Snapshot An 18-year-old African American man with a history of sickle cell trait presents with 1 week of painless gross hematuria. On review of systems, he endorses a 10 pound weight loss within the past 2 months. Physical exam reveals a left-sided abdominal mass. His serum creatinine is found to be elevated. He is sent to the emergency room for urgent CT imaging. (Renal medullary carcinoma secondary to sickle cell trait). Introduction Clinical definition nephropathy associated with sickle cell disease or trait vaso-occlusion renal medullary carcinoma Epidemiology incidence proteinuria 20-25% in sickle cell disease renal insufficiency 5-30% in sickle cell disease risk factors vaso-occlusion sickle cell disease > trait renal medullary carcinoma sickle cell trait > disease patients of African ancestry Pathogenesis normal ↓ O2 tension in the renal medulla is low enough to induce RBC sickling sickling of red blood cells in medulla capillaries cause increased viscosity increased viscosity causes ischemia and infarction in renal medulla this can lead to renal infarcts and papillary necrosis Prognosis prognostic variable negative renal failure increased mortality risk for those with renal failure, regardless of treatment prognosis is < 1 year for renal medullary carcinoma commonly very aggressive and metastasizes early Presentation Symptoms vaso-occlusion nausea vomiting nocturia polyuria painless hematuria history of urinary tract infections renal medullary carcinoma gross painless hematuria weight loss Physical exam vaso-occlusion flank or abdominal pain hypertension renin-mediated renal medullary carcinoma abdominal mass Imaging Ultrasound indications to exclude other abnormalities such as nephrolithiasis recommend views renal findings can detect renal papillary necrosis CT indications if renal medullary carcinoma is suspected (young patient with sickle cell trait and gross hematuria) findings mass in kidney Studies Labs electrolyte abnormalities impaired distal H+ and K+ secretion can cause a renal tubular acidosis hyperkalemia metabolic acidosis ↑ creatinine Urinalysis proteinuria low specific gravity and osmolarity indicates loss of urine concentrating ability Hemoglobin electrophoresis Diagnostic criteria Differential Nephrolithiasis seen on imaging Treatment Conservative hydration and blood transfusions as needed indications isolated hematuria hydration can dislodge blood clots Medical dialysis indications end-stage renal disease Operative renal transplant indications end-stage renal disease not responsive to dialysis Complications End-stage renal disease Renal medullary carcinoma with metastases