The diagnosis of PANDAS is diagnosed clinically, currently relying more on history and physical examination rather than other specific studies. The following five criteria are used to diagnose PANDAS:
- Presence of obsessive-compulsive disorder (OCD) and/or a tic disorder, ADHD symptoms, or oppositional behaviors
- Abrupt onset and/or symptoms vary in intensity
- Association with neurological abnormalities, including motor hyperactivity, or abnormal movements, such as choreiform movements (involuntary jerky movements), other combinations of neuropsychiatric symptoms, such as anxiety, emotional lability, bedwetting, or other regressive behaviors (temper tantrums), personality changes and deterioration in math skills and handwriting
- Onset of symptoms from age 3 years to puberty
- Association with group A beta-hemolytic streptococcal infection (the bacteria that causes strep throat) either by culture or other evidence of infection, such as scarlet fever or by laboratory test evidence
The diagnosis must include the sudden onset of OCD, tics, ADHD, or a rapid worsening of existing symptoms. To make the diagnosis, evidence must exist of a recent or active strep infection either by throat culture or by antibody testing for Streptococcus (for example, antistreptolysin O or antideoxyribonuclease B antibodies).
Along with the clinical diagnosis, it is important to exclude other reasons for the symptoms, and additional testing might be performed for that reason. In fact, distinguishing PANDAS from Tourette’s syndrome (a common tic disorder), OCD, or Sydenham chorea (a movement disorder associated with rheumatic fever also caused by Streptococcus) is not always a simple task.
When running lab tests to look for evidence of infectious triggers Group A Streptococcus should always be considered (which can be asymptomatic and also be present in places other than the throat). A one-time measurement of antibodies is not sufficient for the diagnosis; these antibodies should be measured at two different times (four to six weeks apart) to detect a rise in levels.
Other infectious triggers to consider are Mycoplasma, Lyme disease, Herpes Simplex Virus, Coxsackie virus, Epstein Barr Staph infections, Influenza,particularly H1N1. Other helpful testing to support a diagnosis are MRI’s, the Cunningham Panel, MTHFR and other genetic testing, and a full immunological work up.
Since a diagnosis of PANS implies no specific cause, clinicians will have to evaluate and treat each affected youth on a case-by-case basis; however, the current diagnostic criteria for PANS includes the following three components:
- Abrupt, dramatic onset of OCD or anorexia.
- Concurrent presence of at least two additional neuropsychiatric symptoms with similarly severe and acute onset. These include anxiety; mood swings and depression; aggression, irritability and oppositional behaviors; developmental regression; sudden deterioration in school performance or learning abilities; sensory and motor abnormalities; somatic signs and symptoms.
- Symptoms are unexplainable by a known neurologic/medical disorder