Hyponatremia After Colonoscopy Bowel Preparation: Challenges in Managing Syndrome of Inappropriate Antidiuretic Hormone Without Established Guidelines.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a condition that leads to free water retention and solute excretion, predisposing patients to hyponatremia. We present the case of a 79-year-old female with a history of SIADH well-controlled with fluid restriction and sodium chloride tablets who presented with hyponatremia after bowel preparation. Her medication regimen was not adjusted before she took the bowel preparation. Her SIADH diagnosis was unknown when she presented but was exemplified by her sodium levels dropping while on a normal saline drip on her third day in the hospital. She was able to successfully take the bowel preparation without hyponatremia after oral urea was added to her regimen. There are currently no clinical guidelines for SIADH patients receiving bowel preparation for colonoscopies and no case reports describing this situation. We discuss the pathophysiology behind the patient's fluctuating sodium levels when on various maintenance fluids and when on fluid restriction. This case concludes that it is imperative to either increase solute intake or increase free water excretion for SIADH patients receiving bowel preparation to prevent potentially deadly hyponatremia.

Copeptin's role in traumatic brain injury: The promising quest for a new biomarker.

OBJECTIVE: Traumatic brain injury (TBI) necessitates reliable biomarkers to improve patient care. This study explored copeptin as a potential biomarker in TBI and its relation to vasopressin (ADH) in such patients. METHODS: A cross-sectional study was conducted on 50 TBI patients. Exclusion criteria included specific medical conditions and recent traumatic events. Copeptin and ADH testing were performed within 30 days post-trauma. Patient data, Glasgow Coma Scale (GCS) scores, imaging results, and the need for surgical intervention were obtained from medical charts. RESULTS: Copeptin levels negatively correlated with GCS scores (ρ = - 0.313, p = 0.027), indicating a potential association with trauma severity. Copeptin levels (mean: 3.22 pmol/L, median 2.027 pmol/L, SD = 3.15) tended to be lower than those found in the normal population, suggesting possible neuroendocrine dysfunction post-TBI. ADH levels (mean: 67.93 pmol/L, median 56.474 pmol/L SD = 47.67) were higher than the normal range and associated with the need for surgery (p = 0.048). Surprisingly, copeptin and ADH levels negatively correlated (r = - 0.491; p < 0.001), potentially due to differences in degradation processes and physiological variations in TBI patients. CONCLUSION: Copeptin shows potential as a predictive biomarker for assessing TBI severity and predicting patient outcome. However, its complex relationship with ADH in TBI requires further investigation. Careful interpretation is needed due to potential variations in excretion dynamics and metabolism. Larger studies on TBI patient cohorts are essential to validate copeptin as a reliable biomarker and improve patient care in TBI.

Sertraline Hydrochloride Overdose Resulting in Diabetes Insipidus: A Case Report.

Sertraline hydrochloride belongs to the selective serotonin reuptake inhibitor class of antidepressants, which can cause respiratory depression, hypotension, malignant vomiting, liver function impairment, and other symptoms when taken in excess. To our knowledge, reports of sertraline hydrochloride overdose causing diabetes insipidus in patients are rare. This report describes a unique case of a 17-year-old female patient who developed diabetes insipidus after a one-time oral intake of 20 sertraline hydrochloride tablets (50 mg/tablet) during the later course of treatment. Her symptoms were effectively relieved after treatment with pituitrin.

Syncope and Brugada-Like ECG Pattern in a Patient with Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH).

Syncope is a brief loss of consciousness caused by reduced blood flow to the brain, characterised by sudden onset, short duration and full recovery without intervention. Anamnesis, physical examination and other diagnostic tests such as laboratory analysis and electrocardiogram (ECG) can be conducted to identify the underlying cause of syncope. A Brugada pattern on an ECG in individuals with syndrome of inappropriate antidiuretic hormone secretion (SIADH) who have syncope symptoms may indicate cardiac issues. A 69-year-old man with hypertension and a history of smoking presented with syncope. His vital signs were within normal limits, with no signs of a neurological deficit. The patient met the diagnostic criteria for SIADH, as evidenced by the presence of hyponatraemia (Na 118 mmol/l), a hyperosmolar condition and euvolemia. Upon arrival, a twelve-lead ECG showed ST-segment anomalies that reflected a Brugada ECG pattern. No ventricular arrhythmias were detected during the 24-hour Holter monitoring. Coronary angiography revealed no abnormalities in the coronary arteries. The ECG demonstrated the normalisation of ST elevations and the disappearance of the Brugada ECG pattern after the correction of hyponatraemia. After three months of follow-up the patient, with a normal sodium level, had no episodes of syncope. LEARNING POINTS: Syncope in elderly patients with Brugada-like ECG patterns can arise from cardiac causes, thus necessitating more examinations.Severe hyponatraemia in patients with SIADH can cause syncope and a Brugada-like ECG pattern.Correction of hyponatraemia, after ruling out cardiac causes, can improve syncope and normalise the Brugada-like ECG pattern.

