Central diabetes insipidus as a very late relapse limited to the pituitary stalk in Langerhans cell histiocytosis.

Central diabetes insipidus (CDI) and relapse are frequently seen in multifocal Langerhans cell histiocytosis (LCH). We present two females with multifocal LCH who developed CDI 9 and 5 years after the initial diagnosis, respectively, as a relapse limited to the pituitary stalk. Combination chemotherapy with cytarabine reduced the mass in the pituitary stalk. Although CDI did not improve, there has been no anterior pituitary hormone deficiency (APHD), neurodegenerative disease in the central nervous system (ND-CNS) or additional relapse for 2 years after therapy. It was difficult to predict the development of CDI in these cases. CDI might develop very late in patients with multifocal LCH, and therefore strict follow-up is necessary, especially with regard to symptoms of CDI such as polydipsia and polyuria. For new-onset CDI with LCH, chemotherapy with cytarabine might be useful for preventing APHD and ND-CNS.

Diabetes insipidus following resection of pituitary tumors.

Diabetes insipidus (DI) is a common complication following pituitary surgery and can be transient or permanent. Neurogenic DI occurs following injury to the magnocellular neurons in the hypothalamus that produce and transport arginine vasopressin (AVP) and form the hypothalamo-hypophyseal tract. DI is defined by a constellation of signs and symptoms resulting in dilute high-volume urine output and increasing serum osmolality. The body's inability to concentrate urine leaves the patient dehydrated and leads to metabolic abnormalities that can be life threatening if not recognized and treated in a timely manner with an exogenous AVP analog. The reported incidence of postsurgical central DI varies from 1 to 67%. This wide range likely reflects inconsistencies in the working definition of DI across the literature. Factors affecting the rate of DI include pituitary tumor size, adherence to surrounding structures, surgical approach, and histopathology of pituitary lesion. The likelihood of postoperative DI can be reduced by careful preservation of the neurovascular structures of the hypothalamus, infundibulum, and neurohypophysis. Vigilance and meticulous surgical technique are essential to minimize injury to these critical regions that can lead to postsurgical DI.

[Hypernatremia as a predictor of poor outcomes in children with severe brain injury].

The aim of the study was to elucidate a relationship between the development of hypernatremia and the frequency of poor outcomes in children with severe brain injury (SBI). The retrospective study enrolled 77 children (54 boys and 23 girls) aged 1 month to 18 years, who had SBI in the period of January 2008 to September 2009, and were divided into 3 groups after treatment termination. The admission injury severity criterion was Glasgow coma scale (8 scores or less) rating. Group A comprised 51 children with SBI without hypernatremia; Group B included 14 children with SBI and hypernatremia. Group C consisted of 12 children with SBI, hypernatremia, and polyuremia. The latter group was appraised as a group with evolving central diabetes insipidus. A total of 26 (33.8%) patients had hypernatremia. Poor outcomes (Glasgow outcome scores of 1-3) at 30 days were noted in only Groups B and C: comparison of outcomes in Groups B and C showed the higher incidence of poor outcomes in 10 (84%) Group C patients (with hypernatremia and polyuria) and 4 (28%) children in Group B. Comparison of Groups B and C children indicated that the hazard ratio was 0.3. Therefore, the risk of poor outcomes is much higher in the development of central diabetes insipidous in the presence of hypernatremia.