What is causing pedal edema in a patient with kidney stones, hydroureter, and hydronephrosis, taking Toradol (ketorolac) and Norco (hydrocodone and acetaminophen)?

Causes of Pedal Edema in a Patient with Kidney Stones, Hydroureter, and Hydronephrosis Taking Toradol and Norco

The pedal edema in this patient is most likely caused by Toradol (ketorolac), which can lead to fluid retention, sodium retention, and edema as a direct side effect, especially in the setting of obstructive uropathy from kidney stones. 1

Medication-Related Causes

Toradol (Ketorolac)

• Primary mechanism: NSAIDs like ketorolac inhibit prostaglandin synthesis, which:
  • Reduces renal blood flow
  • Promotes sodium and fluid retention
  • Can worsen existing renal impairment 1
• FDA labeling specifically warns: "Fluid retention, edema, retention of NaCl, oliguria, elevations of serum urea nitrogen and creatinine have been reported in clinical trials with ketorolac tromethamine" 1
• Risk factors in this patient:
  • Obstructive uropathy (hydroureter, hydronephrosis) creates baseline renal compromise
  • Kidney stones further impair renal function

Norco (Hydrocodone/Acetaminophen)

• Less likely to be the primary cause of edema
• However, may contribute through:
  • Pain management leading to reduced mobility
  • Possible mild fluid retention effects

Pathophysiological Mechanism

1. Obstructive Uropathy Baseline:

   • Hydroureter and hydronephrosis indicate urinary obstruction
   • This creates impaired renal function and reduced urine output

2. NSAID Effect:

   • Ketorolac inhibits renal prostaglandins that normally maintain renal blood flow
   • This leads to:
     • Decreased glomerular filtration rate
     • Increased sodium reabsorption
     • Fluid retention manifesting as pedal edema 2

3. Worsening Cycle:

   • Reduced renal function → More fluid retention
   • More fluid retention → Increased pressure on kidneys
   • Increased pressure → Further reduced function

Management Approach

1. Discontinue Toradol:

   • First-line intervention given the clear association with edema 1
   • Replace with non-NSAID analgesic options

2. Consider Alternative Pain Management:

   • Acetaminophen (already in Norco)
   • Tramadol
   • Local measures (heat, positioning)
   • Definitive treatment of kidney stones

3. Address Underlying Obstruction:

   • Urological consultation for management of stones, hydroureter, and hydronephrosis
   • Options may include:
     • Stenting
     • Lithotripsy
     • Surgical intervention if needed

4. Judicious Use of Diuretics:

   • Loop diuretics (furosemide) may help temporarily
   • Monitor for electrolyte abnormalities and worsening renal function
   • Not a long-term solution without addressing the underlying cause 3

Monitoring Parameters

• Daily weight
• Fluid input/output
• Renal function (BUN, creatinine)
• Electrolytes (particularly potassium)
• Urine output
• Resolution of edema

Common Pitfalls to Avoid

1. Adding calcium channel blockers:

   • Dihydropyridine calcium channel blockers (like amlodipine) can worsen pedal edema 3
   • These are associated with dose-related pedal edema, more common in women than men

2. Excessive diuresis:

   • Aggressive diuresis without addressing the underlying cause can worsen renal function
   • Can lead to electrolyte abnormalities and hypotension 3

3. Continuing NSAIDs:

   • Persistent use of ketorolac despite edema can lead to acute renal failure 2
   • NSAIDs should be used with extreme caution in patients with any degree of renal impairment

4. Ignoring the obstructive component:

   • Treating only the edema without addressing the hydroureter/hydronephrosis will lead to treatment failure
   • Definitive management of the stones is essential

By addressing the medication cause (Toradol), managing pain through alternative means, and ensuring proper treatment of the underlying kidney stones and obstruction, the pedal edema should resolve while improving the patient's overall condition.