Expectation of relief can enhance pain relief, according to a new study published in The Journal of Pain by Canadian researchers. This is not a new discovery, but provides additional confirmation of this important clinical observation. The current study was performed in 60 healthy volunteers, 15 of whom expected relief of experimental pain, 15 expected worsening of pain from the procedure, 15 had no expectations, and 15 were in a control group. Pain was induced by electrical stimulation of right leg, while applying an ice pack to the left arm (counterstimulation) was tested as a treatment to reduce pain in the leg. Those who were told that the pain will worsen from the ice pack in fact felt more pain, while those who were expecting relief, experienced less pain. A study published in 2009 by Harvard researchers showed that expectation of relief from acupuncture also translated into stronger relief experienced by volunteers subjected to experimental pain. Their clinical observation was confirmed by functional MRI scans showing stronger activation of pain relieving structures in the brain. The researchers concluded that while acupuncture provides pain relief by sending blocking messages up to the central nervous system, messages regulating pain perception from the brain down can affect pain perception depending on person’s expectations.
This suggests that having a positive expectation when seeing doctors and undergoing various treatments may improve the outcome of these treatments.

Optimists appear to tolerate pain better than pessimists, an old discovery that is supported by a new study published in The Journal of Pain. The study by researchers at the Universities of Florida and Alabama involved 140 older individuals with osteoarthritis. They were subjected to experimental pain (heat was repeatedly applied to the forearm) and also had a variety of psychological tests. Those elderly who were judged to be optimists (based on an established and validated test) had lower pain perception. The study also showed that optimism was associated with lower levels of catastrophizing. Catastrophizing was also measured by validated scale, which includes questions such as “I feel it is never going to get better” and “I can’t stand it anymore”. The good news is that studies have shown that cognitive-behavioral therapy can reduce catastrophizing and improve pain. So, if you are a pessimist, do not give up – see a psychologist and your pain may be easier to control.

Photo credit: JulieMauskop.com

Autoimmune dysfunction can cause pain according to a study just published in Neurology by a group of Mayo Clinic researchers. Dr. CJ Klein and his colleagues examined 316 patients who had antibodies to a structure involved in various nerve functions (voltage-gated potassium channel, or VGKC) and discovered that 159 of them had pain as the initial symptoms and 45 of those had pain as the only symptom of this autoimmune reaction. In 19 of these patients pain was localized to face and head, suggesting that some of the headache patients may also suffer from this condition.
The antibodies to VGKC are known to cause excessive excitability of the nervous system. Some of the patients in the study were previously thought to have fibromyalgia (a condition known to be associated with excessive excitation of the nervous system) or psychogenic (not real) pain. This is an exciting discovery since treatment with immune therapies (such as drugs and intravenous immune globulin, or IVIG) relieved chronic pain in 81% of the Mayo Clinic patients. Epilepsy drugs can also help some of these patients.
The difficulty at this point is in identifying patients who should be tested for VGKC antibodies. Probably, we should test patients with chronic persistent pain that does not easily respond to standard treatments. Another difficulty is that the immunosuppressive drugs can have serious side effects, while IVIG is very expensive and can also cause side effects. So these therapies should be reserved for patients in whom pain causes significant disability and in whom potential benefits outweigh the potential risks.

Likeable patients may receive better care for their pain, according to a study by Belgian researchers. The researchers asked 40 doctors to look at photos of six different patients. Each photo was accompanied by a description such as friendly, egoistic, arrogant, honest, faithful, hypocritical, or reserved. Then the doctors were asked to evaluate the severity of pain in these six patients after they watched a video in which the patients were being evaluated for shoulder pain. Patients with positive descriptions were thought to have more pain than those with negative ones. Most doctors are probably convinced that they treat all patients equally, but this is clearly not true. Doctors and medical students should be informed of these findings so that they constantly remind themselves of the potential bias.

Hypertension appears to increase the risk of trigeminal neuralgia, according to a new study published in Neurology by Taiwanese researchers. They looked at 138,492 people with hypertension and compared them to 276,984 people of similar age and sex who did not have hypertension. The risk of trigeminal neuralgia was one and half times higher in those with high blood pressure. Trigeminal neuralgia is an extremely painful condition with electric-like pain in one or more branches of the trigeminal nerve, which supplies sensation to the face. The likely cause of trigeminal neuralgia is compression of the trigeminal nerve by a blood vessel at the site where the nerve is coming out of the brainstem. Persistently elevated blood pressure tends to make blood vessels harder and more tortuous. Hypertension has been show to be a factor in a similar condition – hemifacial spasm, which results from the compression of the facial nerve by a blood vessel. The usual treatment of trigeminal neuralgia starts with medications, such as oxcarbazepine (Trileptal), carbamazepine (Tegretol), phenytoin (Dilantin), baclofen (Lioresal) and other. If medications are ineffective, invasive treatments are recommended. Botox injections have been reported to provide some patients with good relief, although Botox is probably more effective for hemifacial spasm. ANother procedure is the destruction of the tigeminal nerve ganglion with heat from a radiofrequency probe. This is done under X-ray guidance. Radiofrequency ablation is often effective, but the pain may recur and the procedure may need to be repeated. A more drastic but also more effective approach involves opening the skull and placing a Teflon patch between the nerve and the offending blood vessel. Obviously, this procedure carries a higher risk of serious complications, but in experienced hands it is relatively safe. You can determine the experience of the neurosurgeon by asking how many procedure he or she has performed. Ideally, pick a surgeon who has done it hundreds of times.

At the NYHC, just like at all headache clinics, we see many patients with severe disability. A very interesting study just published in the journal Pain seems to tell us how to predict which of these disabled patients will respond to treatment. Researchers at the Ohio University compared patients whose severe disability improved with treatment and those whose did not. They carefully examined a wide variety of possible factors, including race/ethnicity (African American versus Caucasian American), psychiatric comorbidity, headache management self-efficacy, perceived social support, locus of control, number of headache diagnoses, migraine versus tension-type headache diagnosis, chronic versus episodic headache diagnosis, headache days per month, headache episode severity, and whether the patient attended all scheduled treatment appointments. The only factor that seemed to predict whose disability will improve and whose will not was the attendance of the 3 follow-up visits. Those who came for follow-up visits were much more likely to improve than those who did not – showing up is half the battle.

Botulinum toxin, which most people know as Botox is produced by a bacteria – Clostridium botulinum.  This bacteria actually produces 7 different type of this toxin: A, B, C, D, E, F, and G.  Botox is botulinum toxin, type A, while another commercial product, Myobloc is botulinum toxin, type B.  Researchers, Drs. Dolly, Aoki and their colleagues managed to combine type A and E, according to a report in The Journal of Neuroscience.  Test tube experiments suggest that this combination could prove to be more effective for the treatment of pain than type A alone.  This is a very promising discovery, since Botox is effective for only about two thirds of chronic migraine sufferers.  The combined toxin could be also effective for other types of pain.