Questioning the Cause
PANDAS has its skeptics, who see it as more of a hypothesis than a real disorder. One is neurologist Roger Kurlan, M.D., director of the movement disorders program at Atlantic Neuroscience Institute at Overlook Medical Center, in Summit, New Jersey. He calls studies linking strep and PANDAS flawed, contending that their evidence has been mostly anecdotal and unreliable. "It's not uncommon for tics and OCD to wax and wane," he says. Parents often take their child to the doctor when her symptoms have peaked, he adds, so the fact that they subside after treatment with antibiotics doesn't prove anything. Dr. Kurlan isn't convinced that symptoms come on as suddenly as parents report, either. Most children diagnosed with PANDAS, he says, have had prior tics or obsessive-compulsive symptoms, often for months or years. "The so-called 'onset' is just more severe."
This begs the question: Why is PANDAS linked to strep? "Because strep is extremely common, it can be connected to almost anything," says Dr. Kurlan. Back in the 1950s, researchers tried to lay blame for autism on strep, he notes.
Even PANDAS advocates don't know how common it really is. Some experts estimate it affects 10 to 30 percent of children with OCD (OCD affects 1 to 2 percent of children). Others believe that figure is much higher. Researchers are trying to pinpoint which kids are most susceptible. "Studies have shown that both autoimmune and developmental disorders can increase the risk of OCD and tics," says Tanya Murphy, M.D., professor of pediatrics and psychiatry at the University of South Florida, in Tampa. "So can birth complications, such as maternal infection at birth, prolonged labor, prematurity, and low Apgar scores. And children who have ADHD may have a higher risk."
One reason parents and doctors don't connect strep or other potential infection triggers like mycoplasma (which causes walking pneumonia) to a sudden change in a child's behavior is because there's often a lag, from one to six weeks. Also, many cases of strep are never even diagnosed. Without clear criteria to diagnose PANDAS, there continues to be controversy not only surrounding its existence but the methods used to treat it.
Some doctors, including Dr. Murphy, prefer antibiotics as a first line of treatment. Antibiotics kill strep bacteria, putting the brakes on the antibodies that are meant to attack strep but in PANDAS mistakenly target the brain instead. Some children improve dramatically, particularly those with severe symptoms, says Dr. Murphy. She writes a one-month prescription and then monitors her patient's progress. Others write scrips for a full year's supply before discussing more invasive, costly treatments. Those would be plasmapheresis, a "blood-cleaning" procedure that removes the harmful antibodies, and intravenous immunoglobulin (IVIG) therapy, thought to boost the immune system by delivering concentrated amounts of antibodies from healthy blood donors. A study in The Lancet showed both procedures to be effective in treating strep-induced OCD and tics, and a study at NIMH to replicate those results is currently underway.
But IVIG isn't for everyone. "Just as you wouldn't use a very strong antidepressant in someone with mild depression, you'd only use IVIG for kids whose anxiety is so profound that it doesn't get better with antibiotics," says Rosario Trifiletti, M.D., Ph.D., a neurologist in Ramsey, New Jersey. The procedure is expensive; the cost is based on a child's body weight -- in general, $1,000 per every 10 pounds -- and usually isn't covered by insurance. Unfortunately, without standard guidelines for treatment, IVIG is at risk of overuse.