[Renal hematomas secondary to extracorporeal shockwave lithotripsy]

0.6% of the patients submitted to extracorporeal shock wave lithotripsy (ESWL) present symptomatic renal hematoma that can permanently alter renal function and morphology. The present study analyzes the risk factors, types of renal hematoma secondary to shock waves and treatment.

The study comprised 9 patients with ESWL-induced renal hematoma that had been diagnosed by renal ultrasound and/or urography. Patient evaluation included CT and an isotopic renogram. Two patients had associated arterial hypertension and ischemic coronary heart disease treated with antiaggregants. In 4 patients the renal calculi had produced partial obstruction of the urinary tract.

In 4 patients the ESWL-induced renal hematoma was less than 1/3 of the renal volume and did not alter renal function. These patients have been classified as having type I renal hematoma and have been successfully managed conservatively. In 5 patients the hematoma was more than 1/3 of the renal volume and renal function was impaired. These patients have been classified as having type II renal hematoma. Spontaneous reabsorption of the hematoma facilitated recovery of renal function in one patient, two had persistent hematoma and progressive renal function impairment, and the remaining two patients underwent delayed evacuation of the hematoma on days 30-45. Decompression renal surgery preserved renal function of the two kidneys.

Advanced arteriosclerosis, arterial hypertension, primary coagulation disorders or secondary to antiaggregation therapy and obstruction of the urinary tract increase the risk of ESWL-induced renal hematoma. Renal hematoma following ESWL has been classified as type I or type II. In the latter, renal decompression surgery facilitates recovery of renal function.