Paediatric Acute-Onset Neuropsychiatric Syndrome

Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) is a condition where children suddenly develop severe mental and behavioral changes, often seemingly overnight, transforming happy, healthy children into those struggling with obsessive thoughts, restricted eating, and other distressing symptoms.

Table of contents

• What is PANS?
• PANDAS: A Specific Type of PANS
• Signs and Symptoms
• Who Is Affected?
• What Causes PANS?
• How Is PANS Diagnosed?
• Treatment Approaches
• Disease Course and Outlook

What is PANS?

Pediatric Acute-onset Neuropsychiatric Syndrome is a condition that brings sudden and dramatic changes in children’s mental health and behavior. The most striking feature of PANS is how quickly it appears. Within just 72 hours or less, a child who seemed completely normal can develop severe symptoms that dramatically affect their daily life^[1][2][3].

The condition has two main features that doctors look for. First, children suddenly develop either obsessive-compulsive symptoms (unwanted, urgent thoughts and repetitive behaviors) or severely restricted eating. Second, along with these primary symptoms, at least two other mental, behavioral, or neurological symptoms appear at the same time with similar sudden onset^[1][2].

PANS typically affects children before they reach puberty. The condition follows what doctors call a relapsing-remitting course, meaning that children experience acute flare-ups of psychiatric symptoms followed by periods when symptoms are less severe or nearly absent^[3][4].

Stanford Medicine created the first comprehensive PANS program at an academic institution in 2012, and the field has been growing since then^[1].

PANDAS: A Specific Type of PANS

PANDAS stands for “Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections.” It is considered a subset or specific type of PANS^[4][5].

PANDAS was first identified in the 1990s by researchers at the National Institute of Mental Health. They discovered that five children who suddenly developed obsessive-compulsive disorder and tics had all recently been diagnosed with a strep throat infection (caused by Group A streptococcus bacteria)^[5][6].

The main difference between PANS and PANDAS is the identified trigger. PANDAS specifically requires a documented connection to a streptococcal infection, whereas PANS does not require a known trigger, though it is believed to be triggered by one or more infectious agents^[4][5].

PANDAS has five specific criteria for diagnosis: the presence of obsessive-compulsive disorder or tics, symptoms first appearing between age 3 and puberty, sudden onset with an episodic course, connection to Group A strep infection, and the presence of neurological abnormalities^[5].

Signs and Symptoms

The symptoms of PANS can be frightening for both children and their families. Parents often describe their child as completely changed, saying “this is not my child”^[6].

The psychological and behavioral symptoms that may appear include anxiety or depression, bedwetting, sudden changes in mood or personality (especially rage or irritability), difficulty sleeping, loss of interest in food, fidgeting similar to attention-deficit/hyperactivity disorder, obsessive-compulsive behaviors, separation anxiety, and tics similar to those seen in Tourette syndrome^[4].

Neurological symptoms may include changes in motor skills such as problems with handwriting, difficulty concentrating or learning, poor performance in school, reduced coordination, and sensitivity to light and sound^[4].

Additional symptoms identified in diagnostic criteria include eating restrictions, sensory amplification, behavioral regression, sudden deterioration in school performance, urinary symptoms, and sleep disturbances^[5][7].

These symptoms are thought to start suddenly and occur in episodes. They may last for days or weeks, then disappear and return later^[4].

Who Is Affected?

PANS primarily affects children before they reach puberty, with most reported cases occurring between the ages of 3 and 12 years old^[4][5]. The average age of onset for PANDAS is 6 to 7 years^[5].

Some healthcare providers believe the condition may be more common in boys, though research continues on this aspect^[4].

Children may be at higher risk if they have frequent Group A streptococcal infections such as strep throat or scarlet fever, or if they have a family history of autoimmune diseases or rheumatic fever^[4].

Research suggests that PANS and PANDAS are rare conditions, though the exact number of affected children is not fully known^[4].

Some researchers think it is very uncommon for teenagers or adults to develop mental or neurological symptoms from strep infections, though studies are looking into potential long-term effects^[4].

What Causes PANS?

The cause of PANS is believed to involve the immune system’s response to infections or other triggers. Experts believe that symptoms result from brain changes caused by inflammation triggered by infections, metabolic disturbances, other inflammatory reactions, or psychological trauma^[3][7].

