There are many causes of seizures and the treatment for seizures relies on treating the underlying cause. For example, patients who are hypoglycemic may have seizures, which are corrected by the administration of Dextrose; patients who are hypoxic may have seizures, which are easily corrected by maintaining an airway and providing oxygen and ventilatory support; and for patients who are pregnant they may be suffering from eclampsia, which is treated by the administration of Magnesium Sulfate. However, is Magnesium Sulfate indicated for the pregnant patient who is seizing and has a history of seizures and the medical provider is unsure if this is due to eclampsia or their known seizure condition?
Seizures are defined as “a brief alteration in behavior or consciousness,” which is “caused by abnormal electrical activity of one or more groups of neurons in the brain.” While this is not fully understood, most believe that the “abnormal electrical activity” is often due to “a structural lesion or problems with brain metabolism,” which leads to “changes in the brain cell’s permeability to sodium and potassium ions.” As the brain begins to struggle with changes in sodium and potassium, “the neurons’ ability to depolarize and emit an electrical impulse sometimes results in seizure activity” (Sanders, 2007).
So how are seizures related to pregnancy? After 24 weeks gestation, the mother may experience toxemia of pregnancy, also known as preeclapsia or the more severe form eclampsia. Most often preeclampsia and eclampsia are “characterized by vasospasm, endothelial cell injury, increased capillary permeability, and the activation of the clotting cascade,” which often leads to the classic triad of preeclampsia:
• Hypertension (“blood pressure greater than 140/90 mmHg, an acute rise of 20 mmHg in systolic pressure, or a rise of 10 mmHg in diastolic pressure over prepregnancy levels.”)
• Proteinuria
• Excessive weight gain
Eclampsia incorporates this triad, however it also involves seizures or coma. These signs and symptoms are often a “result from hypoperfusion to the tissue or organs involved;” and in the case of eclampsia, the brain, which is why seizures are seen (Sanders, 2007).
The treatment for eclampsia involves managing the seizures. Diazepam or Lorazepam may be administered in conjunction with providing proper oxygenation and treating reversible causes (e.g. hypoglycemia). In the presence of preeclampsia or eclampsia Magnesium Sulfate is administered (Sanders, 2007), but what if the seizing pregnant patient has a history of seizures and it is unknown if the patient is suffering from a preeclamptic seizure or a breakthrough seizure? Should Magnesium Sulfate still be administered? Sadeh et al. (1991) reports that research has shown “Magnesium Sulfate in acute uncontrolled generalized seizures” has had success in stopping the seizures in the patient presenting with status epileptics.
Sadeh et al. present a case in which a 16-year-old girl was admitted to the hospital for simple partial seizures, which soon turned into tonic clonic seizures. The patient was treated with Phenytoin, but the seizures still persisted the patient was placed on a Magnesium drip. While the patient was on the drip seizures did not occur; however, because the patient stayed into a deep coma and there was “generalized flaccidity and areflexia of the lower limbs the Magnesium Sulfate infusion was discontinued.” Soon after the discontinuation of the Magnesium Sulfate, the seizures began to reappear, which prompted the doctors to place the patient back on the Magnesium Sulfate drip and once again the seizures stopped. Over the next few days, the patient was taken off the Magnesium drip, which resulted in the seizures reoccurring and soon put back on the Magnesium drip, which would soon stop the seizures. Sadeh et al. conclude that the use of Magnesium Sulfate as an anticonvulsant may be a better alternative to seizure therapy in patients experiencing seizures of unknown or specific etiologies. Beck (2002) supports this claim made by Sadeh et al. by saying “[Magnesium Sulfate] depresses the CNS and controls convulsions by blocking [the] release of acetylcholine at the myoneural junction.” Furthermore, Magnesium Sulfate “decreases the sensitivity of the motor end plate to acetylcholine and decreases the excitability of the motor membrane. In fact, over 60 years ago Magnesium Sulfate was used to treat seizures of many etiologies including “uremic seizures and status epileptics as well as eclampsia … however with the advent of newer antiepileptic drugs its employment has been virtually limited to [eclampsia]” (Sadeh, Blatt, Martonovits, Karni, & Goldhammer, 1991).
Seizures, whether they are eclamptic or breakthrough, can be damaging to both the mother and the unborn child. Because patients who are seizing often do not receive proper oxygenation to the tissues, establishing and maintaining an open airway is critical to the outcome of the patient. Once an airway is established proper pharmacological drugs can be used to break the seizure. Furthermore, eclampsia is associated with hypertension that can be deadly to the unborn child. Whether or not it is known if the seizing pregnant patient is seizing because of a prior seizure condition or eclampsia, they should be treated as worst case scenario and Magnesium Sulfate should be administered because of its anticonvulsant effect, it “has a benefcial effect on factors leading to eclampsia,” and because it “can reverse arterial vasocontriction” (Wyllie, Gupta, & Lachhwani, 2006).
Works Cited
Beck, R. (2002). Drug Reference for EMS Providers. Albany, NY: Thompson Learning, Inc.
Sadeh, M., Blatt, I., Martonovits, G., Karni, A., & Goldhammer, Y. (1991). Treatment of Porphyric Convulsions with Magnesium Sulfate. Epilepsia , 32 (5), 712-715.
Sanders, M. (2007). Mosby’s Paramedic Textbook (3rd Edition ed.). St. Louis, Missouri: Elsevier Mosby.
Wyllie, E., Gupta, A., & Lachhwani, D. (2006). The Treatment of Epilepsy. Philadelphi, PA, USA: Lippincott Williams and Wilkins.
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