MALIGNANT HYPERTHERMIA

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

INCIDENCE • 1:12 000 - 1:40 000 • 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 • 1 A known MH patient • 2 Unexpected MH crisis

FULMINANT CRISIS • Tachycardia • Metabolic acidosis,  O2 sat,  pCO2 • 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 CO2

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 • MHS 131 • MHE (h) 100 • MHE (c) 6 • MHN 333

The Cork Families • 98 Pedigrees identified • 74 Probands • 24 Deaths

CONCLUSION • SURVIVAL • Identification of at-risk patients • Appropriate management

MALIGNANT HYPERTHERMIA