This article about myasthenia gravis highlights the central role GPs have in the diagnosis and ongoing management of patients with this rare condition. This is part two of a three-part article.

This is part two of this series.
Read Part 1 >>
Read Part 3 >>

Practice points

• The acetylcholine (ACH) receptor antibody is the most common antibody found.

• MuSK” stands for “muscle-specific kinase” antibody and it targets the postsynaptic neuromuscular junction.

• In patients with generalised clinical myasthenia, approximately 85% of them have ACH receptor antibodies and about 5% to 10% of them have MuSK antibodies.

• If there are pure ocular symptoms, half the patients have ACH receptor antibodies but MuSK antibodies are very rare.

• If antibodies have returned positive and a patient is waiting for a clinic appointment, a CT chest is something easily ordered prior to the patient being referred.

• If the patient is starting to aspirate or has a high respiratory rate, shortness of breath, head drop or swallowing difficulties they should be referred to Emergency.

• Pyridostigmine (Mestinon®) works almost immediately but it is limited in its maximal benefit. Patients take it fifteen to thirty minutes before any activity and may self-titrate the dose.

• Plasma exchange that directly removes the pathological antibodies, and intravenous immunoglobulins are prescribed via the blood bank. Both are expensive and short-acting.

• Long-acting oral treatments include corticosteroids, azathioprine, methotrexate, mycophenolate, and the infusions, such as rituximab and cyclophosphamide, but the latter are chemotherapy drugs.

• Acute, high dose steroids can severely exacerbate myasthenia gravis symptoms and cause them to go into cholinergic crisis requiring intubation.