Share this article on:

Anesthetic Management of Familial Hypokalemic Periodic Paralysis During Parturition

Viscomi, Christopher M. MD; Ptacek, Louis J. MD; Dudley, Donald MD

doi: 10.1213/00000539-199905000-00021
Case Reports

Departments of (Viscomi) Anesthesiology, (Ptacek) Neurology and Howard Hughes Medical Institute, and (Dudley) Obstetrics and Gynecology, University of Utah School of Medicine, Salt Lake City, Utah.

Accepted for publication January 19, 1999.

Address correspondence and reprint requests to Christopher M. Viscomi, MD, University of Utah, Department of Anesthesiology, 50 North Medical Drive #3C444, Salt Lake City, UT 84132. Address e-mail to cviscomi@anesth.med.utah.edu.

Familial hypokalemic periodic paralysis (FHPP) is a rare inherited disease characterized by attacks of severe muscle weakness [1,2] and flaccid muscle paralysis [2,3]. Menstruation [4], pregnancy [2], and anesthesia [3,5-7] have been reported to exacerbate FHPP. Anesthetic management during parturition has not been previously described.

Back to Top | Article Outline

Case Report

An 18-yr-old nulliparous woman with a previous diagnosis of FHPP presented for routine obstetric care at 12 wk gestation. She had a positive insulin-glucose provocative test with subsequent genetic analysis revealing the classic FHPP mutation. She reported that several relatives had FHPP, including a history of ventricular arrhythmias coincident with paralytic episodes. Our patient reported onset of symptoms at the age of 12 yr, with attacks occurring one to three times per month. She described large carbohydrate-rich meals, emotional stress, and exercise as precipitating factors. Weakness would typically last 1-3 days. At the first sign of an attack, she would begin potassium supplementation (approximately 120 mEq/d). She did not have a history of respiratory failure or involvement of oral-pharyngeal muscles. She also noted mild asthma and that bronchodilators worsened her FHPP.

On consultation at 34 wk gestation, her cardiopulmonary and neurologic examinations were normal, with the exception of a slight unilateral ptosis. She reported few paralytic attacks during her first trimester, with a return to one to three attacks per month since that time. She voiced her concern that stress during parturition, labor pain, and expulsive efforts during the second stage of labor might combine to result in a paralytic episode.

An interdisciplinary management plan was developed and included continuous IV KCl supplementation during labor and postpartum, avoidance of IV glucose, insertion of an arterial catheter for frequent assessment of maternal pH and potassium concentration, early regional anesthesia, and outlet forceps delivery after passive descent of the fetus during the second stage of labor.

The patient presented in labor at 40 wk gestation. The cervix was 4 cm dilated and completely effaced. Fetal heart rate assessment was reassuring. Continuous pulse oximetry and electrocardiogram monitoring were initiated. IV and radial arterial catheters were inserted. Lactated Ringer's solution with an additional 40 mEq KCl/L was infused at 200 mL/h. Four hours after admission the patient that reported her contractions were becoming painful. Her cervical examination was 5 cm dilation, 100% effacement, 0 station. An 18-gauge Tuohy epidural needle was inserted in the L3-4 interspace without difficulty. After identification of the epidural space, a 26-gauge Gertie Marx needle was inserted via the epidural needle, and 10 [micro sign]g of sufentanil and 2.5 mg of bupivacaine were injected intrathecally. After removal of the spinal needle, a 20-gauge epidural catheter was inserted. An epidural infusion of 0.0625% bupivacaine with 2 [micro sign]g/mL fentanyl was initiated at 12 mL/h. The patient reported immediate profound analgesia.

Six hours after admission, the patient reported onset of perineal pressure. Cervical examination revealed complete dilation and +3 fetal station. An additional bolus of epidural local anesthetic (bupivacaine 0.25%, 10 mL in divided doses) was administered. Outlet forceps were applied, and a vigorous male fetus weighing 3780 g was delivered with Apgar scores of 9 and 9 at 1 and 5 min after delivery. Potassium chloride supplementation was continued for 8 h after delivery.

The patient experienced no overt episodes of paralysis. She briefly reported mild weakness when she was noted to have complete cervical dilation. Serum potassium concentrations varied between 3.6 and 4.1 mEq/dL during her labor through the first 6 h postpartum. The patient displayed a mild respiratory alkalosis during labor, with arterial pH ranging from 7.41 to 7.44 and PCO2 ranges from 26 to 30 mm Hg.

The patient and her baby were discharged home 30 h after delivery. At a follow-up clinic visit 2 wk postpartum, the patient reported two episodes of mild weakness since discharge, both of which responded to oral potassium supplementation.

Back to Top | Article Outline

Discussion

This report is the first to describe the anesthetic management of a parturient with FHPP. The familial periodic paralyses are a group of disorders involving muscle weakness and skeletal muscle ion channel mutations [8]. Although they share some phenotypic characteristics, hypokalemic and hyperkalemic periodic paralysis differ in the electrolyte alteration associated with weakness, the ion channel mutation responsible for the condition, and the treatment [8-13].

