Canis ISSN: 2398-2942

Hemoglobinuria

Contributor(s): Melissa Wallace

Introduction

  • Presence of free hemoglobin in the urine.
  • Cause: hemoglobin filtered by the glomeruli (true hemoglobinuria) or hemoglobin released by lysis of erythrocytes in urine (hematuria).
  • Signs: reddish discoloration of urine.
  • Diagnosis: blood reaction on urine test strip; lack of erythrocytes in urine sediment; investigation of cause.
  • Treatment: depends on cause.
  • Prognosis: depends on cause.

Pathogenesis

Etiology



Erythrocyte lysis within urine Intravascular hemolysis
  • Hemoglobin filtered by glomeruli.
  • Intravascular hemolysis is more likely to result in hemoglobinuria than is extravascular hemolysis.
  • Idiopathic.
  • Hypophosphatemia.
  • Bacterial infection:
  • Red blood cell parasite infection:
    • Babesiosis - intravascular hemolysis predominates.
  • Chemicals and drugs:
    • Phenothiazine.
    • Methylene blue.
    • Paracetamol.
    • Copper.
    • Ricin.
  • Immune-mediated:
  • Increased red cell fragility:
    • Toxemia.
    • Heat stroke.
    • Radiation.


    Extravascular hemolysis
  • Red blood cell parasite infection:
    • Babesiosis.
  • Immune-mediated:
  • Intracorpuscular defects:
    • Pyruvate kinase deficiency in the Basenji, Beagle, West Highland White Terrier, Cairn Terrier and Miniature Poodle.
    • Hereditary stomatocytosis in Alaskan Malamutes with chondrodysplasia.
  • Fragmentation (microangiopathic disorders):
    • Heartworm disease.
    • Disseminated intravascular coagulation.
    • Hepatic cirrhosis Liver: cirrhosis.
    • Splenic or hepatic hemangiosarcoma.

Pathophysiology

  • Hemoglobinuria may result from either of two main sources:
    • True hemoglobinuria results when hemoglobin is filtered by the glomeruli.
    • Hemoglobinuria also results from hematuria when erythrocytes are lysed within the urine.
  • True hemoglobinuria caused by intravascular or extravascular destruction of erythrocytes → release of hemoglobin into plasma.
  • Hemoglobin is a metalloprotein of molecular weight 64,500 → small enough to pass the glomerular filter.
  • Severe or moderate intravascular hemolysis → free hemoglobin appears in urine.
  • Most of the free hemoglobin in urine is probably secreted as a dimer.
  • True hemoglobinuria is usually accompanied by clinical signs of hemolysis.
  • Hemoglobinuria results from hemolysis only when erythrocytes are destroyed at a rate exceeding the capacity of conversion of hemoglobin to bilirubin → many patients with hemolysis will have bilirubinemia and icterus rather than hemoglobinuria.

Timecourse

  • A few hours to several weeks, depending on cause and severity.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Lobetti R G, Reyers F & Nesbit J W (1996) The comparative role of hemoglobinuria and hypoxia in the development of canine babesial nephropathy. J South African Med Assoc 67 (4), 188-198 PubMed.
  • Lobetti R G & Reyers F (1996) Met-hemoglobinuria in naturally occurring Babesia canis infection. J South African Med Assoc 67 (2), 88-90 PubMed.


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