Diagnosis of MHS

MH is suspected if a person has a family history of severe reactions during anesthesia. The most accurate diagnostic test for MH involves a specialized biopsy from a leg muscle. This involves surgical removal under MH-safe anesthesia of a piece of muscle, usually subjected to standardized laboratory testing. The muscle test is usually performed on an outpatient basis in two centres across Canada: Toronto General Hospital and the Ottawa Hospital, Civic Site. The muscle biopsy test remains the "gold standard" to determine MH susceptibility in individuals.

At present, there is no simple, non-invasive test available for patients. A Canadian team, headed by Dr. David H. MacLennan at the University of Toronto, has devised a simple DNA test for pigs affected by MH. Several research teams around the world are working on ways to diagnose human MH by testing DNA from blood samples. Unfortunately, no single DNA test can be applied to the general population yet, but work is progressing in an exciting direction. Noninvasive testing of muscle using magnetic resonance imaging (MRI), is still under intense research. Several other testing methods have been studied, but have proven unreliable because of a large number of false positive and false negative results.

Treatment of MH

The early stages of a life-threatening MH crisis are often difficult to recognize. There are conditions other than MH that can cause almost identical reactions. Once an MH crisis is suspected, treatment must begin even when the diagnosis is not yet certain, to ensure patient safety. MH can be successfully managed in virtually all cases with the immediate use of the antidote, dantrolene sodium for injection, and by implementing other life-saving measures as outlined and developed by the expert professionals associated with MHAUS. Once the crisis is over, a careful review must rule out other causes and testing for MH susceptibility may be necessary.

Can an MH reaction be prevented?

If a patient is known to be MH susceptible, alternate but more expensive MH-safe drugs can often be used to deliver safe and efficient anesthesia. There are a few rare situations where the drugs of first choice are not reccommended in an MHS patient. In certain rare circumstances, pretreatment with dantrolene may be necessary.

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