Dear Esteemed Colleagues, A 65 year old female patient came to me with a history of 3 weeks of excessive thirst, and polyuria. Weakness and lethargy. All basic test within normal, Diabetic panel normal. Urine output about 4000 ml in a day. Specific gravity within normal, Serum electrolytes normal.

KFT, LFT Normal. Could it be D.I ? If so what do you recommend further tests and the line of treatment ? Thank you for your invaluable inputs in advance.