Diencephalic syndrome: a frequently neglected cause of failure to thrive in infants

Abstract

Purpose: Diencephalic syndrome is an uncommon cause of failure to thrive in early childhood that is associated with central nervous system neoplasms in the hypothalamic-optic chiasmatic region. It is characterized by complex signs and symptoms related to hypothalamic dysfunction; such nonspecific clinical features may delay diagnosis of the brain tumor. In this study, we analyzed a series of cases in order to define characteristic features of diencephalic syndrome.

Methods: We performed a retrospective study of 8 patients with diencephalic syndrome (age, 5-38 months). All cases had presented to Seoul National University Children's Hospital between 1995 and 2013, with the chief complaint of poor weight gain.

Results: Diencephalic syndrome with central nervous system (CNS) neoplasm was identified in 8 patients. The mean age at which symptoms were noted was 18±10.5 months, and diagnosis after symptom onset was made at the mean age of 11±9.7 months. The mean z score was -3.15±1.14 for weight, -0.12±1.05 for height, 1.01±1.58 for head circumference, and -1.76±1.97 for weight-for-height. Clinical features included failure to thrive (n=8), hydrocephalus (n=5), recurrent vomiting (n=5), strabismus (n=2), developmental delay (n=2), hyperactivity (n=1), nystagmus (n=1), and diarrhea (n=1). On follow-up evaluation, 3 patients showed improvement and remained in stable remission, 2 patients were still receiving chemotherapy, and 3 patients were discharged for palliative care.

Conclusion: Diencephalic syndrome is a rare cause of failure to thrive, and diagnosis is frequently delayed. Thus, it is important to consider the possibility of a CNS neoplasm as a cause of failure to thrive and to ensure early diagnosis.

Keywords: Astrocytoma; Brain neoplasms; Failure to thrive; Optic nerve glioma; Pituitary diencephalic syndrome.

Fig. 1. The z scores at the time of diagnosis. (A) z score for weight, -3.15±1.14; (B) z score for height, -0.12±1.05; (C) z score for weight-for-height, -1.76±1.97; and (D) z score for head circumference, 1.01±1.58.

Fig. 2. Patient 4: A 23-month-old infant with failure to thrive. The brain magnetic resonance imaging shows well-defined high signal intensity on T2-weighted images (A), and low signal intensity on T1-weighted images, with a heterogeneous enhancing tumor in the suprasellar area, extendinginto the third ventricle (B).