What is the management for a patient with a hemotoxic snake bite resulting in Acute Kidney Injury (AKI)?

Management of Hemotoxic Snake Bite with Acute Kidney Injury

Activate emergency medical services immediately, administer anti-snake venom as soon as possible, discontinue all nephrotoxic medications including NSAIDs and diuretics, initiate aggressive fluid resuscitation with isotonic crystalloids, and prepare for renal replacement therapy if AKI progresses despite supportive care. 1, 2, 3

Immediate First Aid and Transport

• Call emergency services immediately for any venomous or possibly venomous snake bite, as definitive treatment with antivenom is not available in first aid settings 1
• Rest and immobilize the bitten extremity to minimize systemic venom absorption, as movement increases subcutaneous flow of venom by promoting lymphatic spread 1
• Remove rings and constricting objects from the affected limb to prevent compartment syndrome as swelling progresses 1
• Do NOT apply tourniquets, pressure immobilization bandages, ice, suction devices, or electric shock, as these interventions are potentially harmful and ineffective for North American pit viper bites (which cause >95% of venomous bites and produce hemotoxic/cytotoxic venom) 1

Initial Hospital Management of AKI

Medication Review and Discontinuation

• Immediately discontinue NSAIDs, as they increase AKI risk more than twofold in volume-depleted patients and worsen kidney injury 4, 2
• Withdraw all diuretics, as they exacerbate AKI in hypovolemic states 4, 2
• Stop ACE inhibitors, ARBs, and any aminoglycosides or other nephrotoxic medications to prevent further kidney damage 4, 2

Fluid Resuscitation

• Use isotonic crystalloids (normal saline or Ringer's lactate) as the preferred initial fluid for volume expansion 4, 2
• Avoid starch-containing colloid solutions, as they are associated with harm in AKI 4, 2
• Monitor closely for pulmonary edema with fluid administration, particularly if albumin is used 1, 2
• In patients requiring albumin (such as those with concurrent cirrhosis), administer 1 g/kg/day up to 100 g/day maximum 1

Anti-Snake Venom Administration

• Initiate anti-snake venom as early as possible, as this is the definitive treatment and early administration improves outcomes in snake bite-associated AKI 3, 5
• The "bite-to-needle" time is a critical prognostic factor—delayed antivenom administration significantly increases AKI risk 6

Assessment and Monitoring

Initial Evaluation

• Perform urinalysis to detect hematuria, proteinuria, or abnormal sediment that would suggest structural kidney disease beyond pre-renal AKI 1, 4, 3
• Check complete blood count for evidence of hemolysis, thrombocytopenia, and anemia from bleeding 3, 5, 6
• Obtain coagulation profile (PT, PTT, fibrinogen) as disseminated intravascular coagulation (DIC) is common with hemotoxic venom and contributes to AKI 3, 5, 6
• Assess for rhabdomyolysis with creatine kinase and myoglobin levels, as myotoxicity can cause tubular injury 3, 7

Ongoing Monitoring Parameters

• Monitor serum creatinine daily to assess AKI stage and trajectory 4, 2
• Check blood urea nitrogen, electrolytes (particularly potassium), and bicarbonate to identify metabolic derangements 4, 3
• Track urine output with goal >0.5 mL/kg/hour 4
• Monitor blood pressure, heart rate, and hematocrit as markers of volume status and ongoing bleeding 4, 5
• Perform renal ultrasound to exclude structural abnormalities 1, 3

Pathophysiology-Specific Considerations

Snake venom causes AKI through multiple mechanisms that require targeted management 3, 7:

• Systemic bleeding and vascular leakage lead to renal hypoperfusion and ischemic injury
• Snake venom metalloproteinases (SVMPs) directly degrade the glomerular basement membrane
• Thrombotic microangiopathy from microthrombi deposition in renal microvasculature
• Direct cytotoxic effects of venom on tubular cells
• Rhabdomyolysis with myoglobin accumulation causing tubular obstruction and injury

Renal Replacement Therapy Indications

Consider initiating RRT when 4, 2, 3:

• Severe oliguria or anuria persists despite 48 hours of optimal fluid resuscitation (suggesting acute tubular necrosis rather than pre-renal AKI)
• Refractory hyperkalemia develops
• Severe metabolic acidosis is present
• Volume overload with pulmonary edema occurs
• Uremic complications manifest
• Stage 3 AKI (creatinine >3 times baseline) fails to improve with medical management

In the study by Vikrant et al., 12% of snake bite patients with severe AKI required hemodialysis 6

Pain Management

• Use opioid analgesics (such as dilaudid) for pain control rather than morphine or fentanyl in non-intubated patients 4
• Completely avoid NSAIDs, as they worsen kidney injury in volume-depleted states 4, 2

Nutritional Support

• Provide total energy intake of 20-30 kcal/kg/day 2
• Administer protein at 1.0-1.5 g/kg/day in patients with AKI on renal replacement therapy, or up to 1.7 g/kg/day if on continuous RRT and hypercatabolic 2
• Deliver nutrition preferentially via enteral route 2

Long-Term Follow-Up

Critical caveat: Snake bite-associated AKI requiring dialysis has significant long-term renal consequences 8:

• 41% of survivors show persistent renal involvement (dysfunction, proteinuria, or hypertension) at mean 45-month follow-up
• 5% progress to end-stage renal disease
• 20% have GFR <45 mL/min (CKD stage 3b or worse)

Follow-Up Protocol

• Monitor serum creatinine every 2-4 days during hospitalization 4
• Check creatinine every 2-4 weeks for 6 months after discharge to detect recurrent AKI 4
• Target long-term follow-up to high-risk populations: those with severe AKI, incomplete recovery at discharge, or baseline CKD 2
• Screen for development or progression of chronic kidney disease 2, 8
• Monitor for proteinuria and hypertension as markers of ongoing renal damage 8

Common Pitfalls to Avoid

• Delayed hospital presentation: Patients who initially visit traditional healers before seeking medical care have significantly worse outcomes and higher AKI rates 6
• Inadequate antivenom dosing or delayed administration: The bite-to-needle time is the most modifiable prognostic factor 5, 6
• Assuming AKI will fully resolve: 41% of dialysis-requiring snake bite patients have persistent renal dysfunction, requiring long-term nephrology follow-up 8
• Using pressure immobilization bandaging for pit viper bites: This technique may worsen local tissue injury with cytotoxic venom and is not recommended for North American hemotoxic snakes 1