Introduction: Renal traumas are quite commonly encountered in emergency departments. Low-energy traumas are often considered non-significant, but the presence of a pre-existing renal lesion predisposes the kidneys to more severe damage in the setting of even minor traumas, which may be accompanied by devastating results, should they remain unattended. Case Presentation: Here we report an incidental diagnosis of bilateral ureteropelvic junction obstruction in a patient who presented with unexpected shattered kidney following a low-energy flank injury. Conclusions: Patients with a pre-existing renal lesion are vulnerable to severe traumatic renal injuries, even after minor trauma. The severity of renal injuries may be much more than expected, making the clinical and imaging findings complex and confusing in these patients.