Heterogenous patterns of recovery of thirst in adult patients with adipsic diabetes insipidus

BACKGROUND

The natural history of adipsic diabetes insipidus (ADI) is not well described, and reports of recovery of thirst are rare.

DESIGN AND METHODS

Case histories presentation. ADI was identified by demonstrating absent thirst and arginine vasopressin (AVP) responses to hypertonic saline infusion.

RESULTS

Twelve patients with ADI were identified (craniopharyngioma 5, anterior communicating artery aneurysm (ACOM) repair 4, congenital 1, neurosarcoidosis 1, prolactinoma 1). Three patients died. Six patients had permanent ADI. Three patients had recovery of thirst, with a heterogenous pattern of recovery. In the first case, ADI had developed after clipping of an ACOM aneurysm. Ten years after surgery; he sensed the return of thirst; repeated hypertonic saline infusion showed recovery of thirst and AVP secretion. In the second case, a 41-year-old female with an intrasellar craniopharyngioma developed post-operative ADI with persistent hypernatremia. Two years post-operatively, she complained of thirst, and hypertonic saline infusion showed normalization of thirst but absent AVP responses, confirming recovery of thirst, but with persistent diabetes insipidus (DI). In the third case, a 29-year-old Caucasian had craniotomy and radiotherapy for craniopharyngioma and developed ADI post-operatively. Eight years post-op, she presented with thirst, seizures and pNa of 112 mmol/l. Hypertonic saline infusion showed persistent DI but thirst responses typical of compulsive water drinking; she has had recurrent hyponatraemia since then.

CONCLUSIONS

We report that 3/12 patients with ADI recovered thirst after longstanding adipsia with heterogenous pattern of recovery. Both the mortality of 25% and the recovery rate of 25% should be considered when planning long-term surveillance.

Central Diabetes Insipidus in Infancy With or Without Hypothalamic Adipsic Hypernatremia Syndrome: Early Identification and Outcome

CONTEXT

Neonatal central diabetes insipidus (CDI) with or without adipsia is a very rare complication of various complex hypothalamic disorders. It is associated with greater morbidity and a high risk of developing both hypernatremia and hyponatremia, due to the condition itself or secondary to treatment with vasopressin analogs or fluid administration. Its outcomes have yet to be evaluated.

OBJECTIVE

To investigate the clinical outcomes of patients with neonatal-onset CDI or adipsic CDI with hypernatremia.

DESIGN, SETTING, AND PARTICIPANTS

All patients diagnosed with neonatal CDI in a university hospital-based observational study and followed between 2005 and 2015 were included and analyzed retrospectively.

MAIN OUTCOME MEASURES

The various causes of CDI were grouped. Clinical outcome and comorbidities were analyzed.

RESULTS

Ten of the 12 patients had an underlying condition with brain malformations: optic nerve hypoplasia (n = 3), septo-optic dysplasia (n = 2), semilobar holoprosencephaly (n = 1), ectopic neurohypophysis (n = 3), and unilateral absence of the internal carotid artery (n = 1). The other two were idiopathic cases. During the median follow-up period of 7.8 (4.9-16.8) years, all but one patient displayed anterior pituitary deficiency. Transient CDI was found in three (25%) patients for whom a posterior pituitary hyperintense signal was observed with (n = 2) and without (n = 1) structural hypothalamic pituitary abnormalities, and with no other underlying cerebral malformations. Patients with permanent CDI with persistent adipsia (n = 4) and without adipsia (n = 5) required adequate fluid intake and various doses of desamino-D-arginine-8-vasopressin. Those with adipsia were more likely to develop hypernatremia (45 vs 33%), hyponatremia (16 vs 4%) (P < .0001), and severe neurodevelopmental delay (P < .05) than those without adipsia. Comorbidities were common. The underlying cause remains unknown at the age of 23 years for one patient with CDI and normal thirst.

CONCLUSION

Neonatal CDI may be transient or permanent. These vulnerable patients have high rates of comorbidity and require careful monitoring.

Diagnostic Accuracy of Copeptin in the Differential Diagnosis of the Polyuria-polydipsia Syndrome: A Prospective Multicenter Study

CONTEXT

The polyuria-polydipsia syndrome comprises primary polydipsia (PP) and central and nephrogenic diabetes insipidus (DI). Correctly discriminating these entities is mandatory, given that inadequate treatment causes serious complications. The diagnostic "gold standard" is the water deprivation test with assessment of arginine vasopressin (AVP) activity. However, test interpretation and AVP measurement are challenging.

