Myasthenia gravis and preeclampsia: Dot all the I's and cross all the T's

Abstract

Although rare, the co-occurrence of myasthenia gravis and preeclampsia during pregnancy is responsible for considerable maternal and foetal morbidity and mortality. Both careful selection of medications and a multidisciplinary approach are required for treating such cases. This study presents a case report of a patient with a known history of generalized myasthenia gravis who presented with preeclampsia at 33 weeks' gestation. Subsequently, the patient developed recurrent seizures that necessitated the use of multiple medications, including phenytoin, valproic acid, levetiracetam, and propofol. Magnesium sulphate was not administered due to its blocking effect on calcium channels at the neuromuscular junction. The patient underwent a caesarean section under spinal anaesthesia and gave birth to a baby with intrauterine growth restriction (IUGR). Blood pressure control was achieved with the administration of methyldopa and parenteral hydralazine, an increased dose of pyridostigmine, and intravenous immunoglobulin therapy. The status of the patient's myasthenia gravis remained stable. This case serves to highlight the conflicts in the management of these two disorders and suggests strategies to resolve these conflicts in clinical management.

Myasthenia gravis during pregnancy: what care should be taken?

“…The abortion rate is similar to that of the general population and is not influenced by MG treatment 5 . Among the possible complications of pregnancy, preeclampsia occurs in 6-8% of all pregnancies 19 . An association between preeclampsia and MG is rare, but management of such cases is challenging 20 .…”

“…If systolic pressure is greater than 160 mmHg or diastolic pressure is greater than 110 mmHg, intravenous hydralazine is indicated. Beta blockers and calcium channel blockers should be avoided due to the potential risk of worsening MG symptoms 19,20 . Magnesium sulphate is the gold standard therapy for eclampsia and severe preeclampsia; however, it should not be used in myasthenic patients because it inhibits presynaptic calcium influx at the neuromuscular junction [19][20][21] .…”

“…Beta blockers and calcium channel blockers should be avoided due to the potential risk of worsening MG symptoms 19,20 . Magnesium sulphate is the gold standard therapy for eclampsia and severe preeclampsia; however, it should not be used in myasthenic patients because it inhibits presynaptic calcium influx at the neuromuscular junction [19][20][21] . Options for preventing seizures include levetiracetam and valproic acid, but the latter should be avoided in cases of major hepatic impairment.…”

“…Options for preventing seizures include levetiracetam and valproic acid, but the latter should be avoided in cases of major hepatic impairment. For refractory cases, use of phenytoin may be indicated, although there is a theoretical risk of exacerbating myasthenic weakness by reducing the sensitivity of acetylcholine receptors [19][20][21] . Benzodiazepines can be used for seizure control with caution, due to muscle relaxant effects via central potentiation of gamma amino butyric acid (GABA) release 19 .…”

Terapia com sulfato de magnésio no controle e prevenção de convulsões associadas a pacientes com pré-eclâmpsia / Magnesium sulfate therapy in the control and prevention of seizures associated with patients with pre-eclampsia

“…Nessa pesquisa em questão, um grupo recebeu o regime padrão e o outro recebeu 4mg de 20% de sulfato de magnésio IV por 5 minutos em conjunto com 5gm de 50% de sulfato de magnésio em cada nádega, totalizando 14mg de Vale também ressaltar que embora a terapia por sulfato de magnésio seja padrão ouro para eclâmpsia e pré-eclâmpsia grave, em pacientes miastênicas é causador de uma fraqueza intensa e em insuficiência respiratória, sendo indicado, assim, a fenitoína ou também levetiracetam e ácido valpróico. Com atenção para a hepatotoxicidade do último (HASSAN, 2017). Chama-se também a atenção para que as crises ocorridas na gravidez sejam avaliadas como eclâmpsia até prova em contrário e que devem ser tratadas como tal até que o médico assistente possa realizar uma avaliação adequada (PANDEY et al, 2011).…”