6-year-old female polled Hereford cow (Bos taurus).Cow is in good body condition on native pasture. She was seen to have an elevated respiratory rate and standing in water. After walking, she had muscle fasciculations in her left hind leg. She then died.

Gross Description:  

Both kidneys exhibit multiple abscesses ranging from 2-10 mm diameter containing greenish caseous material. The right kidney is small and fibrotic. The liver is mildly swollen with a pale khaki coloration on cut surface and is friable. There is ulceration in the distal esophagus. The pericardial surface of the right ventricle contains mild petechiation.

Histopathologic Description:

Extending from the renal papilla into the medulla and effacing the normal architecture is irregular, focally extensive necrosis characterized by cellular and nuclear debris. The tubules are ectatic, serpentine and variably lined by vacuolated, attenuated to swollen epithelial cells (degeneration), hypereosinophilic epithelial cells with pyknotic nuclei (necrosis) or hypertrophic crowded epithelial cells with plump vesicular nuclei (regeneration). Tubule lumina often contain deeply eosinophilic proteinaceous material, moderate numbers of degenerate neutrophils and cellular debris. Large numbers of tubules are expanded by anisotropic, refractile, birefringent, pale yellow crystals containing radiating spokes (oxalate crystals) and occasional clusters of coccobacilli. There is moderate expansion of the interstitium with multifocal infiltrates of lymphocytes and plasma cells, mature fibrosis and multifocal loss of tubules and glomeruli. Within necrotic foci are discrete colonies of coccobacili. 

Special Stain: Gram-positive coccobacilli noted within necrotic foci. 

Morphologic Diagnosis:  

Kidney: Pyelonephritis, suppurative, diffuse, severe with tubular ectasia, proteinosis and scant coccobacilli.
Kidney: Nephrosis, multifocal, moderate with tubular necrosis, degeneration and regeneration, interstitial fibrosis, and numerous intratubular oxalate crystals.

Lab Results:  

Culture (routine): Kidney- moderate pure growth of Corynebacterium renale.

Penicillin Resistant

ParameterValueReference Range/ Units
RBC7.065.00-8.00 x 1012/L
PCV3823-44 %
HGB14.68.0-15.0 g/dL
MCV5444-62 fL
MCH21 H14-20 pg
MCHC38 H30-35 g/dL
WBC3.8 L4.0-12.0 x 109 /L
BANDS0.000.00-0.12 x 109 /L
NEUT0.950.60-4.00 x 109 /L
LYMPH2.582.50-7.50 x 109 /L
MONO0.270.03-0.84 x 109 /L
EOS0.000.00-2.40 x 109 /L
BASO0.000.00-0.20 x 109/L
Platelet clumping observed; platelets appear adequate on blood film; Anisocytosis (+); Rouleaux

BUN98.9 H2.1-10.7 mmol/L
CREA2550 H0-186 umol/L
PHOS3.45 H0.80-2.80 mmol/L
Ca2.602.00-2.75 mmol/L
TP105.9 H60.0-85.0 g/L
ALB36.025.0-38.0 g/L
Glob 9.9 H30.0-45.0 g/L
Alb/Glob0.5 L 0.7-1.1
AST998 H0-120 U/L
GLDH190-30 U/L
GGT140-35 U/L
TBIL4.00.0-24.0 umol/L
CK3215 H0-300 U/L
MG1.050.74-1.44 mmol/L
BHB0.100.00-0.80 mmol/L
PROT-RTS130 H65-85 g/L
FIBRIN19 H3-7 g/L
PR/FI6 L 15-100


Corynebacterium renale; oxalate nephrosis

Contributor Comment:  

This case is a classic example of two diseases that occur commonly in cattle; however, what makes this case interesting is that they are occurring concurrently.

The clinical pathology results support the gross and histological findings of severe renal disease, hepatic necrosis (histopathological finding, slide not included), and a significant inflammatory process (elevated immunoglobulins and fibrinogen). The leukogram shows a mild leukopenia, which in this case is likely to be due consumption of leukocytes as part of the inflammatory response. Rouleaux formation is a common finding in hyperglobulinemic or hyperfibrinogenemic states.(7)

Pyelonephritis is an inflammation of the renal pelvis and renal parenchyma, usually resulting from an ascending infection from the lower urinary tract.(3)

In cattle, Corynebacterium renal is a common cause of pyelonephritis.(2) In a survey of clinically affected animals, C. renale was the most common bacteria isolated(1) and in a slaughterhouse survey of cattle with gross kidney lesions, it was the third most predominant organism isolated.(6) It is a facultative commensal organism that is commonly isolated from the urinary tracts of healthy cattle.(1)

Other common causes of pyelonephritis in cattle include:(6,1)
Acute pyelonephritis characteristically begins with necrosis and inflammation of the renal crest in an irregular pattern that, as the disease progresses, results in chronic changes where mononuclear cells replace neutrophils and fibrosis eventually predominates. Chronic pyelonephritis occurs more commonly in cattle than acute disease, with acute pyelonephritis often an incidental finding at post mortem.(3)

Vesicoureteral reflux is the most significant mechanism for transporting bacteria from the bladder to the kidney with refluxed urine occasionally being transported to the urinary space of the glomeruli.(3) Bacteria can spread hematogenously to the kidney, but this is a less common mode. 

Within the kidney, the medullary region is the most susceptible to infection. This is due to its:

Click the slide to view.

3-1. Kidney

3-2. Kidney

3-3. Kidney

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