OBJECTIVE

The objective was to evaluate the accuracy of copeptin, a stable peptide stoichiometrically cosecreted with AVP, in the differential diagnosis of polyuria-polydipsia syndrome.

DESIGN, SETTING, AND PATIENTS

This was a prospective multicenter observational cohort study from four Swiss or German tertiary referral centers of adults >18 years old with the history of polyuria and polydipsia.

MEASUREMENTS

A standardized combined water deprivation/3% saline infusion test was performed and terminated when serum sodium exceeded 147 mmol/L. Circulating copeptin and AVP levels were measured regularly throughout the test. Final diagnosis was based on the water deprivation/saline infusion test results, clinical information, and the treatment response.

RESULTS

Fifty-five patients were enrolled (11 with complete central DI, 16 with partial central DI, 18 with PP, and 10 with nephrogenic DI). Without prior thirsting, a single baseline copeptin level >21.4 pmol/L differentiated nephrogenic DI from other etiologies with a 100% sensitivity and specificity, rendering a water deprivation testing unnecessary in such cases. A stimulated copeptin >4.9 pmol/L (at sodium levels >147 mmol/L) differentiated between patients with PP and patients with partial central DI with a 94.0% specificity and a 94.4% sensitivity. A stimulated AVP >1.8 pg/mL differentiated between the same categories with a 93.0% specificity and a 83.0% sensitivity.

LIMITATION

This study was limited by incorporation bias from including AVP levels as a diagnostic criterion.

CONCLUSION

Copeptin is a promising new tool in the differential diagnosis of the polyuria-polydipsia syndrome, and a valid surrogate marker for AVP. Primary Funding Sources: Swiss National Science Foundation, University of Basel.

Central diabetes insipidus: alert for dehydration in very low birth weight infants during the neonatal period. A case report

CONTEXT

Central diabetes insipidus (CDI) is a rare cause of hypernatremia during the neonatal period. The diagnosis is particularly difficult in very low birth weight (VLBW) newborns.

CASE REPORT

We report on a preterm newborn who presented CDI soon after birth. On the third day of life, signs of dehydration were present despite normal fluid supply. The diuresis rate was 4.4 ml/kg/h. Although the fluid supply was then increased, the dehydration continued, with hypernatremia, normal glycemia, diuresis of 7.4 ml/kg/h and urine density of 1005 mOsmol/l. Thus, a diagnostic hypothesis of diabetes insipidus was raised. A test with a nasal vasopressin analogue (dDAVP) was performed and CDI was confirmed. Reduction of the fluid supply became possible through appropriate treatment.

CONCLUSION

The diagnosis of CDI is rarely made during the neonatal period, especially in VLBW newborns, because of the difficulty in detecting elevated diuresis. Persistent hypernatremia, usually accompanied by hyperthermia despite abundant fluid supply, weight loss and low urine osmolality are important signs of alert.

Secondary nocturnal enuresis related to central diabetes insipidus as an early manifestation of intracranial germinomatous germ cell tumors in a series of male youngsters

Nocturnal enuresis is a common symptom in children. It is usually attributed to benign causes and diagnostic evaluation is not carried out. We report three male young patients initially presenting with short stature and nocturnal enuresis, related to diabetes insipidus, caused by intracranial germinomatous germ cell tumors. In all three cases, water deprivation tests confirmed diabetes insipidus. Extensive endocrinological investigation also showed further hormone deficiencies. Magnetic resonance imaging of the brain revealed the presence of a central nervous system lesion and histology confirmed the final diagnosis. Surgery, radiation with or without chemotherapy was conducted and the patients were treated with hormone replacement therapies. The patients after a long follow-up were free of disease. We present these cases to alert clinicians to bear in mind that the presence of an intracranial germinomatous germ cell tumor should at least be considered in a child presenting with bed wetting, especially if additional symptoms and signs, including late onset puberty and growth delay or morning hypernatremia, may coexist.