An Unusual Presentation of Neurosarcoidosis in a 64-Year-Old Man: A Case Report.

Sarcoidosis is a multisystem granulomatous disorder with an unknown etiology that typically involves the lungs, skin, and lymph nodes, with neurological involvement being relatively rare. We discuss a case of neurosarcoidosis in a 64-year-old man who initially presented with unexplained cognitive impairment, insomnia, hyponatremia, paresthesias, and weight loss and later developed uveitis, diplopia, and dysphagia. Ultimately, findings of hilar and mediastinal lymphadenopathy on chest computed tomography (CT) resulted in bronchoscopy, which led to the diagnosis. This case highlights a rare presentation of sarcoidosis with an unusual constellation of symptoms. We discuss the difficulty involved in diagnosing this disorder as well as its highly variable course.

Case report: Secondary failure to tolvaptan in a patient with SCLC and paraneoplastic SIADH.

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is frequent in lung cancer patients. Here, we report a case with persistent hyponatremia, which suggested malignant SIADH and facilitated an early diagnosis of small cell lung cancer (SCLC). A combined radio-chemotherapy led to a partial remission and resolution of SIADH. An early relapse was indicated by reoccurring severe hyponatremia and increased copeptin levels, which were used as surrogate markers for the antidiuretic hormone (ADH). As palliative immunochemotherapy, together with fluid restriction and solute substitution, were unable to control hyponatremia, treatment with the ADH V2-receptor antagonist tolvaptan was initiated. Over time, the dose of tolvaptan needed to be increased, paralleled by a well-documented exponential increase of copeptin levels. In summary and conclusion, this is a rare case of a secondary failure to tolvaptan with unique documentary evidence of increasing copeptin levels. This observation supports the hypothesis that exceedingly high ADH levels may lead to competitive displacement of tolvaptan from the V2 receptor.

Genetic analysis of nephrogenic diabetes insipidus patients: A study on the Iranian population.

INTRODUCTION: Nephrogenic diabetes insipidus (NDI) is a rare genetic disease that causes water imbalance. The kidneys play a crucial role in regulating body fluids by controlling water balance through urine excretion. This highlights their essential function in managing the body's water levels, but individuals with NDI may have excess urine production (polyuria), that leads to excessive thirst (polydipsia). Untreated affected individuals may exhibit poor feeding and failure to thrive. This disease is caused by mutations in the AVPR2 and the AQP2 genes which have the X-linked and autosomal recessive/dominant inheritance, respectively. Both of these genes are expressed in the kidney. METHODS: Twelve Iranian patients from 10 consanguineous families were studied in this project. DNA was extracted from the whole blood samples of the patients and their parents. All coding exons and exon-intron boundaries of the AVPR2 and AQP2 genes were sequenced in the affected individuals, and the identified variants were investigated in the parents. All variants were analyzed according to the ACMG (American College of Medical Genetics and Genomics) guidelines. RESULTS: In this study, 6 different mutations were identified in the patients, including 5 in the AQP2 gene (c.439G>A, c.538G>A, c.140C>T, c.450T>A, and the novel c.668T>C) and 1 in the AVPR2 gene (c.337C>T) in the present study. DISCUSSION: As expected, all the detected mutations in this study were missense. According to the ACMG guideline, the identified mutations were categorized as pathogenic or likely pathogenic. Unlike previous studies which showed more than 90% of mutations were in the AVPR2 gene, and only less than 10% of the mutations were in the AQP2 gene, it was found that more than 90% of our identified mutations located in the AQP2 gene, and only one mutation was observed in the AVPR2 gene, which seems it may be a result of the high rate of consanguineous marriages in the Iranian population. We observed genotype-phenotype correlation in some of our affected individuals, and some of the mutations were observed in unrelated families from same ethnicity which could be suggestive of a founder mutation.

