What is the initial management of renal infarction?

Initial Management of Renal Infarction

The initial management of renal infarction should include prompt anticoagulation with intravenous heparin followed by oral anticoagulants, along with appropriate fluid resuscitation and pain control. 1, 2

Diagnosis

• Renal infarction should be suspected in patients presenting with sudden onset flank pain, especially in those with risk factors for thromboembolism such as atrial fibrillation, valvular or ischemic heart disease 2
• Laboratory findings typically include hematuria, leukocytosis, and markedly elevated lactate dehydrogenase (LDH) levels 2
• IV contrast-enhanced CT with immediate and delayed images is the recommended diagnostic imaging modality for suspected renal infarction 3
• Duplex ultrasound (DUS) may be used as a first-line imaging modality when renal artery disease is suspected, but is less sensitive than CT for diagnosing renal infarction 3

Immediate Management

• Initiate intravenous unfractionated heparin as soon as the diagnosis is confirmed 4, 5
• Provide adequate fluid resuscitation with normal saline (0.9%) to maintain renal perfusion and prevent further kidney injury 3
• Avoid potassium-containing balanced salt fluids such as Lactated Ringer's solution, as potassium levels may increase markedly even with intact renal function 3
• Provide appropriate analgesia for pain control 2

Anticoagulation Therapy

• For hemodynamically stable patients with renal infarction, anticoagulation with intravenous heparin followed by oral anticoagulants (warfarin) is the mainstay of treatment 1, 4
• Low molecular weight heparin may be used as an alternative to unfractionated heparin 4
• Antiplatelet therapy with aspirin may be considered in patients with atherosclerotic renal artery disease 3
• Continue anticoagulation therapy for at least 3-6 months, or indefinitely if there is an ongoing risk factor such as atrial fibrillation 4

Monitoring and Follow-up

• Monitor renal function with serial creatinine measurements to detect acute kidney injury, which occurs in approximately 20% of patients with renal infarction 1
• Assess urine output regularly to detect oliguria or anuria 3
• Monitor electrolytes, particularly potassium levels 3
• Consider follow-up renal imaging to assess the extent of renal damage and recovery 4

Special Considerations

• In hemodynamically unstable patients with renal infarction who do not respond to resuscitation, immediate intervention (surgery or angioembolization) should be performed 3
• For patients with severe renal vascular injuries without self-limiting bleeding, surgical intervention is indicated 3
• In patients with solitary kidney and moderate to severe renal trauma with arterial contrast extravasation on CT scan, angiography with super-selective angioembolization should be considered as the first choice 3
• In patients with renal dysfunction, special attention must be given to proper dosing of antithrombotic medications 3

Prognosis

• Despite appropriate treatment, renal infarction can lead to acute kidney injury, new-onset decreased renal function, end-stage renal disease, and death 1
• Approximately 11% of patients develop new-onset decreased renal function (eGFR <60 mL/min/1.73m²) following renal infarction 4
• Recurrence of renal infarction is possible even after initial resolution, highlighting the importance of continued anticoagulation and close monitoring 6

Common Pitfalls

• Delayed diagnosis is common as renal infarction is often misdiagnosed as renal colic, pyelonephritis, or acute abdomen 2
• Failure to consider renal infarction in patients with risk factors for thromboembolism presenting with flank pain 2
• Inadequate anticoagulation or premature discontinuation of anticoagulation therapy 4
• Overlooking the need for fluid resuscitation, which is crucial for preserving renal function 3