The hallmark concern for the body living at high altitude is low oxygen. We breathe in less, and thus less is sent throughout our blood stream to our tissues. We are quick to think about how this affects our heart and lungs, but what about our kidneys? What are our kidneys even responsible for?

Kidneys filter, reabsorb, and excrete our blood in the form of urine. They connect our cardiovascular system with our genitourinary system. The flow through the kidneys also helps monitor and adjust our blood pressure. Their importance is truly undervalued. When they receive less oxygen than preferred (hypoxia), they will become injured. Specifically, the glomerulus (term for the filter) will become affected. When this happens, it is not efficient at filtration, and protein will spill out into our urine (proteinuria), a key feature of High Altitude Renal Syndrome (HARS).

Zooming further in below

And even further…

Another issue involves uric acid, the chemical at fault for causing gout. Due to the filter injury sustained from low oxygen, uric acid excretion is affected. It can thus build up in our musculoskeletal system and other tissues. It is famous for causing red, swollen, and painful joints. The enzyme that helps create uric acid (xanthine oxidase) is also turned on by reactive oxygen species during hypoxia. This then causes further uric acid crystal deposition in our body. This can present in patients from adolescent years through adulthood, ranging from fleeting pain to amputations from severe bone infections. We have found that for younger patients, diet plays a lesser part than genetic predisposition and hypoxia.

So how is this treated? We are still researching the best course of action. We can treat with drugs that work by inhibiting the previously specified enzyme: xanthine oxidase. These include oral allopurinol, febuxostat, and even IV pegloticase infusions. But we are primarily focused on prevention and holistic care here, so we would prefer to use supplemental oxygen therapy for those that struggle to maintain oxygen saturations in the healthy ranges. Acetazolamide is also helpful in cases. This medication works to increase our respiratory drive, helping us breathe off CO2 and breathe in more oxygen. Contact us to see what method might be right for you.

This research was brought to us by a stroke of luck. A stranger on an airplane, and a son’s coworker. This stranger happened to be a nephrologist (kidney doctor) who is studying how altitude affects the kidneys. In working with him and his team at University of Colorado Anschutz, the team at Ebert Family Clinic in Frisco, Colorado (9000′) have been ordering broader lab panels (including uric acid) for their patients and seeking those with questionable renal labs. Another patient seen by the Ebert Family Clinic team has been severely impacted by gout. With multiple amputations before the patient’s 30^th birthday, this case has motivated the health care team to prevent this from happening to others in their high altitude community.

Carter Odean is a third-year medical student at Rocky Vista University. He was born and raised outside of Denver, Colorado before heading to Gonzaga University in Spokane, Washington where he studied biology and completed research on an invasive bee species there while playing club lacrosse. After graduating in 2019, he then came back to Denver to complete his Master’s in Biomedical Sciences at Regis University. After Regis, he started as a Clinical Research Coordinator at Anschutz Medical campus, working on multiple Diabetes Mellitus Type 2 research trials. He is in the Rural & Wilderness Track which is his favorite part about school. He plans to work as a rural Pediatrician or Family Medicine Physician. In his free time, you can find him dirt biking, fly fishing, skiing, and relaxing with friends and family. 

References

1. Schoene, R.B. “High altitude renal syndrome: polycythemia, hyperuricemia, microalbuminuria, and hypertension.” High Alt Med Biol. 2002 Spring;3(1):65-73. doi: 10.1089/152702902753639371. PMID: 11949751.
2. Bigham, A.W., Lee, F.S. “Tibetan and Andean patterns of adaptation to high-altitude hypoxia.” Hum Biol. 2014 Oct;86(4):321-37. doi: 10.3378/027.086.0401. PMID: 25700353; PMCID: PMC4438718.
3. Beall, C.M., Cavalleri, G.L., Deng, L., et al. “Natural selection on EPAS1 (HIF2α) associated with low hemoglobin concentration in Tibetan highlanders.” Proc Natl Acad Sci U S A. 2010 Mar 9;107(25):11459-64. doi: 10.1073/pnas.1002443107. Epub 2010 Feb 22. PMID: 20176925; PMCID: PMC2895106.
4. Simonson, T.S., Yang, Y., Huff, C.D., et al. “Genetic evidence for high-altitude adaptation in Tibet.” Science. 2010 Sep 10;329(5987):72-5. doi: 10.1126/science.1189406. PMID: 20616233; PMCID: PMC3490534.
5. Schoene, R.B., Swenson, E.R. “Cobalt-Induced Chronic Mountain Sickness: Pathophysiological Mechanisms and Genetic Susceptibility.” High Alt Med Biol. 2017 Mar;18(1):1-5. doi: 10.1089/ham.2016.0106. PMID: 28145824.Baillie, J.K., Bates, M.G., Thompson, A.A., et al. “Endogenous urate production augments plasma antioxidant capacity in healthy lowland subjects exposed to high altitude.” Chest. 2007 Dec;132(6):S275. doi: 10.1378/chest.132.6.275. PMID: 18079246.
6. Yu, K.H., Wu, Y.J., Tseng, W.C., et al. “Risk of end-stage renal disease associated with gout: a nationwide population study.” Arthritis Res Ther. 2012 Jun 27;14(3):R83. doi: 10.1186/ar3818. PMID: 22738152; PMCID: PMC3446515.
7. Bhat, A., Deshmukh, A., Anand, S., et al. “Acute Myocardial Infarction due to Coronary Artery Embolism in a Patient with Severe Hyperuricemia.” J Assoc Physicians India. 2019 Nov;67(11):90-91. PMID: 31801335.
8. Khanna, D., Khanna, P.P., Fitzgerald, J.D., et al. “2012 American College of Rheumatology guidelines for management of gout. Part 1: systematic nonpharmacologic and pharmacologic therapeutic approaches to hyperuricemia.” Arthritis Care Res (Hoboken). 2012 Oct;64(10):1431-46. doi: 10.1002/acr.21772. PMID: 23024028.
9. Schoene, R.B., Swenson, E.R. “Treatment of Cobalt-Induced Chronic Mountain Sickness.” High Alt Med Biol. 2017 Mar;18(1):74-77. doi: 10.1089/ham.2016.0135. PMID: 28145823.
10. Schoene, R.B., Hackett, P.H., Henderson, W.R., et al. “High Altitude Medicine and Physiology, Fourth Edition.” CRC Press, 2007.
11. Burtscher, M., Mairer, K., Wille, M., et al. “Risk of acute mountain sickness in tourists ascending to 4360 meters by cable car.” High Alt Med Biol. 2004 Summer;5(2):141-6. doi: 10.1089/1527029041352154. PMID: 15265307.
12. Baumgartner, R.W., Bärtsch, P. “Chronic mountain sickness and the heart.” Prog Cardiovasc Dis. 2010 May-Jun;52(6):540-9. doi: 10.1016/j.pcad.2010.02.009. PMID: 20417390.