Management of central diabetes insipidus with oral desmopressin lyophilisate in infants

AIM

To assess the efficiency of oral desmopressin lyophilisate (ODL) in neonatal central diabetes insipidus (CDI).

METHODS

The characteristics of four newborns with CDI treated with ODL were evaluated.

RESULTS

Four newborns with polyuria and hypernatremia were included [male, 2 (50%); mean postnatal age, 19±17 days]. At the time of hypernatremia, the mean serum and urine osmolality values were 310±16 and 179±48 mOsm/kg, respectively. Antidiuretic hormone levels were undetectable (<0.5 pmol/L) in all cases. Magnetic resonance imaging revealed anatomical malformations in all cases. ODL (60 μg/tablet) dissolved in water (3-5 mL) was initiated with a dose of 5 μg/kg/day in two equal doses, together with limitation of water intake to avoid hyponatremia. Serum sodium levels returned to normal in a mean duration of 58±9.9 h with a mean decline rate of 0.37±0.1 mEq/L/h after desmopressin administration. Rehospitalization was required for one of the infants because of hypernatremia due to non-compliance. No episode of hyponatremia was encountered. Weight gain and growth of the infants were normal during the mean follow-up duration of 8.5±1 months.

CONCLUSIONS

ODL appears to be practical and safe in the treatment of CDI during the first year of life.

[A case of possible immunoglobulin G4-related disease (IgG4-RD) with retroperitoneal fibrosis and central diabetes insipidus due to infundibulohypophysitis]

We report a case of possible immunoglobulin G4-related disease(IgG4-RD)that resulted in complications such as retroperitoneal fibrosis and infundibulohypophysitis. The patient was a 72-year-old male who presented with polyuria and polydipsia. Magnetic resonance imaging(MRI)revealed a thickened pituitary stalk and contrast enhancement with gadolinium. T1-weighted imaging revealed that the posterior pituitary high-signal zone had disappeared. Central diabetes insipidus was diagnosed on the basis of results of the hypertonic saline test. In addition, pressure due to retroperitoneal fibrosis resulted in hydronephrosis and elevated serum IgG4 levels. Because it was determined that the patient could have IgG4-RD, he was administered prednisolone, following which a decrease in the size of the pituitary stalk and retroperitoneal fibrosis was observed. IgG4-RD is characterized by elevated serum IgG4 levels and the infiltration of IgG4-positive plasma cells into various organs, including the central nervous system. Recently, IgG4-RD research teams organized by the Ministry of Health, Labour and Welfare established guidelines for the diagnosis of IgG4-RD. According to these guidelines, this case would fall under the category of "possible IgG4-RD." This case suggested that when infundibulohypophysitis is detected by neuroradiology, further investigation into the possibility of IgG4-RD should be recommended.

Draining the edema: a new role for aquaretics?

Investigations into edema formation in nephrotic syndrome have mostly focused on the primary role of sodium. While there is controversy about whether sodium retention is an inherent aspect of nephrotic syndrome (overfill hypothesis) or a secondary consequence (underfill hypothesis), the critical role of sodium in driving fluid retention is generally accepted. Consequently, treatment of edema is based on enhancing renal sodium excretion, using saluretics to block tubular reabsorption of sodium. However, there is also evidence of renal water retention: urine in nephrotic patients is typically highly concentrated (unless urinary concentrating ability is impaired by loop diuretics), and vasopressin levels are commonly elevated. Consequently, aquaretics, i.e., drugs that inhibit renal water reabsorption, may constitute effective treatments for nephrotic edema. In fact, these drugs are already approved for the treatment of non-nephrotic edematous states, such as those encountered in congestive heart or liver failure. In this edition of Pediatric Nephrology, two case reports raise the possibility that aquaretics may also be helpful in the treatment of nephrotic edema. These case reports provide no solid evidence for such treatment, and there clearly are serious concerns about inducing critical hypovolemia with potentially catastrophically consequences, such as thrombosis and shock. Yet these concerns similarly apply to saluretics, which clinicians routinely use in the treatment of edema. In addition, the described powerful effect of aquaretics with respect to the resolution of edema, as well as our understanding of the underlying physiology, argue for a more systematic, yet careful assessment of these drugs in the treatment of nephrotic syndrome.

