JPC SYSTEMIC PATHOLOGY
URINARY SYSTEM
January 2018
U-T08 (NP)

Signalment (JPC Accession #1949349):  A 10-month-old, feedlot calf

HISTORY:  This calf was one of 25 calves treated for signs of anorexia and respiratory disease with oxytetracycline (OTC).  This calf did not respond to treatment and died four days after the initiation of therapy.  A total of 12 of the 25 calves died and were presented for necropsy with similar lesions.

HISTOPATHOLOGIC DESCRIPTION:  Kidney:  Diffusely, tubular epithelium shows one or more of the the following changes:  necrosis characterized by loss of  cellular detail, indistinct cell borders, hypereosinophilic cytoplasm, karyolysis, pyknosis or karyorrhexis, and epithelial detachment from intact basement membranes;  degeneration characterized by swollen, pale, vacuolated cytoplasm; or regeneration characterized by basophilic cytoplasm, large vesiculate nuclei with a prominent nucleolus, and rare mitotic figures.  Lesser affected tubules are often ectatic, lined by attenuated epithelium and  contain either an eosinophilic homogeneous material (proteinaceous fluid), or amorphous granular eosinophilic material that is occasionally admixed with sloughed epithelial cells and cellular debris (hyaline and cellular casts).   Rarely, medullary tubule lumina contain granular basophilic material (mineral).  The interstitium is multifocally expanded by low numbers of lymphocytes, plasma cells, and occasional neutrophils with mild edema, congestion and hemorrhage.                     

MORPHOLOGIC DIAGNOSIS:  Kidney: Tubular degeneration and necrosis, multifocal, marked, with intratubular protein, hyaline and cellular casts, and mild lymphoplasmacytic interstitial nephritis, breed unspecified, bovine.

ETIOLOGIC DIAGNOSIS:  Antibiotic-induced nephrosis

CAUSE:  Oxytetracycline toxicosis

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:  Swelling of mitochondria, hydropic degeneration of tubule cells

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

Acute tubular necrosis in cattle due to nephrotoxins with similar histologic and gross findings:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Breshears MA, Confer AW. The urinary system. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Mosby/Elsevier; 2017:654-655.
  2. Cianciolo RE, Mohr FC. Urinary system. In: Maxie MG,ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. 6th ed. Vol. 2. Philadelphia, PA:Elsevier; 2016: 424.
  3. Lairmore M.D, Alexander A.F, Powers B.E., et al. Oxytetracycline-associated nephrotoxicosis in feedlot calves. J Am Vet Med Assoc. 1984;185:793-795.
  4. Moalli M.R, Dysko R.C, Rush H.G., et al,. Oxytetracycline-induced nephrotoxicosis in dogs after intravenous administration for experimental bone labeling. Lab An Sci. 1996;46:497-502.
  5. TerHune NT, Upson WD. Oxytetracycline pharmacokinetics, tissue depletion, and toxicity after administration of a long-acting preparation at double the label dosage. J Am Vet Med Assoc. 1989;194:911-917.

 


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