Comparative efficacy of low dose, daily versus alternate day plasma exchange in severe myasthenia gravis

OBJECTIVE

To evaluate the comparative efficacy of low dose daily versus alternate day plasma exchange in patients with severe myasthenia.

METHODS

Thirty three patients with myasthenia gravis (Osserman's stage II b and III) were randomized to receive alternate day (n = 17) or daily low dose plasma exchange (n = 16). Plasma exchange were carried on each patient, number of exchanges varying subject to their requirements and 20-25 ml/kg plasma was removed during each session. Myasthenia gravis disease scale (MGDS) score was evaluated before and after the procedure. Time to wean off ventilator, removal of nasogastric tube and total duration of hospital stay were also assessed.

RESULTS

There was no statistically significant difference between daily vs. alternate day group with regards to change in MGDS score, percentage change in MGDS score, and complication rates. A decreased hospital stay was observed in patients on daily plasma exchange which almost reached statistical significance.

CONCLUSION

We conclude from our study that daily and alternate day plasma exchange are similar in their efficacy and complication rates, however the daily schedule could be a preferred modality due to decreased hospital stay.

Plasma exchange for myasthenia gravis

BACKGROUND

Myasthenia gravis is an autoimmune disease mediated by auto-antibodies direct against the nicotinic receptor for acetylcholine. Patients would be expected to benefit from plasma exchange. Non-randomised studies suggest that plasma exchange is beneficial in the short term.

OBJECTIVES

To examine the efficacy of plasma exchange in the short and long term treatment of myasthenia gravis.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group register (searched 17 July 2002) and MEDLINE (January 1966 to June 2002) for randomised controlled trials using myasthenia gravis as the search term. We checked the bibliographies in reports of randomised trials and contacted one author to identify additional published or unpublished data.

SELECTION CRITERIA

Types of studies: All randomised or quasi-randomised studies.

TYPES OF PARTICIPANTS

All patients with myasthenia gravis who were diagnosed by an internationally accepted definition. Types of intervention: Treatment with plasma exchange alone or combined with steroids or immunosuppressive drugs. Types of outcome measures:

PRIMARY OUTCOME MEASURE

~bullet~patients treated for exacerbation: change in a specific muscle score after plasma exchange; ~bullet~patients treated for chronic myasthenia gravis: change in a functional scale.

SECONDARY OUTCOME MEASURES

~bullet~patients treated for exacerbation: change in a functional scale and percentage weaned from mechanical ventilation; ~bullet~patients treated for chronic myasthenia gravis: percentage in remission by the end of one year after first plasma exchange; ~bullet~adverse events.

DATA COLLECTION AND ANALYSIS

One author extracted the data and the two others checked them. Since there was only one trial no formal meta-analysis was required.

MAIN RESULTS

We identified one randomised controlled trial. Improvement in a quantitative muscle score was not significantly greater in patients treated with plasma exchange and prednisone than in patients treated with prednisone alone one month after onset of treatment. More relapses were observed in the plasma exchange and prednisone group in the first year as compared with the prednisone alone group. Problems in recruitment and matching of patients entered into this trial limit the conclusions that can be drawn. On the other hand,experience from many non-randomised studies suggests that plasma exchange is beneficial in myasthenia gravis. Consequently the relative benefits of plasma exchange are still unconfirmed.

REVIEWER'S CONCLUSIONS

There are no adequate randomised controlled trials but many case series report short-term benefit from plasma exchange in myasthenia gravis, especially in myasthenic crisis. There are no adequate randomised controlled trials to determine whether plasma exchange improves the long-term outcome for myasthenia gravis. Further research is need to compare plasma exchange with alternative short-term treatments for myasthenic crisis and to determine the value of long-term plasma exchange for treating myasthenia gravis.

Optimal volume of processed plasma and total number of selective plasmapheresis sessions in the treatment of patients with severe generalized myasthenia gravis

The selection of the technical parameters of plasmapheresis in the treatment of patients with MG varies widely due to the lack of sufficient data from controlled studies to standardize the plasmapheresis procedure. Eight myasthenia gravis (MG) patients (Osserman IIb and III) received either immunoadsorption plasmapheresis (IA) with a IM-TR 350 (Asahi Medical Co., Tokyo, Japan) or double filtration plasmapheresis (DF) with a Cascadeflo AC-1770, with four in each group. A Plasmaflo AP 05 W (Asahi Medical Co., Tokyo, Japan) was used as the plasma separator in both groups. Each course of treatment consisted of five sessions of aphereses on alternate days. Plasma was sampled before and after passing through the column. Samples of plasma were analyzed for acetylcholine receptor antibody (AchRAb) at the start of plasmapheresis and sequentially after every 0.5 L of plasma treated. The IA method cleared significantly more AchRAb during the initial treatment of 1. 5 L of plasma than the DF method, especially in the initial 1 L (P < 0.01). The column saturated after treatment of 1.5 to 2 L of plasma. It is known that over-saturation of column may release the already adsorbed/filtrated antibodies. Longitudinal analysis on the serological changes during the five sessions revealed that the clearance obtained using the IA method was significantly higher and more sustained after the first session of treatment compared to the DF method (P < 0.05). The titers of AchRAb were also noted to rise after the fourth session. These results suggest that 2 L of processed volume is optimal in terms of the functional capacity of a plasmapheresis column in either IA or DF methods, and that a total of four sessions of treatment in one course may provide optimal elimination of AchRAb.

