Central diabetes insipidus after head trauma in cats
2-year-old cat hit by a car 5 days ago, with head trauma now stabilised. Since yesterday he drinks and urinates a great deal; urine specific gravity 1.005. If water is withheld for a few hours, sodium rises.
What is the most appropriate management?
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A. Desmopressin (conjunctival drops or oral tablets) and free access to water, reassessing later whether it is still needed
Correct. Desmopressin replaces ADH and controls the polyuria. Diabetes insipidus after head trauma can be transient, so it is worth checking over time whether it is still needed.
B. Restricting water so that the kidney learns to concentrate
Without ADH the kidney cannot concentrate however much water is restricted: the cat would become dehydrated and develop hypernatraemia with a risk of seizures.
C. Hydrochlorothiazide as first-line treatment
Thiazides reduce polyuria somewhat, but they are much less effective than desmopressin in the central form. They are reserved mainly for the nephrogenic form.
D. Furosemide to correct the hypernatraemia
Furosemide increases urinary water loss and would worsen dehydration. Hypernatraemia is corrected by gradually replacing free water.
lightbulb Key takeaway
Central diabetes insipidus is rare in cats; causes include head trauma, pituitary tumours and idiopathic forms. With water always available the animal copes well: the danger arises when it cannot drink (hospitalisation, travel, vomiting), because hypernatraemia develops within hours.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.