SEVERE MUSCULAR RIGIDITY AT BIRTH: MALIGNANT HYPERTHERMIA SYNDROME? K. SEWALL, R.M.M. FLOWERDEW AND P, BROMBERGER ABSTRACT A case of severe muscular rigidity in a premature male infant born by Caesarean Section under general anaesthesia is described. A probable diagnosis of malignant hyperthermia was sup- ported by the clinical symptoms of muscular rigidity and cyanosis, a ereatinine phosphokinase of 24,630 I.U. (Normal 0-100) and a urinary myoglobin of 248 mg/I (normal 6-35). The muscle tone and laboratory values slowly returned to normal over a period of days. Anaesthetic management for a ventriculoperitoneal shunt performed at seven weeks of age included pre and postoperative treatment with dantrolene. No crisis occurred at this time. The parents, who have normal CPK and a negative family history, were advised to treat the child as if he had malignant hyperthermia until such time as a definitive diagnosis can be made. SEVERE MUSCLE RIGIDITY at birth is an uncom- given intravenously followed by a continuous mon event and may have several different infusion at 2g/hour. Four hours later, foetal aetiologies including, possibly, malignant hy- bradycardia was noted on an external foetal perthermia. The crisis of this syndrome rarely monitor (Doppler). Artificial rupture of mem- occurs in the very young age groups but has been branes produced dark, blood-tinged amniotic reported by Henschel and Koh ~ in a fourteen- fluid and severe foetal bradycardia. Placental ab- month-old child while dePinna ~ described a pos- ruption was diagnosed; an immediate Caesarean sible aborted crisis in a nine-week old infant. This Section was done. Rapid induction with report describes an infant who was rigid at birth thiopentone, succinylcholine, orotracheal intu- following general anaesthesia for a Caesarean bation was followed by oxygen, nitrous oxide and section. The clinical course appeared consistent 0.5 per cent halothane. Delivery was completed with a malignant hyperthermia crisis but a muscle in less than five minutes. Management was un- biopsy for a positive diagnosis was unobtainable complicated. The placenta showed a 40 per cent at the time because of the infant's small size. separation. Subsequently at seven weeks of age the infant The infant was a 1550g male of 32 weeks ges- required a ventriculoperitoneal shunt. The tational age) He had marked muscular rigidity anaesthetic management for this procedure is de- and cyanosis which persisted despite orotracheal scribed. intubation and controlled ventilation with oxy- gen. Chest expansion was poor, although breath CASE REPORT sounds were equal. Limb muscles felt as if they were in continuous spasm. The extremities were A twenty-six-year-old white woman, GS, P1, flexed and could not be straightened. Ab2, in early labor at an estimated 34 week gesta- On arrival at the Neonatal Intensive Care Unit tion, was referred to Maine Medical Center with a approximately 15 minutes later, the neonate's diagnosis of pregnancy-induced hypertension. extremities were still rigid and flexed. The initial Since pelvic ultrasonography indicated a 29-week arterial blood gas determination indicated com- foetus, terbutaline was used to inhibit labour and bined metabolic and respiratory acidosis, cH + betamethasone to accelerate foetal pulmonary 83.18 nmol/I (pH 7.08), Paco~ 6.18 kPa (51 torr), maturation. The hypertension responded to bed HCO3 16 mmol/l, Pao~ 8.0 kPa (60 torr), at FIn2 rest. On the third day, bifrontal headache, 1.0. Temperature was 350 C, pulse 150, blood epigastric pain, oedema and a blood pressure of pressure 40mm Hg, creatine phosphokinase 175/105 mm Hg indicated progression of the dis- (CPK) 24,360 I.U. (0-100),* calcium 8.6 mg per ease. A 4g bolus of magnesium sulphate was cent (8.5-10.0),* magnesium 3.9rag per cent (0.8-2.6),* and glucose less than 10 mg per cent K. Sewall, M.D., R.M.M. Flowerdew, M.B.B.S., (35-160).* Urine was "Hemastick" positive but FFARCS, Associate Anaesthesiologists; P. Brom- berger, M.D., Attending Paediatrician, Associate contained no red blood cells on microscopic Neonatologist, Maine Medical Center, Portland, Maine examination. Muscle rigidity resolved over a 04102, U.S.A. four-hour period although muscle firmness per- 279 Canad. Anaesth. Soc. J., vol. 27, no. 3, May 1980 280 CANADIAN ANAESI-HETISTS ~ SOCIETY JOURNAL sisted for several days. Ventilatory support was scope and rectal, nasal, and axillary temperature necessary for the first two days but was easily probes were attached. The room was kept warm withdrawn. At 48 hours the CPK was 9075 I,U. (26~ C) to maintain normothermia and a heat- and urinary myoglobin was 248mg/1 (6-35).