Investigators used pediatric-specific standards to examine the influence of body measurements and sexual maturation on the development of idiopathic intracranial hypertension (IIH), and found a surprising result. IIH in younger children is not always associated with obesity.
After analyzing the medical records of 233 patients, the authors identified 3 subgroups of this condition: young children (girls younger than 7 and boys younger than 8.5 years) who are not overweight; early adolescents who are either overweight or obese, and late adolescents (boys and girls older than 12.5 years) who are mostly obese. Data also show the early adolescent group may be taller than average (P=0.002 in girls; P=0.02 in boys). It’s unclear whether these 3 subgroups indicate an underlying disease progression or distinct disease subgroups.
Previous studies examining the role of excess body weight in children with IIH did not use standardized, pediatric-appropriate measurements, nor did they consider the contribution of pubertal status to the presentation and prognosis of this condition. To address this issue, investigators used the recently revised diagnostic criteria for pseudotumor cerebri syndrome in children to identify and confirm cases of pediatric IIH from 8 international tertiary medical centers, and then examined the relationship between anthropometric features and the development of secondary sexual characteristics.
They used BMI Z-scores, which measures relative weight adjusted for age and sex, while pubertal status was assessed using Tanner staging (breast, pubic hair, and testicular development, where appropriate) and/or menstrual history, rather than unreliable and generalized puberty age brackets.
Interestingly, there was a relatively equal gender ratio in those with young IIH presentation, yet the proportion of male children decreased significantly as age at diagnosis increased (P < 0.001). Boys accounted for 64% of participants younger than 8 years, 32% of participants aged 8 to 13, and only 14% of participants were older than 13 years.
On average, the BMI Z-scores of the youngest patients were within the normal range, but began to exceed the overweight threshold (1.04) in those aged 6.7 years in girls and 8.7 years in boys. Thus, as the age at diagnosis increased, so too did the likelihood of obesity and the proportion of female patients.
A sub-analysis of 57 patients with pubertal status measurements revealed that participants who were prepubertal at diagnosis tended to be of normal weight, whereas participants who had entered puberty demonstrated higher BMI and weight Z-scores. In addition, early adolescent girls had significantly higher height Z-scores compared to the estimated age- and gender-matched national average (7-12.5 years, P=0.048; >12.5 years, P=0.01). Boys in this age group were also taller than the control sample, but the results did not reach statistical significance.
There is evidence that the secretion and action of growth hormone in the body differs in overweight children; a mechanism the authors hypothesize may link the development of IIH with the early puberty growth acceleration noted in the young adolescent group. Further research is needed to elucidate which events of childhood development are associated with IIH and which are coincidental. The authors recommend a prospective study measuring how changes in gonadal and adrenal steroids affect pathogenesis in patients entering puberty.