MALIGNANT HYPERTHERMIA Dr. Mary Lehane Malignant Hyperthermia Investigation Unit Cork University Hospital

INCIDENCE 1: : Male = Female No racial difference

MORTALITY 5 % - 80 %

TRIGGERS All volatile anaesthetic agents Suxamethonium

GENETICS Autosomal dominant Chromosome 19 Gene RYR 1 Mutations –78 single point mutations identified to date

PRESENTATION 1A known MH patient 2Unexpected MH crisis

FULMINANT CRISIS Tachycardia Metabolic acidosis,  O 2 sat,  pCO 2 Muscle rigidity Electrolyte disturbance Arrhythmias Myoglobinuria Hyperthermia

DIAGNOSIS, consider MH if Masseter muscle spasm after sux Unexplained, unexpected tachycardia Unexplained, unexpected increase in end - tidal CO 2

EARLY MANAGEMENT 1 STOP ALL ANAESTHETIC VAPOURS CHANGE TO CLEAN ANAESTHETIC BREATHING SYSTEM ABANDON SURGERY IF FEASABLE

EARLY MANAGEMENT 2 DANTROLENE MEASURE ABGs, K + AND CK MEASURE CORE TEMP COOL PATIENT

OTHER COMPLICATIONS Arrhythmias Hyperkalaemia Metabolic Acidosis Disseminated Intravascular Coagulopathy Renal Failure

POST CRISIS MANAGEMENT WARN PATIENT AND FAMILY REFER FOR INVESTIGATION –ie muscle biopsy MEDIC ALERT

INVESTIGATION Family history Muscle biopsy In - vitro contracture tests Histology Resting CPK etc Mutation screening

KNOWN MH PATIENT Inform anaesthetist and theatre Prepare anaesthetic machine etc All hospitals should carry dantrolene All staff carry responsibility

The Cork Experience 560 Patients biopsied MHS131 MHE (h) 100 MHE (c) 6 MHN333

The Cork Families 98 Pedigrees identified 74 Probands 24 Deaths

CONCLUSION SURVIVAL Identification of at-risk patients Appropriate management