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This study found that about a quarter of patients meeting strict PANS criteria who underwent lumbar punctures (LP) had cerebrospinal fluid (CSF) abnormalities, with the most common being elevated CSF protein and albumin quotient. These patients also exhibited signs of inflammation and autoimmunity, such as low complement levels, high immune complexes, non-specific autoantibodies, vasculopathy, and arthritis.

Interestingly, the “other psychiatric deterioration” group—those referred for PANS but not meeting strict criteria—had an even higher frequency (45%) of CSF abnormalities. Many of these patients also showed systemic inflammation, with conditions like thyroiditis and arthritis, and had symptoms overlapping with PANS, including obsessive-compulsive behaviors and food restrictions.

Both groups demonstrated a notable prevalence of arthritis, emphasizing systemic inflammation’s potential role, possibly affecting the blood-brain barrier (BBB). While the study was not designed to assess the significance of these differences, it suggests an overlap in psychiatric symptoms and inflammatory features across the groups, which may involve complement activation and vascular inflammation, similar to what’s seen in Long Covid.

• Children with PANS had lower levels of IgG antibodies (a type of immune protein) in their plasma during a symptom flare compared to matched controls.
• PANS IgG drawn at flare shows elevated binding to CINs in both mouse and human brain.
• PANS IgG binding to CINs reduces their activity using p-rpS6 as a marker.
• Reduction of PANS IgG binding to CINs parallels symptom improvement during recovery.
• Elevated IgG binding to CINs is resolved in the same subject during symptom recovery.
• The study suggests that at least a subset of PANS cases have a neuroimmune pathogenesis.

Whelan JP. Strep Throat and the Backstory for PANS and PANDAS. JAMA Netw Open. 2024;7(7):e2421636. doi:10.1001/jamanetworkopen.2024.21636

• Longitudinal analysis (Ma et al.) of 193 children with PANS revealed that 28% developed arthritis over 4 years, showing unusual rheumatic profiles like Achilles enthesitis (56%), inflammatory back pain (64%), and sacroiliac joint tenderness (69%). Only 2% had typical childhood arthritis.
• Back pain is a common concern among Whelan’s 600 families, often challenging to differentiate true spondyloarthropathy from pain amplification due to poor sleep, which almost all PANS patients experience.
• Ultrasonography in 40 children found effusions or synovitis, suggesting real back arthritis in many.
• A high prevalence of antihistone antibodies (20%) may result from multiple medications. 55% of children with PANS also had a coincident eating disorder.
• Frequent infections in two-thirds of these children may explain elevated inflammatory markers and the abrupt onset of tics, OCD, and behavioral issues, possibly due to “PANDA-genic” bacterial strains in genetically susceptible hosts.