Can a high fever cause a rise in creatinine (serum creatinine) from 0.87 to 1.2 milligrams per deciliter (mg/dL) in an adult patient with no prior history of kidney disease?

Can High Fever Cause Creatinine to Rise from 0.87 to 1.2 mg/dL?

Yes, high fever can absolutely cause a creatinine rise from 0.87 to 1.2 mg/dL, representing a 0.33 mg/dL increase that meets KDIGO criteria for Stage 1 acute kidney injury (AKI). 1

Understanding the Creatinine Change

This creatinine rise from 0.87 to 1.2 mg/dL represents:

• An absolute increase of 0.33 mg/dL, which exceeds the KDIGO threshold of ≥0.3 mg/dL for diagnosing AKI 1
• A relative increase of approximately 38% from baseline, approaching the 50% threshold for AKI diagnosis 1
• This change qualifies as Stage 1 AKI if it occurred within 48 hours, or if the creatinine increased ≥50% within 7 days 1

Mechanisms by Which Fever Causes Creatinine Elevation

High fever causes prerenal acute kidney injury through several mechanisms:

Volume Depletion

• Fever increases insensible fluid losses through sweating, increased respiratory rate, and reduced oral intake 2
• Prerenal causes account for 27-50% of all AKI cases and should be evaluated first 3
• Volume depletion reduces renal perfusion pressure, decreasing glomerular filtration rate 3

Increased Metabolic Demand

• High fever (especially ≥40°C) increases metabolic rate and oxygen consumption 2
• This can lead to relative hypoperfusion of the kidneys even without overt hypovolemia 2

Infectious Etiologies

• Severe infections causing high fever can directly cause AKI through sepsis-related mechanisms 2, 4
• Malaria, leptospirosis, and hemorrhagic fever with renal syndrome are classic examples where fever and AKI coexist 2, 5, 4
• In severe malaria, creatinine elevation to 1.48 mg/dL was documented alongside high fever 2

Clinical Context Matters

Reversibility

• If this is purely prerenal AKI from fever-related volume depletion, it should be completely reversible with appropriate fluid resuscitation 3
• Improvement in creatinine should be evident within 48-72 hours of addressing the underlying cause 3

Red Flags Requiring Further Investigation

You must evaluate for more serious causes if:

• Oliguria is present (<0.5 mL/kg/h for >6 hours), which would indicate more severe AKI 1, 3
• Fever persists despite appropriate treatment, suggesting ongoing infection 2
• Creatinine continues to rise despite volume repletion 3
• Urinalysis shows proteinuria, hematuria, or cellular casts suggesting intrinsic renal disease 1, 3

Diagnostic Approach

Immediate Assessment

• Check urinalysis with microscopy to exclude intrinsic renal disease (look for proteinuria >500 mg/day, hematuria, or casts) 1, 3
• Assess volume status clinically (mucous membranes, skin turgor, orthostatic vital signs) 3
• Calculate fractional excretion of sodium (FENa): <1% confirms prerenal etiology 1
• Review medication list for nephrotoxins (NSAIDs, ACE inhibitors, diuretics) 3

Establish Baseline

• Use the most recent known creatinine value (0.87 mg/dL in this case) as the baseline—this is superior to any estimation method 1
• The 0.87 mg/dL baseline is actually in the normal range, making this rise more clinically significant 1

Management Strategy

If Prerenal (Most Likely with Isolated Fever)

• Discontinue or reduce diuretics if the patient is taking them 3
• Provide volume repletion with isotonic crystalloids (normal saline or lactated Ringer's) 3
• Treat the underlying cause of fever aggressively 2
• Reassess creatinine in 48-72 hours—it should improve if this is purely prerenal 3

If No Improvement

• Consider nephrology consultation if creatinine fails to improve or continues to rise 3
• Renal ultrasound to exclude obstruction (postrenal cause) 1, 3
• Further workup for intrinsic renal disease if urinalysis is abnormal 1, 3

Important Caveats

Don't Wait for Higher Thresholds

• The outdated threshold of creatinine ≥1.5 mg/dL often indicates GFR has already fallen to ~30 mL/min 3
• Small increases in creatinine (≥0.3 mg/dL) are independently associated with approximately four-fold increased hospital mortality 1

Special Populations

• In patients with cirrhosis and ascites, focus exclusively on creatinine changes rather than urine output, as these patients are often oliguric despite normal GFR 1, 3
• In elderly patients or those with low muscle mass, even "normal" creatinine values may mask significant kidney dysfunction 6

Medication Review is Critical

• NSAIDs can potentiate or independently cause AKI, especially in the setting of volume depletion from fever 3
• ACE inhibitors/ARBs can cause AKI when combined with volume depletion 3
• Ensure the patient avoids nephrotoxic medications during recovery 3