proteinuric

Proteinuric is an adjective used in medicine to describe conditions in which protein is present in the urine. Proteinuria, the excretion of excess urine protein, is not normal. Small amounts can occur transiently, but persistent proteinuria suggests kidney or urinary tract disease.

Patterns of proteinuria reflect different mechanisms. Glomerular proteinuria results from damage to the glomerular filtration barrier and often shows albumin as the main protein. Tubular proteinuria stems from tubular dysfunction that limits reabsorption of filtered proteins. Overflow proteinuria occurs with very high plasma levels of certain proteins. Orthostatic proteinuria is common in adolescents and tends to resolve when lying down.

Diagnosis relies on urine testing. A dipstick test screens for protein but may miss low levels; quantitative measurements use the urine albumin-to-creatinine ratio or protein-to-creatinine ratio, and sometimes 24-hour collection. Nephrotic-range proteinuria is greater than 3.5 g/day and is usually associated with hypoalbuminemia, edema, and hyperlipidemia. Microalbuminuria, typically about 30–300 mg/day, is an early marker of kidney disease, especially in diabetes and hypertension.

Management focuses on the underlying cause and protection of kidney function. Key strategies include blood pressure control and blockade of the renin–angiotensin system (ACE inhibitors or ARBs) to reduce protein leakage. Diabetes control and treatment of primary glomerular diseases are important; dietary protein restriction may be considered in some chronic kidney disease cases.

Prognosis varies with cause and response to therapy. Persistent proteinuria signals higher risk of progression to chronic kidney disease and cardiovascular events, but effective treatment can reduce proteinuria and slow disease progression.