Hypophysitis in 2014

Central diabetes insipidus: a late sequela of BNT162b2 SARS-CoV-2 mRNA vaccine?

BACKGROUND

The development of an effective vaccine is a powerful tool to contain the global spread of coronavirus disease 2019 (COVID-19). Still, it raises potential safety concerns about the subsequent enhancement of associated immunopathology. Increasing evidence shows that the endocrine system, including the hypophysis, may be involved in COVID-19. Moreover, occasional but increasing reports of endocrine disorders involving the thyroid have been reported after the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. Among them, a few cases encompass the pituitary. Here we report a rare case of central diabetes insipidus following SARS-CoV-2 vaccination.

CASE PRESENTATION

We report a 59-year-old female patient with a 25-year history of Crohn's disease in long-term remission, who presented with sudden onset of polyuria eight weeks after administration of an mRNA SARS-CoV-2 vaccination. Laboratory evaluation was consistent with isolated central diabetes insipidus. Magnetic resonance imaging displayed involvement of the infundibulum and the posterior hypophysis. Eighteen months after the vaccination, she is still under desmopressin treatment and had stable pituitary stalk thickening on magnetic resonance imaging. Although Crohn's disease-associated hypophysitis has been reported, it is scarce. In the absence of other recognizable causes of hypophysitis, we believe the involvement of the hypophysis in our patient may have been triggered by the SARS-CoV-2 vaccine.

CONCLUSIONS

We report a rare case of central diabetes insipidus potentially associated with SARS-CoV-2 mRNA vaccination. Further studies are needed to understand better the mechanisms underlying autoimmune endocrinopathies development in the context of COVID-19 infection and SARS-CoV-2 vaccination.

Recent insights into the pathogenesis of autoimmune hypophysitis

INTRODUCTION

Hypophysitis is an inflammation of the pituitary gland and a rare case of hypopituitarism. Despite the expanding spectrum of histological variants and causative agents, its pathogenesis is far to be fully understood. The present review is focused on recent evidence concerning the pathogenesis of autoimmune hypophysitis by searching through online databases like MEDLINE and Scopus up to May 2021.

AREAS COVERED

Hypophysitis frequently develops in the context of a strong autoimmune background, including a wide spectrum of subtypes ranging from the commonest form of lymphocytic hypophysitis to the newly described and less common IgG4-, anti-PIT-1, and ICI-induced forms. A peculiar combination of genetic predisposition, pituitary damage and immunological setting represents the pathogenetic basis of autoimmune hypophysitis, which is characterized by diffuse infiltration of the gland by lymphocytes and variable degrees of fibrosis followed by pituitary cell destruction. Anti-pituitary antibodies (APA) have been described in sera from patients suffering from autoimmune hypophysitis, though their pathophysiological significance remains largely unknown and their diagnostic value limited.

EXPERT OPINION

In recent years hypophysitis has gained interest due to the increased number of new diagnoses and the recognition of novel subtypes. Further studies could lead to improvements in biochemical/immunological diagnosis and targeted treatments.

Hypophysitis Outcome and Factors Predicting Responsiveness to Glucocorticoid Therapy: A Prospective and Double-Arm Study

CONTEXT

Primary autoimmune hypophysitis (PAH) evolves in most untreated cases in irreversible hypopituitarism. PAH outcome, instead, after immunosuppressive treatment has not been completely clarified.

OBJECTIVE

To evaluate hypophysitis and pituitary function outcomes.

DESIGN

A prospective, double-arm study with a 2-year follow-up.

SETTING

Referral center for pituitary disease.

PATIENTS

Twenty PAH cases.

INTERVENTIONS

Oral prednisone 50 mg/d or conservative strategy by observation.

MAIN OUTCOME MEASURES

Primary endpoint was the improvement/stabilization/worsening of PAH from baseline to a 2-year visit. Secondary endpoint was the improvement/stabilization/worsening of pituitary function from baseline to a 2-year visit.

