The central diabetes insipidus associated with septo-optic dysplasia (de Morsier syndrome)

Septo-optic dysplasia

Septo-optic dysplasia (SOD) or de Morsier's syndrome is a rare congenital disorder characterized by a classic triad of: (a) optic nerve hypoplasia, (b) agenesis of septum pellucidum and corpus callosum, and (c) hypoplasia of the hypothalamic-pituitary axis. This chapter will outline the key information regarding the etiology and epidemiology of this syndrome with a focus on its comprehensive management. Particular attention will be paid to the diagnostic stage and the most relevant differential diagnosis, before moving to the complexities of its treatment. In fact, although SOD is not curable, many aspects of this syndrome can be improved through a tailored multidisciplinary approach consisting in hormonal replacement, corrective ophthalmological surgery, management of epileptic seizures, and active neuropsychological support.

Neuroimaging of central diabetes insipidus

Central diabetes insipidus (CDI) occurs secondary to deficient synthesis or secretion of arginine vasopressin peptide from the hypothalamo-neurohypophyseal system (HNS). It is characterized by polydipsia and polyuria (urine output >30mL/kg/day in adults and >2l/m²/24h in children) of dilute urine (<250mOsm/L). It can result from any pathology affecting one or more components of the HNS including the hypothalamic osmoreceptors, supraoptic or paraventricular nuclei, and median eminence of the hypothalamus, infundibulum, stalk or the posterior pituitary gland. MRI is the imaging modality of choice for evaluation of the hypothalamic-pituitary axis (HPA), and a dedicated pituitary or sella protocol is essential. CT can provide complimentary diagnostic information and is also of value when MRI is contraindicated. The most common causes are benign or malignant neoplasia of the HPA (25%), surgery (20%), and head trauma (16%). No cause is identified in up to 30% of cases, classified as idiopathic CDI. Knowledge of the anatomy and physiology of the HNS is crucial when evaluating a patient with CDI. Establishing the etiology of CDI with MRI in combination with clinical and biochemical assessment facilitates appropriate targeted treatment. This chapter illustrates the wide variety of causes and imaging correlates of CDI on neuroimaging, discusses the optimal imaging protocols, and revises the detailed neuroanatomy required to interpret these studies.

Sphenoethmoidal meningoencephalocele with variable hypopituitarism: A case report and review of literature

Sphenoethmoidal meningoencephalocele is a rare congenital meningocele with unclear clinical course. Its clinical symptoms are diverse, and this disease is widely observed across all ages. The prognosis of this disease depends on the severity of the central nervous system complications. We reported a case of sphenoethmoidal meningoencephalocele incidentally discovered in a 2-yr-old patient, with the subsequent appearance of diabetes insipidus at school age. An endocrinological evaluation performed when the patient was nine years old using the TRH/CRH/LH-RH load test showed a low response of gonadotropins and slightly hyper-response and normal response of ACTH and TSH, respectively. GH provocative tests indicated severe GH deficiency. Desmopressin and GH treatment efficiently improved his growth rate and quality of life. His pituitary function had presumably been normal from the neonatal period to infancy, but the dysfunction gradually progressed over the next few years along with his physical growth. The symptoms were suspected to be the product of the natural course of his hypothalamus or pituitary gland degeneration, or were otherwise due to gradual damage by chronic mechanical compression or extension. These findings underscore the importance of conducting careful systemic management in the long term, specifically with respect to the endocrinological evaluation of sphenoethmoidal meningoencephalocele.