Malignant hyperthermia revealed by cardiac arrest after paediatric sevoflurane induction: a case report

¹Anesthesiology Department, Hedi Chaker University Hospital, Sfax, Tunisia, ²Pediatric Surgery Department, Hedi Chaker University Hospital, Sfax, Tunisia, ³Pediatric Department, Hedi Chaker University Hospital, Sfax, Tunisia

^&Corresponding author
Anouar Jarraya, Anesthesiology Department, Hedi Chaker University Hospital, Sfax, Tunisia

Introduction    

Malignant hyperthermia (MH) is a rare and severe pharmacogenetic disorder of skeletal muscle [1] that manifests clinically as a hypercatabolic crisis caused by volatile anesthetic or succinylcholine exposure [1]. The prevalence is about 1/100 000 administered anesthetics in general population [2] but its mortality remains high (10% to 70%) [2].Classic clinical symptoms of MH include hypercarbia, tachycardia, masseter contraction and hyperthermia [1]. Severe cardiac arrhythmia leading to cardiac arrest may be seen later [3], but the occurrence of cardiac arrest with asystole immediately after sevoflurane administration is original. We describe the case of one-year boy who presented immediate cardiac asystole with delayed classic symptoms of MH after sevoflurane exposure.

Patient and observation     

Patient information: we present a case report of a 14 months boy scheduled for inguinal hernia cure. The patient had no co-morbid condition with any past history of surgery or any previous anesthetic exposure. However, the patient had good psychomotor development and acquired walk at the age of one year. Our patient had correct preoperative hemostasis blood analysis. On the day of surgery, preoperative temperature was 37°C and starvation instructions were respected.

We begin external cardiac massage and manual ventilation with 100% oxygen and adrenaline administration (250 μg/bolus/2min then continuous adrenaline infusion 1000μg/h). The cardiac resuscitation lasted 25 minutes, then, a cardiac activity was noted with tachycardia up to 160b/min, with a high blood pressure 132/80 mmHg that allowed the progressive withdrawal of adrenalin infusion. A rising trend in end tidal CO² was noticed (40 mmHg). A small rise in temperature with maximum 38°C was recorded by nasopharyngeal probe.

Two hours after, we tried to awake the patient but he was always unconscious and developed a tachycardia with 180 b/min and tachypnea 50c/min, so a propofol infusion (10mg/kg/h) was restarted, and the patient was referred to the Pediatric Intensive Care Unit (PICU). In the PICU, 5 hours after sevoflurane exposure, the patient had increasing hyperthermia up to 40°C, tachycardia up to 200/min, polypnea (70/min) and 99% oxygen saturation. Active cooling was started. Blood sample showed severe acidosis (pH 7.22 and lactate: 3.8mmol/l) with hypercarbia (63mmHg) hyperkalemia (5.8 mEq/L) and rahabdomyolysis and renal failure (creatine phosphokinase (CPK) up to 2936 and creatinine:104μmol/L).

Diagnostic assessments: to confirm the diagnosis of MH, muscular biopsy was done and showed muscular dystrophy. Genetic mutations in ryanodine receptor type 1 (RYR1) were tested positive. MH was confirmed.

Therapeutic interventions: the patient was referred to the intensive care unit for to monitor the temperature, blood pressure, heart rate, breathing and response to treatment. We opted to symptomatic treatment by body cooling and mechanical ventilation with high concentration of oxygen. The patient gets extra fluids through a central IV line. The collapsus was treated by saline co-load and noradrenaline infusion. However, Dantrolene, drug of choice for malignant hyperthermia that acts by stopping the release of calcium into the muscle, is unavailable in our country.

Follow-up and outcomes: the patient developed multivisceral failure and died 72 hours later. All family members of the patient were made aware of suspected diagnosis of malignant hyperthermia and risks of recurrence in other family members on future exposure to anesthesia.

Discussion     

Malignant hyperthermia (MH) is a potentially fatal pharmacogenetic disease [4]. The initial signs of MH generally occur soon after triggering agents´ exposure or at any time during anaesthesia maintenance and rarely few hours later [4]. The first signs of MH are hypercarbia, sinus tachycardia and masseter spasm [4]. However, peaked T waves and arrhythmias may occur later due to acute hyperkalemia. In addition, the youngest children have small muscular mass that may explain that the metabolic disorders may occur later [4]. In our case, these severe disorders appeared within 2 minutes and caused cardiac asystole immediately which seems to be original and which make the diagnosis of malignant hyperthermia difficult. Using clinical grading scale to assess the likelihood of a MH may be useful in these cases [5]. This scale will gather different clinical and biological elements in favor of MH and take consideration to related diseases like muscular dystrophy [5,6].

As the majority of reported cases are caused by mutations in two genes: RYR1 gene (ryanodine receptor type 1) and CACNA1S gene (voltage-dependent L type calcium channel alpha 1S subunit), genetic study can help in the diagnosis and prevent similar accidents in the family [7]. While invitro contracture test remains the gold standard for malignant hyperthermia susceptibility (MHS) diagnosis [8]. Symptomatic resuscitation of MH according to the recent guidelines is mandatory [9], and Dantrolene remains the drug of choice for this disease. It must be introduced as soon as the diagnosis is suspected. Since its introduction, MH mortality has fallen from 80% to less than 5% [10]. Its mechanism of action is to bind to ryanodine receptors and block calcium release causing muscle relaxation [10], unfortunately, this drug was not available in our country and the evolution was fatal for our patient in spite of resuscitation.

Conclusion     

The presented case highlights that MH is a rare but severe pharmacogenetic disorder that manifestations may vary. Classic signs of MH were delayed few hours after sevoflurane exposure and the immediate signs were cardiac asystole which is original. The treatment of MH is based on symptomatic resuscitation but also Dantrolene administration that should be present in all anesthesiology departments.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Anouar Jarraya and Bilel Louati contributed to the redaction of the manuscript. Manel Kammoun contributed to the correction of the manuscript. Saloua Ammar contributed to data collection. Hsairi Manel and Loulik Mouna contributed to the medical resuscitation and was in charge the patient.

References