Over the course of history, "tics
and obsessive-compulsive symptoms occur so frequently together in the same
patient or in different members of the same family that they are now considered
by some investigators to be alternate manifestations of the same neuropsychiatric
disorder" (Garvey, Giedd and Swedo 1998). This neuropsychiatric disorder
has come to be known as pediatric autoimmune neuropsychiatric disorder
associated with streptococcal infections, or PANDAS, which has come to puzzle
scientists and doctors alike over recent decades. PANDAS is a disorder that is
characterized by the sudden onset of symptoms similar to those seen in tic and obsessive-compulsive
disorders (OCD). A child is only diagnosed with PANDAS when there is a clinical
history of having a streptococcal infection prior to the sudden onset of these
symptoms. These children make up a subgroup of children that have been
diagnosed with Sydenham’s chorea, which is a disease that has been found to be
closely related to OCD and tic disorders, therefore suggesting that PANDAS is
also a part of this group.
Issues that have arisen can in part
be attributed to the small sample sizes used for testing, which do not provide
scientists samples that will allow them to look at all of the possibilities
that may play a role into the sudden onset of these disorders. However, a
connection was found between streptococcal infections and PANDAS, but is
debated as to whether this streptococcal infection causes the onset of PANDAS
and in result the onset of OCD and tic disorders. According to Dr. Edward L.
Kaplan, current research is not evident enough to identify a causative
relationship. Kaplan mentions that not all children show the symptoms of a
streptococcal infection, and are therefore simply carriers, resulting in a lack
of clinical records of a streptococcal infection that were being used to
previously diagnose children with PANDAS.
Currently, the etiology of the
disease is unknown, and scientists agree that more research needs to be done in
order to come to a definitive classification of this disorder. This disorder is
one in which it is debated as to whether the streptococcal infection is what is
causing the disorder or if it is just coincidence. However, evidence that has
been presented thus far supports the hypothesis that the onset of PANDAS and
tic and obsessive-compulsive disorders are causative as more research is revealing the two disorders being present together in many individuals. However, in order to
fully understand the etiopathogenesis of PANDAS, we would first need to fully
understand the etiopathogenesis of the disorders closely related to it,
starting with Syndenham’s chorea, which currently serves as the medical model
for PANDAS. Whether or not the onset of PANDAS is due to an evolutionary advance of streptococcus or just coincidence is a question that must be answered by the use of genetically similar disease to piece together the current enigma that is PANDAS.
Works Cited:
Garvey, M., Giedd, J., & Swedo,
S. (1998). PANDAS: the search for environmental triggers of pediatric
neuropsychiatric disorders. Lessons from rheumatic fever. Journal Of
Child Neurology, 13(9), 413-423.
PANDAS to CANS: Evolution of a
controversial disorder | Infectious Diseases in Children. (n.d.). Healio:
Medical Specialty News, Journals, and Free CME. Retrieved from
http://www.healio.com/pediatrics/news/print/infectious-diseases-in-children/%7BCAFAB629-3452-44AF-BA2D-4D99A8012DFC%7D/PANDAS-to-CANS-Evolution-of-a-controversial-disorder
Snider, L., & Swedo, S. (n.d). PANDAS: current status
and directions for research. Molecular Psychiatry, 9(10),
900-907.Word Count: 479
Melissa Martinez
I am little confused: so PANDAS is indeed caused by Streptococcus, hence the name, but the causative relationship has yet to be proven?
ReplyDeleteTo answer your question, yes and no. Scientists are having a lot of trouble trying to figure out what the exact cause of the disease is, especially as it relates to tics and OCD. A lot of the confusion comes from the inability to identify which children had streptococcus. Previously, a child would be diagnosed with PANDAS if they had a clinical history of a streptococcus infection. However, recent studies have shown that streptococcus can be still present in a child without showing any symptoms, therefore making the clinical history method pretty much obsolete, and extremely difficult to tell if whether or not PANDAS and tics/OCD have a causative relationship.
DeleteI don't really see the link between strep, PANDAS, and evolution. If the relation between strep and PANDAS has not been identified, then how can the assumption be made that these are because of evolution? Since evolution favors traits that are beneficial in some way and increase fitness, how would OCD in this situation be selected for?
ReplyDeleteThe point that I was attempting to make in the article was that by identifying children that have been diagnosed with PANDAS (which was as a result of the onset of tics/OCD post-strep infection), scientists are using a lot of evolutionary techniques to try to understand the true relationship between strep, PANDAS, and tics/OCD. A lot of the readings dealt with genetic markers in order to identify these relationships, and whether PANDAS is as a result of strep or if PANDAS is actually the root cause of all tics/OCD cases.
DeleteI think it is interesting to consider the evolutionary relationship between two diseases that we might not consider related at first sight. Perhaps there is a genetic predisposition to having the tics and OCD tendencies that is activated by strep, and the mechanisms involved are due to a specific pathway that co-evolved between step and the disorders. As is stated, much more research is necessary!
ReplyDeleteInteresting observation but I also think more research needs to be done. This should be easy especially with the current biomedical technologies
ReplyDelete