[PET-CT documented complete remission of Erdheim-Chester disease, lasting more than 4 years from treatment initiation with cladribine]

Erdheim-Chester disease is a very rare histiocytic disease. It represents one form of juvenile xanthogranuloma in WHO classification of blood diseases. The disease often causes B symptoms, skeletal pain and also may cause diabetes insipidus and retroperitoneal fibrosis. Selection of therapy depends on published case reports and small clinical trials. There are no recommendations for treatment based on randomized studies. Interferon α is probably the most commonly used drug for this disease. Some remissions have been described after treatment. However, long-term interferon α application is needed which is associated with numerous side effects. There are limited experiences with clabridine in this indication. In Pubmed Medline database, we have found 3 publications dedicated to description of treatment response after cladribine in Erdheim-Chester disease and other 7 papers evaluating effect of cladribine on juvenile xanthogranuloma forms, mostly with positive outcome. Based on these 10 publications we choose cladribine as first-line treatment in our patient. The treatment started in October 2009 with combination of 2-chlorodeoxyadenosine (Litak) 5 mg/m2 sc. + cyclophosphamide 150 mg/m2 iv. + dexamethasone 24 mg iv., five days consecutively. These cycles were repeated monthly. Mentioned formula was submitted 4 times and 3 times in limited application on day 1 - 3. The reason of that was neutropenia grade 3. All symptoms disappeared after treatment. Only diabetes insipidus persisted because damage of pituitary stalk is irreversible. Therapeutic effect was monitored by PET-CT imaging, initially every 6 months, later in 12-month intervals. PET-CT imaging showed complete remission of disease and 4.5 years duration of remission after treatment. The treatment was well tolerated with no complications implying hospitalization. Only mild thrombocytopenia and neutropenia remains after 4.5 years. Based on case report and publications we consider cladribine as appropriate firs-line drug for Erdheim-Chester disease. Therapeutic failure after 3-4 cycles may suggest other options (interferon α, anakinra, vemurafenib), but only in the case if healthcare provider is willing to cover this new and more expansive treatment than therapy with cladribine.

Adipsia increases risk of death in patients with central diabetes insipidus

Central diabetes insipidus (CDI) is caused by deficiency of arginine vasopressin, an antidiuretic hormone. Patients with CDI manifest polyuria which is usually compensated for by increases in water intake. However, some patients are not able to sense thirst due to the destruction of osmoreceptors in the hypothalamus. These adipsic CDI patients are easily dehydrated and the consequent dehydration could be life-threatening. The objective of this study was to investigate the prognosis of adipsic CDI patients. We have reviewed 149 patients with CDI in three hospitals using databases of the electronic medical recording systems, and examined whether adipsia could affect the morbidity and mortality in CDI patients with multivariable analyses. Twenty-three patients with CDI were adipsic while the remaining 126 patients were non-adipsic. The multivariate analyses showed that the incidence of serious infections which required hospitalization was significantly higher in the adipsic CDI patients compared to that in non-adipsic CDI patients (p <0.001). A total of 6 patients with CDI died during the follow-up (median duration; 60 months, range 1 to 132 months). Four of them were adipsic, three of whom died of infection. The statistical analyses revealed that the risk of death in adipsic CDI patients was significantly higher than in non-adipsic patients (p =0.007). It is thus suggested that adipsic CDI patients were susceptible to serious infections which could be the causes of death.

[A practical algorithm for polydipsia in children]

There is a lack of consent on a clinical diagnostic work-up for children with polydipsia. This can result in a delay in diagnosis in some children and unnecessary investigations in others. We describe three children who presented with polydipsia. Two of them were diagnosed with psychogenic polydipsia and one with central diabetes insipidus. We discuss the differential diagnosis and relevant clinical signs before going on to propose a clinical diagnostic algorithm that can be used in children with polydipsia. A systematic diagnostic work up for children with polydipsia helps to differentiate between those in whom polydipsia is unlikely to have a somatic cause and those where a water deprivation-test is indicated. A water deprivation test in children is an invasive procedure and should be performed by a paediatric endocrinologist or nephrologist.

