Milk of calcium in the inferior calyx of a hydronephrotic kidney in a tetraplegic patient - a diagnosis to be made before scheduling for extracorporeal shock wave lithotripsy

Study design: A Case Report of renal milk of calcium in a tetraplegic subje ct. Objectives: To increase the awareness of renal milk of calcium in spinal co rd injury (SCI) physicians. Renal milk of calcium contains a colloidal susp ension of calcium crystals. Since upright views of the kidneys are not perf ormed in tetraplegic subjects, the renal milk of calcium may be misinterpre ted as renal lithiasis by routine radiography taken in supine position. Setting: Regional Spinal Injuries Centre, Southport, England. Method: In a I l-year-old male with traumatic tetraplegia, X-ray of abdomen in supine position showed multiple opacities in the region of the left kid ney. These radio opaque shadows were interpreted as renal calculi. Subseque ntly, computed tomography (CT) of the kidneys was performed. Results: CT confirmed the presence of calculi in the mid-polar calyx. Howev er, the density situated in the inferior calyx of the hydronephrotic left k idney exhibited a horizontal upper edge. This specific radiological finding as observed in the CT of kidneys, provided the clue to the presence of mil k of calcium in the inferior calyx of the hydronephrotic left kidney. Conclusion: As plain film of the abdomen in standing position is not perfor med in SCI patients, physicians caring for SCI patients should have a high index of suspicion for renal milk of calcium. Prompt diagnosis of renal mil k of calcium will help to avoid unnecessary surgery, or extracorporeal shoc k wave lithotripsy.