The Ophthalmologist and Malignant Hyperthermia

AMERICAN JOURNAL OF OPHTHALMOLOGY FRANK W. N E W E L L , Publisher and Editor-in-Chief Tribune Tower, Suite 1415, 435 North Michigan Ave., Chicago, Illinois 60611 EDITORIAL BOARD Thomas M. Aaberg, Milwaukee Mathea R. Allansmith, Boston Douglas R. Anderson, Miami Charles J. Campbell, New York Ronald E. Carr, New York Claes H. Dohlman, Boston Fred Ederer, Bethesda Eugene Helveston, Indianapolis Frederick A. Jakobiec, New York

Herbert E. Kaufman, New Orleans Steven G. Kramer, San Francisco Carl Kupfer, Bethesda Irving H. Leopold, Irvine Robert Machemer, Durham A. Edward Maumenee, Baltimore Irene H. Maumenee, Baltimore Edward W. D. Norton, Miami G. Richard O'Connor, San Francisco Arnall Patz, Baltimore

Deborah Pavan-Langston, Boston Steven M. Bodos, New York Stephen J. Ryan, Los Angeles David Shoch, Chicago Bruce E. Spivey, San Francisco Bradley R. Straatsma, Los Angeles H. Stanley Thompson, Iowa City Gunter K. von Noorden, Houston George O. Waring, Atianta

Published monthly by the Ophthalmic Publishing Company Tribune Tower, Suite 1415, 435 North Michigan Avenue, Chicago, Illinois 60611 Directors: A. EDWARD MAUMENEE, President; DAVID SHOCH, Vice President; FRANK W. NEWELL, Secretary and Treasurer; EDWARD W. D. NORTON, BRUCE E. SPIVEY, BRADLEY R. STRAATSMA

THE OPHTHALMOLOGIST AND MALIGNANT H Y P E R T H E R M I A General anesthesia adds to t h e risk of ophthalmic surgery. The ophthalmologist rarely considers malignant hyperthermia, an often fatal hereditary (autosomal domi­ nant) pharmacogenetic trait, triggered by exposure to anesthetic agents that cause rapid production of tremendous amounts of heat, generalized skeletal muscle con­ traction, and associated metabolic acidosis. 1 Malignant hyperthermia is a true medical emergency; if t h e syndrome is not recognized, serious consequences may follow. Triggers for susceptible individuals in­ clude most forms of inhalation anesthet­ ics; worsening occurs with simultane­ ously administered succinylcholine. The syndrome is more common in males, rarely occurs in those more than 50 years old or less than 2 years old, and currently has a mortality of 28%. 2 The first signs include tachycardia (double to triple t h e baseline rate) and skeletal rigidity; later, pyrexia and coma develop before death. 3 Successfully treated patients may have

severe muscle pain and spasms for weeks, along with late-onset myoatrophy. Per­ manent central nervous system deficits are frequent, and renal failure occasional­ ly develops. 2 The syndrome is important to all sur­ geons who use general anesthesia, and especially to ophthalmologists because there is a higher incidence in children (one in 15,000 cases) 4 and because af­ fected individuals are more likely to have myopathy and blepharoptosis that may lead to general anesthesia for ophthalmic surgery. 5 There are a number of steps that can be taken to detect susceptible patients b e ­ fore anesthesia is administered. 6 The most important is t h e identification of other family members who have already had problems because of the autosomal dominant nature of the condition. 7 In this issue of T H E JOURNAL, Waterman de­ scribes the detection of malignant hyper­ thermia syndrome and methods of treat­ ing it. Confirmation of t h e presence of the syndrome may b e obtained by laboratory

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VOL. 92, NO. 4 testing. This can be important, because hypothermie reaction to anesthesia has an incidence of 1.4%.8 This reaction alone justifies avoiding further anesthesia. Waterman details the steps necessary for laboratory identification of affected individuals. This requires a specialized physiologic laboratory 9,10 and an open muscle-biopsy specimen from the pa­ tient. Systemic assays such as plasma creatine kinase can suggest the diagnosis, but the presence of considerable overlap makes the results nondiagnostic. 11 A recent discovery has simplified the diagnosis and identification of affected patients. An assay using a blood sample measures a decrease in the ratio of adenosine triphosphate and adenosine diphosphate to adenosine monophosphate, inosine monophosphate, and other nucleotides in isolated platelets exposed to halothane in vitro. Solomons, McDermott, and Mahowold 12 found no overlap be­ tween normal and affected individuals. The diagnosis can be made by venipuncture sampling, definitively identifying af­ fected individuals without a muscle biop­ sy. Identified patients who require general anesthesia can be treated preoperatively with a regimen that includes dantrolene sodium, an excitation-contraction uncoupler of skeletal muscle, 13 along with the extensive preoperative and postoper­ ative metabolic support described in Wa­ terman's article. This technique is gener­ ally well tolerated and offers the best chance for such patients. We recently used the platelet assay successfully. A 2-year-old child under­ went general endotracheal inhalation an­ esthesia (halothane) during goniotomy for congenital glaucoma. Probably as a result of a dehydration caused by a 24-hour fast, the child suffered a sustained increase in temperature and rapid heart rate during anesthesia. Both subsided by the end of the procedure. As a result of this episode,

