Refractory bulbar and respiratory dysfunction in a young Chinese woman with seronegative, muscle-specific tyrosine kinase antibody-positive myasthenia gravis: response to cyclophosphamide and rituximab treatment.

The use of cyclophosphamide and rituximab for patients with refractory myasthenia gravis has shown promising results. We report on a 31-year-old Chinese woman with acetylcholine receptor antibody-negative and muscle-specific tyrosine kinase antibody-positive generalised myasthenia gravis who had refractory bulbar dysfunction and respiratory failure despite immunosuppressive therapy and thymectomy, and partial and sustained responses to cyclophosphamide and rituximab treatment, respectively. Myasthenia crisis was diagnosed when she presented in the third trimester of pregnancy with dysphagia, bilateral ptosis, prominent fatigability, and respiratory failure. She required prolonged intensive care and non-invasive ventilatory support despite several courses of intravenous immunoglobulins and plasmapheresis. Pulse cyclophosphamide 500 mg/m(2) was given monthly for 4 consecutive months with a partial response. Rituximab 500 mg weekly was subsequently given for 4 weeks with a dramatic and sustained response. She remained symptom-free and assumed full maternal care at 1 year. To the authors' knowledge, this is the first report of a Chinese patient with refractory myasthenia gravis who responded to cyclophosphamide and rituximab.

An expedited stroke triage pathway: the key to shortening the door-to-needle time in delivery of thrombolysis.

OBJECTIVES: To assess time management of stroke thrombolysis triage and functional outcomes in patients receiving recombinant tissue plasminogen activator for hyperacute stroke, and identify bottlenecks in delivery of the treatment. DESIGN: Prospective study. SETTING: A university teaching hospital in Hong Kong. PATIENTS: Patients with suspected hyperacute stroke referred to the stroke thrombolysis team during October 2008 to September 2009. MAIN OUTCOME MEASURES: Time performance records including door-to-stroke team, door-to-needle, and onset-to-thrombolysis times. Functional outcomes by modified Rankin Scale score at 3 months, and thrombolysis-related complications including haemorrhagic transformations and mortality. RESULTS: During the 12-month period, 95 thrombolysis calls were received; recombinant tissue plasminogen activator was given intravenously to 17 (18%) of the patients and intra-arterially to 11 (12%). The mean (standard deviation) door-to-stroke team and the door-to-needle times for intravenous recombinant tissue plasminogen activator patients were 33 (25) and 80 (25) minutes, respectively; both were about 20 minutes longer than that recommended by the National Institute of Neurological Disorders and Stroke. The mean National Institute of Health Stroke Scale score for patients received intravenous recombinant tissue plasminogen activator was 16 (standard deviation, 7). The mean (standard deviation) onset-to-treatment time was 144 (42) minutes. Nine (53%) patients who received intravenous recombinant tissue plasminogen activator achieved favourable outcomes at 3 months, with a modified Rankin Scale score of 0 to 1. Symptomatic haemorrhage and mortality occurred in one (6%) patient. CONCLUSION: A dedicated stroke triage pathway is essential to ensure efficient and safe delivery of thrombolysis therapy. Improvements in door-to-stroke team time through integration with emergency medicine staff and neuroradiologists may improve thrombolysis eligibility.

Detection and characterisation of beta-globin gene cluster deletions in Chinese using multiplex ligation-dependent probe amplification.

BACKGROUND: Deletions in the beta-globin cluster causing thalassaemia and hereditary persistence of fetal haemoglobin (HPFH) are uncommon and difficult to detect. Data in Chinese are very scarce. AIMS: To use a recently available technique to investigate the frequencies and nature of beta-globin cluster deletions in Chinese. METHODS: 106 subjects with phenotypes of thalassaemia or HPFH and suspected to have deletions in the beta-globin cluster were studied. A commercially available kit employing multiplex ligation-dependent probe amplification (MLPA) was used to screen for deletions. Gap PCR and direct nucleotide sequencing were used to characterise deletions detected. RESULTS: 17 deletions in the beta-globin cluster were found in 17 patients: 8 of Chinese ((A)gammadeltabeta)(0) thalassaemia, 7 of Southeast Asian (Vietnamese) deletion and 2 of Thai ((A)gammadeltabeta)(0) thalassaemia. The only type of deletion detected in deltabeta-thalassaemia was Chinese ((A)gammadeltabeta)(0) thalassaemia. The deletional form of HPFH was rarely seen in only 1 case of Thai ((A)gammadeltabeta)(0) thalassaemia. Deletions presenting as beta-thalassaemia trait and raised HbF were all of the Southeast Asian (Vietnamese) deletion type. When these deletions were co-inherited with classical beta-thalassaemia mutations in compound heterozygous states, the phenotypes could be very variable. CONCLUSIONS: In the Chinese population, there are only relatively few types of deletions seen in the beta-globin cluster. MLPA is a fast and effective way of screening for these deletions. Characterisation of these deletions allows the development of simpler and more specific PCR-based tests for routine diagnostic use. Accurate prediction of phenotype is not always feasible. The molecular defects in many cases of HPFH still await discovery.

Clinical phenotype of haemoglobin Q-H disease.

Seven patients of Chinese origin who had haemoglobin (Hb) Q-H disease were studied. They were found to have a similar clinical phenotype to that of patients with deletional Hb H disease, who have a near identical genotypic configuration. The complete absence of Hb A in Hb Q-H disease and the similar clinical phenotype to deletional Hb H disease lends support to the observation that Hb Q-Thailand shares similar functional properties with Hb A.