Comparative Safety and Effectiveness of Urea and Tolvaptan for the Management of Hyponatremia.

Background: The optimal management of euvolemic and hypervolemic hyponatremia remains controversial. The effectiveness of the vasopressin receptor antagonist tolvaptan on serum sodium normalization has been well described in the literature, although the associated risk of serum sodium overcorrection limits its use. Urea has been proposed as an alternative treatment option due to its milder serum sodium raising effects and adverse event profile. Objective: This study aimed to compare urea and tolvaptan for their serum sodium raising effects and potential for overcorrection. Methods: In a multicenter retrospective review, 46 hospitalized patients who received either urea or tolvaptan for the management of hyponatremia were evaluated for the rate of serum sodium normalization and overcorrection. Results: Mean serum sodium concentrations at baseline were 125.91 mEq/L and 123.83 mEq/L for patients treated with urea and tolvaptan, respectively. After 12 hours, tolvaptan was associated with a significantly higher rate of serum sodium increase compared with urea (5.05 mEq/L vs 1.10 mEq/L; P = .001). However, no statistically significant differences were observed in the mean change in serum sodium concentrations at 24 hours, 48 hours, or with the proportion of patients who reached a serum sodium concentration of 135 mEq/L. Overcorrection rates were significantly higher with tolvaptan compared with urea at 43% and 9%, respectively. Conclusion: The results of this study suggest that urea has a comparable effectiveness profile to tolvaptan for the management of hyponatremia with a significantly reduced risk of overcorrection.

Hyponatremia-associated hospital visits are not reduced by early electrolyte testing in older adults starting antidepressants.

BACKGROUND: Clinical practice guidelines recommend early serum electrolyte monitoring when starting antidepressants in older adults due to the increased risk of hyponatremia. It is unclear whether this monitoring improves outcomes. METHODS: Population-based, retrospective cohort study of Ontario adults aged ≥66 years who initiated therapy with a selective serotonin reuptake inhibitor (SSRI) or selective norepinephrine reuptake inhibitor (SNRI) between April 1, 2013, and January 31, 2020. The index date was the date of the first such prescription, and the exposure of interest was serum electrolyte measurement during the subsequent 7 days. The primary outcome was any emergency department or hospital admission with hyponatremia within 8-60 days of antidepressant initiation. Poisson regression models compared individuals who had versus did not have their serum electrolytes tested in the week following SSRI/SNRI initiation, weighting by propensity score-based overlap weights. RESULTS: Among the 420,085 patients aged ≥66 years initiating treatment with an SSRI/SNRI, 26,808 (6.4%) had serum electrolytes measured in the subsequent 7 days and 6109 (1.5%) subsequently presented to hospital with hyponatremia. The time from drug initiation to hospitalization varied (median 29, interquartile range [IQR] 17-44 days), and the median sodium concentration measured in the community (136, IQR 133-138 mmol/L) was marginally higher than those at the time of hospitalization (132, IQR 130-134 mmol/L). Patients who underwent electrolyte testing in the week following SSRI/SNRI treatment were more likely to attend an emergency department (ED) or hospital with hyponatremia within 8-60 days relative to those who did not (relative risk = 2.31, 95% confidence interval: 2.16-2.46). CONCLUSIONS: Testing serum electrolytes in the week after starting an SSRI/SNRI is not associated with a reduced risk of a hospital visit with hyponatremia. These findings do not support current guidelines recommending routine electrolyte monitoring.

Atypical Clostridium difficile Infection in a Pregnant Patient: A Case Study on Non-Diarrheal Presentation and Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Complication.

