Iso osmolar urine is seen in -
Acute tubular necrosis (ATN) is a medical condition involving the death of tubular epithelial cells that form the renal tubules of the kidneys. ATN presents with acute kidney injury (AKI) and is one of the most common causes of AKI. Common causes of ATN include low blood pressure and use of nephrotoxic drugs Acute tubular necrosis is classified as a "renal" (i.e. not pre-renal or post-renal) cause of acute kidney injury. Diagnosis is made by a FENa (fractional excretion of sodium) > 3% and presence of muddy casts (a type of granular cast) in urinalysis. On histopathology, there is usually tubulorrhexis, that is, localized necrosis of the epithelial lining in renal tubules, with focal rupture or loss of basement membrane. Proximal tubule cells can shed with variable bility and not be purely "necrotic".isosmolar urine is seen Ref Harrison20th edition pg 234
ATN
Severe dehydration
Diabetes insipidus
PCKD
Kidney