EDITORIAL

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the child was suspected of being suscep­ tible to malignant hyperthermia syn­ drome. When examination with the child under anesthesia was indicated to deter­ mine the success of the goniotomy, the anesthesiologists were concerned about the risks. A blood sample was drawn and assayed by the platelet nucleotide test. The result was normal and routine inhala­ tion anesthesia was administered without incident. The child can now be anesthe­ tized for any required examination with­ out complex and potentially hazardous preparation. This syndrome and its attendant haz­ ards should be known to ophthalmolo­ gists; if this convenient and accurate technique proves to be reliable, we can expect fewer difficulties in patient man­ agement. RICHARD E. BENSINGER RICHARD H. HASCHKE

REFERENCES 1. Areans, J., and McKinnon, W.: Malignant hyperpyrexia during anesthesia. J.A.M.A. 125:919, 1971. 2. Steward, D.: Malignant hyperthermia. The acute crisis. Int. Anesthesiol. Clin. 17:1, 1979. 3. Ryan, J. : Treatment of acute hyperthermic cri­ sis. Int. Anesthesiol. Clin. 17:153, 1979. 4. Britt, B., and Kalow, W. : Malignant hyperther­ mia. A statistical review. Can. Anesth. Soc. J. 17:293, 1970. 5. Britt, B., Endryni, I., and Peters, P.: Screening of malignant hyperthermia susceptible families by CPK measurement and after clinical investigation. Can. Anesth. Soc. J. 23:263, 1976. 6. Britt, B.: Preanesthetic diagnosis of malignant hyperthermia. Int. Anesthesiol. Clin. 17:63, 1979. 7. Denborough, M., Forster, J., and Maplestone, P.: Anesthetic deaths in a family. Br. J. Anesth. 34:395, 1963. 8. Ramono, P., and Robinson, T. J.: General an­ esthetic morbidity and mortality in eye surgery at a children's hospital. Pediatr. Ophthalmol. Strabismus 18:17, 1981. 9. Nelson, T., Bedell, D., and Jones, E. : Porcine malignant hyperthermia. Effects of temperature and extracellular calcium concentration on halothane in­ duced contraction of susceptible skeletal muscle. Anesthesiology 42:301, 1975. 10. Britt, B., Endrenyi, I., and Kalow, W.: The ATP depletion test. Can. Anesth. Soc. J. 23:624, 1976.

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11. Isaacs, H., and Barlow, M.: The genetic back­ ground to malignant hyperthermia revealed by serum creatine phosphokinase estimation in asymp­ tomatic relatives. Br. J. Anesth. 42:1077, 1970. 12. Solomons, C. N., McDermott, N., and Mahowald, M.: Screening for malignant-hyperthermia with a platelet bioassay. N. Engl. J. Med. 303:642, 1980. 13. Young, R., and Delwaide, P. : Spasticity. Drug therapy. Part I. N. Engl. J. Med. 304:28, 1981.

CORRESPONDENCE Letters to the Editor must be typed double-spaced on 8V2 x 11-inch bond paper, with 1'/2-inch margins on all four sides, and limited in length to two man­ uscript pages.

OCTOBER, 1981

1%), both manufactured by Barnes-Hind Pharmaceuticals, Inc., are common in ophthalmologists' offices. The two drugs are packaged in bottles of similar size, shape, and color, and both products have orange labels and similar eyedroppers and caps (Figure). Eppy/N could be ad­ ministered instead of Fluress, particular­ ly in a dimly illuminated room. This mistake could precipitate an attack of angle-closure glaucoma. Ophthalmolo­ gists should be aware of the similarity of the packaging of these drugs and should check labels carefully before instilling any medication in the eye. L E O N PARTAMIAN,

M.D.

M I C H A E L KASS,

M.D.

St. Louis,

Missouri

Similar Packaging of Ophthalmic Drugs Editor: The letter, "Dangers of similar packag­ ing," by M. B. Rumelt (Am. J. Ophthalmol. 91:804, 1981), has prompted us to report another potentially dangerous sim­ ilarity in the packaging of ophthalmic eyedrops. Fluress (fluorescein sodium 0.25%) and Eppy/N (epinephryl borate

Figure (Partamian and Kass). The bottles contain­ ing Fluress and Eppy/N are similar in size, shape, and color; the labels and eyedroppers are also similar.

Retrieving a Lost Contact Lens from a Sink Editor: Although contact lenses are sometimes dropped down the drain of a sink, they can often be retrieved without damage. If a contact lens is lost in the drain, one should close the drain immediately and turn off the water. The contact lens should adhere to the side of the drain or in the trap. Place a piece of cloth or adhesive tape over the slip nuts of the J-bend (trap), unscrew the nuts, and re­ move the trap. Next, empty the trap and flush its contents through the strainer. If the contact lens is not there, turn the water on and allow it to flow through the pipe, swirling it to wash anything off the sides, and through the strainer. In most cases the contact lens appears in the strainer in an undamaged condi­ tion, thus avoiding the inconvenience and cost of ordering another contact lens. When you replace the trap, be sure to wrap thread seal tape around the pipe or