Hyposthenuria refers to a low specific gravity to the urine. It is typically caused by a failure of the renal tubules to concentrate the urine.
Differential diagnosis of a low urinary specific gravity:
(1) sickle cell anemia
(2) diabetes insipidus
(3) water intoxication
(4) drugs
(5) renal tubular disorders
(6) chronic renal insufficiency
(7) antidiuretic hormone resistance (hypercalcemia, hypokalemia, lithium toxicity)
(8) in vitro dilution
(7) malignant hypertension
