This post is about a condition about Fibromyalgia, a
condition that affects 2-4% of the population. It affects women eight times more
often than men, but it does, bizarrely, appear to be related to autism and is seen
by some as a comorbidity. I would go
further and suggest that perhaps I have stumbled upon the missing females with
autism.
When you look at all the
proposed drugs and supplements, there is a 90% overlap between the two
conditions, even things like low dose naltrexone and flavonoids, like quercetin,
crop up.
As we have seen earlier in this blog, autism is a disease
related to the auto-immune system and inflammatory pathways. There are many other diseases with similar
origins, one example being arthritis.
Fibromyalgia tends to get lumped together with arthritis. Families with autism present tend to have
higher levels of arthritis and there are even some overlapping therapies, such as
vagus nerve stimulation.
Fibromyalgia caught my attention, because it seems to be
uncannily closely related to autism, but there are some distinct
differences. Classic “full-on” fibromyalgia
is a disease about pain, whereas in autism people tend to have a high pain
threshold. Nonetheless, if you Google
“Fibromyalgia with Autism” you will find no shortage of people suffering from
both and pondering a connection.
Comorbidities are interesting, because they can indicate
possible new therapies. The people
researching fibromyalgia are not generally the same people as the autism
researchers. The underlying pathologies
though are very likely overlapping, even though neither is fully understood.
Fibromyalgia is neither degenerative nor curable, but it
is treatable.
Symptoms of
Fibromyalgia
We can split these into two categories, pain-related and
pain-unrelated. In the case of autism we
should look at pain-unrelated, but in the case of relatives we should look at
both. You will probably be able to
diagnose a non-autistic family member with symptoms of this syndrome.
Pain-related:-
·
Widespread
muscle pain and joint pain, the effects of these symptoms varies from person to
person and from day to day. Many people
have flare-ups. There are specific pain
areas, and these are shown below:
·
Long-term
studies suggest that it is not progressive, it does not cause permanent damage
to your muscles, bones, joints or organs.
Pain-unrelated:-
This is a long list and typically only some will apply to
any one person:-
·
Cognitive dysfunction, such as:
o
Difficulty following directions when driving
o
Losing your train of thought in the middle of a sentence
o
Difficulty paying attention
o
Memory problems
o
Difficulty expressing ideas in words
·
Depression, anxiety, irritability, overreaction, anger outbursts, unpredictable
mood swings, phobias and personality changes
·
Difficulty swallowing
·
Headaches
·
Restless leg syndrome
·
Sensitivity to the cold, and/or having
cold hands and feet
·
Palpitations
·
Sensitivity to light and noise intolerance.
·
Clumsy walking, dropping things
·
Hair loss
Fibromyalgia vs autism
There are
some other similarities/differences with autism.
·
It
often takes years to get a diagnosis and some doctors do not believe the
condition exists
·
There
is a specialist doctor that should know about it – the Rheumatologist, although
Neurologists sometimes get involved
·
It
is not curable, but it is treatable
·
It
is usually diagnosed on very subjective measures
The firm
with the blood test is called, interestingly, “Epigenetics”. If you make a blood test for Fibromyalgia,
there is a good chance that the same researchers could develop one for autism. They are measuring the level of pro-inflammatory
cytokines.
The test is
expensive, about $750. Who knows how
accurate the result is; they claim 99%.
In the UK, the
National Health Service maintains that no test for Fibromyalgia exists.
A Neuro-immuno-endocrine disorder
Evidence exists that fibromyalgia is a
neuro-immuno-endocrine disorder. Elevations in substance P,
IL-6
and IL-8
as well as corticotropin-releasing hormone
have been found in the cerebral spinal fluid of fibromyalgia
suffering individuals. Increased numbers of mast cell
numbers have been found in skin biopsies of some individuals with fibromyalgia.
Theoharides, who I have quoted extensively in early post
on mast cells and autism, appears here too:-
Abstract
Fibromyalgia (FMS) is a debilitating
disorder characterized by chronic diffuse muscle pain, fatigue, sleep
disturbance, depression and skin sensitivity. There are no genetic or
biochemical markers and patients often present with other comorbid diseases, such
as migraines, interstitial cystitis and irritable bowel syndrome. Diagnosis
includes the presence of 11/18 trigger points, but many patients with early
symptoms might not fit this definition. Pathogenesis is still unknown, but
there has been evidence of increased corticotropin-releasing hormone (CRH) and substance P (SP) in the CSF of FMS
patients, as well as increased SP, IL-6 and IL-8 in their serum. Increased
numbers of activated mast cells were also noted in skin biopsies. The
hypothesis is put forward that FMS is a neuro-immunoendocrine disorder where
increased release of CRH and SP from neurons in specific muscle sites triggers
local mast cells to release proinflammatory and neurosensitizing molecules.
There is no curative treatment although low doses of tricyclic antidepressants
and the serotonin-3 receptor antagonist tropisetron, are helpful. Recent
nutraceutical formulations containing the natural anti-inflammatory and mast
cell inhibitory flavonoid quercetin hold promise since they can be used together
with other treatment modalities.
Treatment
Classic
treatment involves tricyclic antidepressants, which are actually very
closely related to the early antihistamine drugs.
Even though low brain serotonin is a feature of the disease, counter-intuitively,
it has been found that serotonin-3 receptor antagonists are effective;
this is the opposite of what was expected.
Tropisetron is a favoured
antagonist, but there are several others.
Tropisetron is also a α7-nicotinic receptor agonist, which
you may recall, I highlighted as interesting in posts on the cholinergic system
and autism.
This blog is
about autism, so let us go back to a previous paper I looked at.
In that paper tropisetron is put forward as a potential autism treatment.
10.1.2 ᾳ7 nAChRs
It is possible to use ᾳ7 nAChR agonists to
treat neuroinflammation in ASD. There is strong evidence that activation of the
ᾳ7 nAChR expressed on monocytes and
macrophage, by inhibiting NF-kappaB nuclear translocation, suppresses cytokine
release by them, and that this cholinergic anti-inflammatory pathway that
provides a bidirectional link between the nervous and immune system, inhibits
the innate immune response. Hence, a reasonable case can be made for the use of
ᾳ7 nAChR agonists to treat neuroinflammation
in ASD.
A second candidate drug, Tropisetron is a partial agonist of the ᾳ7 nAChR. Auditory sensory gating P50 deficits are correlated with
neuropsychological deficits in attention, one of the principal cognitive
disturbances in schizophrenia. In a clinical trial with 33 schizophrenic
patients administration of tropisetron,
without placebo, significantly improved auditory sensory gating P50 deficits in
non-smoking patients with schizophrenia. In mice, the early postnatal period
represents a critical time window essential for brain development. The
administration of tropisetron from postnatal days 2-12
(P2-P12) in mice did not induce significant cognitive,
schizophrenia-like or emotional alterations in tropisetron-treated animals as
compared to controls, when tested in multiple behavioral assays.
It is the
non-conventional treatments that overlap with autism, things like GH, IGF-1 and
low dose naltrexone etc. The interesting therapies relate to treating the non-pain symptoms. There are many such therapies and some have been used for decades, one or two may be interesting
for autism; they may indeed be more effective in autism that in fibromyalgia. There is even an overlap with therapies I am already investigating.