Muscle biopsy and IVCT at the RMH

Genetic Testing at the RMH

Dr M Denborough and Dr R Lovell wrote a letter to the editor in The Lancet in July 1960 describing a case at the Royal Melbourne Hospital (RMH) with characteristics we now identify as Malignant Hyperthermia (MH). They identified the dominant genetic nature of this disorder of unknown cause when they described a young man who survived a severe reaction to anaesthesia, 10 of whose relatives had died under general anaesthesia.


Since 1972, The Royal Melbourne Hospital has been assisting the Australian population by providing an advice, research and testing service for this rare but important disease, which has significant anaesthetic and surgical consequences. The unit has tested over 400 patients and identified approximately 80 families with MH. The RMH is one of only three testing centres in Australia. The unit has been under the control of the Department of Anaesthesia and Pain management since May 2001.


The only recognised test for MH is a muscle biopsy which is a procedure that can only be performed in one of the 4 testing centres in Australia and New Zealand as it requires a live muscle sample.
Because of the limitations of the muscle biopsy, MH testing centres throughout the world have been trying to devise another less invasive test.

For all referrals and enquiries please contact:
Dr Robyn Gillies MB BS FANZCA – Staff Anaesthetist
Phone: 9342 7540 or through switchboard 9342 7000
Fax: 9342 8623
Email: robyn.gillies@mh.org.au
 

Muscle biopsy and IVCT at the RMH.
This involves admission to the Royal Melbourne Hospital for a day (you should not need to stay overnight).
The procedure is usually performed under a non-triggering general anaesthetic, although an alternative is a nerve block without a general anaesthetic. A cut is made in the outer thigh area and a piece of muscle removed about the half the size of ones index finger. The muscle itransported by our medical scientist to the laboratory where it is tested for susceptibility to Malignant Hyperthermia.

The amount of muscle removed should not affect the function of that muscle. The scar is about 5 c.m. long and heals as a thin line without stitch marks. Crutches may be required for the first day or so after the procedure.
The potential surgical risks include bleeding, infection, numbness and pain at the surgical site. The anaesthetic risks are low when the MH triggering drugs are avoided. Risks include rare allergic reactions to local anaesthesia. There  may be some weakness in the leg until the anaesthetic wears off (within 12 hours) if the procedure is performed under local anaesthetic nerve block.


Genetic Testing at the RMH
If a family member has had a positive IVCT, they may be eligible to have their DNA analysed (by a blood test) to look for changes in the DNA that are known to be responsible for MH. Once a change (defect) has been identified in a family member, any other members of that family can be tested for that specific defect. If they have the defect they can then know that they are susceptible to MH. If they do not have the defect they will still require the muscle biopsy and IVCT to determine their MH status. This is because there are some families who have more than one DNA defect causing MH.