Growth retardation due to panhypopituitarism and central diabetes insipidus following Russell's viper bite

Russell's viper envenomation and its related complications, especially acute kidney injury, is an important cause of morbidity and mortality in tropical developing countries of South Asia. Unusual complications, especially hypopituitarism, are rare and probably missed due to lack of clinical suspicion and diagnostic facilities. We report a rare presentation of growth retardation resulting from hypopituitarism due to Russell's viper envenomation along with central diabetes insipidus. Awareness of the fact that hypopituitarism may occur in this clinical setting is necessary for early diagnosis and treatment, especially among general care practitioners taking care of these patients.

[Acute myeloid leukemia with monosomy 7 and inv(3)(q21q26.2) complicated with central diabetes insipidus]

A 20-year-old female presented with thirst, polyposia, and polyuria and was referred to our hospital because of leukocytosis and anemia. Bone marrow aspiration revealed 66.8% myeloperoxidase-positive blasts and trilineage myelodysplasia. The karyotype was 45, XX, inv(3)(q21q26.2), -7[19]. Therefore, a diagnosis of AML with inv(3)(q21q26.2) complicated by -7 was made. Moreover, hyposthenuria and a low anti-diuretic hormone (ADH) level were observed. Although cerebrospinal fluid analysis was normal, magnetic resonance imaging (MRI) revealed the absence of hyperintensity in the neurohypophysis in T1-weighted images. Therefore, she was also diagnosed with diabetes insipidus. After she was administered a desmopressin nasal spray, the volume of urine produced decreased. Following treatment with second induction therapy containing high-dose cytarabine for AML, she achieved complete remission in the bone marrow. Moreover, when the abnormality on MRI and the volume of urine were normalized, she discontinued desmopressin. Although diabetes insipidus is a rare complication of AML, the majority of AML patients who have diabetes insipidus have the abnormal karyotypes with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) and monosomy 7. Further study is required to clarify the pathogenesis and develop a strategy for the treatment of this category of AML.

Suprasellar non-Langerhans cell histiocytosis (Erdheim-Chester disease)--a case report

Erdheim-Chester disease (ECD) is an uncommon non-Langerhans cell histiocytosis that affects multiple body systems and can present clinically in a myriad of ways. An adult onset is most common with bony involvement and constitutional symptoms. We report the case of a 52-year-old female presenting with diabetes insipidus and a suprasellar mass on imaging, with no evidence of extracerebral involvement. Histopathology was consistent with ECD.

[Perioperative management of a child with central diabetes insipidus who underwent two surgeries before and after desmopressin administration]

A 14-year-old girl weighing 32 kg was diagnosed with suprasellar tumor causing hydrocephalus, hypothyroidism, adrenal dysfunction and central diabetes insipidus. She was treated with levothyroxine and hydrocortisone and urged to take fluid to replace urine. She was scheduled to undergo ventricular drainage to relieve hydrocephalus prior to tumor resection. For the first surgery, desmopressin was not started and urine output reached 4,000 to 6,000 ml x day(-1), urine osmolality 64 mOsm x l(-1) and urine specific gravity 1.002. Anesthesia was induced with sevoflurane and maintained with propofol and remifentanil. Maintenance fluid was with acetated Ringer's solution and urine loss was replaced with 5% dextrose. Bradycardia and hypotension occurred after intubation, which was treated with volume load. Infusion volume was 750 ml and urine output was 1100 ml during 133 min of anesthesia. Postoperative day 1 nasal desmopressin was started. Ten days later, partial tumor resection was performed. Anesthesia was induced with propofol and fentanyl and maintained with sevoflurane and remifentanil. Infusion volume was 610 ml, urine output 380 ml, and blood loss 151 ml during 344 min of anesthesia. Hemodynamic parameters were stable throughout the procedure. Pathology of the tumor was revealed to be germinoma. Bradycardia and hypotension experienced during the first surgery was suspected to be caused by preoperative hypovolemia brought by polyuria. Desmopressin was proved to be effective to treat excessive urine output and to maintain good perioperative water balance.

