Sunday, 2 June 2013

Can leeches cure migraines?

BFTF recently read an article in MailOnine by TV motoring correspondent Emma Parker Bowles on her experience using a leeches to cure migraines.

The article (entitled "Gruesome, medieval and utterly bizarre... but leeches freed me from awful migraines") had a number of characteristics consistent with being "psuedoscience". In particular, the following points caught BFTF's attention:

a) Evidence presented does not relate to the condition at hand (migraines)
"In the 1980s, leeches began to be used by reconstructive plastic surgeons needing to remove stagnant blood from reattached limbs, to stave off gangrene. But now there are numerous studies into medical uses for leeches. One found that a single session of leeching – the medical application of bloodsucking leeches – can significantly reduce knee pain caused by arthritis for at least two months. Researchers from the University of Duisburg-Essen in Germany claimed improvement levels were comparable to those achieved with daily moderate doses of painkillers such as ibuprofen... The secret is in the leeches’ saliva: it apparently contains a large number of analgesic, anaesthetic, and blood-thinning compounds that tackle pain and inflammation, say the researchers."
But these are differnet applications to those that Bowles was using the leeches for (i.e. to stop migraines). Whereas the clinical uses mentioned relate to the use of leeches directly on the area affected, the procedure Bowles was undertaking involved the placement of leeches on the side of the head where they were separated from the brain by the skull. And, in any case, it is unlikely that Bowles was experiencing a migraine at the time the leeches were applied, so it seems unclear to BFTF exatly what the "analgesic, anaesthetic, and blood-thinning compounds" were supposed to be acting on.

Incidentally, the article does not provide references so BFTF cannot check the cited papers themselves, but the German study may be a follow up to this 2003 investigation and another study points out that investigations in to leech therapy are difficult to perform as the patients inevitably know whether they are being treated by leeches or by another method :

"Leech therapy can reduce symptoms caused by osteoarthritis. Repeated use of the leeches appears to improve the long-term results. We have not determined whether the positive outcome of the leech therapy is caused by active substances released during the leeching, the placebo effect, or the high expectations placed on this unusual treatment form"

BFTF can find no reference in the online medical database PubMed for the use of leeches to cure migraines. In fact, internet references seem to largely relate to the MainOnline article itself.

So, in summary, there seems to be no evidence for the efficacy of leeches to treat migraines, not is any plausible explanation for their mechanism of action offered.

b) Wide ranging claims are made
It always makes BFTF suspicious when wide ranging claims are made with no evidence for their efficacy. In this case, Bowles comments that :

"Google led me to Alicja, a Russian/Polish hirudotherapist [leech therapist] with ten years’ experience. She is based in Las Vegas and New York but she has clients from all around the world. She says the secretions from leeches’ saliva can be used to treat the entire spectrum of physiology: blood-clotting, digestion, connective tissue, disease, pain, inhibition of enzymes, and as a treatment for inflammation."

c) No evidence that the procedure worked even in this case
Bowles states that

"I could go for six months without suffering [a migraine], then there would be a whole week of agony"


and that she has not had a migraine since the leech therapy. As the leech therapy appears to have been performed this year (2013) and that the date of the article is 1st June, it is not clear that the frequency of migraines has changed for Bowles.

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