This medical condition has either been superseded or has become inactive
| Specific Conditions |
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| Indication for Ig Use |
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| Level of Evidence | Clear evidence of benefit (Category 1) |
| Description and Diagnostic Criteria |
MG is an autoimmune disease associated with the presence of antibodies to acetylcholine receptors (AChR) or to muscle-specific tyrosine kinase (MuSK) at the neuromuscular junction. Some patients with myasthenia gravis are antibody negative. Clinical features are characterised by fluctuating weakness and fatigability of voluntary muscles, namely levator palpebrae, extraocular, bulbar, limb and respiratory muscles. Patients usually present with unilateral or bilateral drooping of eyelid (ptosis), double vision (diplopia), difficulty in swallowing (dysphagia) and proximal muscle weakness. Weakness of respiratory muscles can result in respiratory failure in severe cases or in acute severe exacerbations (myasthenic crisis). Diagnosis is suspected based on the clinical picture described above, without loss of reflexes or impairment of sensation. Repetitive nerve stimulation typically shows a decreasing response at 2–3 Hz, which repairs after brief exercise (exercise facilitation). Edrophonium can be used for confirmation. Other useful investigations include serum anti-AChR or MuSK antibody titre, or SFEMG (single-fibre electromyography). |
| Justification for Evidence Category |
A Cochrane review of four randomised controlled trials (RCTs) (a total of 147 children and adult patients) found benefit but no significant difference between IVIg and plasma exchange, and no significant difference between intravenous immunoglobulin (IVIg) and methylprednisolone. One of the four studies found no benefit of IVIg (i.e. no significant difference between IVIg and placebo). The individual trials were of poor design and some had small numbers of participants, so more research is needed (Biotext 2004). Anecdotal evidence of efficacy has come from clinicians. There is insufficient placebo-controlled evidence for IVIg use as a steroid-sparing agent or before thymectomy in stable MG, although multiple case reports suggest benefit in this context. The Asia–Pacific Advisory Group (Kornberg 2004) supports the use of IVIg over a single day for the treatment of myasthenia gravis exacerbations, in myasthenic crisis, or in patients with severe weakness poorly controlled with other agents. It does not support the use of IVIg for maintenance in stable moderate or severe MG, unless other therapies have failed and IVIg has shown benefit. Effectiveness of IVIg is equivalent to steroids and plasma exchange, but IVIg may be easier to administer than plasma exchange and avoids the side effects of steroids. |
| Diagnosis Requirements |
A diagnosis must be made by a Neurologist. |
| Qualifying Criteria for Ig Therapy |
As an alternative to plasma exchange in acute exacerbation of MG (myasthenic crisis).
As an alternative treatment to plasma exchange prior to surgery and/or thymectomy.
As maintenance therapy for moderate to severe MG when other treatments have been ineffective or caused intolerable side effects.
AND
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| Review Criteria for Assessing the Effectiveness of Ig Use |
As an alternative to plasma exchange in acute exacerbation of MG (myasthenic crisis).
As an alternative treatment to plasma exchange prior to surgery and/or thymectomy.
As maintenance therapy for moderate to severe MG when other treatments have been ineffective or caused intolerable side effects.
IVIg should be used for three to six months (three to six courses) before determining whether the patient has responded. If there is no benefit after three to six courses, IVIg therapy should be abandoned.
Review by a Neurologist is required within six months and annually thereafter. A trial off period should be conisdered at each review. Documentation of clinical efficacy is necessary for continuation of IVIg therapy. For stable patients on maintenance treatment, review by a Neurologist is required at least annually. On review of the initial authorisation period Clinical effectiveness of Ig therapy can be demonstrated by:
On review of a continuing authorisation period Clinical effectiveness of Ig therapy can be demonstrated by:
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| Dose |
As an alternative to plasma exchange in acute exacerbation of MG (myasthenic crisis).
The aim should be to use the lowest dose possible that achieves the appropriate clinical outcome for each patient. Refer to the current product information sheet for further information. As an alternative treatment to plasma exchange prior to surgery and/or thymectomy.
The aim should be to use the lowest dose possible that achieves the appropriate clinical outcome for each patient. Refer to the current product information sheet for further information. As maintenance therapy for moderate to severe MG when other treatments have been ineffective or caused intolerable side effects.
Aim for minimum dose to maintain optimal functional status.
The aim should be to use the lowest dose possible that achieves the appropriate clinical outcome for each patient. Refer to the current product information sheet for further information. |
| Bibliography |
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| Biotext 2004, ‘Summary data on conditions and papers’, in A systematic literature review and report on the efficacy of intravenous immunoglobulin therapy and its risks, commissioned by the National Blood Authority on behalf of all Australian Governments, pp. 188–9. Available from: http://www.nba.gov.au/pubs/pdf/report-lit-rev.pdf Darabi, K, Abdel-Wahab, O & Dzik, WH 2006, ‘Current usage of intravenous immunoglobulin and the rationale behind it: the Massachusetts General Hospital data and review of the literature’, Transfusion, vol. 46, no. 5, pp. 741–53. Gajdos, P, Chevret, S & Toyka, K 2003, ‘Intravenous immunoglobulin for myasthenia gravis (Cochrane Review)’, in The Cochrane Library, Issue 2, John Wiley & Sons, Ltd, Chichester, United Kingdom. Kornberg, AJ, for the Asia–Pacific IVIg Advisory Board 2004, Bringing consensus to the use of IVIg in neurology. Expert consensus statements on the use of IVIg in neurology, 1st edn, Asia–Pacific IVIg Advisory Board, Melbourne. |