[Renal function in therapeutic starvation (author's transl)]

Area of Science:

• Nephrology
• Metabolic Disorders

Background:

• Therapeutic starvation is associated with various complications, yet renal issues are infrequently documented.
• Few studies detail the specific renal complications arising from prolonged fasting.

Observation:

• Starvation significantly reduces glomerular filtration rate by approximately 50%.
• Renal uric acid clearance decreases due to impaired tubular secretion, leading to hyperuricemia.
• Ketone bodies compete with uric acid for tubular secretion sites during fasting.

Findings:

• Renal complications include acute kidney injury, uric acid nephropathy, renal ischemia, and exacerbation of pre-existing kidney disease.
• Reversible salt-losing nephropathies have been observed in some cases.
• Hyperuricemia during starvation is linked to impaired tubular uric acid secretion.

Implications:

• Maintaining adequate fluid intake and monitoring urinary output are essential for preventing renal complications during fasting.
• Pre-fasting assessment of renal function (urinalysis, BUN, creatinine, uric acid) and regular monitoring are vital.
• Avoid uricosuric agents and intravenous pyelography during therapeutic starvation to prevent adverse renal events.