Arteriovenous malformations, also known as arteriovenous fistulas (AVF), are rare pathologies characterized by abnormal connections between the arterial and venous systems. It has a higher incidence in the right kidney, predominantly affecting women in the third and fourth decade of life. Its clinical manifestations vary according to its size, its etiology, its evolution time, as well as its location, and can be characterized by the presence of micro or macroscopic hematuria, lumbar or flank pain, nausea, vomiting and arterial hypertension. The case is presented of a 39-year-old patient who presented right lumbar pain approximately 96 hours ago, accompanied by hematuria that has increased sharply in the subsequent 24 hours.