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January 31st, 2009 --
Two questions which I
hear fairly often are: Is Chiari fatal? and Can it go away on its
own?.
These questions
represent both the fear and hope that most people feel when they first
encounter Chiari. Since chances are good that a newly diagnosed
patient has not heard of Chiari, their mind races to the end points of what
may happen. However, these questions do also represent, in a real
sense, the extremes of Chiari outcomes.
It is important to keep
in mind that the vast majority of Chiari cases do not involve either death
or spontaneous resolution. Much more likely is the case where a person
will have some symptoms and if they are bad enough will undergo surgery.
If they do or don't have surgery, either way, patients by necessity will
learn to live with whatever symptoms and limitations they have. There
is no real evidence whether Chiari has an effect on a patient's average
lifespan, although it would be somewhat surprising if it didn't since many
people with Chiari are less active which can of course lead to other health
problems.
But, as the medical
literature has documented, there are Chiari cases which involve death and
there are Chiari cases which seem to heal miraculously. Although very
uncommon, these types of Case Reports continue to appear on a semi-regular
basis in the medical literature.
For example, in the
September, 2008 issue of the American Journal of Forensic Medicine &
Pathology, Stephany et al. report the case of a 27 year old man who appeared
to die suddenly due to Chiari. This man had a 3 month history of falls
and worsening headaches. He also had a long history of sleep apnea
which was getting progressively worse leading up to his death. In the
end, he collapsed suddenly in front of witnesses and passed away. An
autopsy revealed a significant 20mm Chiari malformation with scarring of the
cerebellar tonsils. Given his previous symptoms, the pathologists
believe the cause of death was related to Chiari. This case is the
latest in a handful of such reports. These reports are the most direct
way that Chiari can be fatal, but it can also have an indirect effect.
There is strong evidence that depression is common among Chiari patients,
which in some can lead to suicide and suicide attempts. There is
virtually no data on whether this is more prevalent among in the Chiari
community than in the general population.
At the other end of the
spectrum are reports such as the one by Miller et al in the November, 2008
issue of the Journal of Neurosurgery: Pediatrics. The report
documents identical twins who started to develop breathing problems around
one year of age. After many tests, an MRI revealed a Chiari
malformation in each twin (12mm and 10mm). Surgery was offered,
but since the breathing problems were not severe, the parents decided to
wait and observe. Over a period of time the breathing episodes became
less frequent and eventually went away completely. MRIs at the age 6
showed that the cerebellar tonsils in both children had ascended (to 6mm and
<3mm) and had regained a normal rounded shape. At the time of
publication, the children appear to have no symptoms related to Chiari.
Like the sudden death report, this is the latest in a string of Case Reports
detailing spontaneous resolution of Chiari. The mechanism behind these
cases is not clear, although in a young child it may have to do with the
relative growth rates of the skull and brain.
I tell people all the
time that Chiari affects everyone differently. While this is true, it
would be nice to learn more about the natural history of Chiari in order to
predict which cases lie in the middle and which lie at the extremes.
-- Rick
Labuda
Sources:
Sudden death in a 27-year-old man with Chiari I malformation.
Stephany JD, Garavaglia JC, Pearl GS. Am J Forensic Med Pathol. 2008
Sep;29(3):249-50.
Spontaneous
resolution of Chiari malformation Type I in monozygotic twins. Miller JH,
Limbrick DD, Callen M, Smyth MD. J Neurosurg Pediatrics. 2008
Nov;2(5):317-9.
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