Clostridium difficile (C. difficile) is a Gram-positive, spore-producing bacterium that often leads to pseudomembranous colitis, typically manifesting as watery diarrhea. The risk factors for C. difficile infection (CDI) include exposure to broad-spectrum antibiotics, immunocompromised states, advanced age, usage of proton pump inhibitors (PPI), and comorbid conditions such as chronic kidney disease (CKD). This report details a case involving a 23-year-old pregnant woman who presented with symptoms of abdominal pain and constipation. She was diagnosed with a urinary tract infection (UTI) and treated with ceftriaxone. During her hospitalization, she was administered opioid pain relievers and underwent an intensive bowel regimen. Despite these measures, her constipation and abdominal discomfort persisted, and magnetic resonance imaging (MRI) of the abdomen revealed significant dilatation of the large bowel. The patient, discovered to have hyponatremia, underwent further evaluation. This revealed elevated urine osmolality and decreased blood plasma osmolality, indicative of a syndrome of inappropriate antidiuretic hormone secretion (SIADH). The patient received treatment with hypertonic saline. Later in her hospital stay, she tested positive for CDI through stool analysis and was treated with oral vancomycin. This case underscores the importance of considering CDI as a differential diagnosis in cases of ileus, abdominal pain, and constipation, especially in patients with notable risk factors for CDI. It highlights that the presence of diarrhea or watery bowel movements is not a necessary symptom for CDI testing.

Right-sided Herpes Zoster Ophthalmicus Complicated by Bilateral Third, Fourth, and Sixth Cranial Nerve Palsies and Syndrome of Inappropriate Antidiuretic Hormone Secretion: A Case Report.

Cases of herpes zoster ophthalmicus (HZO) complicated by bilateral ophthalmoplegia are rare, and no cases of bilateral third, fourth, or sixth cranial nerve palsies have been reported. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a rare complication of HZO. We herein report an 80-year-old Japanese woman with right-sided HZO complicated by meningoencephalitis and discuss the pathogenesis of this condition. She developed bilateral third, fourth, and sixth cranial nerve palsies and SIADH almost simultaneously during treatment for HZO. The bilateral cranial palsy spontaneously resolved within a few months.

The syndrome of inappropriate antidiuretic hormone associated with nasal and paranasal malignant tumors.

PURPOSE: To investigate the clinical characteristics of the syndrome of inappropriate antidiuretic hormone (SIADH) associated with nasal and paranasal malignant tumors. METHODS: Patients with locally advanced or recurrence/metastatic malignant tumors of the nasal and paranasal sinuses were included. The SIADH was diagnosed according to the diagnostic criteria. The clinical characteristics of SIADH patients were retrospectively analyzed. RESULTS: Six patients (6/188, 3.2%) met the diagnostic criteria of SIADH, including four olfactory neuroblastoma (4/26, 15.4%), one neuroendocrine carcinoma (1/9, 11.1%), and one squamous cell carcinoma (1/63, 1.6%). Five patients (83.3%) had severe hyponatremia; however, the hyponatremia could be improved by fluid restriction or tolvaptan. Three patients' SIADH were recovered during the chemotherapy and the other three were recovered after the surgery. CONCLUSION: The incidence of SIADH associated with nasal and paranasal malignant tumors is relatively more common in olfactory neuroblastoma and neuroendocrine carcinoma. The hyponatremia caused by SIADH may be corrected by fluid restriction or tolvaptan, and the SIADH may be recovered through anti-tumor therapy.

Tolvaptan for Treatment of Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) in a Child with Corpus Callosum Agenesis.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the common causes of euvolemic hyponatremia (serum Na+ < 135 mEq/L) in hospitalized children. It is characterized by increased serum ADH, leading to water retention via its action on V2 receptors in the distal renal tubules. Various conditions such as pain, the postoperative state, drugs, central nervous system infections, tumors, malformations, and pneumonia can predispose a person to SIADH. The conventional treatment of SIADH includes fluid restriction and salt supplementation. Occasionally, this may fail to control hyponatremia, mandating pharmacological therapy. V2-receptor antagonists are an FDA-approved therapy for adults with euvolemic and hypervolemic hyponatremia. However, there is limited experience with their use in the pediatric population. Here, the authors present a girl with corpus callosum agenesis with severe symptomatic hyponatremia due to SIADH who was successfully managed with the V2-receptor antagonist tolvaptan.

Urine concentration impairment in sickle cell anemia: genuine nephrogenic diabetes insipidus or osmotic diuresis?