RESULTS

Twelve patients (57.1%) were treated with a glucocorticoid-immunosuppressive therapy, and eight patients (42.9%) were observed. At the 2-year visit, PAH improvement/recovery occurred in eight immunosuppressive-treated (66.7%) patients and in two untreated patients (25%). PAH worsened in three untreated patients (37.5%) and was considered stable in four immunosuppressive-treated (33.3%) and three untreated patients (37.5%). Improvement/recovery of pituitary function occurred more frequently in immunosuppressive-treated patients (58.3%) compared with untreated ones (25%; P = 0.04). Responsiveness to immunosuppressive treatment is correlated with antipituitary antibody presence (P = 0.01), occurrence of diabetes insipidus at PAH diagnosis (P = 0.01), absence of the physiological neuropituitary "bright spot" on T1-weighed images (P = 0.01), and pituitary stalk at optical chiasm larger than 3.9 mm (area under the curve: 0.97, sensibility: 100%, specificity: 100%; P = 0.04). On the other hand, we failed to identify factors predicting the outcome, among untreated patients.

CONCLUSIONS

Glucocorticoid treatment of hypophysitis improves pituitary secretion and should be encouraged in accordance with the evaluation of endocrine-, immunological-, and morphological-predictive markers.

Neuro-radiological features can predict hypopituitarism in primary autoimmune hypophysitis

Primary autoimmune hypophysitis (PAH) is considered an underdiagnosed disease, due to the difficulty in reaching a definitive diagnosis. PAH clinical diagnosis remains an exclusion diagnosis. We aimed to correlate PAH neuro-radiological signs to endocrine features and evaluate their prognostic role. 24 PAH cases were enrolled and classified according to neuro-radiological signs: in 12 adeno-hypophysitis (AHs), 8 infundibulo-neuro-hypophysitis (INHs) and 4 pan-hypophysitis (PHs). Secondary hypogonadism developed more frequently in INHs as compared to AHs (54.5% vs. 27.3%, p = 0.05), without no difference with PHs (p = 0.6). Diabetes insipidus occurred more frequently in INHs cases (72.7%, p < 0.001) and in PHs cases (27.3%, p = 0.007), as compared to AHs cases (0%). Similarly, all cases of GHD occurred in INHs (100%) as compared to AHs (0%, p < 0.001) and PHs (0%, p < 0.001). The pituitary stalk (PS) showed a pseudo-triangular shape (larger at the optical chiasma) in INHs and a pseudo-cylindrical shape (larger both at the optical chiasma and at the pituitary insertion) in PHs. The PS pseudo-triangular shape correlated to the occurrence of GHD and diabetes insipidus (p < 0.001/p = 0.03). At the 1-year follow-up, improvement of baseline radiological features positively correlated with the loss of the neuro-pituitary "bright spot" on T1-weighted images (OR 0.16; 95% CI 0.03-0.9 p = 0.02) and with a PS diameter at the optical chiasma level larger than 4.1 mm (AUC 0.97, sensibility 80%, specificity 100%, OR 6; 95% CI1.1-28.8, p = 0.01) Our data suggest that neuro-radiological PAH classification in PH, AH and INH can predict pituitary dysfunction and that some neuro-radiological features, such as the pituitary stalk diameter and the loss of the neuro-pituitary bright spot on T1w images can play a role as a positive prognostic marker of the radiological hypophysitis outcome.

Immunoglobulin G4 (IgG4)-Related Hypophysitis

We report two different cases of IgG4-related hypophysitis. In the first case, a pituitary lesion was accompanied by lymphocytic meningitis possibly mimicking tuberculous meningitis. The second case was unassociated with involvement of other organs. No histologic differences were noted between the two cases indicating that the morphologic features of the hypophysial lesion do not depend on the presence of other lesions. The pathogenesis of IgG4 hypophysitis is not known, and further study is necessary to explore the cause, progression, and influencing factors of this disease.

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.