Central diabetes insipidus due to lymphocytic infundibuloneurohypophysitis

Autoimmune diabetes insipidus

Once central diabetes insipidus (CDI) has been diagnosed, every effort should be made to reveal its underlying cause. Autoimmune CDI should be considered in the differential diagnosis of idiopathic CDI and also of mass lesions of the sella region. An autoimmune etiology of CDI was first suggested in 1983 by the detection of autoantibodies to hypothalamic vasopressin-producing cells (AVPcAb) in adults and also in children with the disease, using the indirect immunofluorescence test. The major autoantigen for autoimmune CDI has now been recognized as rabphilin-3A, a protein of secretory vesicles of the neurohypophyseal system. The detection of autoantibodies to rabphilin-3A by Western blotting or of AVPcAb provides strong evidence for the diagnosis of autoimmune CDI. Autoimmune CDI is recognized mostly in patients who had also been diagnosed with endocrine autoimmune disorders. The radiological and morphological correlate with autoimmune DI is lymphocytic infundibuloneurohypophysitis (LINH) as detected by magnetic resonance imaging and biopsies that show massive infiltration of the posterior pituitary and the infundibulum with lymphocytes and some plasma cells, and fibrosis in the later stages of the disease. LINH may be associated with lymphocytic anterior hypophysitis. Both may either appear spontaneously or on treatment with immune checkpoint inhibitors.

Rapid exacerbation of lymphocytic infundibuloneurohypophysitis

RATIONALE

Lymphocytic hypophysitis is a relatively rare autoimmune disease defined by lymphocytic infiltration to the pituitary. Its rarity and wide spectrum of clinical manifestations make clarification of the pathology difficult. Here, we describe a case we examined from the primary diagnosis to final discharge, showing the serial progression of lymphocytic infundibuloneurohypophysitis (LINH) to panhypopituitarism with extrapituitary inflammatory invasion in a short period, and responding favorably to high-dose glucocorticoid treatment.

PATIENT CONCERNS

Polyuria, General fatigue and Nausea/Vomiting.

DIAGNOSES

Central diabetes insipidus (CDI), Lymphocytic infundibuloneurohypophysitis (LINH).

INTERVENTIONS

Desmopressin acetate, High-dose glucocorticoid (GC) treatment.

OUTCOMES

He was prescribed desmopressin acetate and subsequently discharged. A month later, he revisited our hospital with general fatigue and nausea/vomiting. A screening test disclosed hypopituitarism with adrenal insufficiency. MRI revealed expanded contrast enhancement to the peripheral extrapituitary lesion. He received high-dose GC treatment and the affected lesion exhibited marked improvement on MRI, along with the recovery of the anterior pituitary function.

LESSONS

This case demonstrates the potential for classical LINH to develop into panhypopituitarsim. We consider this is the first documentation of approaching the cause of atypical LINH with progressive clinical course from the pathological viewpoint.

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.

Lymphocytic infundibulo-neurohypophysitis and infundibulo-panhypophysitis regarded as lymphocytic hypophysitis variant

Lymphocytic infundibulo-neurohypophysitis (LINH) was first reported by Saito et al. and Imura et al. as a cause of idiopathic central diabetes insipidus. Magnetic resonance (MR) imaging with a contrast medium demonstrates thickening of the pituitary stalk, enlargement of the neurohypophysis, or both with homogeneous enhancement. Histological examination reveals a posterior pituitary that is heavily infiltrated by lymphocytes with occasional plasma cells and other inflammatory cells. In early reports of the disorder, the lesion seemed to be limited to the neurohypophysis, but the present review showed cases with a combination of hypopituitarism and diabetes insipidus. Some of them showed partial hypopituitarism. The so-called lymphocytic infundibulo-panhypophysitis (LIPH) is now regarded as a lymphocytic hypophysitis variant. LINH and LIPH are essentially self-limited. In typical cases, conservative care with steroids and hormone replacement is recommended. Surgical intervention should be avoided because the natural course of the disorder may be self-limited. Pathophysiology of the disorder is still unknown. The unique clinical manifestations of the disorder are discussed and reviewed here.