The urine concentration impairment responsible for hyposthenuria in sickle cell nephropathy is currently thought to be a consequence of renal medulla lesions, which lead to nephrogenic diabetes insipidus. The objective of the present study was to investigate the mechanism of hyposthenuria in patients with sickle cell anemia. We performed an observational study of patients with homozygous SS sickle cell anemia and data available on the fasting plasma antidiuretic hormone (ADH) concentration. A total of 55 patients were analyzed. The fasting plasma ADH values ranged from 1.2 to 15.4 pg/mL, and 82% of the patients had elevated ADH values and low fasting urine osmolality (<505 mosmol/kgH2O). Plasma ADH was positively associated with plasma tonicity and natremia (P < 0.001). None of the patients experienced polyuria and fasting free water clearance was negative in all cases, thus, ruling out nephrogenic diabetes insipidus. The tertile groups did not differ with regard to fasting urine osmolality, plasma renin level, mGFR, or several hemolysis biomarkers. The negative fasting free water clearance in all cases and the strong association between 24-h osmolal clearance and 24-h diuresis favors the diagnosis of osmotic diuresis due to an impaired medullary gradient, rather than lesions to collecting tubule.NEW & NOTEWORTHY The urine concentration impairment in sickle cell anemia is an osmotic diuresis related to an impaired renal medullary gradient leading to an ADH plateau effect. The fasting plasma ADH was high in the context of a basic state of close-to-maximal urine concentration probably driven by short nephrons maintaining a cortex-outer medullary gradient (about 400 milliosmoles). The patients had a low daily osmoles intake without evidence of thirst dysregulation so no one experienced polyuria.

Asian Variant Intravascular Lymphoma: A Look at the Laboratory Data of Lactase Dehydrogenase and Soluble Interleukin-2 Receptor.

Asian variant intravascular lymphoma (AIVL) is a rare type of intravascular lymphoma that occurs in Asian populations. Syndrome of inappropriate antidiuretic hormone selection (SIADH) frequently occurs in patients with AIVL. Because it remains difficult to diagnose and has a poor prognosis, markers for early diagnosis are required. Although lactase dehydrogenase (LD) and soluble interleukin-2 receptor (sIL-2R) are diagnostic candidates, these markers do not appear to have been used often in prior studies. We present the case of an 87-year-old Japanese man with AIVL complicated by unexplained SIADH with a complaint of anorexia. Computer tomography showed splenomegaly but no lymphadenopathy. Elevated LD and sIL-2R were detected in the blood. The patient was diagnosed with AIVL through a random skin biopsy and was successfully treated with chemotherapy. When a patient presents with SIADH, we should actively look at or measure blood LD and sIL-2R for early diagnosis of ALVL. Further cases are warranted to determine these observations.

A rare case of concomitant Lambert-Eaton myasthenic syndrome and syndrome of inappropriate antidiuretic hormone secretion in a patient with small cell lung carcinoma.

Small cell lung carcinoma (SCLC) is a neuroendocrine carcinoma with a poor prognosis and is a common cause of paraneoplastic syndromes. Paraneoplastic syndromes are characterized by neurological and endocrinological problems in patients with malignancy and are often associated with difficulty in induction of chemotherapy. Here we report the case of a patient with SCLC concomitant with two paraneoplastic syndromes, syndrome of inappropriate antidiuretic hormone secretion (SIADH) and Lambert-Eaton myasthenic syndrome (LEMS), who was treated with a platinum-doublet chemotherapy regimen. A 66-year-old male patient presented with a 1-month history of progressive proximal muscle weakness, ataxia gait and 5 kg of body weight loss. The laboratory tests revealed hyponatremia due to SIADH and the existence of antibodies against P/Q-type voltage-gated calcium channels. The nerve conduction study showed a low amplitude of compound muscle action potential (0.38 mv), a 34% decrement on 3-Hz stimulation, and a 1939% increment after maximum voluntary contraction in 10 seconds (7.75 mv). The endobronchial ultrasound transbronchial needle aspiration biopsy revealed the pathological findings of SCLC. A 2-cycle chemotherapy regimen of irinotecan plus cisplatin resulted in temporary tumor shrinkage that lasted 2 months, but the improvement of proximal muscle weakness and hyponatremia were maintained over the tumor re-progression period after chemotherapy. Although paraneoplastic syndromes accelerate the decrease in performance status, chemotherapy for SCLC may improve symptoms related to paraneoplastic syndromes and could be considered in similar cases.

