What is PANDAS, and why is it now called PANS?
PANDAS is the sudden onset of a neuropsychiatric disorder: OCD, anorexia, psychosis or cognitive problems. Initially, PANDAS was only associated with strep and scarlet fever. With a strep infection, a child's immune system can become confused and start to attack an area of the brain called the basal ganglia. It turns out that other infections like mycoplasma, certain viruses and Lyme disease can also produce the same problems. They changed the name to reflect that. Now it's any sudden-onset neuropsychiatric disease.
How to identify a PANDAS child (strep)
- Regular OCD develops slowly, the onset of the PANDAS form of OCD is rapid.
- The PANDAS form of OCD occurs in close association with a strep infection. However, regular OCD can occur at any time. Confirmation of a strep infection is usually done using a throat culture and/or blood test for strep antibodies.
- Unlike regular OCD, children with the PANDAS form of OCD usually have involuntary movements of the arms, legs and face.
- The PANDAS form of OCD usually develops between the ages of 3 and before puberty.
What is an anti-streptococcal antibody titer?
The anti-streptococcal antibody titer determines whether there is immunologic evidence of a previous strep infection. Two different strep tests are commercially available: the antistrepolysin O (ASO) titer, which rises 3-6 weeks after a strep infection, and the antistreptococcal DNAase B (AntiDNAse-B) titer, which rises 6-8 weeks after a strep infection.
What does an elevated anti-streptococcal antibody titer mean? Is this bad for my child?
An elevated anti-strep titer (such as ASO or AntiDNAse-B) means the child has had a strep infection sometime within the past few months, and his body created antibodies to fight the strep bacteria. Some children create lots of antibodies and have very high titers (up to 2,000), while others have more modest elevations. The height of the titer elevation doesn’t matter. Further, elevated titers are not a bad thing. They are measuring a normal, healthy response – the production of antibodies to fight off an infection. The antibodies stay in the body for some time after the infection is gone, but the amount of time that the antibodies persist varies greatly between different individuals. Some children have "positive" antibody titers for many months after a single infection.
When is a strep titer considered to be abnormal, or “elevated”?
The lab at NIH considers strep titers between 0-400 to be normal. Other labs set the upper limit at 150 or 200. Since each lab measures titers in different ways, it is important to know the range used by the laboratory where the test was done – just ask where they draw the line between negative or positive titers.It is important to note that some grade-school aged children have chronically “elevated” titers. These may actually be in the normal range for that child, as there is a lot of individual variability in titer values. Because of this variability, doctors will often draw a titer when the child is sick, or shortly thereafter, and then draw another titer several weeks later to see if the titer is “rising” – if so, this is strong evidence that the illness was due to strep. (Of course, a less expensive way to make this determination is to take a throat culture at the time that the child is ill.)
Should an elevated strep titer be treated with antibiotics?
No. Elevated titers indicate that a patient has had a past strep exposure but the titers can not tell you precisely when the strep infection occurred. Children may have "positive" titers for many months after one infection. Since these elevated titers are merely a marker of a prior infection and not proof of an ongoing infection it is not appropriate to give antibiotics for elevated titers. Antibiotics are recommended only when a child has a positive rapid strep test or positive strep throat culture.
Can penicillin be used to treat PANDAS or prevent future PANDAS symptom exacerbations?
Penicillin and other antibiotics kill streptococcus and other types of bacteria. The antibiotics treat the sore throat or pharyngitis caused by the strep. by getting rid of the bacteria. However, in PANDAS, it appears that antibodies produced by the body in response to the strep infection are the cause of the problem, not the bacteria themselves. Therefore one could not expect antibiotics such as penicillin to treat the symptoms of PANDAS. Researchers at the NIMH have been investigating the use of antibiotics as a form of prophylaxis or prevention of future problems. At this time, however, there isn’t enough evidence to recommend the long-term use of antibiotics.
What about treating PANDAS with plasma exchange or immunoglobulin (IVIG)?
The results of a controlled trial of plasma exchange (also known as plasmapheresis) and immunoglobulin (IVIG) for the treatment of children in the PANDAS subgroup was published in “The Lancet,” Vol. 354, October 2, 1999. All of the children participating in the study had clear evidence of a strep infection as the trigger of their OCD and tics, and all were severely ill at the time of treatment. The study showed that plasma exchange and IVIG were both effective for the treatment of severe, strep triggered OCD and tics, and that there were persistent benefits of the interventions.
Dr. Sue Swedo