What should I do if my kidney function suddenly declines?

Immediate Action for Sudden Kidney Function Decline

If your kidney function has suddenly declined after being normal just days ago, immediately stop all NSAIDs (ibuprofen, naproxen, etc.), hold ACE inhibitors/ARBs and diuretics temporarily, ensure adequate hydration, and seek urgent medical evaluation to identify and treat reversible causes. 1

Critical First Steps

Immediately Discontinue Nephrotoxic Medications

• Stop all NSAIDs immediately - these drugs cause dose-dependent reduction in renal blood flow and can precipitate acute kidney injury, especially in volume-depleted states 1, 2
• Temporarily hold ACE inhibitors and ARBs - these medications can worsen kidney function during acute decline, particularly if volume depletion or bilateral renal artery stenosis is present 1
• Hold diuretics temporarily - volume depletion episodes are associated with decreased urine volume and worsening kidney function 1
• Discontinuation of NSAIDs is usually followed by recovery to the pretreatment state 2

Identify and Reverse Pre-Renal and Post-Renal Causes

• Rule out volume depletion - ensure you are well-hydrated unless contraindicated by heart failure 1
• Check for urinary obstruction - particularly important in older men where prostatic hypertrophy can cause sudden deterioration 1
• Avoid further nephrotoxic exposures - including contrast dye studies unless absolutely necessary 1

When to Seek Urgent Medical Attention

Immediate Evaluation Required If:

• Sustained decrease in kidney function >20% after excluding reversible causes like dehydration 1
• Rapid deterioration - doubling of serum creatinine over 1-2 months 1
• Symptoms of uremia - nausea, confusion, decreased urine output 1
• Signs suggesting acute interstitial nephritis - fever, rash, or recent medication changes 1, 3

Medical Evaluation Priorities

Your physician should systematically assess:

• Volume status - determine if dehydration or overload is present 1
• Medication review - identify all potentially nephrotoxic agents including over-the-counter NSAIDs 1, 2
• Urinary obstruction - physical examination and imaging if indicated, especially in men 1
• Recent exposures - contrast dye, new medications, infections 1

Laboratory Monitoring

• Frequent monitoring of serum creatinine, electrolytes (particularly potassium), and urine output 1
• Urine analysis to detect proteinuria, hematuria, or signs of interstitial nephritis 1

Common Pitfalls to Avoid

Do Not Continue "Sick Day" Medications

Critical warning: When at risk for volume depletion (illness, vomiting, diarrhea), you must hold ACE inhibitors/ARBs and diuretics 1. Many patients continue these medications during acute illness, worsening kidney injury.

NSAIDs Are Particularly Dangerous

• NSAIDs may be particularly harmful under conditions of preexisting kidney insufficiency or diminished kidney blood flow 1
• Even short-term NSAID therapy carries risk of acute kidney injury 2, 4
• Approximately 1% of NSAID users develop clinically detectable renal complications, but the absolute number is large given widespread use 4

Avoid Combination Nephrotoxic Agents

• Combinations of NSAIDs with ACE inhibitors/ARBs and diuretics result in increased nephrotoxicity 5
• Patients taking multiple nephrotoxic medications are at highest risk 3

Medication Management During Recovery

Safe Alternatives for Pain

• Use acetaminophen for non-inflammatory pain instead of NSAIDs 1
• Consider low-dose opiates (monitor for constipation) 1
• Short courses of oral or intra-articular corticosteroids for acute inflammatory conditions 1

When to Resume ACE Inhibitors/ARBs

• Do not stop ACE inhibitors/ARBs if serum creatinine increases modestly (up to 30%) and stabilizes 1
• Stop if kidney function continues to worsen or refractory hyperkalemia develops 1
• Resume only after volume status is optimized and kidney function stabilizes 1

Nephrology Referral Indications

Seek specialist kidney care for:

• Abrupt sustained fall in GFR >20% without clear reversible cause 1
• GFR <30 mL/min/1.73 m² (even if stable, specialist input is warranted) 1
• Persistent proteinuria >1 g/day (ACR ≥60 mg/mmol or PCR ≥100 mg/mmol) 1
• Unexplained deterioration despite addressing reversible factors 1