A retrospective study on tolvaptan prescription in clinical practice in patients with syndrome of inappropriate secretion of antidiuretic hormone (SIADH) using the Japanese claims database.

We aimed to survey the status of tolvaptan administration in routine clinical practice since the approval of a novel indication for treating syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in Japan. Data from a population of 3,152 patients aged ≥18 years and diagnosed with SIADH between July 1, 2020 and June 30, 2021 were extracted from a Japanese database. Tolvaptan was administered to 586 patients while 2,566 patients were followed up without tolvaptan. In the tolvaptan-treated group, the standard initial doses were 3.75 mg and 7.5 mg in 290 (49.5%) and 250 (42.7%) patients, respectively. The dose was increased in 112 (38.6%) and 71 (28.4%) and decreased in 8 (2.8%) and 46 (18.4%) of patients with 3.75 and 7.5 mg initial doses, respectively. Of the total 586 SIADH patients treated with tolvaptan, serum sodium concentrations were analyzed in 60 patients. In both treatment groups of 3.75 and 7.5 mg initial doses, the serum sodium concentration was elevated from the second day of treatment and reached 135 mEq/L on the fourth day, which was maintained for 2 weeks. Rapid correction of hyponatremia (>10 mEq/L increase in serum sodium concentration over 1 day or >18 mEq/L increase over 2 days) occurred in 26.7% patients with a 7.5 mg initial dose (4 of 15 patients) but not in the patients with a 3.75 mg initial dose (n = 16), suggesting that an initial dose of 3.75 mg of tolvaptan may be a better choice for the safe and proper correction of hyponatremia.

Immediate drop of urine osmolality upon tolvaptan initiation predicts impact on renal prognosis in patients with ADPKD.

BACKGROUND AND HYPOTHESIS: Tolvaptan, a vasopressin V2 receptor antagonist, is used for treating autosomal dominant polycystic kidney disease (ADPKD). We focused on changes in urinary osmolality (U-Osm) after tolvaptan initiation to determine whether they were associated with the therapeutic response to tolvaptan. METHODS: This was a single-centre, prospective, observational cohort study. Seventy-two patients with ADPKD who received tolvaptan were recruited. We analysed the relationship between changes in U-Osm and annual estimated glomerular filtration rate (eGFR) in terms of renal prognostic value using univariable and multivariable linear regression analyses. RESULTS: The mean value of U-Osm immediately before tolvaptan initiation was 351.8 ± 142.2 mosm/kg H2O, which decreased to 97.6 ± 23.8 mosm/kg H2O in the evening. The decrease in U-Osm was maintained in the outpatient clinic 1 month later. However, the values of U-Osm showed higher variability (160.2 ± 83.8 mosm/kg H2O) than did those in the first evening of tolvaptan administration. Multivariate analysis revealed that the baseline eGFR, baseline urinary protein, and U-Osm change in the evening of the day of admission (initial U-Osm drop) were significantly correlated with the subsequent annual change in eGFR. CONCLUSIONS: U-Osm can be measured easily and rapidly, and U-Osm change within a short time after tolvaptan initiation may be a useful index for the renal prognosis in actual clinical practice.

Central Diabetes Insipidus in Children as a Diagnostic Challenge.

Central diabetes insipidus (CDI) is a disorder in the pediatric population resulting from antidiuretic hormone deficiency. The excessive production of dilute urine characterizes it and manifests with polyuria, nocturia, and polydipsia. The diagnostics of CDI is often challenging, especially concerning the underlying condition of the disease. This article highlights the diverse clinical presentation of children with CDI and diagnostic difficulties among patients with polyuria and polydipsia. The article also reviews the etiology, symptoms, diagnostic workup, and management of CDI. We present 4 pediatric patients (aged 3-13.5 years) diagnosed with CDI of different etiology: 1 due to septo-optic dysplasia/optic nerve hypoplasia and 3 due to acquired processes such as Langerhans cell histiocytosis and germ cell tumor in 2 patients. Central diabetes insipidus was the first manifestation of a tumor or granuloma in all presented patients with acquired pathology. The patients sometimes need long-term follow-up to establish the proper final diagnosis.