by Leslie E. Packer, PhD
Last updated January 2009
“PANDAS” is an acronym for Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections.
The term PANDAS is generally used to describe a subgroup of children who have either a tic disorder (such as Tourette’s Syndrome) or Obsessive-Compulsive Disorder and whose tics, obsessions, and/or compulsions worsen dramatically shortly after streptococcal infections or children who have no prior history or tics, obsessions, and compulsions but who suddenly “explode” in symptoms following a Group A ß-hemolytic streptococcal (GABHS) infection. What parents refer to as “strep throat” is a GABHS infection.
Perhaps the simplest way for parents to understand PANDAS is to think of the military term “friendly fire,” a euphemism for “Oops, we hurt our own troops.” When someone has an infection, the antibodies in our system are supposed to fight the infection. In PANDAS, however, the antibodies seem to attack the cells in the basal ganglia of the brain, causing abnormal movements and other neuropsychiatric symptoms. Some researchers have found infection-related abnormalities in other disorders that are also linked to the basal ganglia, e.g., Attention Deficit Hyperactivity Disorder, anxiety disorders, and mood disorders.
Before proceeding, and to allay any concerns parents might have: there is no evidence that a strep infection can cause Tourette’s Syndrome or Obsessive-Compulsive Disorder in a child who is not already biologically vulnerable to having those disorders.
The National Institute of Health researchers use the following five criteria to diagnose PANDAS (all five criteria must be met):
- Presence of a tic disorder and/or OCD;
- Pediatric onset of symptoms (age 3 years to puberty);
- Episodic course of symptom severity with sudden onset or acute exacerbations that are in:
(a)Temporal association with group A Beta-hemolytic streptococcal infection (indicated by a positive throat culture for strep and/or elevated anti-streptococcal antibody titer); and
(b)Association with neurological abnormalities (hyperactivity/fidgetiness/restlessness, or adventitious movements such as the choreiform movements of Sydenham).
WHAT DOES THE RESEARCH SHOW?
Although a complete review of all of the research is beyond the scope of this web site, I thought it might be helpful to mention a few recent studies that attempt to investigate any association between strep infections and exacerbations of tics, obsessions, and/or compulsions.
In 2005, Mell et al. (pdf) provided some compelling data suggesting an association between infection and TS/OCD. Using a retrospective review of charts of children who had been diagnosed with TS or OCD during a seven year period, they found that children with OCD, TS, or a tic disorder were significantly more likely than non-case controls to have had a prior strep infection in the 3 months before the onset of tic or OCD symptoms, and the risk of Tourette’s was even higher in children who had experienced multiple strep infections within 12 months.
Their findings were not fully replicated in a later study by Murphy, Snider, et al. (2007) (pdf). The latter investigators also used a 3-month window between infections and symptom measures, i.e., any exacerbation within 3 months of infection was treated as evidence of a relationship. Using that window, the investigators found a strong relationship between infection and symptoms, but the symptoms that were exacerbated were not necessarily what we might expect: balance/swaying and non-tic grimacing seemed to account for most of the relationship between infection and exacerbated symptoms. A stronger association was detected between infection and behavior.
Using different design and criteria, Kurlan, Johnson, et al. (2008) examined exacerbations of tics and obsessive-compulsive symptoms in children who met diagnostic criteria for PANDAS and children with TS/OCD who did not meet diagnostic criteria for PANDAS. The children were studied over a 2-year period. There were three significant findings of note here: (1) children who met diagnostic criteria had more exacerbations and more infections than the non-PANDAS controls, (2) when exacerbations did occur within 4 weeks following an infection, it was only in the group who met diagnostic criteria for PANDAS, and (3) the number of exacerbations that were temporally linked to infection was quite small (5 out of 64 exacerbations), indicating that although strep infections might contribute to some exacerbations in a subset of children with TS/OCD, strep infections did not account for most exacerbations.
A more recent study by Line t al. (2010) suggests another possible relationship: that for a subset of children with tics and early-onset OCD, infections may not be followed by an increase in tics or OCD symptoms, but the infections may act to increase the power of psychosocial stressors to increase symptoms later on.
The preceding studies address the issue of whether infections are associated with exacerbations or acute-onset of TS or OCD. As reviewed, there is some evidence that supports an association in some children, but that is not the same as demonstrating that PANDAS is a distinct disorder in its own right.
While researchers pursue the scientific issues, what do parents and educators need to know?
First, if you think your child has a strep infection, you need to take your child to the doctor. Strep infections can have serious complications so even if an infection isn’t worsening your child’s TS or OCD, your child may need antibiotics for the infection.
Second, if your child seems to exhibit a relationship between infections and tics or OCD worsening, then you can use that knowledge to reassure them that any increase they are experiencing is from the infection and that it will subside. You can also use that knowledge to help your child’s teachers know what to expect if your child has been ill.
Some children or teens may have a clearer relationship between infections and symptom worsening. One of my own children has had multiple “silent” infections. I call them “silent” because she is not aware of any infection or sore throat or symptoms. Indeed, the only way I can tell she has an infection is if she suddenly starts displaying certain types of worsening of her OCD or mood symptoms. When those symptoms appear, I typically tell her to go to her physician, who almost invariably finds that she has strep or some other infection.
Although this discussion of PANDAS deals with specifically with strep infections and TS or OCD, some investigators have reported significant exacerbation in handwriting or ADHD symptoms or severe separation anxiety or mood issues.
It is also important to note that other types of infections may also produce comparable results. Another acronym that appears less frequently in the literature is PITANDS (Pediatric Infection-Triggered Autoimmune Neuropsychiatric Disorders). The terms “PANDAS” and “PITANDS” may not be not wholly interchangeable. A. J. Allen, MD, distinguishes between PANDAS and PITANDS, where PITANDS includes triggering by bacterial or viral infection. In his usage, PANDAS would be a subset of PITANDS [personal communication, November 25, 2000]. Budman et al., (1997) have also reported viral infection-triggered exacerbations in symptoms.
Finally, the “P” in PANDAS or PITANDS stands for “Pediatric.” By definition, an adult cannot have PANDAS. Does that mean that no adults have infection-triggered exacerbations of symptoms? No. It merely means that investigators are looking only at children (for now, anyway).