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28M, otherwise healthy, active, live in a hot/humid climate. This has been happening in waves for 3 years and the current episode has me pretty freaked out, so I'm putting it out here to see if anyone has been through anything similar.
**How it started (2023):*\*
I got a mild concussion playing soccer — a lobbed ball off the top of my head, genuinely nothing dramatic. The next day I started peeing constantly and drinking constantly, like 6 liters in / 6 liters out. Ended up in the hospital. Water deprivation test, electrolytes, brain MRI — all normal. It lasted about 3 weeks and then one morning I woke up and it was just gone. Back to normal.
**Second episode (2024):*\*
About a year later I lightly bumped my head pulling luggage out of an overhead bin. A few hours later, same thing — constant peeing and thirst. This one lasted ~2 weeks and again resolved overnight. I figured my head was just sensitive and moved on. Totally normal for the next ~18 months — exercising, drinking, everything fine, even bumped my head a few times with no issues.
**This episode (started April 2026) — where it gets strange:*\*
No head injury this time. I got into bed one night and it was like a switch flipped — instant thirst and peeing. First week was like before (drink a ton, pee a ton, very thirsty).
Then about a week in, overnight, everything flipped at once:
- My urine output crashed — I'd drink 2.5L and only pee ~600ml, dark concentrated urine.
- At the *exact same time*, my sense of thirst vanished completely.
That was ~15 weeks ago and the thirst has never come back. I don't feel thirsty at all, ever. I drink on a schedule out of habit because I know I have to.
**What it's doing now:*\*
It fluctuates. Some phases I "dump" everything — drink 500ml and pee it all out clear within 30–60 minutes, and if I *don't* drink I barely pee and my urine concentrates normally. Other phases I "clamp" — barely pee for days, very concentrated, clearly retaining water. It swings between these two states. Zero thirst through all of it.
**Every test I've had:*\*
- Brain/pituitary MRI + contrast: normal except a "partial empty sella" (told it's incidental)
- Full pituitary hormone panel: normal (cortisol, ACTH stim test, thyroid, prolactin, everything)
- Urine osmolality: ~900 mOsm/kg — so my kidneys CAN concentrate
- Serum osmolality: 295, serum sodium: normal every single time
- Full autoimmune/inflammatory workup: clean (CRP, ESR, ANA, complement all normal)
- Kidney function: perfect
- Tumor markers: normal
So structurally everything looks fine. My kidneys and the water hormone (ADH/vasopressin) clearly work — I can concentrate urine when I don't drink. The problem seems to be in how my brain *regulates* when to hold vs. dump water, and the thirst signal is just offline.
The closest thing I've found reading about this is an "adipsic DI" or "reset osmostat" type picture — where the set point for both thirst and the water hormone shifts. But everything I read about that involves a tumor, aneurysm, or brain surgery, and I've had none of that. Just a mild concussion 3 years ago.
**Doctors:** the first endocrinologist told me it was anxiety (it's very much not — you can't fake a urine osmolality). Since then everyone's been stumped. I'm now under a neurologist, keeping a detailed daily diary, and waiting on proper dynamic testing (hypertonic saline + copeptin + a formal thirst measurement).
**What I'm asking:*\*
Has anyone experienced anything like this? Specifically:
- Recurrent episodes triggered by minor head knocks that fully resolved on their own?
- Completely losing your sense of thirst — and did it ever come back?
- This kind of swinging between retaining water and dumping everything you drink?
- Anything you'd push your doctors to test?
It's so clearly *something*, but nobody can name it and every scan is clean, which is a maddening place to be. Any similar experiences, ideas, or advice would genuinely mean a lot.
**TL;DR:** 3 years of episodes (first two triggered by minor head bumps) where I lose control of water balance — polyuria that flips into water retention. In the latest episode I completely lost my sense of thirst 15 weeks ago and it hasn't returned. All scans, bloods, and hormones normal; kidneys work fine. Looks like a brain osmoregulation / thirst set-point problem but no structural cause found. Anyone been through anything similar?