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Read-Only Case Details Reviewed: Feb 2009

January 2018 U-T05

Signalment (JPC #1896466):  York/Landrace pig

HISTORY:  Tissue from a 9-month-old York/Landrace female pig from a confinement operation in Illinois.  Several other sows had died following a 2-5 day illness.  This animal was presented alive and alert but with posterior paresis and rectal prolapse.  At necropsy the kidneys were pale, yellow to tan, with scattered petechiae.  The animal appeared dehydrated.  Urinalysis revealed the following:

1. Color ‑ yellow 5. Ketones ‑ negative
2. Character – clear 6. Glucose ‑ trace
3. Specific gravity ‑ 1.011/td> 7. Blood ‑ moderate
4. Protein ‑ 30.0 mg/dl 8. pH ‑ 5.0

Urine sediment:  2-3 RBC’s/hpf with rare WBC’s.  Crystals:  None observed

HISTOPATHOLOGIC DESCRIPTION:  Kidney:  Diffusely, there is complete disruption of cortical tubule architecture.  Cortical tubules are surrounded by increased clear space (edema), and cortical tubular epithelium is often completely lost.  Remaining cortical tubular epithelium is either markedly swollen with abundant clear to vacuolated cytoplasm (degeneration) or hypereosinophilic, angular and shrunken with pyknotic nuclei (necrosis).  Cortical and occasionally medullary tubules are ectatic, dilated up to 4 times normal, and occasionally contain sloughed cellular and nuclear debris (granular casts).  Multifocally, tubules contain abundant translucent, pale yellowish, anisotropic crystals arranged in sheaves, prisms, and rosettes (calcium oxalate) which are often in contact with the tubule basement membrane.  Multifocally, medullary tubules contain eosinophilic proteinaceous fluid. Diffusely, the medullary tubules are separated by an increased amount of loosely arranged, fibrillar eosinophilic and finely beaded material (fibrin), reactive fibroblasts in a loose matrix (fibroplasia), and edema.  Multifocally, there are mild interstitial lymphoplasmacytic infiltrates.  Multifocally within glomeruli, Bowman’s space is dilated, occasionally contains small amounts of fibrin and/or proteinaceous fluid, and there is hypertrophy of the parietal epithelium.

MORPHOLOGIC DIAGNOSIS:  Kidney, cortical and medullary tubules:  Degeneration,necrosis, and loss diffuse, severe, with calcium oxalate crystals, tubular proteinosis, and lymphoplasmacytic interstitial nephritis, York/Landrace, porcine.

ETIOLOGIC DIAGNOSIS:  Oxalate nephrosis

CAUSE:  Ethylene Glycol (EG)








  Oxalate nephrosis Melamine-cyanuric acid

H&E appearance

Pale yellow; arranged in sheaves, rosettes or prisms; may be difficult to see

Gold to brown; large round crystals with radiating striations; easily seen

Location in nephron

Proximal tubules

Distal nephron




Stains with

Von Kossa

Oil Red O

Clinical Path difference

Usually prominent hypocalcemia

Usually normal serum calcium



  1. Breshears MA, Confer AW. The urinary system.  In: Zachary JF, ed. Pathological Basis of Veterinary Disease. 6th ed. Philadelphia, PA: Mosby Elsevier Inc.; 2017:675-676, 679.
  2. Ciancolo RE, Mohr FC. Urinary system. In: Maxie MG, ed.  Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 2. 6th St. Louis, MO: Elsevier; 2016:425.
  3. Haschek WM, Rousseaux CG, Wallig MA. Fundamentals of Toxicologic Pathology. 2nd ed. London, UK: Academic Press-Elsevier. 2010;276-279,290,295.
  4. Latimer, KS. Duncan and Prasse’s Veterinary Laboratory Medicine Clinical Pathology.  5th Ames, IA: Wiley-Blackwell; 2011:430-432.
  5. Mitchell EP, Church ME, Nemser SM, et. al. Pathology and epidemiology of oxalate nephrosis in cheetahs.  Vet Pathol. 2017;54(6):977-985.
  6. Speight KN, Boardman W, Breed WG, et al. Pathological features of oxalate nephrosis in a population of koalas (Phascolarctos cinereus) in South Australia. Vet Pathol. 2013;50(2):299-307.
  7. Tripathi NK, Gregory CR, Latimer KS. Urinary system.  In:  Latimer, KS.  Duncan and Prasse’s Veterinary Laboratory Medicine Clinical Pathology.  5th Ames, IA: Wiley-Blackwell; 2011:271-272.

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