Cholinergic crisesexcessive cholinergic medication leads to nausea, vomiting, muscle weakness, abdominal pain, and diarrhea.
All three of these can be life threatening, but a refractory crisis is a medical emergency. Those with bulbar myasthenia are at particular risk because they may be unable to swallow or even ask for help.
Myasthenia is manageable but not curable. Oral pyridostigmine is the first-line treatment. Thymectomy is recommended but postponed until ater pregnancy (Sanders, 2016). Anticholinesterase medications improve symptoms by impeding acetylcholine degradation but seldom produce normal muscle function. Ironically, overdose is manifest by increased weness-cholinergic crisisthat may be diicult to diferentiate from myasthenic symptoms. Most of those refractory to anticholinesterase therapy respond to immunosuppressive therapy with glucocorticoids, azathioprine, or cyclosporine in pregnancy. When short-term, rapid clinical improvement is needed-such as for a surgical procedure or a myasthenic crisis-high-dose IVIG or plasma exchange is usually efective (Barth, 2011; Cortese, 2011; Sanders, 2016).
Because the greatest period of risk is within the first year following diagnosis, postponing pregnancy until there is sustained improvement is reasonable. Antepartum management of myasthenia includes close observation with liberal rest and prompt treatment of infections (Heaney, 2010; Kalidindi, 2007). Women in remission who become pregnant while taking corticosteroids or azathioprine should continue these. hymectomy has been successfully performed during pregnancy in refractory cases (Ip, 1986). Acute onset of myasthenia or its exacerbation demands prompt hospitalization and supportive care. Plasmapheresis and high-dose IVIG are options for emergency situations (Drachman, 2015).
Although pregnancy does not appear to afect the overall course of myasthenia, fatigue common to most pregnancies may be exacerbated, and the expanding uterus may compromise respiration. Maternal hypotension or hypovolemia are ideally avoided as they can trigger crises. he clinical course of myasthenia during pregnancy is unpredictable, and frequent hospitalizations are the norm. Up to a third of women have worsening myasthenia during pregnancy, and exacerbations occur equally in all three trimesters (Djelmis, 2002; Podciechowski, 2005). In women with stable disease, most will remain stable throughout pregnancy but likely worsen in the first few months postpartum (Sanders, 2016).
Myasthenia gravis has no significant adverse efects on pregnancy outcomes (Wen, 2009). Preeclampsia is a concern because magnesium sulfate may precipitate a severe myasthenic crisis (Hamaoui, 2009; Heaney, 2010). Although phenytoin use is also problematic in this regard, its adverse efects are less troublesome. hus, many choose it for neuroprophylaxis in women with severe preeclampsia.