Can a Person with Undiagnosed Diabetes Insipidus Go 12 Hours Without Water?
No, a person with undiagnosed diabetes insipidus (DI) cannot comfortably or safely go 12 hours without drinking water—they would experience severe discomfort from intense thirst and risk life-threatening hypernatremic dehydration. 1
Why This Is Physiologically Impossible
The hallmark of diabetes insipidus is an intact and hypersensitive thirst mechanism that drives patients to drink large volumes of fluid constantly. 1 Patients with DI typically maintain normal serum sodium levels at steady state precisely because their osmosensors trigger overwhelming thirst that compels them to drink water frequently throughout the day and night. 1
- Patients with DI commonly produce 3-20+ liters of dilute urine per 24 hours, depending on severity, which translates to massive ongoing water losses that must be continuously replaced. 1, 2
- The thirst drive in DI is so powerful that patients describe it as unbearable and all-consuming, not something they could simply ignore for 12 hours. 1
- Even during sleep, patients with DI typically wake multiple times to drink water and urinate, a phenomenon called nocturia with nocturnal polydipsia. 1
What Happens During Water Restriction
When a person with undiagnosed DI is deprived of water access for 12 hours, they develop rapid and severe hypernatremia (serum sodium >145 mmol/L, often >160 mmol/L) with associated neurological symptoms. 1, 3
- A documented case report describes a 21-year-old woman with undiagnosed central DI who developed severe hypernatremia and dramatic symptoms when her normal water intake was curtailed during perioperative fasting. 3 She had previously drunk copious amounts of water throughout each day to compensate for her condition, and when this was restricted, she rapidly decompensated. 3
- Symptoms of hypernatremic dehydration include severe headache, confusion, lethargy, seizures, and can progress to coma and death if untreated. 1
- The inability to access water in DI is considered a life-threatening medical emergency. 1, 4
The Critical Distinction: Adipsic DI
There is one rare exception: adipsic diabetes insipidus (ADI), where patients have both DI and an absent or deficient thirst response. 5 However, this represents a distinct and extremely rare variant (only ~100 cases described in medical literature) and is NOT typical undiagnosed DI. 5
- Patients with ADI experience marked morbidity and mortality precisely because they lack the protective thirst mechanism, leading to recurrent severe hypernatremia, venous thromboembolism, and increased death risk. 5
- ADI requires intensive medical management with prescribed daily water intake and fixed desmopressin therapy, as these patients cannot self-regulate. 5, 6
Clinical Reality of Undiagnosed DI
Most patients with undiagnosed DI have already developed compensatory behaviors—drinking water constantly throughout the day—even before diagnosis. 3 They may not realize this is abnormal, attributing it to personal preference or habit.
- The classic presentation includes polyuria (>3 L/24h in adults), polydipsia, and inappropriately dilute urine (osmolality <200 mOsm/kg) with high-normal or elevated serum sodium. 1
- Children with undiagnosed DI may present with failure to thrive, hypernatremic dehydration, and "greedy" drinking behavior. 1
- Infants and young children with DI cannot clearly express thirst and are at particularly high risk during any period of restricted water access. 1
Bottom Line
If someone claims they "didn't bother them" to go 12 hours without water, they almost certainly do NOT have diabetes insipidus. The overwhelming thirst and resulting discomfort are pathognomonic features of the condition. 1, 2 The only exception would be the exceedingly rare adipsic variant, which carries severe health consequences and would not go unnoticed clinically. 5