Anesthetic considerations for myasthenia gravis and pregnancy

Recommendations of the AGG (Section Maternal Disease) for Myasthenia Gravis in Pregnancy

Myasthenia gravis is an autoimmune disease with a range of clinical presentations which manifest as combinations of weakness of the ocular, bulbar, and respiratory muscle groups and muscles of the extremities. Young women of reproductive age are most commonly affected. Preconception planning, the impact of pregnancy, prepartum management, drug therapy in pregnancy, myasthenic and cholinergic crises, fetal monitoring, peripartum management including analgesia and anesthesia during labor and cesarean section as well as neonatal management and neonatal myasthenia gravis are described here and the appropriate recommendations are given.

Myasthenia gravis and pregnancy

Myasthenia gravis (MG) is an autoimmune disorder with bimodal age of presentation, occurring in young women of reproductive age and at an older age in men. Occasionally, MG is diagnosed during pregnancy. Management of MG includes symptomatic treatment with cholinesterase inhibitors and immunosuppressive therapy for controlling the disease activity. Treatment of MG in women of reproductive age, who may be contemplating pregnancy, requires discussion regarding the choice of medication as well as the understanding of risks/adverse effects involved with various treatments. During the peripartum period, it is essential to ensure careful monitoring of the disease state along with the well-being of the mother and fetus and to coordinate neonatal monitoring overseen by a multidisciplinary team comprising a high-risk maternal fetal medicine specialist, a neurologist familiar with these complex issues, and a neonatologist.

Myasthenia gravis and pregnancy: anaesthetic management--a series of cases

BACKGROUND AND OBJECTIVE

Myasthenia gravis is an autoimmune neuromuscular disease, usually affecting women in the second and third decades. The course is unpredictable during pregnancy and puerperium. Myasthenia gravis can cause major interference in labour and partum and exacerbations of the disease frequently occur. The aim of this series of cases is to analyse retrospectively the anaesthetic management of myasthenia gravis patients and complications during the peripartum period.

MATERIALS AND METHODS

Retrospective, single centre study from clinical files of female myasthenia gravis patients who delivered between 1985 and 2007 at Hospital de Santo António, Porto, Portugal.

RESULTS

Seventeen myasthenia gravis patients delivered between 1985 and 2007 in Hospital Santo António. Two women were not included in the study as they had a spontaneous abortion in the first trimester. Four patients presented exacerbations of the disease during pregnancy, no exacerbation occurred in eight patients and three patients presented their first symptoms of myasthenia gravis during pregnancy (without diagnosis at time of delivery). Concerning the eight patients without exacerbations of the disease during pregnancy, pregnancy was brought to term in 87.5% of the cases; five women were submitted to nonurgent caesarean section (62.5%); and epidural block was performed in six patients (75%). No complications related to anaesthesia occurred in the peripartum period. Concerning the four patients with exacerbations of the disease, pregnancy was brought to term in three cases (75%); three women were submitted to nonurgent caesarean section (75%); and epidural block was performed in three patients (75%). One patient underwent an uncomplicated thymectomy under general anaesthesia during pregnancy and, in the postpartum period, there was a myasthenic crisis in another patient. Concerning the three patients without a myasthenia gravis diagnosis at partum, one woman already being followed for presenting muscular weakness had a vaginal delivery under epidural block, without complications; another patient, presenting discrete supine dyspnoea, was submitted to elective caesarean section under spinal block and developed severe dyspnoea that required mechanical ventilation and ICU admission; and in the remaining case, a woman presenting mild blurred vision was submitted to general anaesthesia, which resulted in delayed emergence, muscular weakness and respiratory failure. Pregnancy went full term in all cases (100%). No newborn had a myasthenic crisis.

CONCLUSION

Myasthenia gravis can interfere slightly with pregnancy and partum, although exacerbations of the disease occur frequently. Strict surveillance and therapeutic optimisation are crucial. In women with controlled disease, caesarean section should be carried out only if there are obstetric reasons. Locoregional anaesthesia is preferred, mainly epidural block. A good multidisciplinary cooperation, specific precautions and surveillance can certainly contribute to an improved outcome in myasthenia gravis patients during the peripartum period.

The preoperative assessment of obstetric patients

The importance of early identification and management of the high-risk obstetric patient is emphasised in the Confidential Enquiry into Maternal and Child Health (CEMACH) report. High-risk patients who need anaesthetic input include those with airway problems, cardiorespiratory disease and rare genetic conditions, such as malignant hyperthermia and suxamethonium apnoea. Anaesthetic options for labour analgesia as well as anaesthesia for operative delivery will need to be discussed in detail with the patient if a delivery management plan is to be constructed. Input from other medical teams, such as cardiologists or haematologists, are often needed. Ultimately, these measures should reduce maternal morbidity and mortality.

