Transient polyuria related to central diabetes insipidus caused by lymphocytic infundibulo-neurohypophysitis in a patient treated for Graves' disease

Manifestation of Central Diabetes Insipidus in a Patient with Thyroid Storm

We herein report a case of central diabetes insipidus complicated with thyroid storm. A middle-aged woman who was receiving treatment for Graves' disease suddenly complained of polydipsia, polyuria and general fatigue. Laboratory tests showed hyperthyroidism, hypernatremia, hypoosmolar urine and a decreased plasma vasopressin level. The occurrence of central diabetes insipidus with hyperthyroidism was revealed on the basis of pituitary magnetic resonance imaging, a water deprivation test and a desmopressin test. The clinical co-existence of diabetes insipidus and hyperthyroidism is very rare; however, the complication should be considered when hypernatremia and/or dehydration progress in patients with Graves's disease as a common autoimmune-related etiology.

Lymphocytic infundibulo-neurohypophysitis: a clinical overview

Lymphocytic infundibulo-neurohypophysitis is an uncommon inflammatory disorder postulated to be autoimmune in origin. Because of the location of inflammation, it selectively affects the posterior lobe of the pituitary (neurohypophysis) and pituitary stalk (infundibulum). The most common presentation is central diabetes insipidus. Although the definitive diagnosis is established histologically by a pituitary biopsy, radiological imaging can be valuable in diagnosing this condition. In this paper, we provide an overview of the pathophysiology, investigations, management, and outcomes of lymphocytic infundibulo-neurohypophysitis.

Subclinical diabetes insipidus

Subclinical central diabetes insipidus (CDI) can be the outcome of a number of diseases that affect the hypothalamus-infundibulum-post hypophysis axis. One of the most common forms of subclinical CDI is linked to an autoimmune pathogenesis even if other causes may be also responsible. Among these, pregnancy, traumatic and surgical brain injury and some infiltrative, vascular, infectious and neoplastic diseases have been reported with increasing frequency. The natural history of autoimmune CDI seems to evolve through 4 functional stages according to the presence of antibodies to vasopressin-secreting cells (AVPcAb) and the relationship between their behavior overtime, the variations of posterior pituitary function and the characteristics of hypothalamic-hypophyseal region on magnetic resonance imaging. This staging is of crucial importance for the therapeutic strategy, taking into account that some stages could be still reversible. Several medical treatments have been suggested to interrupt the progression toward clinical CDI but the results are still discussed.

Lymphocitic infundibulo-neurohypophysitis mimicking a pituitary adenoma

A rare case of infundibulo-neurohypophysitis mimicking a pituitary adenoma is presented. A 69-years-old female patient developed polyuria and polydipsia. Laboratory analysis revealed central diabetes insipidus. No hormonal abnormalities. Cranial-magnetic resonance imaging (MRI) showed a left sided mass in the adenohypophysis presuming a pituitary adenoma. The mass had contact to both internal carotids. Admission to our department for neurosurgical treatment followed. Ophthalmologic examination and neurological examination yielded normal findings. A second MRI focussing on the sellar-region showed a left-sided (T2-MRI.hyperintense), distended adenohypophysis, without contrast enhancement in T1. The stalk appeared thickened. T1-weighted sequences of the neurohypophysis showed loss of signal intensity. We diagnosed an infundibulo-neurohypophysitis and abstained from surgical removal. The patient was discharged under treatment with corticosteroids and desmopressin. Hypophysitis is rare and shows special clinical characteristics. Despite defined radiological features to differentiate between hypophysitis and adenoma the possibility of misdiagnosis, and unnecessary surgical procedures, should always kept in mind.