Variant of lymphocytic infundibulo-neurohypophysitis presenting with unique clinical and radiological features

Lymphocytic hypophysitis (LYH) is a chronic inflammation that primarily affects the pituitary gland. This disorder has recently been classified into lymphocytic adenohypophysitis (LAH), lymphocytic infundibulo-neurohypophysitis (LINH), and lymphocytic infundibulo-panhypophysitis (LIPH) according to the affected area. We report a case of LINH in a 68-year-old woman who presented with diabetes insipidus (DI). In this case, the posterior lobe was affected in both endocrinological assessment and magnetic resonance imaging (MRI) findings. In contrast, the anterior pituitary was not affected in endocrinological assessment but was affected in MRI findings. Indeed, the patient did not develop hypopituitarism. We believed that these clinical and radiological features were unique in regard to the classification of LYH. To confirm the classification of LYH and the distinction from pituitary adenoma, a pituitary biopsy was performed. Based on the pathological and endocrinological assessment, the patient's disorder was finally diagnosed as a variant of LINH. Current evidence recommends that surgical intervention for LYH should be avoided because the natural course of LYH is essentially self-limiting. Therefore, the accumulation of the knowledge of many variants of LYH is important for the preoperative differential diagnosis of pituitary masses. Our clinical observation could be useful for avoiding unnecessary surgical intervention.

Partial central diabetes insipidus in patient with common variable immunodeficiency

Approximately 20% of patients with common variable immunodeficiency (CVID) have any autoimmune disease, as concurrent as prior to diagnosis, even during follow-up. In recent years, cases of CVID associated to endocrine autoimmune diseases have been reported. To our knowledge, no cases of CVID with diabetes insipidus has been reported previously. The authors present the case of a 37-year-old male, diagnosed of CVID, who had thirst, polyuria and nocturia for several years. After a water deprivation test and a complete resolution of patient's symptoms with vasopressin (DDAVP) treatment, diagnosis of partial central diabetes insipidus was finally made. Patients diagnosed of CVID could develop water misbalance due to posterior hypophysis autoimmune disorder. A high index of clinical suspicion, an early diagnosis and treatment of these disease could avoid future complications and improve the quality of life of these patients.

Profound hypernatremia due to central diabetes insipidus

Diabetes insipidus is a rare endocrine disorder in paediatric patients. Polyuria is a cardinal manifestation that is extremely difficult to recognize in diapered infants. Careful urine quantification is the key to diagnosis in appropriate clinical setting. We report a case of a 4 months old infant presenting with an acute life threatening event following an episode of vomiting and decreased oral intake. She had profound hypernatremia which persisted after stabilization. Polyuria unrecognized by the mother was revealed by 24-hour urine output measurement. A diagnosis of diabetes insipidus was made after appropriate laboratory investigations including serum and urine osmolality. The central nature of the disease was confirmed by neuroimaging which showed holoprosencephaly.

Anterior hypopituitarism is rare and autoimmune disease is common in adults with idiopathic central diabetes insipidus

OBJECTIVE

Central diabetes insipidus is a rare clinical condition with a heterogenous aetiology. Up to 40% of cases are classified as idiopathic, although many of these are thought to have an autoimmune basis. Published data have suggested that anterior hypopituitarism is common in childhood-onset idiopathic diabetes insipidus. We aimed to assess the incidence of anterior hypopituitarism in a cohort of adult patients with idiopathic diabetes insipidus.

DESIGN AND PATIENTS

We performed a retrospective review of the databases of two pituitary investigation units. This identified 39 patients with idiopathic diabetes insipidus. All had undergone magnetic resonance imaging scanning and dynamic pituitary testing (either insulin tolerance testing or GHRH/arginine and short synacthen testing) to assess anterior pituitary function.

RESULTS

One patient had partial growth hormone deficiency; no other anterior pituitary hormonal deficits were found. Thirty-three percent had at least one autoimmune disease in addition to central diabetes insipidus.

CONCLUSIONS

Our data suggest that anterior hypopituitarism is rare in adult idiopathic diabetes insipidus. Routine screening of these patients for anterior hypopituitarism may not, therefore, be indicated. The significant prevalence of autoimmune disease in this cohort supports the hypothesis that idiopathic diabetes insipidus may have an autoimmune aetiology.

