In nine out of 10 cases diagnosing myasthenia is easy. The clinical features are typical as are the positive antibody/classical neurophysiological aspects. The treatment is straightforward and gratifying (early response and remission).

It is the remaining 1 in 10 that cause problems. This advice reflects years of working in a specialist centre with those very clients.

  • Managing myasthenia is as much an art as a science. Experience defines what works for the individual.
  • Spend time at the outset explaining the nature of the condition, the principles of treatment, and the likely time-course of future events. This is critical to successful long-term management. It may be difficult but it is time wisely invested. I would identify this as being one of the greatest failings of patient management.
  • Long-term management needs to be with one individual. It is not a condition that can be managed long-term by the GP or a succession of inexperienced trainees.
  • A specialist myasthenia nurse can contribute enormously to both of the above.
  • The patient must have ready access to the consultant or nurse to answer urgent management queries
  • Patients need to know about the myaware website.

Medical treatment

There are only three approaches to medical treatment

  • Symptomatic (Pyridostigmine)
  • Immunosuppressive (Steroids, second-line agents [azathioprine, ciclosporin, mycophenolate mofetil, methotrexate, rituximab, etc.]
  • Immunomodulatory
    • Thymectomy (long-term)
    • Plasma exchange (short-term)
    • IVIg (short-term)

Numerous publications cover treatment approaches and we are currently drawing up guidelines with the Association of British Neurologists which may prove helpful.

Remember:

  • Pyridostigmine provides adequate symptomatic relief in only a minority of patients. Start with a small dose but increase fairly rapidly. Maximum dose eight tablets daily. If inadequate response within a month move on to immunosuppression
  • The main reason for failure with steroids (prednisolone) is inadequate dose or duration of therapy. Second-line agents are slow to act.
  • Consider thymectomy early in younger AChR-antibody-positive patients. VATS is cosmetically much more acceptable than sternotomy.

Seronegative myasthenia

The presence of specific antibodies removes any doubt about the diagnosis. With a typical clinical picture the absence of antibodies may be of no concern, especially if further diagnostic support comes from neurophysiology. But be wary of:

  • The patient with seronegative ocular myasthenia, particularly if they fail to respond to treatment. Think about:
    • Mitochondrial chronic progressive ophthalmoplegia
    • Intracranial pathology (low threshold for MRI)
    • Oculopharyngeal muscular dystrophy
  • The patient with seronegative generalised myasthenia who doesn’t respond to treatment. Remember rare, sometimes adult onset, congenital myasthenic syndromes

Lambert-Eaton syndromes

This is much less likely to be encountered than myasthenia and clinically very different (lower limb onset, little ocular involvement). The therapeutic approach to management is similar especially in non-cancer-related cases. Specific symptomatic therapy with 3,4-diaminopyridine.

If in doubt refer to a colleague with a specific interest in the area. Management may remain local or be transferred to a specialist clinic or both.