Orthostatic albuminuria, also known as orthostatic proteinuria is defined by raised levels of urine protein excretion while in an upright position. In orthostatic albuminuria urine protein excretion returns to normal while in a supine position, such as laying down. Orthostatic albuminuria is the most common cause of isolated

proteinuria Proteinuria is the presence of excess proteins in the urine. In healthy persons, urine contains very little protein, less than 150 mg/day; an excess is suggestive of illness. Excess protein in the urine often causes the urine to become fo ...

in those under 20. The prevalence of orthostatic albuminuria is suspected to be between 2 and 5%, however some studies suggest that it is more common. Orthostatic albuminuria is diagnosed if urine protein levels are normal in a morning urine sample and there are no other obvious causes of

albuminuria Albuminuria is a pathological condition of elevated albumin protein in the urine (often measured as urine albumin-to-creatinine ratio of >30 milligrams of albumin per 1 gram of creatinine per day). It is a type of proteinuria, and is the most com ...

. Patients with orthostatic albuminuria are often asymptomatic and there is no indication for any type of treatment or interventions.

Causes

The exact causes of orthostatic albuminuria are unknown however three different theories have been proposed, a normal variant, subtle glomerular abnormalities, exaggerated

hemodynamic Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously ...

response, and left renal vein entrapment.

Diagnosis

There is no standard test for orthostatic albuminuria. Physical examination as well as a past medical history can help determine the extent of symptoms in some individuals. Urine analysis,

urine cytology Urine cytology is a test that looks for abnormal cells in urine under a microscope. The test commonly checks for infection, inflammatory disease of the urinary tract, cancer, or precancerous conditions. It can be part of a broader urinalysis. If a ...

, complement activity,

urine culture Bacteriuria is the presence of bacteria in urine. Bacteriuria accompanied by symptoms is a urinary tract infection while that without is known as asymptomatic bacteriuria. Diagnosis is by urinalysis or urine culture. ''Escherichia coli'' is the ...

, and

serological Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection (against a given mi ...

studies can help differentiate orthostatic albuminuria from other causes of

. Recumbent and upright urine protein to creatinine ratio is often used as a screening test. 24-hour split urine testing is often tested. Additional causes of albuminuria include glomerulopathy,

acute tubular necrosis Acute tubular necrosis (ATN) is a medical condition involving the death of tubular epithelial cells that form the renal tubules of the kidneys. Because necrosis is often not present, the term acute tubular injury (ATI) is preferred by pathologis ...

Alport syndrome Alport syndrome is a genetic disorder affecting around 1 in 5,000–10,000 children, characterized by glomerulonephritis, end-stage kidney disease, and hearing loss. Alport syndrome can also affect the eyes, though the changes do not usually affec ...

toxins A toxin is a naturally occurring poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived ...

, proximal renal tubular acidosis,

diabetes mellitus Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained hyperglycemia, high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or th ...

malignancies Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not ...

polycystic kidney disease Polycystic kidney disease (PKD or PCKD, also known as polycystic kidney syndrome) is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney. These ...

infections An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

, and

chronic kidney disease Chronic kidney disease (CKD) is a type of long-term kidney disease, defined by the sustained presence of abnormal kidney function and/or abnormal kidney structure. To meet criteria for CKD, the abnormalities must be present for at least three mo ...

Outlook

The long-term prognosis of orthostatic albuminuria hasn't yet been established. Based on current research, it seems that orthostatic albuminuria is a benign condition and typically resolves spontaneously within a couple years.

References

External links

Cleveland Clinic Cleveland Clinic is an American Nonprofit organization, nonprofit Academic health science center, academic Medical centers in the United States, medical center based in Cleveland, Ohio. Owned and operated by the Cleveland Clinic Foundation, an O ...

br>Orthostatic Proteinuria
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Causes

Diagnosis

Outlook

See also

References

Further reading

External links