JPC SYSTEMIC PATHOLOGY
URINARY SYSTEM
January 2015
U-M20

Signalment (JPC # 2082446):  Quarter horse

HISTORY:  This 3-year-old quarter horse was recumbent on presentation to the veterinary hospital.  The animal's condition continued to deteriorate and was euthanized. 

HISTOPATHOLOGIC DESCRIPTION:  Skeletal muscle:  Diffusely, myocytes are either degenerative characterized by sarcoplasmic swelling, pallor, and vacuolation with loss of cross striations, or necrotic characterized by hypereosinophilic sarcoplasm, fragmentation of myofibrils, and nuclear pyknosis or karyolysis.  Multifocally the perimysium and endomysium are expanded by abundant hemorrhage, fibrin, edema, and moderate numbers of degenerate neutrophils and fewer lymphocytes. Blood vessels are diffusely congested.

Kidney:  Diffusely, renal tubules exhibit one or more of the following changes: ischemic necrosis characterized by hypereosinophilic, shrunken epithelium with pyknotic nuclei and multifocal sloughing of tubular epithelium with disruption of the tubular basement membrane (tubulorrhexis); degeneration characterized by pale, vacuolated, swollen epithelial cells; regeneration characterized by epithelium with abundant basophilic cytoplasm and vesiculate nuclei; and tubular ectasia characterized by luminal distension and attenuation of epithelium.  Ectatic tubule lumina often contain one of the following: orange-red, globular, hyaline material (myoglobin); eosinophilic, finely granular material (proteinaceous fluid); or abundant sloughed epithelial cells (cellular cast) and/or karyhorrectic debris (granular casts).  Multifocally, there are perivascular and peritubular interstitial lymphoplasmacytic aggregates admixed with fewer neutrophils and macrophages. Diffusely, there is mild interstitial edema and congestion.  Multifocally there is hypertrophy of the parietal epithelium of Bowman’s capsule.

MORPHOLOGIC DIAGNOSIS:  1. Skeletal muscle:  Degeneration and necrosis, acute, diffuse, marked, with marked hemorrhage, Quarter horse, equine.

  1. Kidney, tubules: Necrosis, degeneration, and regeneration, diffuse, moderate, with myoglobin casts and granular casts.

ETIOLOGIC DIAGNOSIS:  Myoglobin-associated acute tubular injury 

CONDITION:  Exertional rhabdomyolysis, azoturia, tying-up syndrome, equine paralytic myoglobinuria, and Monday morning disease 

GENERAL DISCUSSION: 

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:             

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

                        

 

Plasma color

Urine clears on centrifugation

Urine clears with saturated ammonium sulfate

RBC’s in urine

Myoglobinuria

Clear

No

No

No

Hemoglobinuria

Pink

No

Yes

No

Hematuria

Clear

Yes

N/A

Yes

 

COMPARATIVE PATHOLOGY: 

Rhabomyolysis:

REFERENCES: 

  1. Bosch X, Poch E, Grau JM. Rhabdomyolysis and acute kidney injury.  New England Jour Med. 2009;361:62-72.
  2. Breshears MA, Confer AW. The urinary system.  In: Zachary JF, ed. Pathological Basis of Veterinary Disease. 6th ed. Philadelphia, PA: Mosby Elsevier Inc.; 2017:654-656.
  3. Buergelt CD, Del Piero F. Color atlas of equine pathology.  1st    Ames, IA: Wiley Blackwell; 2014:293
  4. Cooper BJ, Valentine BA. Muscle and tendon. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:221-224.
  5. Herraez P, Sierra, E, Arbelo M, Espinoa A, Fernandez A. Rhabdomyolysis and myoglobinuric nephrosis (capture myopathy) in a striped dolphin. J Wildl Dis. 2007;43(4):770-4.
  6. Lattimer KS.   Case studies.  In:  Lattimer KS.  Ed.  Duncan & Prasse’s Veterinary Laboratory Medicine: Clinical Pathology. 5th ed. Ames, IA: Wiley-Blackwell; 2011:427-429.
  7. Quist EM, Dougherty JJ, Chaffin MK, Porter BF. Diagnostic Exercise: Equine Rhabdomyolysis. Vet Pathol. 2011;48(6):E52-58.
  8. Sierra E, Espinosa de los Monteros A, et. al. Muscle pathology in free-ranging stranded cetaceans.  Pathol. 2017;54(2):298-311.
  9. Tripathi NK, Gregory CR, Latimer KS. Urinary system. In: Latimer KS, ed. Duncan & Prasse’s Veterinary Laboratory Medicine: Clinical Pathology. 5th ed. Ames, IA: Wiley-Blackwell; 2011:261-262.
  10. Valentine, BA. Skeletal muscle.  In: Zachary JF, ed. Pathological Basis of Veterinary Disease. 6th ed. Philadelphia, PA: Mosby Elsevier Inc.; 2017:917, 925, 938-939, 951.

 


Click the slide to view.



Click on image for diagnostic series.



Back | Home | Contact Us | Links | Help |