An Uncommon Case of a Patient with CVID and PANDAS

Introduction Pediatric autoimmune neuropsychiatric disorder associated with Streptococcus infections (PANDAS), a subset of pediatric acute-onset neuropsychiatric syndrome (PANS), is characterized by new-onset neuropsychiatric symptoms temporally associated with Streptococcus infection. Some patients with PANS/PANDAS have also been found to have antibody deficiency (IgG, IgA, and vaccine antibody to Streptococcus pneumoniae). However, PANDAS in patients with common variable immunodeficiency (CVID) has not been previously reported. Case Presentation A 16-year-old male with CVID and psoriasis was diagnosed with PANDAS at 9 years old after a febrile illness with group A Streptococcus infection. Given his ongoing severe neuropsychiatric symptoms, including obsessive compulsive disorder, he transitioned from intravenous immunoglobulin (IVIG) dosing for CVID to a higher dose (2 gram/kg/month) for the treatment of PANDAS. He did not have additional major infections, and after approximately a year of higher dose IVIG treatment, his neuropsychiatric symptoms of PANDAS improved. Discussion The prevalence of PANDAS in children with CVID is unclear. The mechanism of IVIG in the treatment of PANDAS has not been elucidated. Mechanisms may involve the binding and neutralization of autoantibodies by anti-idiotypic antibodies and also the eradication and prevention of streptococcal infection. PANDAS should be considered on the differential for patients with CVID and antibody deficiency who develop new onset or suddenly worsening neuropsychiatric symptoms in the setting of an acute upper respiratory tract infection. Prompt diagnosis, timely treatment of an underlying streptococcal infection, and appropriate doses of IVIG, especially in patients with immunodeficiency, may prevent the development of severe PANDAS and improve the quality of life of patients.