To the Editor:—

We read with great interest the article by Dr. Uratsuji concerning a case of rhabdomyolysis after abdominal surgery in the hyperlordotic position. 1The authors concluded that rhabdomyolysis and the increase of creatine kinase (CK), lactate dehydrogenase, and serum myoglobin were sufficiently explained by lumbar muscle damage. However, malignant hyperthermia (MH) as another possible cause was not ruled out.

First, it is important to know whether this patient was anesthetized before this incident and whether the patient’s family members had anesthetic complications or a history of muscle disease. This patient had an elevated CK of 168 U/l at rest, which might be caused by subclinical myopathy. Furthermore, it is well known that MH is characterized by a hypermetabolic response to inhalational anesthetics (e.g.,  sevoflurane) or depolarizing muscle relaxants, leading to muscle rigidity, metabolic acidosis, hypercapnia, tachycardia, and fever. However, relevant clinical parameters necessary for interpretation of this syndrome, such as temperature, end-tidal carbon dioxide concentration, arterial blood gases, heart rate, and muscle tone (i.e.,  rigidity or masseter spasm) were not presented. With these clinical parameters, it would be possible to predict the qualitative likelihood of susceptibility to MH using the Clinical Grading Scale (CGS). 2In this case, the raw-score rank of the CGS has a minimum of 15 points (CK elevation > 10.000 U/l; MH rank 3, which is defined as somewhat less than likely). However, one might speculate that the use of all clinical indicators of the CGS might produce a higher MH rank. 3 

The clinical course of MH is highly variable (e.g.,  fulminant, moderate, and mild forms) and postoperative rhabdomyolysis may be the only symptom of MH. Although the probability of MH susceptibility in patients with anesthesia-induced rhabdomyolysis is only 0.07, 4the in vitro  contracture tests with halothane and caffeine are necessary for diagnosis of MH susceptibility. 5,6This view is also emphasized in several case reports that present clinical courses of postoperative rhabdomyolysis after the use of volatile anesthetics. 7–9 

We recommend that the qualitative likelihood of susceptibility to MH should be assessed using the CGS in all cases with MH-like symptoms. Furthermore, all patients with clinical suspicion of MH should undergo muscle biopsy for in vitro  contracture tests, histologic examination, and genetic screening.

1.
Uratsuji Y, Ijichi K, Irie J, Sagata K, Nijima K, Kitamura S: Rhabdomyolysis after abdominal surgery in the hyperlordotic position enforced by pneumatic support. A NESTHESIOLOGY 1999; 91:310–2
2.
Larach MG, Localio AR, Allen GC, Denborough MA, Ellis FR, Gronert GA, Kaplan RF, Muldoon SM, Nelson TE, Ørding H, Rosenberg H, Waud BE, Wedel DJ: A clinical grading scale to predict malignant hyperthermia susceptibility. A NESTHESIOLOGY 1994; 80:771–9
3.
Richthofen von V, Wappler F, Fiege M, Scholz J: Prediction of malignant hyperthermia susceptibility with the clinical grading scale. A NESTHESIOLOGY 1997; 86(suppl):A997
4.
Ellis FR, Halsall PJ, Christian AS: Clinical presentation of suspected malignant hyperthermia during anaesthesia in 402 probands. Anaesthesia 1990; 45:838–41
5.
Larach MG, North American Malignant Hyperthermia Group: Standardization of the caffeine halothane muscle contracture test. Anesth Analg 1989; 69:511–5
North American Malignant Hyperthermia Group:
6.
Ørding H, Brancadoro V, Cozzolino S, Ellis FR, Glauber V, Gonano EF, Halsall PJ, Hartung E, Heffron JJA, Heytens L, Kozak-Ribbens G, Kress H, Krivosic-Horber R, Lehmann-Horn F, Mortier W, Nivoche Y, Ranklev-Twetman E, Sigurdson S, Snoeck M, Stieglitz P, Tegazzin V, Urwyler A, Wappler F: In vitro contracture test for diagnosis of malignant hyperthermia following the protocol of the European MH Group: Results of testing patients surviving fulminant MH and un-related low-risk subjects. Acta Anaesthesiol Scand 1997; 41:955–66
7.
Rubiano R, Chang JL, Carroll J, Sonbolian N, Larson CE: Acute rhabdomyolysis following halothane without succinylcholine. A NESTHESIOLOGY 1987; 67:856–7
8.
Harioka T, Sone T, Toda H, Miyake C: Malignant hyperthermia in a hemodialysis patient. Anesth Analg 1989; 69:119–21
9.
Portel L, Hilbert G, Gruson D, Favier JC, Gbikpi-Benissan G, Gardinaud JP: Malignant hyperthermia and neuroleptic malignant syndrome in a patient during treatment for acute asthma. Acta Anaesthesiol Scand 1999; 43:107–10