///2009 Abstract Details
2009 Abstract Details2018-05-01T17:45:11+00:00

Optimum Anesthetic Management of Labor in a Primigravida with Myasthenia Gravis

Abstract Number: 81
Abstract Type: Case Report/Case Series

Eric Olness MD1 ; Richard Driver MD2

Introduction: Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction (NMJ) that can be exacerbated during the peripartum period. MG causes a decrease in functional NMJ acetylcholine receptors. MG patients are sensitive to the motor and respiratory effects of many anesthetic agents. We report optimal management of labor analgesia in a primigravid patient with MG.

Case: A 24yo G1 at 37 0/7 wks presented with SROM. The patients medical history included thymectomy for MG in 2003 with no bulbar or extraocular muscle weakness at time of admission and no complications with the pregnancy. Medications included only PNV; she had stopped pyridostigmine in 2007. A lumbar epidural was successfully placed using a saline LOR technique. After catheter placement and a lidocaine/epinephrine test dose, 8ml of 0.2% ropivacaine was administered in two divided doses. PCEA was initiated with a 12ml/hr continuous infusion of 0.1% ropivacaine with 2mcg/ml of fentanyl, and bolus dose 4ml q 15min. Sensory level to pin prick following loading was T9 (R) and T5 (L). The patient was comfortable and had an uncomplicated spontaneous vaginal delivery of a 3000g female infant after a 3-4 hour labor; APGARs 8/9. The patient walked and voided within 4 hours and was discharged home 2 days later. No clinically evident muscular weakness was observed.

Discussion: MG is characterized by fluctuating muscle weakness and fatigability without reflex, sensory, or coordination abnormalities.1 MG symptoms or crises may be precipitated by pregnancy, physical or emotional stress, surgery, or systemic illness.2 Worsening symptoms occur in approximately 1/3 of pregnant patients with the highest frequency in the first trimester, but can occur any time during pregnancy.3 Patients with MG have an increased sensitivity to many anesthetic agents, including neuromuscular blockers and the respiratory depressant effects of opioids. Epidural analgesia can decrease stress and fatigue and provide adequate anesthesia in the event operative vaginal delivery is required.1,4 The combination of PCEA, low concentration LA, and adjunctive opioid minimizes the risk of motor impairment. Ropivacaine was chosen due to reports of potentially decreased motor blockade. This technique provided safe and effective labor analgesia for this MG patient.

References:

1) Clin Obstet Gynecol. 2005; 48: 48-56

2) J Obstet Gynecol. 2007; 27: 30-32

3) Sem Neurol. 2004; 24: 95-100

4) Acta Anaesthesiol Scand. 2007; 51: 831-38

SOAP 2009