Watch Out For Three-Parent Children

Mitochondria are organelles which provide the energy to cells. Mitochondrial DNA is inherited from the mother. There are a number of genetic mitochondrial disorders which can cause stroke, blindness, ataxia, neuropathy, and a disorder termed Leigh syndrome.

DNA blood tests can diagnose these disorders as well as identifying mothers who are “carriers.” It is estimated that 2500 women of childbearing age in the UK carry this risk.

A team led by Professor Doug Turnbull in the UK has developed the “pro-nuclear transfer” technique. Nuclear material of the parents’ fertilized egg, which contains the damaged mitochondria, is removed and is implanted into a donor’s healthy egg from which the nuclear material has been removed. The undamaged mitochondria of the donor’s egg remains. There is a similar technique in the US, but there, fertilization takes place after the parents’ DNA is implanted into a healthy egg.

Which mother does the child look like? Mitochondrial DNA contains only 37 genes compared with 23,000 in the nuclear genome. Thus, the donor will have little effect on the child’s DNA.

As expected there are religious objections. Nevertheless, the UK will likely approve this procedure to start in 2016.

The above is a summary of an article by Andrew Jack in the Financial Times, January 20, 2016.

After 50 Years, EMG Remains An Abused Diagnostic Test

Kudos to the authors of a study published in Neurology, January 19, 2016, with lead author Narayanaswami, who tried to establish sensitivity and specificity of needle EMG for diagnosis of radiculopathy. Both were over 70%. Keep in mind, however, that this was done by experienced electromyographers in an academic setting. These results do not automatically translate for neurologists or physiatrists in “community” practice. Many are well trained, experienced, and perform high-quality, ethical, and cost-efficient studies. A significant number, however, do not, and there is great abuse, especially in the workers’ compensation setting.

An editorialist in the journal Muscle & Nerve many years ago bemoaned the fact that an EMG report was considered the “WOG” (Word of God). I estimate I have performed 15,000 EMGs in my career. I recall, as a consultant for Medicare, viewing a video of a neurologist who billed four extremities as well as cervical spine, thoracic spine, lumbar spine, each as an extremity; and every possible motor and sensory nerve and F-wave in all patients, irrespective of diagnosis. Incredibly, he claimed he could do all this in 30 minutes. It would have been comical if it were not outrageous to watch him run around the exam table sticking needles in at random and stimulating nerves at supramaximal intensity each time.

If only the medical community and regulatory authorities targeted abuse and made consistent efforts to improve the quality and cost-effectiveness of EMG. The Medicare administration threw up its hands in doing meaningful reform and instead reduced reimbursement by about 50%. This has led to reduced quantity but certainly not to increased quality.

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How Much Sumatriptan Is Too Much?

All triptans are contraindicated in patients with coronary artery disease. Many physicians are unaware of the risk of myocardial infarction with use of triptans in this patient group. In the absence of significant risk factors, this risk is extraordinarily rare. GSK has reportedly sold at least 1 billion Imitrex brand tablets. In a review of sumatriptan postmarketing experience, the authors identified 451 serious cardiac effects out of 236 million migraine attacks and more than 9 million patient exposures over 6 years. In most, though apparently not all, risk factors for coronary artery disease were present.

Upon this background comes a report of 53 patients with chronic cluster headaches who had daily attacks and used 2 or more 6 mg sumatriptan injections per day for at least 2 years. About 40% possibly developed some “tolerance” but still believed that this was their best option.

The highest manufacturer’s recommended daily dose is 2 injections of 6 mg each per 24 hours. Most cluster headache patients need more.

In that 2-year study, no patients needed to stop medication nor were there any serious adverse effects, and no EKG abnormalities were found.

For years, headache specialists have been allowing cluster headaches to use multiple doses of injectable sumatriptan a day, and this study gives some comfort to support that approach.

See Neurology, January 12, 2016, lead author Leone.