Muscle Biopsies in the Diagnosis of Neuromuscular Disorders
A mother recently sent me an e-mail asking about the reliability of a muscle biopsy on her daughter. It would be done at her local hospital. Her daughter walks with a walker and has multiple problems, but still no specific diagnosis. The child's doctors thought a muscle biopsy might be helpful.
I replied that it would most likely be a waste of time to have the biopsy done at the local hospital. It takes a very sophisticated neuromuscular laboratory to have technicians who know how to do the many up-to-date stains and other studies. Few hospitals in the United States have adequate facilities for doing muscle biopsies. I have reviewed muscle biopsies from all over the U.S., even from major medical schools, and found that most were unreadable.
The other problem is that most surgeons want a child to have a general anesthetic when they do a muscle biopsy.This means a hospital admission and the risk of Malignant Hyperthermia. A muscle biopsy should be done as an outpatient procedure with the use of a local anesthetic. The major neuromuscular centers in the world do punch biopsies, which only leave a very small scar. A local anesthetic is all that is needed This is not common practice in this country, probably because muscle diseases, such as muscular dystrophy, myositis, and congenital myopathies receive so little funding and so little attention.
We are far behind England, Italy, France, Turkey, Japan, Italy, and Tunisia in our diagnosis and treatment of muscle diseases. Pediatric neurologists receive little training in the diagnosis of muscle disorders and generally are not taught to read and interpret muscle biopsies.
Anesthesia in Neuromuscular Disorders
An anesthesiologist called me today to check about the risk of Malignant Hyperthermia in an adult patient who had been diagnosed as having either Charcot -Marie-Tooth disease or Arthrogryposis. It is hard to believe that an adult patient doesn't have a more accurate diagnosis, but this seems to be fairly common problem in the U.S. now with the minimal amount of training neurologists and orthopedists get in these disorders.
I asked if the young man had had nerve conductions times done and he said the mother did not know the answer to that question. Then I asked if he saw high arched feet and he said 'Yes." I suggested then that the doctor ask the mother if any family members had difficulty buying shoes. This is a common complaint of Charcot-Marie-Tooth patients. I also suggested he looked at the mother's hands to see if she had any muscle loss and decrease in strength; also a common symptom in this disorder.
I added further that if the patient had a form of arthrogryposis that it could actually be a case of congenital muscular dystrophy. This would make the risk of Malignant Hyperthermia more possible. Any patient can have two disorders, but by the time a patient becomes an adult, an accurate diagnosis should be established. We are tragically far behind many other countries in the world in the diagnosis and treatment of patients with neuromuscular disorders.
Dr. Thompson blogs at http://drthompsonsbooks.typepad.com/