Should I order intravenous (IV) fluids for a patient with a suspected infected kidney stone?

Management of Suspected Infected Kidney Stone

Intravenous fluids should be administered promptly to patients with suspected infected kidney stones, particularly when there are signs of severe dehydration or sepsis. 1

Initial Assessment and Management

When evaluating a patient with suspected infected kidney stone, focus on:

• Vital signs (fever, tachycardia, hypotension)
• Signs of systemic infection or sepsis
• Hydration status
• Degree of obstruction
• Renal function

Urgent Management Steps:

1. Fluid Resuscitation

   • Administer isotonic crystalloids (normal saline or lactated Ringer's) 1
   • Target adequate urine output (>0.5 mL/kg/hr) 1
   • Initial bolus of 1-2 L followed by maintenance fluids based on clinical status 1

2. Antimicrobial Therapy

   • Collect blood and urine cultures before starting antibiotics 1
   • Initiate broad-spectrum antibiotics covering gram-negative and gram-positive organisms 1
   • Adjust based on culture results and local antibiogram 1

3. Urinary Drainage

   • In patients with obstructing stones and suspected infection, urgently drain the collecting system with a stent or nephrostomy tube and delay stone treatment 1
   • This is critical to allow drainage of infected urine and antibiotic penetration 1

Evidence for Fluid Management

The KDIGO guidelines recommend using isotonic crystalloids rather than colloids for expansion of intravascular volume in patients at risk for AKI or with AKI 1. This is particularly relevant in patients with infected kidney stones who may develop AKI due to obstruction and infection.

The Infectious Diseases Society of America guidelines state that "isotonic intravenous fluids such as lactated Ringer's and normal saline solution should be administered when there is severe dehydration, shock, or altered mental status" 1. In patients with ketonemia, initial intravenous hydration may be needed to enable tolerance of oral rehydration 1.

Stone Management Considerations

After the acute infection is controlled:

• For stones ≤10 mm: Consider medical expulsive therapy (alpha-blockers) 2, 3
• For stones >10 mm: Surgical intervention is typically required 1, 2
• Stone analysis should be performed to guide future prevention strategies 1, 2

Fluid Management After Acute Phase

Once the patient is stabilized:

• Increase oral fluid intake to achieve urine volume of at least 2.5 liters daily 2, 4
• This is the strongest evidence-based recommendation for all stone formers 2
• Beverages associated with lower stone risk include coffee, tea, wine, beer, and orange juice 2
• Avoid sugar-sweetened sodas 2, 4

Common Pitfalls to Avoid

1. Delaying drainage in obstructive pyelonephritis

   • Obstructive pyelonephritis is a urologic emergency that can lead to sepsis and death 5
   • Never delay drainage of the collecting system when infection behind an obstructing stone is suspected

2. Excessive fluid administration

   • While hydration is important, excessive IV fluids can lead to volume overload, particularly in patients with heart failure or CKD 6
   • Monitor fluid status carefully and adjust based on clinical response

3. Relying solely on forced hydration to pass stones

   • Cochrane review found no reliable evidence to support the use of high-volume fluid therapy for acute ureteric colic 7
   • Focus on appropriate pain control and timely intervention rather than excessive hydration

4. Neglecting metabolic evaluation

   • After resolution of the acute episode, consider 24-hour urine collection to identify metabolic abnormalities 2
   • This can guide long-term prevention strategies

In summary, prompt administration of IV fluids is an essential component of managing patients with suspected infected kidney stones, particularly when there are signs of dehydration or sepsis. However, the definitive treatment requires drainage of the collecting system and appropriate antimicrobial therapy.