Central Diabetes Insipidus in Suprasellar Germ Cell Tumor - Paradoxically Presenting With Oliguria

Q: Why can central diabetes insipidus be missed in patients with limited communication?

When thirst and related symptoms cannot be expressed, volume depletion and AKI may dominate the clinical picture. In severe cases, oliguric or anuric AKI can paradoxically mask polyuria.

Q: What clinical clue prompted suspicion of an alternative diagnosis to typical AKI recovery?

Persistent or unexplained hypernatremia during recovery suggested the need to consider alternative diagnoses such as unmasked diabetes insipidus, rather than attributing findings solely to resolving AKI.

Q: How was the diagnosis of central diabetes insipidus confirmed in the report?

A trial of sublingual desmopressin improved polyuria and hypernatremia, and a formal water deprivation test later supported CDI, showing a marked rise in urine osmolality after desmopressin administration.

Sep 30, 2026

Uploaded by Jake

Central diabetes insipidus can manifest as oliguric acute kidney injury, particularly when patients cannot reliably communicate thirst or symptoms. During recovery from AKI, polyuria may be expected; however, persistent or unexplained hypernatremia should raise suspicion for alternative explanations such as previously unrecognized diabetes insipidus. This report describes a 14-year-old boy with Down syndrome whose severe oliguric AKI later evolved into marked polyuria, leading to identification of an underlying suprasellar germ cell tumor.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Introduction

Background and clinical risk in limited communication

Case Report

Presentation, shock, and AKI assessment

Workup for persistent hypernatremia and confirmation of CDI

Clinical Case Reports CASE REPORT OPEN ACCESS Central Diabetes Insipidus in Suprasellar Germ Cell Tumor Paradoxically Presenting With Oliguria Karen Kin Nam Wong | Manson Chon In Kuok | Winnie Kwai Yu Chan Department of Paediatrics, Queen Elizabeth Hospital, Hong Kong SAR, China Correspondence: Manson Chon In Kuok ([mansonkuok@gmail.com](mansonkuok@gmail.com)) Received: 23 August 2025 | Revised: 23 December 2025 | Accepted: 2 January 2026 Keywords: acute kidney injury | central diabetes insipidus | germ cell tumor | oliguria ABSTRACT Central diabetes insipidus may present as oliguric acute kidney injury (AKI), particularly in patients with communication difficulties. While polyuria is common in AKI recovery, persistent or unexplained hypernatremia should prompt suspicion for alternative diagnoses such as unmasked diabetes insipidus to ensure timely recognition and appropriate management. 1 | Introduction Central diabetes insipidus (CDI) is a common endocrinopathy and may be an initial presenting feature in children with intracranial malignancies involving the suprasellar region [1] . It results from a deficiency of arginine vasopressin (AVP) secondary to damage to the posterior pituitary gland or hypothalamus, leading to impaired water reabsorption in the renal collecting ducts and subsequent marked polyuria. The resulting increase in serum osmolality stimulates the thirst center, causing compensatory polydipsia, which in most patients helps prevent significant dehydration. However, in individuals with intellectual disability or limited communication abilities, they may not be able to express or respond appropriately to thirst. This places them at increased risk of volume depletion and acute kidney injury (AKI) . In severe cases, oliguric or anuric AKI may paradoxically mask polyuria and the diagnosis of CDI. We herein report a 14-year-old boy with Down syndrome who initially presented with severe oliguric AKI requiring renal replacement therapy. During recovery, he developed marked polyuria leading to the diagnosis of CDI; subsequent evaluation revealed an underlying suprasellar germ cell tumor. 2 | Case Report A 14-year-old boy with Down syndrome, who had intellectual disability and limited communication, presented with decreased oral intake and reduced urine output. He had poor oral intake for 10 days, a 2-day history offever, and oliguria less than 500 mL/day with concentrated urine. On admission, he was in hypovolemic shock with a blood pressure of 89/50 mmHg anda heart rate of 128 bpm. He was clinically dehydrated with dry skin turgor, with prolonged capillary refill time > 2 s. He was tachypneic with a respiratory rate of 28 breaths per minute. Otherwise, his respiratory and abdominal examinations were unremarkable, and there was no skin rash or evidence of arthritis. Laboratory tests revealed significantly impaired kidney function, with a urea level of 48.6 mmol/L and creatinine level of 1269 μmol/L (estimated glomerular filtration rate [eGFR] 4 mL/ min/1.73m2) . He also had significant electrolyte disturbances including hypernatremia (168 mmol/L) and hyperphosphatemia (3.18 mmol/L) . Arterial blood gas analysis showed metabolic This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. © 2026 The Author(s). Clinical Case Reports published by John Wiley & Sons Ltd. Clinical Case Reports, 2026; 14:e71832 1 of 4 [https://doi.org/10.1002/ccr3.71832](https://doi.org/10.1002/ccr3.71832) acidosis with pH 7.32, bicarbonate of 14.2 mmol/L, and base excess of −10.2 mmol/L. His serum lactate was within normal range at 1.1 mmol/L (Ref: 0.5–2.2 mmol/L) . His hemoglobin and platelet count were within normal ranges. His urinalysis showed proteinuria of 1.54 g/g Cr (Ref: < 0.20 g/g Cr) . Further in

FAQs

Why can central diabetes insipidus be missed in patients with limited communication?

When thirst and related symptoms cannot be expressed, volume depletion and AKI may dominate the clinical picture. In severe cases, oliguric or anuric AKI can paradoxically mask polyuria.

What clinical clue prompted suspicion of an alternative diagnosis to typical AKI recovery?

Persistent or unexplained hypernatremia during recovery suggested the need to consider alternative diagnoses such as unmasked diabetes insipidus, rather than attributing findings solely to resolving AKI.

How was the diagnosis of central diabetes insipidus confirmed in the report?

A trial of sublingual desmopressin improved polyuria and hypernatremia, and a formal water deprivation test later supported CDI, showing a marked rise in urine osmolality after desmopressin administration.

Sep 30, 2026

Uploaded by Jake