OVERVIEW
The goal of this post is to describe the diagnosis of PANDAS: Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcus
FEATURES OF PANDAS
PANDAS is a group of neurological and psychiatric symptoms that are associated with streptococcal infections.
Streptococcus is a group (or genus) of bacteria that can cause human infection. The most common infection, especially in children, is strep throat. Bacteria called Group A Streptococcus cause strep throat and other human infections. For simplicity, Group A Streptococcus will be abbreviated to GAS in this posting.
PANDAS is defined by the sudden (acute) onset of tics or obsessive-compulsive behavior and other neurological and psychiatric symptoms before puberty, following or in the presence of GAS infection.1
We discussed in a previous post that tics are repetitive and stereotyped movements or vocalizations (sounds or words) that are suppressible, meaning that patients can learn to prevent the tics. Typically, tics begin gradually and wax and wane in intensity and frequency according to activities, sleepiness, and stress. With PANDAS, the tics begin abruptly and are associated with other psychiatric symptoms. Laboratory testing confirms that a GAS infection is present or was present in the recent past.
Obsessive-compulsive behaviors refer to a pattern of unreasonable thoughts and fears (called obsessions) that lead to repetitive behaviors (called compulsions). These obsessions and compulsions interfere with daily activities and cause significant distress. An excessive fear of germs is a common example of an obsession. It is normal to wash your hands after touching something dirty or being around somebody with a cold. Constant fears of contamination by germs that results in compulsive hand-washing, however, is abnormal. Compulsive hand-washing would be frequent, throughout the day, interfering with normal activities, and it might lead to sore and chapped hands. Obsessive-compulsive disorder (OCD) will be discussed separately in a future post.
DIFFICULTIES WITH THE PANDAS DIAGNOSIS
Unfortunately, PANDAS can be difficult to diagnose. Three potential reasons for missed diagnoses and incorrect diagnoses are described below:
(1) Tics are common, and sometimes tics can occur abruptly even without associated GAS infection.
(2) GAS infections are common in grade-school aged individuals, so we expect that some patients with tics will also have evidence of GAS infection simply because both are common. Additionally, people can carry GAS in the noses, throats, and other body areas without actually being infected. So, a child with new-onset tics could have laboratory evidence of GAS without having a true infection.
(3) Several psychiatric symptoms are common among patients with tics. We discussed this in a prior post.
SUMMARY
When tics and neuropsychiatric symptoms begin abruptly in a prepubertal child, it is probably reasonable to evaluate for evidence of GAS infection and PANDAS. However, the diagnosis of PANDAS requires more research. In the next post we will discuss a related disorder called PANS (Pediatric Acute-onset Neuropsychiatric Syndrome).
References
1. Chang K, Frankovich J, Cooperstock M, Cunningham MW, Latimer ME, Murphy TK, Pasternack M, Thienemann M, Williams K, Walter J, Swedo SE; PANS Collaborative Consortium. Clinical evaluation of youth with pediatric acute-onset neuropsychiatric syndrome (PANS): recommendations from the 2013 PANS Consensus Conference. J Child Adolesc Psychopharmacol. 2015;25:3-13