In a patient with dengue and suspected leptospirosis, presenting with acute kidney injury (AKI) and oliguria, is furosemide (Lasix) a suitable trial for diuresis?

Furosemide Should NOT Be Used as a Trial for Diuresis in This Clinical Scenario

In a patient with dengue, suspected leptospirosis, and acute kidney injury with oliguria (100 cc in 6 hours), furosemide should NOT be administered as a "trial for diuresis" because diuretics do not prevent or treat AKI itself—they only manage volume overload, and using them in the absence of clear fluid overload risks worsening renal perfusion and precipitating further kidney injury. 1

Primary Evidence Against Furosemide Use

The KDIGO guidelines explicitly recommend against using diuretics to prevent AKI (Grade 1B) or to treat AKI except when managing volume overload (Grade 2C). 1 Randomized controlled trials and meta-analyses clearly demonstrate that furosemide does not prevent AKI and may actually increase mortality when used for this purpose. 1

• Furosemide cannot convert oliguric to non-oliguric AKI and lacks evidence of benefit for this indication. 1
• The drug should only be used in hemodynamically stable patients with AKI who have documented volume overload. 1
• In hemodynamically unstable patients or those without volume overload, furosemide can precipitate volume depletion, hypotension, and further renal hypoperfusion. 1

Specific Considerations for Leptospirosis-Associated AKI

Leptospirosis-induced AKI has unique characteristics that make furosemide particularly inappropriate as a diagnostic or therapeutic trial:

• Leptospirosis-associated AKI is typically nonoliguric and hypokalemic, with tubular dysfunction preceding glomerular filtration rate decline. 2
• Historical data from 1978 showed that high-dose furosemide (2 g/24 hours) in leptospirosis patients produced excellent diuresis but did not alter renal function or clinical course, with duration of renal failure remaining unchanged compared to controls. 3
• A 2007 study suggested potential benefit from combining dopamine (renal dose) with furosemide in mild leptospirosis-associated AKI (serum creatinine 2.4-5 mg/dL), but this was in a specific subset with fractional excretion of sodium 1.21-2.08%, not as a diagnostic trial. 4

Critical Assessment Required Before Any Diuretic Consideration

Before even considering furosemide, you must establish:

Volume Status Assessment

• Document clear evidence of fluid overload: pulmonary edema, significant peripheral edema, elevated jugular venous pressure, or pulmonary crackles. 5
• In dengue patients, this assessment is particularly critical because dengue can cause capillary leak syndrome with intravascular volume depletion despite total body fluid overload.

Hemodynamic Stability

• Systolic blood pressure must be ≥90-100 mmHg for furosemide to be considered. 5
• Assess for signs of hypovolemia: decreased skin turgor, hypotension, tachycardia. 6

Contraindications to Exclude

• Marked hypovolemia (absolute contraindication). 5, 6
• Severe hyponatremia (serum sodium <120-125 mmol/L). 5
• Anuria (absolute contraindication). 5
• Hypotension without circulatory support. 5

Appropriate Management Algorithm for This Patient

Step 1: Immediate Assessment

• Check serum creatinine, electrolytes (particularly sodium and potassium), and assess volume status clinically. 1
• Review all medications and withdraw any nephrotoxic agents. 1
• In leptospirosis with AKI, hypokalemia is common and must be corrected. 2

Step 2: Address Underlying Causes

• Initiate appropriate antibiotic therapy for leptospirosis (penicillin G or doxycycline), which is effective even in late/severe phases. 2
• Ensure adequate but not excessive fluid resuscitation—in dengue, avoid aggressive fluid loading due to capillary leak risk.
• Monitor for pulmonary hemorrhage risk, particularly in leptospirosis. 2

Step 3: Renal Replacement Therapy Consideration

• For critically ill leptospirosis patients with AKI, early and daily hemodialysis is recommended rather than attempting diuretic trials. 2
• Use low-volume infusion strategies due to pulmonary hemorrhage risk. 2

Step 4: If Volume Overload Develops

Only if the patient develops documented fluid overload with adequate blood pressure:

• Start with low-dose furosemide 20-40 mg IV (not as a "trial" but as treatment for volume overload). 5, 1
• Monitor hourly urine output with bladder catheter. 1
• Check electrolytes every 12-24 hours. 1
• Assess renal function daily. 1

Common Pitfalls to Avoid

• Never use furosemide expecting it to "improve" renal function or convert oliguria to non-oliguria—this is not evidence-based and may cause harm. 1
• Do not interpret diuretic response as a measure of renal recovery—urine output after furosemide does not indicate improved kidney function, only tubular responsiveness to the drug. 7
• Avoid combining furosemide with other nephrotoxic medications, as each nephrotoxin increases AKI odds by 53%. 1
• In dengue patients, excessive diuresis can worsen intravascular volume depletion despite peripheral edema. 6

FDA Safety Warnings

The FDA explicitly warns that furosemide "is a potent diuretic which, if given in excessive amounts, can lead to profound diuresis with water and electrolyte depletion" requiring "careful medical supervision." 6 Excessive diuresis may cause "dehydration and blood volume reduction with circulatory collapse and possibly vascular thrombosis and embolism, particularly in elderly patients." 6

Your patient's oliguria (100 cc in 6 hours) represents approximately 0.28 mL/kg/h for a 60 kg patient, which is below the 0.5 mL/kg/h threshold, but this should prompt investigation for prerenal azotemia, intrinsic renal injury, or obstruction—not empiric diuretic administration. 5