Clinical features suggesting renal hypouricemia as the cause of acute kidney injury: a case report and review of the literature

Abstract

Hypouricemia is defined as a level of serum uric acid below 2 mg/dl. Renal hypouricemia is related to genetic defects of the uric acid tubular transporters urate transporter 1 and glucose transporter 9. Patients with renal hypouricemia can be completely asymptomatic or can develop uric acid kidney stones or acute kidney injury, particularly after exercise. Renal hypouricemia is especially challenging to diagnose in patients with acute kidney injury, due to the nonspecific clinical, hematochemical and histological features. No common features are reported in the literature that could help clinicians identify renal hypouricemia-acute kidney injury. Currently available guidelines on diagnosis and management of renal hypouricemia provide limited support in defining clues for the differential diagnosis of renal hypouricemia, which is usually suspected when hypouricemia is found in asymptomatic patients. In this paper we report a case of renal hypouricemia-acute kidney injury developing after exercise. We carried out a review of the literature spanning from the first clinical description of renal hypouricemia in 1974 until 2022. We selected a series of clinical features suggesting a diagnosis of renal hypouricemia-acute kidney injury. This may help clinicians to suspect renal hypouricemia in patients with acute kidney injury and to avoid invasive, costly and inconclusive exams such as renal biopsy. Considering the excellent outcome of the patients reported in the literature, we suggest a “wait-and-see” approach with supportive therapy and confirmation of the disease via genetic testing.

Relationship of Serum Uric Acid with Kidney Function Decline Mediated by Systemic Arterial Stiffness: A Retrospective Cohort Study in Japan

“…Accordingly, individuals with hypouricemia may be susceptible to the organic free radicals constantly generated by the activities of daily living. Therefore, hypouricemia increases oxidative stress and induces post-exercise renal artery spasm, resulting in the loss of kidney function [33,34]. However, in the present study, in which KFD was defined as the decrease in eGFR to below 60 mL/min/1.73 m 2 during the study period, the group with the lowest SUA showed the lowest risk of KFD (Figure 1B).…”

A case of renal hypouricemia due to T217M mutation in SLC22A12 incidentally associated with IgA nephropathy

“…Renal hypouricemia is a rare inherited disorder characterized by impaired urate reabsorption in the proximal tubule resulting in low urate levels (1). Uric acid kidney stone or acute kidney injury may develop, especially after exercise (2). To date, there have been few reports of hypouricemia associated with IgA nephropathy.…”

Association between oxidative balance score and serum uric acid and hyperuricemia: a population-based study from the NHANES (2011–2018)

“…However, intracellular uric acid has been linked to elevated inflammation and heightened oxidative stress ( 4 ). Extensive research has identified high serum uric acid levels as an independent risk factor for various chronic kidney and joint disorders ( 5 ), including gout ( 6 ), chronic arthritis ( 7 ), joint deformity, and uric acid kidney stones ( 8 ), as well as chronic metabolic diseases such as hypertension ( 9 ), diabetes ( 10 ), and metabolic syndrome, along with cardiovascular disease ( 11 ).…”