Updated: 10/15/2018

Sickle Cell Nephropathy

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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
    • presence of HbS 
  • Diagnostic criteria
    • generally, this is a diagnosis of exclusion
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
 

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