Causes of Kidney Infarction
Renal artery lesions are the most frequent cause of kidney infarction, accounting for approximately 81% of cases, followed by cardioembolic sources (particularly atrial fibrillation) at 9-56% depending on the population studied. 1, 2
Primary Etiologic Categories
Kidney infarction results from acute disruption of renal blood flow through three main mechanisms 1, 2:
1. Renal Artery Lesions (Most Common: 81%)
This is the predominant cause and requires extensive arterial exploration to identify the underlying vascular disease. 1
- Atherosclerotic disease accounts for 34% of renal artery lesions 1
- Dissecting hematoma represents 23% of arterial lesions 1
- Fibromuscular dysplasia causes 19% of arterial lesions 1
- Renal artery thrombosis occurs in 7.5% of cases 2
- Renal artery occlusion was observed in 40% of patients in one series 1
2. Cardioembolic Sources (9-56%)
Atrial fibrillation is the single most important cardioembolic risk factor, present in 28-55% of renal infarction cases. 2, 3, 4
- Atrial fibrillation serves as the primary embolic source 2, 3, 4
- Valvular heart disease contributes to embolic risk 4
- Ischemic heart disease increases thromboembolic potential 4
- Prior thromboembolic events occur in 11% of patients 4
3. Hypercoagulable States (6%)
Thrombophilic conditions account for approximately 6% of renal infarctions. 2
- Coagulopathies predispose to thrombotic events 2, 4
- Estroprogestinic therapy was present in 11% of one case series 4
- Sickle cell anemia can cause multiple "slit-like" focal infarcts with enlarged kidneys 5
4. Idiopathic (4-30%)
When extensive workup fails to identify a cause, only 4-30% of cases remain truly idiopathic, with the wide range reflecting thoroughness of investigation. 1, 2
Associated Risk Factors
Beyond the primary causes, several conditions increase susceptibility 4:
- Hypertension is present in 44% of patients 4
- Obesity affects 33% of patients 4
- Peripheral vascular disease occurs in 17% 4
- Smoking is present in 17% 4
- Diabetes mellitus affects 11% 4
Traumatic Causes
Trauma typically causes unilateral global infarction patterns, distinguishing it from other etiologies. 5
- Trauma-related infarction presents as unilateral global involvement 5
- This contrasts with embolic causes, which produce multifocal bilateral involvement 5
Clinical Implications
The distribution pattern on imaging helps identify the underlying mechanism: multifocal bilateral infarcts suggest embolism, while unilateral global infarcts suggest trauma or arterial dissection. 5
- Right and left kidneys are equally affected overall 1
- Embolic sources cause multifocal involvement of both kidneys 5
- Arterial lesions may present with either focal or global patterns 1, 5
Critical Diagnostic Pitfall
A significant proportion of renal infarctions are initially misdiagnosed (often as pyelonephritis), leading to delayed treatment and worse outcomes. 3, 4 The key distinguishing feature is that 72% of patients present with acute flank pain, but unlike pyelonephritis, they typically lack fever and pyuria 4.