Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections (PANDAS) is a complex medical condition affecting children. This syndrome is defined by the dramatic, acute onset of neuropsychiatric symptoms following an infection with Group A Streptococcus (GAS) bacteria, the organism responsible for strep throat. The immune response to the bacteria becomes misdirected, leading to inflammation within the brain. While the defining features involve behavioral and movement abnormalities, the condition is neurological in nature. Seizures are not considered a primary feature of the PANDAS diagnosis, but the underlying neurological inflammation can influence the brain’s electrical stability, making the query relevant.
The Autoimmune Mechanism
PANDAS is rooted in an autoimmune process that targets the brain. The body generates antibodies to fight the invading Group A Streptococcus bacteria. A process called molecular mimicry occurs when these antibodies, designed to neutralize the bacterial proteins, mistakenly recognize and attack similar-looking proteins found on a child’s own brain cells.
The primary target of this misguided immune attack is the basal ganglia, a collection of structures deep within the brain that regulates motor control, behavior, and emotion. When the antibodies bind to neurons in the basal ganglia, they trigger inflammation and disrupt normal function. This disruption directly causes the sudden, dramatic onset of the characteristic behavioral and motor symptoms.
The specific bacterial component implicated is N-acetyl-beta-D-glucosamine (GlcNAc), which shares structural similarities with neuronal receptors in the basal ganglia. This cross-reactivity leads to a form of post-infectious basal ganglia encephalitis. Affected neurons include those expressing dopamine D1 and D2 receptors, which are crucial for movement and mood regulation.
Core Neuropsychiatric Symptoms
The hallmark of PANDAS is the sudden, acute, and dramatic onset of symptoms, with parents often recalling the exact day their child’s behavior changed “overnight.” The condition is characterized by the presence of Obsessive-Compulsive Disorder (OCD), a tic disorder, or both, which interfere significantly with daily functioning. OCD symptoms include intense fears of contamination or repetitive rituals, while tics involve sudden, repetitive movements or vocalizations.
Children experience an array of associated neuropsychiatric symptoms that appear just as abruptly. These often include severe separation anxiety and emotional lability, characterized by extreme mood swings and sudden rage. Motor abnormalities are also common, such as a sudden deterioration in fine motor skills leading to messy handwriting (dysgraphia).
Regarding seizures, they are not a standard diagnostic feature of PANDAS but have been reported in a small subset of individuals with the broader Pediatric Acute-onset Neuropsychiatric Syndrome (PANS). The inflammation in the basal ganglia may lower the seizure threshold in susceptible individuals. Seizures associated with the condition can be varied, including focal, generalized, or absence seizures, but their presence is rare compared to the defining behavioral symptoms.
Clinical Diagnostic Criteria
The diagnosis of PANDAS is clinical, relying on a physician’s assessment of specific symptoms and their course, as there is no single definitive laboratory test. The National Institute of Mental Health (NIMH) established five criteria that must be met for a diagnosis to be made.
The first criterion is the presence of obsessive-compulsive disorder or a tic disorder severe enough to impact the child’s life. The second specifies a pre-pubertal onset, with symptoms appearing between the ages of three and the onset of puberty.
The clinical course must be characterized by an unusually abrupt and dramatic onset of symptoms, often followed by an episodic, relapsing-remitting pattern. This means the symptoms may nearly disappear between episodes, only to return with full severity following another infection. The fourth requirement is a distinct association with a Group A Streptococcal infection, documented by a positive throat culture or elevated antibody titers. Finally, the child must display neurological abnormalities during symptom exacerbations, such as motoric hyperactivity or unusual movements.
Treatment Modalities
The treatment strategy focuses on addressing both the underlying infection and the resulting autoimmune response. The initial step involves treating any active Group A Strep infection with antibiotics to eradicate the bacteria and remove the immune system’s trigger.
When symptoms are moderate to severe, immune-modulating therapies may be used to interrupt the autoimmune process. These advanced treatments include Intravenous Immunoglobulin (IVIG) and plasma exchange (plasmapheresis). IVIG infuses pooled antibodies from healthy donors, while plasma exchange removes harmful autoantibodies from the patient’s blood.
Symptom management is also integral, often involving behavioral and pharmacological interventions. Cognitive Behavioral Therapy (CBT), particularly Exposure and Response Prevention (ERP), helps manage OCD symptoms. Selective serotonin reuptake inhibitors (SSRIs) may also be used to control obsessive-compulsive and anxiety symptoms.