Double filtration plasmapheresis in myasthenia gravis--analysis of clinical efficacy and prognostic parameters

OBJECTIVES

The aim of this study was to evaluate the efficacy of double filtration plasmapheresis (DFP) in the treatment of patients with myasthenia gravis (MG) and to analyze the possible prognostic factors related to responsiveness to DFP.

MATERIALS AND METHODS

We treated 45 MG patients, 26 women and 19 men aged 21-72 years, with DFP for 5 consecutive sessions. All were affected by severe generalized or respiratory weakness with an Osserman's classification of group 2 or 3 and had not responded to previous treatments.

RESULTS

Thirty-eight out of 45 patients (84%) achieved significant improvements after DFP. The baseline MG score and removal rate for immunoglobulin G (IgG) were significantly higher in the patients with good response than in the other response groups. Poor responders were more likely to have thymoma and a longer interval among sessions of DFP. Better response in patients with age at onset of less than 40 years was associated with higher MG score. Serum concentration of all proteins tested fell as follows (mean +/- SD): IgM, 88+/-7%; IgA, 71+/-11%; IgG, 59+/-14%; globulin, 52+/-11%; AchRAb, 47+/-14%; and albumin, 27+/-10%. All the patients tolerated plasmapheresis well except for 2.2% who experienced hypotension.

CONCLUSION

In this study, DFP was effective and safe in the treatment of patients with severe generalized MG. The factors correlating with the better clinical response were high MG score, a thymic pathology of non-thymoma, daily apheresis, young age at onset, and high removal rate for IgG.

Plasmapheresis in myasthenia gravis. A comparative study of daily versus alternately daily schedule

OBJECTIVES

The aim of this study was to compare the efficacy of different protocols of plasmapheresis in the treatment of myasthenia gravis (MG).

MATERIALS AND METHODS

We treated 30 MG patients with plasmapheresis on either a daily or alternately daily schedule for 5 consecutive sessions. Acetylcholine receptor antibody (AchRAb), serum proteins including albumin, globulin, immunoglobulin G (IgG), IgA, and IgM, and MG score were measured before and after the course of plasmapheresis in each group of patients.

RESULTS

The mean percent reductions of serum proteins including IgA (81.5% vs 69.7%), IgM (95.6% vs 87.1%), and globulin (63.2% vs 50.1%) were significantly higher in the daily group. There were no significant differences in AchRAb and IgG levels after treatment between these 2 groups. However, the reduction of MG score was greater in the daily group. All the patients tolerated plasmapheresis well except for 2.7% of them who experienced hypotension.

CONCLUSION

Our results suggest that daily plasmapheresis may be more effective in the treatment of patients with advanced MG.

A short plasma exchange protocol is effective in severe myasthenia gravis

Plasma exchange has been reported to be a successful therapeutic procedure for the treatment of severely compromised myasthenic patients, but the optimal regimen in terms of costs or clinical benefit has not so far been determined. We have investigated the efficacy of a short plasmapheresis protocol of two exchanges 1 day apart in a series of 70 patients with severe forms of myasthenia gravis. Patients were evaluated before and 7 days after the first exchange. A positive outcome was observed in 70% of the plasma exchange cycles performed. Disease severity did not seem to be a negative prognostic factor for the efficacy of this short protocol, which was well tolerated by patients. In only 1 case were major side-effects observed. In spite of its short duration, the exchange treatment plus concomitant immunosuppressive drug therapy was not followed by early clinical deterioration.

Azathioprine as a single drug or in combination with steroids in the treatment of myasthenia gravis

Azathioprine (Aza) has been used alone or in combination with steroids for two groups of myasthenic patients. Positive responses were noted in 75% of patients on Aza alone and in 70% receiving the combined regimen. The clinical course of the two groups differed in terms of respiratory crisis and need for plasma exchange. With an appropriate Aza administration schedule side-effects were not a limiting factor to its use. Aza treatment induced a reduction in anti-AchR-antibody level that was correlated with clinical improvement and greatly decreased the need for steroids.