Infection-triggered anorexia nervosa in children: clinical description of four cases.

Background: Anorexia nervosa (AN) is a serious illness with no definitive treatment. Clinical and research evidence led to the hypothesis that some children with AN may have a pediatric autoimmune neuropsychiatric disorder associated with streptococcus (PANDAS), similar in pathogenesis to other hypothesized PANDAS disorders.

Methods: Four youngsters (ages, 11-15 years) with PANDAS AN were treated with an open trial of antibiotics, in addition to conventional treatment. They were evaluated for eating disorder and obsessive-compulsive symptoms, and for weight gain. Evidence of streptococcal infection came from clinical evaluation, throat cultures, and two serological tests: anti-deoxyribonuclease B (anti-DNase B) and anti-streptolysin O (ASO) titers. The "rheumatic" marker D8/17 was also measured. This B-cell alloantigen is associated, in several publications, with poststreptococcal autoimmunity: Rheumatic fever (RF), Sydenham's chorea (SC), and possibly PANDAS obsessive compulsive disorder (OCD) and tic disorders.

Results: There was clinical evidence of possible antecedent streptococcal infection in all four patients, two of whom had comorbid OCD, with possible infection-triggered AN. All four had the rheumatic marker: A percentage of D8/17-positive B cells of 28-38%, with a mean of 33% (12% or more is considered positive for the marker). The patients responded to conventional treatment plus antibiotics with weight restoration and decreased eating disorder and obsessive-compulsive symptoms. Three needed to gain weight and did so.

Conclusions: There may be a link between infectious disease and some cases of AN, which raises the possibility of new treatment.