EDSS scores,the relapse rates and conversion to MS,NMO between two groups.4 of the patients deaths during the follow-up period,3 and 1 patients in the long and the short spinal cord segments group respectively.Of the 39 patients with APTM, relapses occurred in 16 patients (41%),9 patients developed CDMS by either the Poser criteria or the MacDonald criteria sclerosis (MS),6 patients developed NMO.Recurrent transverse myelitis in 1 patients. Among patients with ACTM , only 1 patients(20%) conversed to NMO. The mean EDSS score during the peak of the illness for APTM was 5.03±1.69 and for ACTM was 7.60±1.25(p<0.001). The mean EDSS score after therapy for APTM was 4.50±2.89 and for ACTM was 7.12±2.17(p<0.001).There were manifest differences in the rates of relapse and conversion to MS,and EDSS scores between APTM and ACTM.Conclusion: ATM remained a monophasic event in most of patients.The length of the involved spinal cord segments can not be regarded as prognostic factor separately. It is important to distinguish APTM and ACTM.Though patients of the APTM have mild disability,their risks of developing CDMS and relapse appears to be significantly higher than patients of ACTM. Immunosuppressive agents or immunomodulator may be administered to prevent recurrence. Clinical impairment of patients with ACTM appears to be severe at onset and after treatment,but with lower risks to relapse. Rehabilitation exercises are more important for patients with ACTM.