JPC SYSTEMIC PATHOLOGY
URINARY SYSTEM
February 2015
U-T12

Signalment (JPC#1901183):  12-year-old, male horse, breed unspecified

HISTORY:  This horse was one of three pastured horses observed eating large quantities of wilted leaves from a fallen red maple tree (Acer rubrum).  Clinically, the horses were depressed, lethargic, anorectic, cyanotic, and icteric. 

HISTOPATHOLOGIC DESCRIPTION:  Kidney:  Diffusely within the cortex and extending into the medulla, tubules exhibit one or more of the following changes: ectatic, lined by attenuated epithelium, contain brightly eosinophilic to red, hyaline to granular material with occasional crystalline structures (hemoglobin or hyaline cast) or eosinophilic homogenous material (proteinosis) occasionally admixed with sloughed epithelial cells and necrotic cellular debris (granular casts); tubular epithelial cells are either swollen with cytoplasmic vacuolization and large, vesiculate nuclei (degenerate) or are shrunken and hypereosinophilic with pyknosis (necrotic); and/or the tubular basement membrane is fragmented (tubulorrhexis).  Multifocally, glomerular uriniferous spaces are distended with proteinaceous fluid,  and there is multifocal periglomerular fibrosis.  Multifocally, there are few neutrophils within tubules and the surrounding interstitium.  There is multifocal thickening of the basement membranes of tubules and Bowman’s capsule.

MORPHOLOGIC DIAGNOSIS:  Kidney:  Tubular degeneration and necrosis, subacute, diffuse, marked, with tubulorrhexis and hemoglobin, hyaline, and granular casts, breed not specified, equine.

ETIOLOGIC DIAGNOSIS:  Hemoglobinuric nephrosis

CAUSE:  Red maple leaf (Acer rubrum) toxicosis

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

Peracute form:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

Causes of methemoglobinemia:

Causes of Heinz body anemia:

References:

  1. Agrawal K, Ebel JG, Altier C, et al. Identification of protoxins and a microbial basis for red maple (Acer rubrum) toxicosis in equines. J Vet Diagn Invest. 2013;25(1):112-119.
  2. Alward A, Corriher CA, Barton MH, et al. Red maple (Acer rubrum) leaf toxicosis in horses: a retrospective study of 32 cases.  J Vet Intern Med. 2006;20:1197-1201.
  3. Boes KM, DurhamAC. Bone marrow, blood cells, and the lymphoid/lymphatic system. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017: 746-747
  4. Breshears MA, Confer AW. The urinary system. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:655
  5. Brockus CW. Erythrocytes. In: Latimer ed. Duncan and Prasse’s Veterinary Laboratory Medicine Clinical Pathology. 5th ed. Ames, Iowa: Wiley-Blackwell; 2011:12-13, 20.
  6. Cianciolo RE, Mohr FC. Urinary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier; 2016: 429-430
  7. Haschek WM, Rousseaux CG, Wallig MA. Fundamentals of Toxicologic Pathology. 2nd San Diego, CA: Elsevier; 2010: 276, 308, 500
  8. Miler MA, Buss PE. . Rhinoceridae (Rhinoceroses). In: Miller RE, Folwer ME, eds. Fowler’s Zoo and Wild Animal Medicine. Vol 8. St. Louis, MO: Elsevier; 2015: 544
  9. Tripathi NK, Gregory CR, Latimer KS. Urinary system. In: Latimer ed. Duncan and Prasse’s Veterinary Laboratory Medicine Clinical Pathology. 5th ed. Ames, Iowa: Wiley-Blackwell; 2011:262.
  10. Valli VEO, Kiupel M, Bienzle D. Hematopoietic system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St. Louis, MO: Elsevier; 2016: 126
  11. Walter KM, Moore CE, Bozorgmanesh R, et al. Oxidant-induced damage to equine erythrocytes from exposure to Pistacia atlantica, Pistacia terebinthus, and Pistacia chinensis. J Vet Diagn Invest. 2014;26(6):821-826.


Click the slide to view.



Click on image for diagnostic series.



Back | Home | Contact Us | Links | Help |