FHPP is an autosomal dominant inherited condition characterized by intermittent attacks of proximal muscle weakness and flaccid paralysis. Severe perioperative attacks have necessitated urgent intubation and controlled ventilation [3]. Rarely have complete respiratory arrest and death resulted [11].

The clinical management of FHPP [8] includes avoiding known triggers of attacks, such as psychological stress, surgery, and anesthesia. Medications known to cause intracellular shift of potassium (e.g., beta-agonists) may also provoke paralysis.

Because of the rarity of the condition, perinatal experience with FHPP is limited [14,15]. General anesthesia, postoperative stress, glucose-containing IV solutions, and long-acting neuromuscular blockers are associated with postoperative paralytic episodes.

The major goals of our management plan were avoidance of carbohydrate loads, administration of IV potassium supplementation, and avoidance of maternal hyperventilation during labor. Epidural analgesia minimizes pain-induced hyperventilation and lowers maternal serum catecholamines, both of which may prevent decreases in serum potassium levels [16-18]. The epidural analgesia technique chosen was designed to minimize muscle weakness associated with larger doses of local anesthetics. We chose to avoid an epinephrine-containing local anesthetics because of the known risk of precipitating hypokalemia with sympathomimetics [19]. Had uterine hyperstimulation occurred after intrathecal analgesia, we planned on administering IV nitroglycerin (instead of terbutaline) for uterine relaxation. Passive descent of the fetus during the second stage with elective outlet forceps delivery was chosen to avoid the need for active maternal expulsive efforts.

In summary, we report the management of a parturient with FHPP. Avoidance of IV glucose, potassium supplementation, early epidural analgesia, and a passive second stage of labor may have aided in the prevention of paralytic episodes.

Back to Top | Article Outline

REFERENCES

1. Engle AG. Periodic paralysis. In: Engle AG, Banker BQ, eds. Myology: basic and clinical. New York: McGraw-Hill, 1986:1843-70.
2. Links TP, Smit AJ, Molenaar WM, et al. Familial hypokalemic periodic paralysis: clinical, diagnostic, and therapeutic aspects. J Neurol Sci 1994;122:33-43.
3. Siler JN, Discavage WJ. Anesthetic management of hypokalemic periodic paralysis. Anesthesiology 1975;43:489-90.
4. Sarova-Pinhas I, Braham J, Shalev A. Premenstrual periodic paralysis. J Neurol Neurosurg Psychiatry 1981;44:1162-4.
5. Horton B. Anesthetic experiences in a family with hypokalemic familial periodic paralysis. Anesthesiology 1977;47:308-10.
6. Lema G, Urzua J, Moran S, Canessa R. Successful anesthetic management of a patient with hypokalemic periodic paralysis undergoing cardiac surgery. Anesthesiology 1991;74:373-5.
7. Rollman JE, Dickson CM. Anesthetic management of a patient with hypokalemic familial periodic paralysis for coronary artery bypass surgery. Anesthesiology 1985;63:526-7.
8. Machkhas H, Ashizawa T, Ptacek L. Familial periodic paralyses. Curr Neurol 1996;16:65-92.
9. Ptacek L, Tawil L, Griggs RC, et al. Dihydropyridine receptor mutations cause hypokalemic periodic paralysis. Cell 1994;77:863-8.
10. Ptacek LJ, Gouw L, Kwiecinski H, et al. Sodium channel mutations in paramyotonia congenita and hyperkalemic periodic paralysis. Ann Neurol 1992;33:300-7.
11. Riggs JE. Periodic paralysis: a review. Clin Neuropharmacol 1989;12:249-57.
12. Tanabe T, Beam KG, Powell JA, et al. Restoration of excitation-contraction coupling and slow calcium current in dysgenic muscle by dihydropyridine receptor complimentary DNA. Nature 1976;336:134-9.
13. Lehman-Horn F, Sipos I, Jurkatt-Rott K, et al. Altered calcium currents in human hypokalemic periodic paralysis myotubes expressing mutant L-type calcium channels. In: Dawson DC, Frizzell RA, eds. Ion channels and genetic disease. New York: Rockefeller University, 1995:101-3.
14. Sipos I, Jurkatt-Rott K, Harasztosi C, et al. Skeletal muscle DHP receptor mutations alter calcium currents in human hypokalemic periodic paralysis myotubes. J Physiol 1995;483:299-306.
15. Griggs RC, Engel WK, Resnick JS. Acetazolamide treatment of hypokalemic periodic paralysis: prevention of attacks and improvement of persistent weakness. Ann Intern Med 1970;73:39-48.
16. Melnick B, Chang JL, Larson CE, Bedger RC. Hypokalemic familial periodic paralysis. Anesthesiology 1983;58:263-5.
17. Rooney RT, Shanahan EC, Sun T, Nally B. Atracurium and hypokalemic familial periodic paralysis. Anesth Analg 1988;67:782-3.
18. Fisher A, Prys-Roberts C. Maternal pulmonary gas exchange: a study during normal labor and extradural blockade. Anaesthesia 1968;23:350-3.
19. Brown MJ, Brown DC, Murphy MB. Hypokalemia from beta-2 receptor stimulation by circulating epinephrine. N Engl J Med 1983;309:1414-9.
© 1999 International Anesthesia Research Society