* ing/cooling blanket was placed on the operating Thrombocytopenia (platelets 36,000 cumm) and table. An arterial line was inserted by cut-down transient renal insufficiency with oliguria, blood using procaine HCI for local anaesthesia. Body urea nitrogen 39mg per cent (10-20)* and temperature remained normal despite the infant's creatinine 1.9 nag per cent (0.5-1.0)* complicated crying. Anaesthesia was induced with thiopen- recovery. Cultures from nose, rectum, umbilical tone and fentanyl and maintained with oxygen, cord, blood, cerebrospinal fluid and urine taken nitrous oxide, and incremental doses of fentanyl. prior to antibiotic treatment showed no growth. Tracheal intubation was accomplished without On the fifth day a lumbar puncture revealed relaxants. Respiration was controlled. Ventila- grossly bloody cerebrospinal fluid. On the ninth tory compliance appeared decreased but limb day a computerized tomography scan confirmed musculature remained relaxed. Anaesthesia was a grade Ill ~s intraventricular haemorrhage. uneventful except for a moderate degree of The mother's postoperative course was com- hyperventilation which was shown by arterial plicated by anaemia and thrombocytopenia. blood gas measurements during operation. No The pregnancy-induced hypertension subsided acidosis, rigidity or rise in temperature occurred. slowly. She was discharged on the ninth post- Residual narcotic depression was antagonized by operative day still complaining of decreased vis- naloxone. ual acuity and requiring diuretic therapy. Careful Monitoring was continued in the Neonatal In- review of the family history revealed nothing to tensive Care Unit; recovery was uneventful, The suggest malignant hyperthermia. Both parents CPK preoperatively was 40 i.U., during opera- had normal resting CPK. tion 85 I.U. and I 11 I.U., and postoperatively 141 I.U. Postoperative oral dantrolene was continued ANAESTHETIC MANAGEMENT for three days, during which time the infant re- mained lethargic and fed slowly, returning to his The infant's hydrocephalus, resulting from the preoperative state when the dantrolene was stop- intraventricular haemorrhage, was treated ini- ped. The infant was discharged home on the 63rd tially with serial lumbar punctures. In the seventh day. The parents were warned to treat the child as week a ventriculoperitoneal shunt was inserted if he had malignant hyperthermla until a muscle operatively. Anaesthetic management followed biopsy suitable for in vitro testing might be ob- the guidelines set forth by Britt, Kwong, En- tained for definitive diagnosis. At 6 months drenyi.~ The infant weighed 2.5 kg. Pretreatment follow-up, the infant has visual and auditory de- with dantrolene sodium, as suggested by Kerr, ficits and his major motor development is de- Wingard. and Gatz, z and Harrison 4 was started layed. three days before operation with 3 mg by mouth four times daily, reduced after 24 hours to 3 mg DISCUSSION three times daily because the infant became ex- cessively lethargic and fed poorly. Special The striking clinical feature in this case was the anaesthetic precautions included a vapour-free muscle rigidity present at birth, associated with a anaesthesia machine and circuit (Jackson Rees marked elevation of the CPK, and myoglo- modification of Ayres-T-piece) and an operating binuria, all of which gradually resolved over the room which had not been used for the previous 24 first week of life. The differential diagnosis of hours, in addition to the conventional drugs, a transient muscle rigidity in the newborn includes supply of intravenous dantrolene, ~ the drug of neonatal tetanus, tetany, encephalitis, menin- choice for treating the crisis of malignant hyper- gitis, kernicterus, heroin withdrawal, and phe- thermia ~.s.6 was available in the operating room. nothiazine intoxication, 7 all of which were un- The patient, unpremedicated and with an in- likely in this case. Reported causes of persistent travenous line. was taken to the operating room muscle rigidity at birth include continuous where an electrocardiogram, precordial stetho- peripheral nerve hyperactivity, 7 degenerative or destructive cervical cord lesions,S and congenital *( ) indicates normal range. myopathies. ~ Sclerema neonatorum, a woody in- t Eaton Laboratories, Norwich, New York. duration of subcutaneous tissue which occurs in SEWALL, el (1l.: RIGIDITY AT BIRTH: MALIGNANT HYPERTHERMIA SYNDROME7 281 severely ill premature and term infants, is often patients with crisis, however, all three enzymes, associated with overwhelming sepsis or a severe MM, BB and MB are present. Unfortunately en- hypotensive episode and becomes apparent 24 to zyme fractionation, which might have helped 48 hours after the precipitating event. This case is confirm the diagnosis, was not done. unique in that muscle enzymes, muscle mass and Even though the diagnosis of MHS was tone all returned to normal within a week of birth. equivocal the clinical features were sufficient to Severe neonatal asphyxia is most often as- warrant MHS precautions for anaesthetic and sociated with hypotonia at birth, l~ Maternal gen- surgical procedures until a definite answer is ob- eral anaesthesia j2 and neonatal hypermag- tained. nesaemia ~3 are other factors which predispose to An intraventricular haemorrhage occurred, flaccidity at birth. This infant was exposed to all probably as a result of perinatal asphyxia and of these factors but was nevertheless rigid at prcmaturity. Post-haemorrhaglc hydrocephalus birth.