What are the clinical and laboratory criteria for diagnosing Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections (PANDAS) and Pediatric Acute‑onset Neuropsychiatric Syndrome (PANS) in a child?

Diagnosing PANDAS and PANS

Direct Answer

PANDAS diagnosis requires meeting all five clinical criteria simultaneously: presence of OCD and/or tic disorder, prepubertal onset (ages 3 to puberty), abrupt symptom onset or episodic course, temporal association with Group A Streptococcal infection, and associated neurological abnormalities (particularly choreiform movements). 1 However, the American Heart Association considers PANDAS "a yet-unproven hypothesis" and recommends against routine laboratory testing for GAS solely to diagnose PANDAS. 1, 2

PANDAS Diagnostic Criteria (All Five Must Be Present)

1. Presence of OCD and/or tic disorder - Not just nonspecific behavioral symptoms like screaming, crying, or tantrums, which are too nonspecific and could represent normal developmental variation 2

2. Prepubertal onset - Between 3 years of age and the start of puberty 3

3. Abrupt onset and relapsing-remitting symptom course - Sudden, dramatic onset rather than gradual progression 3

4. Temporal association with Group A Streptococcal (GAS) infection - Documented relationship between strep infection and neuropsychiatric symptom onset 1

5. Associated neurological abnormalities during exacerbations - Particularly choreiform movements, adventitious movements, or motoric hyperactivity 1, 3

PANS Diagnostic Criteria (Broader Category)

PANS represents a broader concept that encompasses sudden-onset obsessive-compulsive symptoms triggered by various infections and insults beyond streptococcal infection. 1 PANS is not strictly linked to group A streptococcal infections but can be triggered by various infectious or environmental factors. 4 Research has shifted from PANDAS to this broader PANS category. 1

PANS patients typically present with:

• Obsessive symptoms 5
• Behavioral regression 5
• Somatic symptoms 5
• Neuropsychological deficits in visual-motor abilities, short- and long-term memory, and processing speed 5

Diagnostic Algorithm

Step 1: Screen for All Five Clinical Criteria

• Document presence of OCD and/or tic disorder (not just behavioral changes) 1
• Confirm prepubertal onset 1
• Establish abrupt onset pattern 1
• Identify choreiform movements or other neurological abnormalities 1, 2

Step 2: Document Temporal Relationship

• Establish clear temporal association between GAS infection and neuropsychiatric symptom onset 1

Step 3: Laboratory Testing (When Clinically Indicated)

• Obtain streptococcal antibody titers: Anti-streptolysin O (ASO) titer and Anti-DNase B titer 1, 2
  • ASO peaks 3-6 weeks after infection 2
  • Anti-DNase B peaks 6-8 weeks post-infection 2
• Interpret using age-appropriate reference ranges - Normal levels are higher in school-age children than adults 1
• Throat culture if symptomatic - Indicated if the patient still has any throat symptoms 2

Step 4: Exclude Other Causes

• Rule out Sydenham chorea (major manifestation of rheumatic fever with similar autoimmune mechanism) 6
• Distinguish from classic OCD (which has gradual onset, not abrupt) 6
• Consider other differential diagnoses 1

Key Distinguishing Features

Choreiform movements are the key distinguishing neurological features that help differentiate PANDAS from normal developmental behavioral variations. 1 New motor or vocal tics that weren't present before are essential to assess. 2

Critical Diagnostic Pitfalls to Avoid

Pitfall 1: Overdiagnosis Based on Antibody Titers Alone

Elevated streptococcal antibody titers are common in school-age children and do not confirm PANDAS without meeting all five clinical criteria. 1 Age-specific reference ranges are essential for interpretation. 1

Pitfall 2: Misinterpreting Nonspecific Behavioral Symptoms

Screaming, crying, and tantrums alone are too nonspecific without the specific neuropsychiatric features (OCD, tics) and neurological abnormalities. 1 Behavioral changes alone could represent normal developmental variation, especially in a child described as "always moody." 2

Pitfall 3: Routine Laboratory Screening

The American Heart Association explicitly recommends against routine laboratory testing for GAS solely to diagnose PANDAS. 2, 6 Testing should be guided by clinical presentation meeting the five criteria.

Pitfall 4: Absence of Biological Markers

The absence of biological markers or instrumental alterations makes the diagnosis of PANS and PANDAS a matter of exclusion. 5 This requires careful clinical assessment rather than relying on laboratory findings alone.

Important Caveats

• PANDAS remains controversial: The American Heart Association states it "should be considered only as a yet-unproven hypothesis" with a controversial evidence base. 1, 6
• No routine prophylaxis or immunotherapy: The American Heart Association recommends against long-term antistreptococcal prophylaxis and immunoregulatory therapy (IVIG, plasma exchange) as first-line treatment. 2, 6
• Diagnosis is clinical: Requires careful medical history and thorough physical examination focusing on the five specific criteria. 7
• More standardized criteria needed: Developing more standardized diagnostic criteria and identifying specific laboratory markers to facilitate PANDAS diagnoses are crucial areas for future research. 3