Can Acute Kidney Injury (AKI) lead to the development of kidney stones?

Can AKI Lead to New Onset of Kidney Stones?

Yes, acute kidney injury (AKI) significantly increases the risk of developing kidney stones, with a dose-response relationship where higher stages of AKI confer greater risk of future stone formation. 1

Evidence for the AKI-Kidney Stone Association

The most definitive evidence comes from a large retrospective cohort study of 137,635 patients demonstrating that AKI is independently associated with subsequent kidney stone presentations 1. This relationship persisted across multiple analytical approaches:

• In unadjusted analysis, AKI increased kidney stone risk with a hazard ratio of 1.32 (95% CI 1.16-1.50) 1
• In propensity-matched analysis, the association strengthened to HR 1.67 (95% CI 1.40-1.99), confirming the relationship after controlling for confounding variables 1
• Both inpatient AKI (HR 1.19,95% CI 1.01-1.39) and outpatient AKI (HR 1.59,95% CI 1.30-1.94) were significantly associated with future stones compared to patients without AKI 1

Dose-Response Relationship

A critical finding is the dose-response relationship: higher stages of AKI are associated with progressively greater risk of kidney stone development 1. This suggests that the severity and duration of kidney injury directly influences the likelihood of subsequent stone formation.

Proposed Mechanisms

While the exact pathophysiological mechanisms remain under investigation, AKI may modify kidney stone risk through several potential pathways:

• Long-term alterations in urine composition following an AKI episode may create conditions favorable for stone formation 1
• Tubular injury and dysfunction from AKI could affect urinary concentrating ability and solute handling 2
• Persistent kidney damage even after apparent recovery may alter the urinary milieu, as patients with AKI can have ongoing injury despite normalized creatinine 3

Clinical Implications for Follow-Up

Given this association, patients recovering from AKI require enhanced surveillance:

• Follow-up at 3 months post-AKI should include assessment not only for CKD development but also screening for stone risk factors 3
• More severe AKI (stage 3) warrants earlier and more intensive follow-up given the dose-response relationship with stone risk 3, 1
• Patients with incomplete recovery or persistent kidney dysfunction (AKD stages 0B/C, 1-3) represent particularly high-risk populations requiring closer monitoring 3

Bidirectional Relationship

It's important to note the bidirectional nature of this relationship:

• Kidney stones can cause AKI, particularly in children and young adults, with 23% of pediatric stone patients presenting with AKI in emergency settings 4
• AKI can predispose to future stone formation, creating a potential cycle of kidney injury 1

Important Caveats

• The association between AKI and kidney stones should be examined in additional cohorts and populations for verification, as current evidence comes primarily from a single large Australian cohort 1
• Patients with pre-existing CKD who develop AKI represent an especially high-risk group for both stone formation and progressive kidney disease 3, 5
• Nephrotoxic medications should be avoided during and after AKI episodes, as they may compound kidney damage and potentially increase stone risk 3, 6