This blog post, is incomplete, I should really check for references and the veracity of some of my comments and inclusions… with these caveats in mind… please continue to read… This isn’t a whinge or moan, and those that like to beat up on those who talk about health problems can hop off now and play with their prejudice elsewhere.
I was looking at some posts on an HNPP group the other day, and a question came up regarding links between migraine and HNPP and bouts of persistent facial pain. The poster was asking whether migraines were directly linked to HNPP, ie caused by the PMP22 deletion or some of the other deleted genes in the deleted region on Chromosome17.
I didn’t think that there was a direct link, although of course not all the genetic causes of migraine have been found, but those that have appear to involve genes on other chromosomes other than 17. These genetic variants tend to be calcium channelopathies. Whilst I’m sure I don’t have a known genetic variant, ie familial hemeplegic migraine, it’s intersting to note that the medication that I find very helpful in reducing the effects of migraine, is a calcium channel blocker amongst other effects such as anti-histamine, and some actions attributable to it’s relationship to the major tranquillizers. The drug BTW is Cinnarizine, and was originally prescribed for me as a vestibular sedative with effects on the micro-circulation of the inner ear, which I believe is also due to calcium channel blocking.
I digress, or perhaps I just witter!
Anyway, Before I was diagnosed with HNPP, I was diagnosed as having Meniere’s Disease, or at least I had three of the four classic symptoms of Meniere’s disease, namely, sensori-neural hearing loss, tinnitus and bouts of rotational vertigo (severe dizziness). I didn’t think that there were any links between the two diseases, but I was quite surprised to find that Meniere’s Disease was far more common in the small group of people with HNPP than would have been expected. It could of course be just coincidence or misdiagnosis, but as Meniere’s Disease is supposed to be relatively rare (2 to 5 per 10,000) I found it surprising that there were approx 3-5% of people with HNPP that had meniere’s disease. BTW the incidence of HNPP is approx. 2-5 per 100,000.
Another curious thing is that at least one of these people who has HNPP and Meniere’s disease, also suffers from Trigeminal Neuralgia, and perhaps the linch pin in all this, Migraines. The chance of this happening by coincidence must be extremely small, which doesn’t mean that it isn’t but surely begs the question, is there a causal relationship?
I was diagnosed with Migraine when I was in my teens, but it was also noted that there was an element of neck pain and, as the neurologist at the time mentioned, occipital nerve impingment due to weak and over-tightening neck muscles. My Teenage years were also the time when HNPP started to become more pronounced than just numb finger tips when carrying shopping bags, and numb thumb and forefinger when using scissors. I started to experience ulnar nerve involvement, numbness of little and third fingers which seemed to just come out of nowhere, and sudden episodes of foot and lower leg weakness, not to forget the ever increasing episodes dead arms and legs. I once lost all power in one arm after a minor bicycle accident that took nearly 9 months to fully resolve.
A few years later, aged 21, I awoke with what I perceived as high tone hearing loss (HL) and unbearable tinnitus. I also experienced intense facial pain for three or four months with this HL and tinnitus. My GPs were unsympathetic, and assumed it was just a viral illness, and after repeated visits totally dismissed the symptoms as fictitious. Migraine’s were also troublesome but less so than earlier in my life. I remember all this very well as I was training to be a psychiatric nurse, and my ill health was getting me into hot water with the management. But unfortunately without support from my GPs for my unusual symptoms, this became a very unhappy period of my life.
I really have digressed or wittered far off the beaten track….
Back to Migraine and Trigeminal neuralgia. A few years ago the migraines stepped up in frequency, and this time I had the classic tell tale signs of scintillating scotomas during the aura phase. Sometimes the auras became persistent with visual snow, blimps and bright spots (scotomas) and impression that I could see ‘space’, like a multi-faceted mesh. Also extreme ataxia and balance disturbance with feelings of depersonalisation (sorry it’s the psych nurse lingo coming out). This bore some resemblance to at least some of the episodes of vertigo I experienced during the very active phase of Meniere’s disease, but perhaps that is just similarity rather than causality.
Then the bouts of TN started, though on relflection maybe I had had this before, and my reading of the new info (bearing in mind I hadn’t read much about migraine for some 30 years), led me to think whether there was some mechanism by which migraine, through it’s involvement of the T.nerve, was triggering bouts of Trigeminal neuralgia. But is the TN I suffer from due in part to the HNPP, as HNPP is a demyelinating peripheral neuropathy, which has been reported as causing TN in some rare cases.
So consulting Dr. Google with extreme caution as always, I started probing for possible links, and I was stunned to find this article which takes it’s info from the book, “Striking Back: The Trigeminal Neuralgia Handbook”, pp. 113-115.
(Unfortunately the above link is no longer active, a google search for “Striking Back: The Trigeminal Neuralgia Handbook”, pp. 113-115 , reveals the following link and a few others.
Some quotes from the article
“For some migraine headache sufferers, there is a risk for sustaining permanent cranial nerve damage. When this type of complications persists, there can be long term health complications aside from the chronic migraine pain…..”
“One of the most common long term nerve complications seen in migraine headache sufferers involves a condition known as trigeminal neuralgia.”
Caveat: Without access to the book I cannot vouch for the accuracy of this articles interpretation, or the references from which the book asserts this link.
If this is the case, and TN is seen as a rare complication for some migraine sufferers, then I would think that having HNPP actually increases this risk. The T.Nerve is inherently affected by this disease i.e. all peripheral spinal nerves including at least 10 of the 12 cranial nerves (omitting the olfactory and optic nerves which are thought to be CNS tracts rather than belonging to the PNS) have a deficit of the PMP22 protein which normally helps to bind together the layers of PNS compact myelin.
It is also interesting to see that over the years Doctors and researchers are begining to narrow down the potential causes of Meniere’s disease, there are quite a few different flavours of the disease, some thought to be due to inner ear fluid imbalance, others due to trauma, nerve compressions, perilymph fistulae, auto-immune disease, and of interest to me, Migraine.
Migraine associated vertigo (MAV) has now been well established as one cause of vertigo and tinnitus, it was thought not to cause hearing loss, although recent studies (as reported by a long time expert into vertigo) do seem to suggest that hearing loss is possible in some cases of MAV, possibly due to ischaemia or changes in blood flow during the attacks of migraine. I have yet to find confirmation of this so yet this should be treated with caution.
I must add link and references to this… but I wanted to get this train of thought written down, so that it doesn’t just pass me by and forgotten, though I don’t think I’d ever be able to forget, due to the many symptomatic reminders.