It’s estimated that 1 to 3 percent of children fit criteria for Obsessive-Compulsive Disorder (OCD) and 10 to 25 percent of school-age children will develop tics or related neuropsychiatric disorders. Pediatricians and researchers now question if the onset of these disorders could be related to routine childhood strep infections. Here, Robert Fuhlbrigge, MD, PhD, assistant in Medicine and attending in Pediatric Rheumatology at Children’s Hospital Boston, explains the possible connection.
Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS) are neurological disorders associated with common Group A-Beta-hemolytic streptococcus (GABHS) infections. The theory is that the normal immune response to strep bacteria becomes misdirected and attacks the brain, specifically the basal ganglia. This hypothesis, termed molecular mimicry, is familiar to physicians as the etiology of cardiac valve damage and Sydenham’s chorea in acute rheumatic fever (ARF). The question is whether a similar process can cause cases of acute onset OCD, tics or Tourette’s syndrome.
The difficulty in diagnosing PANDAS lies in the frequency of the associated symptoms: Tics and obsessive or compulsive behaviors are common, and most children display repetitive behaviors at certain stages of development. Similarly, GABHS infections are common. Some children displaying new tics or OCD symptoms will have coincidental evidence of a current or recent strep infection, regardless of any possible etiologic association. Unfortunately, there isn’t a diagnostic test or validated criteria set for PANDAS yet. Similar to ARF, suspicion of PANDAS is elevated in patients with abrupt onset of neuropsychiatric symptoms in the context of a preceding strep infection (positive culture and/or rising anti-strep antibody titer).
It’s still a controversial diagnosis. The hypothesis is coherent, but supporting evidence is weak. Research shows that anti-neuronal antibodies are found more often in the blood of patients with neuropsychiatric symptoms than in patients who have had strep but don’t have neuropsychiatric symptoms, but it’s not a perfect association. Animal studies have been mixed and there aren’t post-mortem studies of human brains from patients with PANDAS reported.
The best we can do is to be aware of the possibility and look for the association when appropriate. Patients with acute onset of tics or OCD should be interviewed for a history of recent throat infection and tested for strep by culture and the presence of anti-streptolysin O (ASLO) and anti-DNase B antibodies. If the history and laboratory studies are negative, then no association can be identified and the patient does not have PANDAS. If they are positive, the patient should be followed over time.
If flares of symptoms occur without evidence of recurrent strep, or if strep infections occur without changes in symptoms, the patient does not have PANDAS and should not be given antibiotic prophylaxis. However, as with acute rheumatic fever, if recurrent symptoms develop in association with strep infections prophylaxis should be considered. I find it takes approximately one year of monitoring to confirm or refute the diagnosis in those patients who meet the initial screening requirements.
Therapy has to be separated into prophylaxis for strep and treatment of the associated neuropsychiatric symptoms. The only role for antibiotics is to prevent recurrent strep infections and reduce the risk of future injury to the affected regions of the brain. It’s important to recognize that antibiotics won’t treat neuropsychiatric symptoms.
Physicians should consider referral to Psychiatry to treat specific symptoms and to Rheumatology if there are questions of test interpretation or prophylaxis for strep. Once a monitoring plan is established, the physician can provide the needed care with intermittent assistance. Again, in the acute phase, management of the neuropsychiatric symptoms is paramount. At present, there is no conclusive evidence that early treatment with immune suppressive medications, plasmapheresis or intravenous immunoglobulin will improve neuropsychiatric symptoms or alter the course of the disorder.
The only way to prevent it would be to prevent all strep infections. Given the very low incidence of the disorder, it isn’t reasonable to place all school-age children on long-term antibiotics. We recommend the same care provided for ARF prevention: School-age children with unexplained fever or sore throats should be evaluated for strep and, if confirmed, treated with an appropriate course of antibiotics. There is no evidence for additional preventive measures.
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