Can a 68-year-old patient with chronic kidney disease (CKD) undergo Ahmed valve and scleral patch surgery with impaired renal function, as evidenced by elevated Blood Urea Nitrogen (BUN) and creatinine levels, and decreased Glomerular Filtration Rate (GFR), after recently starting Diamox (acetazolamide)?

Ahmed Valve Surgery in a 68-Year-Old Patient with Worsening Renal Function After Starting Diamox

This patient should not undergo Ahmed valve and scleral patch surgery until the acute kidney injury is stabilized and Diamox (acetazolamide) is discontinued, as it is contraindicated in patients with marked kidney dysfunction.

Assessment of Current Renal Status

The patient presents with:

• Chronic kidney disease with acute worsening
• Recent decline in renal function:
  • GFR decreased from 61 to 34 ml/min/1.73m²
  • BUN increased from 14 to 29 mg/dL
  • Creatinine increased from 1.0 to 1.6 mg/dL
• Recent initiation of Diamox (acetazolamide)

Classification of Kidney Disease

The patient's current GFR of 34 ml/min/1.73m² places them in Stage 3b CKD according to KDOQI guidelines 1. However, the acute decline in renal function (nearly 50% reduction in GFR) indicates an acute kidney injury superimposed on chronic kidney disease.

Diamox and Renal Function

Diamox (acetazolamide) is explicitly contraindicated in patients with marked kidney dysfunction according to FDA labeling 2. The temporal relationship between starting Diamox and the acute decline in renal function strongly suggests medication-induced kidney injury.

The patient's current presentation demonstrates:

• A 45% decrease in GFR (from 61 to 34)
• A 60% increase in creatinine (from 1.0 to 1.6)

Even small increases in creatinine (as little as 0.1 mg/dL) during hospitalization have been associated with worse outcomes 3, and this patient's increase of 0.6 mg/dL is substantial.

Perioperative Risk Assessment

Recommendations for Surgery

1. Discontinue Diamox immediately

   • Acetazolamide is contraindicated in patients with marked kidney dysfunction 2
   • While acetazolamide can increase serum chloride levels, its nephrotoxic effects outweigh potential benefits in this case 4

2. Stabilize renal function before proceeding with surgery

   • Allow 2-4 weeks for kidney function to recover after stopping Diamox
   • Recent research shows acetazolamide-induced GFR reductions are typically reversible after discontinuation 5

3. Preoperative evaluation

   • Reassess GFR, BUN, and creatinine after Diamox discontinuation
   • Consider nephrology consultation to optimize renal function

4. Perioperative management if surgery becomes necessary

   • Maintain adequate hydration
   • Avoid nephrotoxic agents
   • Maintain mean arterial pressure between 60-70 mmHg (>70 mmHg if hypertensive) 1
   • Consider prophylactic antibiotics based on nephrology recommendations 1

Rationale for Postponing Surgery

1. Increased perioperative risk

   • Diabetes and CKD are independent risk factors for developing acute renal failure in the perioperative period 1
   • Acute decline in renal function increases risk of perioperative complications

2. Contraindicated medication

   • Diamox is specifically contraindicated in patients with marked kidney and liver disease 2
   • The acute decline in renal function temporally related to Diamox initiation suggests direct medication effect

3. Reversible cause

   • The acute kidney injury is likely reversible after discontinuing the offending agent
   • Research shows acetazolamide-induced GFR reductions are typically reversible after a 2-week washout period 5

Monitoring After Diamox Discontinuation

1. Monitor serum creatinine, BUN, and electrolytes weekly
2. Reassess GFR after 2-4 weeks
3. Proceed with surgery only when:
   • GFR has stabilized or improved
   • No evidence of ongoing acute kidney injury
   • Electrolyte abnormalities have resolved

Common Pitfalls to Avoid

1. Continuing Diamox despite worsening renal function

   • Acetazolamide can cause further deterioration in kidney function in patients with existing renal impairment

2. Rushing to surgery without addressing reversible causes of kidney injury

   • Addressing the medication-induced kidney injury first will reduce perioperative risk

3. Inadequate perioperative fluid management

   • Patients with CKD require careful hydration before procedures involving contrast media 1

4. Failure to adjust medication dosages

   • Decreased GFR in elderly patients requires adjustment in drug dosages 1

By addressing the reversible cause of acute kidney injury first, the patient's surgical risk can be significantly reduced, leading to better outcomes for both renal function and the ophthalmologic procedure.