PANDAS, or Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections, involves the sudden onset of obsessive-compulsive disorder (OCD) and/or tics in children following a Group A Strep infection. The “P” in PANDAS defines the disorder as occurring within a specific developmental window, generally from age three up to the start of puberty. While the technical diagnosis of PANDAS is exclusive to children, the underlying autoimmune mechanism can manifest across the entire lifespan. Adults can experience acute, infection-triggered neuropsychiatric symptoms that are managed similarly to the pediatric disorder.
Defining PANDAS: The Age Criteria
The official diagnostic criteria for PANDAS strictly limit the onset of symptoms to the pre-pubertal period, typically before age 12 or the onset of puberty. This constraint is rooted in the original research linking Group A Streptococcus (GAS) to the acute onset of neuropsychiatric symptoms. Because of this technical boundary, a person experiencing their first episode of post-streptococcal OCD at age 25 cannot receive a PANDAS diagnosis. This age restriction exists because the immune system’s vulnerability to this autoimmune reaction is most pronounced in younger, developing brains. However, symptoms that begin in childhood may continue or recur after a person enters adulthood. When a case presents post-puberty, clinicians must use a broader diagnostic framework that acknowledges the lifelong potential for immune memory and inflammatory response.
The Adult Presentation: PANS and Autoimmune Syndromes
When an acute, infection-triggered neuropsychiatric syndrome occurs in an adolescent or adult, it is usually categorized as PANS, or Pediatric Acute-onset Neuropsychiatric Syndrome. PANS does not have an age restriction and can be triggered by a wide range of infectious or inflammatory agents. PANDAS is technically a subtype of PANS where the infection is specifically Group A Strep. Adult cases often involve triggers beyond Strep, such as Mycoplasma pneumonia, Epstein-Barr virus, Lyme disease, or the Herpes Simplex Virus (HSV).
The core pathology involves the immune system mistakenly attacking healthy brain tissue, particularly the basal ganglia, which controls motor function and emotional processing. This process is a form of Autoimmune Encephalitis (AE), the most accurate term for these adult-onset conditions. AE encompasses multiple syndromes where antibodies target specific neuronal proteins, such as in Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis.
The symptoms of PANS and AE in adults mirror those seen in children, including severe OCD, tics, anxiety, and extreme mood lability. Adult cases may also include psychosis, memory loss, or seizures. They often focus more on profound psychiatric and cognitive changes rather than dramatic motor symptoms. AE is increasingly recognized as a cause of acute psychiatric illness in adults, often requiring specialized neurological and immunological care.
Persistence or Recurrence: Symptoms Across the Lifespan
The experience of PANDAS-like symptoms in adulthood generally falls into two categories: persistence or recurrence. Persistence occurs when symptoms of OCD, tics, or anxiety diagnosed in childhood never fully resolve or continue to wax and wane. The initial autoimmune process may leave a lasting vulnerability, making the patient susceptible to flare-ups even without a new infection.
Recurrence involves an adult who was symptom-free for years suddenly experiencing an acute return of neuropsychiatric symptoms, often following an illness. This can be debilitating, as the patient must deal with the sudden return of severe symptoms. Furthermore, some adults experience a truly new onset of PANS or AE without any prior childhood history of PANDAS.
In these de novo adult cases, the acute onset of symptoms like severe anxiety, intrusive thoughts, or movement disorders may be the first indication of an underlying autoimmune process. Immune memory suggests that a prior, perhaps undiagnosed, infection may have sensitized the immune system, leading to a delayed reaction in later life. Recognizing this immune-mediated presentation is a major challenge for adult medicine, as these symptoms are frequently misdiagnosed as purely psychiatric conditions.
Clinical Approach to Diagnosis and Treatment in Adults
Diagnosing PANS or Autoimmune Encephalitis in adults requires a comprehensive, multi-disciplinary approach involving neurologists, psychiatrists, and immunologists. The process starts by rigorously ruling out other causes of acute psychiatric or neurological change, such as tumors, stroke, or infectious encephalitis.
Diagnostic Tools
Diagnostic testing often includes:
- Specialized blood tests to look for anti-neuronal antibodies, which target specific brain receptors.
- Magnetic resonance imaging (MRI) of the brain to check for characteristic signs of inflammation.
- A lumbar puncture to analyze the cerebrospinal fluid (CSF), which can reveal elevated white blood cell counts or specific autoantibodies.
Treatment focuses on two goals: addressing any active infection and modulating the misdirected immune response. If a bacterial infection is found, antibiotics are administered.
Immunomodulation Therapies
The primary treatment for the autoimmune component is immunomodulation, which uses medications to calm the overactive immune system. First-line therapies often include high-dose corticosteroids, followed by or combined with intravenous immunoglobulin (IVIG) or plasma exchange (PLEX). IVIG involves infusing pooled antibodies from healthy donors to “reset” the immune system. PLEX involves physically filtering the patient’s blood to remove harmful antibodies. These advanced therapies require administration in a hospital setting and highlight the severity of the underlying brain inflammation.