WASHINGTON, DC— A unique group of pediatric patients with a possible infection-triggered form of anorexia nervosa was reported at the 51st Annual Meeting of the American Academy of Child and Adolescent Psychiatry. Designated as pediatric autoimmune neuropsychiatric disorders associated with streptococcus anorexia nervosa (PANDAS AN), the disorder may be part of the PANDAS spectrum of disorders that also includes obsessive-compulsive disorder (OCD) and tics, suggested researchers from Creighton University School of Medicine and Children’s Hospital in Omaha.

It was the first detailed report of a group of patients exhibiting signs of a potentially infection-triggered form of anorexia nervosa, noted the investigative team. When asked by Neuropsychiatry Reviews what propelled the team’s work, Mae Sokol, MD, Director of the Eating Disorders Program at the hospital, explained: “Many parents told me their children’s anorexia nervosa first started shortly after infections. These tended to be cases where anorexia nervosa began abruptly in relatively normal children. This is not the usual way anorexia nervosa begins—it is usually a more gradual onset.”

RELATED STUDIES, RELATED DISORDERS

The investigators were also encouraged by work being done on OCD and streptococcal infections at the National Institute of Mental Health. Streptococcal infection is known to trigger rheumatic fever and a form of rheumatic fever that affects the brain, Sydenham’s chorea. “Strep triggers Sydenham’s chorea and rheumatic fever by a postinfectious, autoimmune process, similar to what we think happens in PANDAS,” Dr. Sokol related. “We therefore used strep lab tests available to test for rheumatic fever and Sydenham’s chorea, and psychological assessments ... used for PANDAS OCD. We are finding that these youngsters who have PANDAS AN may form a distinct group of anorexia nervosa patients.”

In the study, systematic evaluation of 21 patients with anorexia nervosa was conducted at admission to inpatient eating disorders treatment. The criteria seemed to identify a subset of pediatric patients with anorexia nervosa whose symptoms were possibly triggered by group A beta-hemolytic streptococcal (GABHS) infection.

In order to receive a diagnosis of PANDAS AN, participants had to fulfill the DSM-IV criteria for anorexia nervosa at the time of admission to the study and exhibit increased psychiatric symptoms that did not occur exclusively during stress or physical illness. Also, there had to be evidence of GABHS infection such as a history of streptococcal illness: upper respiratory infection, pharyngitis, sinusitis, or flu-like syndrome; positive throat culture for GABHS; or positive serologic findings within 12 months after onset of anorexia nervosa symptoms.

Additionally, other criteria included prepubertal onset of the eating disorder symptoms and acute onset of the first episode of anorexia nervosa and/or exacerbation of eating symptoms within a one-day to one-month period; the eating disorder symptoms that lead to anorexia nervosa must begin within one day to six months of the onset of streptococcal infection. Concomitant neurologic abnormalities such as tics, choreiform movements, or motor hyperactivity during symptom exacerbations were also factors.

SUDDEN ONSET

The 21 participants (18 female; age range, 10.5 to 18) were predominantly white and had all been admitted to an inpatient eating disorders specialty treatment program for treatment of anorexia nervosa; age at eating disorder symptom onset ranged from 9.7 to 16. In these patients, symptom onset was usually acute and sudden, the team noted. There was also a temporal relationship between an upper respiratory infection and the onset of eating disorder symptoms. Some of the patients had documented GABHS infection. Other participants displayed symptoms of pharyngitis or upper respiratory infections, but no throat culture had been obtained. Comorbid psychiatric conditions, most commonly depression, were seen in more than half of these patients upon admission.

Is PANDAS AN a common disorder? That is a difficult question to answer, acknowledged Dr. Sokol, who believes “a small percentage of anorexia nervosa patients have PANDAS as an antecedent factor for the development of their illness.” To Dr. Sokol, for whom the findings came as no surprise, the connection between infection and anorexia nervosa is not a tenuous one. “The mind and the body are not separate entities. They make up the whole individual. It is therefore not that surprising that physical changes caused by infections might affect psychological factors. But it is something we know very little about, and it is exciting to learn about this.”

THE THREAT OF INFECTION

It is Dr. Sokol’s hope that physicians will screen their patients for anorexia nervosa and for the possibility of PANDAS AN. “However, this is only research at this time—it should not influence treatment decisions,” she cautioned. All children, and especially those with malnutrition from eating disorders, should be protected from infections, including streptococcal infection, she advised. “Washing hands is very important, as well as getting a throat culture and treating bacterial infections with antibiotics. Youngsters with eating disorders should get the flu shot yearly. Because of malnutrition, youngsters with anorexia nervosa qualify to get the flu shot this year, despite the shortage.”

Further research is needed to verify the existence of a PANDAS AN group and elucidate its characteristics. The investigators are now studying a larger group of PANDAS AN patients and will compare them to anorexia nervosa patients who do not have PANDAS characteristics. They are also trying to find treatments that may be effective for this group of anorexia nervosa patients.

—Heidi W. Moore

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