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 in those under 20.[5] The prevalence of orthostatic albuminuria is suspected to be between 2 and 5%,[6] however some studies suggest that it is more common.[7] Orthostatic albuminuria is diagnosed if urine protein levels are normal in a morning urine sample and there are no other obvious causes of albuminuria.[8] Patients with orthostatic albuminuria are often asymptomatic and there is no indication for any type of treatment or interventions.[4]

Orthostatic albuminuria
Other namesOrthostatic proteinuria, Postural proteinuria, Postural albuminuria.
The structure of Human serum albumin (HSA) complexed with 6 palmitic acid molecules
Pronunciation
  • ȯr-thə-ˈsta-tik /ælˌbjuməˈn(j)ʊriə/[1][2]
SpecialtyUrology Edit this on Wikidata
Usual onsetUnder 30 years old.[3]
Diagnostic methodUrine test strip, Urine protein/creatinine ratio, 24 hour urine collection, renal function tests, and urine microscopy.[3]
Differential diagnosisTransient proteinuria.[4]
PrognosisBenign.[3]
Frequency3 to 5% of adults and teenagers.[3]

Causes

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The exact causes of orthostatic albuminuria are unknown however three different theories have been proposed, a normal variant, subtle glomerular abnormalities, exaggerated hemodynamic response, and left renal vein entrapment.[9]

Diagnosis

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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, complement activity, urine culture, and serological studies can help differentiate orthostatic albuminuria from other causes of proteinuria. Recumbent and upright urine protein to creatinine ratio is often used as a screening test. 24-hour split urine testing is often tested.[10]

Additional causes of albuminuria include glomerulopathy, acute tubular necrosis, Alport syndrome, toxins, proximal renal tubular acidosis, diabetes mellitus, malignancies, polycystic kidney disease, infections, and chronic kidney disease.[8]

Outlook

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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.[11]

See also

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References

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  1. ^ "Definition of Orthostatic". Merriam-Webster. November 10, 2023. Retrieved November 24, 2023.
  2. ^ "albuminuria". Oxford English Dictionary. Oxford University Press. July 2023. Retrieved 24 November 2023.
  3. ^ a b c d Moses, Scott (February 17, 2017). "Orthostatic Proteinuria". Family Practice Notebook. Retrieved November 24, 2023.
  4. ^ a b "UpToDate". UpToDate. Retrieved November 24, 2023.
  5. ^ Uehara, K.; Tominaga, N.; Shibagaki, Y. (May 25, 2014). "Adult orthostatic proteinuria". Clinical Kidney Journal. 7 (3): 327–328. doi:10.1093/ckj/sfu040. ISSN 2048-8505. PMC 4377758. PMID 25852903.
  6. ^ Mazzoni, M. B. M.; Kottanatu, L.; Simonetti, G. D.; Ragazzi, M.; Bianchetti, M. G.; Fossali, E. F.; Milani, G. P. (July 23, 2010). "Renal vein obstruction and orthostatic proteinuria: a review". Nephrology Dialysis Transplantation. 26 (2): 562–565. doi:10.1093/ndt/gfq444. ISSN 0931-0509. PMID 20656752. Retrieved November 24, 2023.
  7. ^ Vehaskari, V. Matti; Rapola, Juhani (1982). "Isolated proteinuria: Analysis of a school-age population". The Journal of Pediatrics. 101 (5): 661–668. doi:10.1016/s0022-3476(82)80287-4. ISSN 0022-3476. PMID 7131137. Retrieved November 24, 2023.
  8. ^ a b AK, Leung; AH, Wong; SS, Barg (2017). "Proteinuria in Children: Evaluation and Differential Diagnosis". American Family Physician. 95 (4): 248–254. ISSN 1532-0650. PMID 28290633. Retrieved November 24, 2023.
  9. ^ Ingold, Curtis J.; Bhatt, Harshil (August 8, 2023). "Orthostatic Proteinuria". StatPearls Publishing. PMID 32965979. Retrieved November 24, 2023.
  10. ^ Kovvuru, Karthik; Kanduri, Swetha R.; Thongprayoon, Charat; Cheungpasitporn, Wisit (2020). "Diagnostic approach to orthostatic proteinuria: a combination of urine micro-proteinuria with ultrasonography of the left renal vein". Annals of Translational Medicine. 8 (12): 779. doi:10.21037/atm.2020.02.50. ISSN 2305-5839. PMC 7333150. PMID 32647704.
  11. ^ Arslan, Zümrüt; Koyun, Mustafa; Erengin, Hakan; Akbaş, Halide; Aksoy, Gülşah Kaya; Çomak, Elif; Akman, Sema (May 11, 2020). "Orthostatic proteinuria: an overestimated phenomenon?". Pediatric Nephrology. 35 (10): 1935–1940. doi:10.1007/s00467-020-04586-4. ISSN 0931-041X. PMID 32394189. S2CID 218592496. Retrieved November 24, 2023.

Further reading

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