Undiagnosed myasthenia gravis masquerading as eclampsia

This case describes an apparently healthy 21-year-old parturient who presented at term with a prolapsed cord requiring immediate cesarean section. She experienced postoperative seizures. After a presumptive diagnosis of eclampsia, magnesium sulfate was given. During a complicated postoperative course, ventilatory failure necessitating multiple intubations eventually led to a new diagnosis of myasthenia gravis. This report describes how the signs and symptoms of myasthenia gravis may mimic post-partum eclampsia as well as worsen the side effects of magnesium therapy.

Myasthénie, grossesse et accouchement : à propos de dix cas

OBJECTIVE

To study the reciprocal interferences between pregnancy and myasthenia gravis (MG) and to describe obstetric and anaesthetic management during labour and the post-partum period.

STUDY DESIGN

Retrospective, single centre study.

METHODS

The files of 10 patients with MG, who delivered between October 1994 and May 2002, were examined.

RESULTS

No stillbirth occurred and all pregnancies were brought to term. All patients were maintained on their long-term anticholinesterase medications during pregnancy. Seven exacerbations were detected and controlled, five by increasing the anticholinesterase treatment, one by using plasmapheresis and one by using intravenous immunoglobulins. No patient required admission to the intensive care unit during pregnancy. All patients had a pre-anaesthetic visit at/near 33 weeks of gestation. Delivery was induced for six patients. Regional analgesia was performed early in labour (epidural, n = 7; combined spinal-epidural = 2) using low concentrations of local anaesthetic and no complication was detected. Three patients required a caesarean section for an obstetrical indication. Seven patients delivered vaginally using instrumental extraction (n = 5). During the post-partum period, four patients were monitored in the intensive care unit during 48 h and close neurological follow-up disclosed no exacerbation during the first 6 post-partum weeks.

CONCLUSIONS

MG has no significant effect on the course of pregnancy and delivery, but MG exacerbation can occur, especially in the first trimester. Regional analgesia is medically indicated and must be performed early in labour, using low concentration of local anaesthetic to lessen the risk of motor block.

Immunosuppressive drugs and pregnancy

Immunosuppressive therapy is a common practice in modern medicine. Typical uses of immunosuppressive drugs during pregnancy include the treatment of rheumatic diseases and transplant recipients. The purpose of this article is to assess and summarize current knowledge regarding the use of immunosuppressive drugs in pregnancy, focusing primarily on their effects on the mother and fetus.

Spinal anaesthesia in obstetrics

Spinal anaesthesia has been used since the 1800s but, due to a number of complications, the popularity of this technique has waxed and waned. In the 1950s, it was the most widely used method of anaesthesia and analgesia in obstetrics but it fell out of fashion with the arrival of the epidural technique which allowed a continuous method of delivering analgesia with relatively few complications. Hypotension and the high incidence of postdural puncture headaches were two reasons for the decline in the popularity of spinal anaesthesia in the young, otherwise healthy pregnant population. With the development of newer needles and bevel designs and methods whereby the incidence of hypotension can be minimized, spinal anaesthesia is making a reappearance in obstetrical anaesthesia spheres. The purpose of this article is to review the history, effects, technique, indications, contraindications and complications of this method of anesthesia as it applies to the obstetrical patient.

Anesthesia for pediatric neurological and neuromuscular diseases

Children with neurological and neuromuscular diseases often present anesthetic problems in the perioperative period. The anesthetic technique can play a significant role in altering the state of the brain during neurosurgical procedures through effects on the cerebral circulation and metabolism. Pre-existing neuromuscular disease may also have specific anesthetic implications such as cardiorespiratory involvement (eg, myotonia dystrophica), the potential for drug interactions (eg, myasthenia gravis) or abnormal responses to commonly used drugs (eg, malignant hyperthermia). In this review, the perioperative anesthetic considerations in a number of common neurological and neuromuscular conditions in the pediatric patient are discussed.

Prediction of the need for postoperative mechanical ventilation in myasthenia gravis: thymectomy compared to other surgical procedures

In a recent report Leventhal, Orkin, and Hirsh described a scoring system felt to be of value in predicting the need for postoperative mechanical ventilation in patients with myasthenia gravis undergoing thymectomy. Leventhal, et al. identified four risk factors felt to have predictive value, namely: (1) duration of myasthenia gravis greater than or equal to 6 years, (2) chronic respiratory disease, (3) dose of pyridostigmine greater than or equal to 750 mg per day, and (4) vital capacity less than or equal to 2.9 litres. Forty-six patients with myasthenia gravis who received 68 general anaesthetics were studied retrospectively. They represented the past 10 years' anaesthetic experience with myasthenia gravis at the Vancouver General Hospital. The patients were divided into two groups: (1) those who underwent thymectomy, and (2) those who underwent procedures other than thymectomy. Using the risk factors of Leventhal, et al., a predictive score was assessed for each patient; the time of postoperative tracheal extubation was also noted for each patient. From this study it was concluded that the scoring system proposed by Leventhal, et al. may have been of some value in predicting whether or not a particular patient undergoing thymectomy was likely to need ventilation postoperatively. In 41 myasthenics who had procedures other than thymectomy, however, this scoring system was found to be of no value.