Central diabetes insipidus and hypothalamic type of hypopituitarism associated with atypical location of Rathke's cleft cyst

A 68-year-old woman was admitted to determine the pathogenesis of weight loss and polyuria. Physical findings on admission showed BMI of 20.9, blood pressure of 147/69 mmHg, and that she had ciliac, axillar and pubic hair loss. Laboratory findings showed that plasma adrenocorticotropic hormone (ACTH) was 4.6 pg/mL with serum cortisol of 1.2 µg/dL. Serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were markedly reduced. Serum growth hormone (GH) and insulin growth factor (IGF)-1 were 0.054 ng/mL and 25 ng/mL, respectively. Serum prolactin was as high as 85.6 ng/mL. The levels of all the pituitary hormones were elevated in response to a mixture of exogenous corticotrophin-releasing hormone (CRH), luteinizing hormone-releasing hormone (LH-RH), thyrotropin-releasing hormone (TRH), and growth hormone-releasing hormone (GRH). However, there was no response of ACTH and GH release to insulin-induced hypoglycemia and no response of LH and FSH release to clomiphene. Urine volume was more than 4,000 mL, with low urine osmolality of 134 mmol/kg. Plasma arginine vasopressin (AVP) was 0.8 pg/mL. There was no increase in urine osmolality and plasma AVP in response to 5% hypertonic saline load. Magnetic resonance imaging revealed Rathke's cleft cyst at the pituitary stalk level, but there was no abnormal finding in the hypothalamus. These findings indicate central diabetes insipidus and hypothalamic type of hypopituitarism, resulting from the atypical location of Rathke's cleft cyst.

Reversible impairment of the processing of proopiomelanocortin into ACTH in pituitary enlargement suspected of lymphocytic hypophysitis

We describe a 64-year-old woman with a cystic pituitary mass presenting with central diabetes insipidus. Brain magnetic resonance imaging (MRI) with enhancement showed enlargement of the pituitary gland with cystic portions and thickening of the pituitary stalk with homogeneous enhancement. Combined anterior pituitary stimulation test and insulin-induced hypoglycemic test confirmed the diagnosis of panhypopituitarism, including adrenocortical insufficiency due to pituitary and hypothalamic dysfunction by stalk compression. Interestingly, the response of serum cortisol to CRH was low and delayed, in contrast to the marked increase in plasma ACTH. Molecular analysis of her plasma ACTH by Sephadex G75 gel exclusion chromatography coupled with radioimmunoassay (RIA) indicated a peak for high molecular weight ACTH, i.e., proACTH, in addition to that for 1-39 ACTH. Three years later, enlargement of the pituitary gland with cystic portions and thickening of the pituitary stalk disappeared completely, followed by the decrease in plasma proACTH level. By the results of endocrinological study and the change of pituitary MRI findings, lymphocytic hypophysitis was suggested. Synthesis of immature ACTH is generally thought to be due to impaired processing of the precursor proopiomelanocortin (POMC) through activation of prohormone convertase (PC)-1 by CRH. It is possible that the immature ACTH in this case was produced by impaired processing of the precursor POMC due to decreased CRH, dysfunction of corticotrophs in the anterior pituitary by compression of the normal pituitary, or antibodies targeting hypothalamic and/or pituitary cells. This report suggested that impaired processing of POMC may unusually play a role in adrenocortical insufficiency exhibited in lymphocytic hypophysitis.

Pituitary and systemic autoimmunity in a case of intrasellar germinoma

Germinomas arising in the sella turcica are difficult to differentiate from autoimmune hypophysitis because of similar clinical and pathological features. This differentiation, nevertheless, is critical for patient care due to different treatments of the two diseases. We report the case of an 11-year-old girl who presented with diabetes insipidus and growth retardation, and was found to have an intra- and supra-sellar mass. Initial examination of the pituitary biopsy showed diffuse lymphocytic infiltration of the adenohypophysis and absent placental alkaline phosphatase expression, leading to a diagnosis of hypophysitis and glucocorticoid treatment. Because of the lack of clinical and radiological response, the pituitary specimen was re-examined, revealing this time the presence of scattered c-kit and Oct4 positive germinoma cells. The revised diagnosis prompted the initiation of radiotherapy, which induced disappearance of the pituitary mass. Immunological studies showed that the patient's serum recognized antigens expressed by the patient's own germinoma cells, as well as pituitary antigens like growth hormone and systemic antigens like the Sjögren syndrome antigen B and alpha-enolase. The study first reports the presence of pituitary and systemic antibodies in a patient with intrasellar germinoma, and reminds us that diffuse lymphocytic infiltration of the pituitary gland and pituitary antibodies does not always indicate a diagnosis of autoimmune hypophysitis.