Hypopituitarism in children: The role of Magnetic resonance Imaging (MRI).

Abstract

Background:
Childhood hypopituitarism is a clinical syndrome of deficiency in pituitary hormone production. Presentation varies from asymptomatic to acute collapse depending on the etiology, rapidity of onset, and predominant hormone involved.

Objective:
To study the frequency, and type of hypothalamic-pituitary axis abnormalities observed on MRI in patients with hypopituitarism and correlate it with MRI findings.


Design and setting:
A retrospective hospital based cohort study was conducted at the pediatric and radiology departments, King Khalid University Hospital (KKUH) Riyadh, Saudi Arabia.


Materials and methods:
The medical records of 202 patients who were diagnosed to have hypopituitarism were retrospectively reviewed. Data included were age, sex, clinical presentation, and results of the relevant laboratory investigations and radiological images.

Results:
During the period under review, a total of 202 patients were diagnosed with hypopituitarism, of these 142 (70.3%) were males and 60 (29.7%) were females. The mean age was 8.9 years (range 0-18 years). The clinical presentation varies from asymptomatic to symptomatic the severity of which depend on hormone deficiency and the etiology. Beside the congenital causes, a diversity of acquired causes were encountered with a non-tumor causes being the commonest. Magnetic resonance imaging (MRI) of the brain was performed in 173 (85.6%) of patients. Single hormone deficiency [growth hormone (GH), and adrenocorticotropic hormone (A.C.T.H)], thyroid stimulating hormone (TSH), luteinizing hormone (LH) and follicle stimulating hormone[FSH], i.e partial hypopituitarism, in 125 (72.3%) patients while, multiple pituitary hormone deficiency (MPHD) in 48 (27.7%) patients. Diabetes insipidus was found in 17(9.8%). Among those patients with magnetic resonance imaging (MRI) were done, the majority (95%) of patients with isolated hormone deficiency had normal MRI findings, while in those patients with MPHD (>50%) revealed abnormal findings varies from empty sella syndrome to anterior pituitary hypoplasia or aplasia. The hypophyseal stalk abnormalities were also evident (thin or interruption). Central diabetes insipidus is rare in children and characterized by the loss of the posterior pituitary bright spot, and thickening of the pituitary stalk were commonly associated.

Conclusion:
Magnetic resonance imaging (MRI) is useful tool in evaluating the hypothalamic-pituitary axis in children. Wide spectrum of MRI findings were encountered. The majority were isolated hormone deficiency (partial hypopituitarism), who had normal MRI findings. The majority of MPHD patients were associated with variable defects (anterior pituitary gland hypoplasia or aplasia and stalk interruptions or thinning). Lack of posterior pituitary gland bright spot, and thickening of the pituitary stalk are commonly associated with central diabetes insipidus (CDI). MRI provide high resolution images of the pituitary gland, pituitary stalk and adjacent structures. It delineated the various neoplastic conditions such as hypothalamic glioma, germiuoma, teratoma, langernhans cell, histiocytosis, leukemic infiltrates, and granulomatosis such as sarcoidosis.