An immune-mediated process is thought to be at work, where the central nervous system is affected by different pathogen-driven immune responses^[3]. In cohorts of well-characterized PANS patients, evidence of post-infectious autoimmunity or neuroinflammation has been found in more than 80% of cases^[10].

Some researchers believe that when the immune system produces antibodies to fight bacteria that caused a strep infection, these antibodies may mistakenly attack healthy cells in other tissues because the cells look similar to those of the strep infection. These antibodies may affect tissues in the child’s brain, leading to the psychological and neurological symptoms^[4].

Various infections besides strep have been suggested as possible triggers, including Mycoplasma pneumonia, influenza, upper respiratory infections, sinusitis, Lyme disease, and perianal strep infections^[5][6].

Several theories exist about why some children develop PANS after infections while others do not. These include differences in bacterial strains (only certain strains may trigger symptoms), genetic vulnerability in how the body clears infections or manages inflammation, and the location of the strep infection in the body^[5].

How Is PANS Diagnosed?

There is no single test to diagnose PANS. Instead, healthcare providers make the diagnosis based on the pattern of symptoms and their sudden onset^[4][5].

PANS is considered a diagnosis of exclusion, meaning that doctors must rule out other possible causes for the neuropsychiatric symptoms. Conditions that need to be ruled out include Sydenham’s chorea, systemic lupus erythematosus, and autoimmune encephalitis^[9].

A healthcare provider will perform a physical exam and carefully evaluate the child’s symptoms^[4]. The assessment focuses on identifying the sudden onset (within 72 hours) of obsessive-compulsive symptoms or severely restricted food intake, along with at least two other acute neuropsychiatric symptoms^[9].

For PANDAS specifically, documentation of a preceding strep infection is required. However, many cases in the community are diagnosed based on a history of exposure to a known strep infection, particularly in siblings or after overnight stays with friends or relatives. The strep bacteria that produce post-infectious complications often do not cause obvious symptoms like sore throat or fever, so infections may go undetected and untreated for long periods^[5].

Doctors may test for active strep infections through throat swabs, and may also examine other areas including the tonsils and perianal region, as strep can be present in multiple locations^[5].

Treatment Approaches

Treatment for PANS is individualized based on each child’s specific symptoms and needs. The approach depends on three complementary modes of intervention^[10]:

First, treating the symptoms themselves with psychoactive medications, psychotherapies (particularly cognitive behavioral therapy), and supportive interventions. Cognitive behavioral therapy is a form of psychotherapy that can help children better manage mental health symptoms^[4][10].

Second, removing the source of inflammation with antimicrobial interventions. Children with an active strep infection need antibiotics. Some children may benefit from preventive antibiotic treatment^[4][10].

Third, treating disturbances of the immune system with immunomodulatory or anti-inflammatory therapies. These may include non-steroidal anti-inflammatory drugs, steroids, intravenous immunoglobulin (IVIG), or plasmapheresis (a procedure that filters the blood)^[10][13].

Management should prioritize addressing the most impairing psychiatric symptoms. Treatment effectiveness should be evaluated frequently and modified as needed. Treatment can be reduced or stopped when symptoms resolve, but may need to be restarted due to the relapsing-remitting nature of the condition^[9].

Treatment severity is often based on the degree of symptoms. Mild cases have symptoms that cause disruptions at home or school and occupy a few hours a day. Moderate cases have distressing symptoms that interfere with daily activities and occupy 50-70% of waking hours. Severe cases have incapacitating or life-threatening symptoms^[13].

Disease Course and Outlook

PANS follows a relapsing-remitting course. This means children experience episodes of acute psychiatric symptoms alternating with periods when symptoms are less severe or relatively quiet^[9][3].

The condition may be followed by a chronic course with cognitive deterioration in some cases^[3]. The symptoms can last for days or weeks before improving, though they may return later^[4].

Follow-up care is recommended at regular intervals: 1, 3, 6, and 12 months if symptoms resolve or stabilize and treatment options have been sufficiently tried^[9].

Getting accurate diagnosis, proper treatment, and family support can make a profound difference for both the child’s health and the entire family’s well-being^[1]. Stanford Medicine and other institutions have developed comprehensive programs that combine groundbreaking research with tailored care for patients and their families^[1].

PANS, PANDAS, Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infections