JPC SYSTEMIC PATHOLOGY
MUSCULOSKELETAL SYSTEM
April 2019
M-T05

Signalment (JPC # 2329125):  14 week-old male beagle

HISTORY:  This dog was part of a toxicologic study.

HISTOPATHOLOGIC DESCRIPTION:  Femur, articular cartilage:  Focally expanding the intermediate or transitional zone of articular cartilage is a slit-like fissure that elevates the overlying cartilage, which is uneven and undulant.  The fissure contains few free chondrocytes and irregular clusters and strands of eosinophilic fibrillar material (unmasked collagen fibers), which line the margins and project perpendicularly into the fissure lumen (fibrillation).  Adjacent chrondrocytes are shrunken, hypereosinophilic, and pyknotic (necrosis) and are embedded in cartilaginous matrix that is expanded by clear space (edema).  Multifocally bordering the fissure are chondrones, with 2-4 chondrocytes within one lacuna and the cartilage matrix is pale with altered staining properties.  In another region of the articular cartilage there is a 0.5X2mm area where the cartilage matrix is pale, amphophilic, granular and fibrillated and chondrocytes within this area are pyknotic, necrotic or lost.

MORPHOLOGIC DIAGNOSIS:  Femur, articular cartilage, intermediate (transitional) zone:  Degeneration and necrosis, focally extensive, moderate, with cleft formation and fibrillation, beagle, canine.

ETIOLOGIC DIAGNOSIS:  Quinolone-induced arthropathy

CAUSE:  Quinolone compounds

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS: 

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS: 

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Beluche LA, Bertone AL, Anderson DE, Kohn CW, Weisbrode SE. In vitro dose-dependent effects of enrofloxacin on equine articular cartilage. Am J Vet Res. 1999;60:577-582.
  2. Burkhardt JE, Hill MA, Turek JJ, Carlton WW. Ultrastructural changes in articular cartilages of immature beagle dogs dosed with difloxacin, a fluoroquinolone. Vet Pathol. 1992;29:230-238.
  3. Davenport CLM, Boston RC, Richardson DW. Effects of enrofloxacin and magnesium deficiency on matrix metabolism in equine articular cartilage. Am J Vet Res 2001;62:160-166.
  4. Egerbacher M, Wolfesberger B, Gabler C. In vitro evidence for effects of magnesium supplementation in quinolone-treated horse and dog chondrocytes. Vet Pathol. 2001;38:143-148.
  5. Gunson D, Gropp KE, Varela A. In: Wallig MA, Haschek WM, Rousseaux CG, et al, eds. Fundamentals of Toxicologic Pathology. San Diego, CA: Academic Press; 2018:775-776,788-789.
  6. Labelle P. The eye. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. St. Louis, MO: Elsevier. 2017:1318.
  7. Yabe K, Satoh H, Ishii Y, Jindo T, Sugawara T, Furuhama K, Goryo M, Okada K. Early patho physiologic features of arthropathy in juvenile dogs induced by ofloxacin, a quinlone antimicrobial agent. Vet Pathol. 2004;41:673-681.


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