JPC SYSTEMIC PATHOLOGY

DIGESTIVE SYSTEM

September 2024

D-B17

 

Signalment (JPC #2370239): Holstein cow

 

HISTORY: This cow presented with acute icterus, tachycardia, hemoglobinuria, and fever.

 

HISTOPATHOLOGIC DESCRIPTION: Liver: Approximately 5% of the hepatic parenchyma contains multifocal random areas of necrosis characterized either by hepatocytes with retained architecture and loss of differential staining (coagulative necrosis) or loss of architecture and replacement with eosinophilic and karyorrhectic debris (lytic necrosis) admixed with viable and necrotic neutrophils, fewer eosinophils, macrophages, lymphocytes, plasma cells, hemorrhage, fibrin, and edema, as well as several distinct, round to oval, clear foci up to 2mm in diameter that contain flocculent, eosinophilic material (emphysema). Blood vessels in the areas of necrosis have neutrophils transmigrating the vessel walls which disrupt and obscure the vessel wall (vascular necrosis). Along the periphery of the necrotic foci are multifocal colonies of 1x7µm bacilli. The hepatic cords adjacent to the areas of necrosis are disorganized and contain several individualized hepatocytes that are shrunken with hypereosinophilic cytoplasm and pyknotic nuclei (single cell death), remaining viable hepatocytes are swollen with vacuolated cytoplasm (degeneration) and the neighboring sinusoids are moderately expanded by fibrin and cellular debris. Portal areas contain aggregates of neutrophils with fewer eosinophils, macrophages, and lymphocytes. One (two) section(s) of liver are diffusely autolytic and contains multifocal to coalescing foci of emphysema.  

 

MORPHOLOGIC DIAGNOSIS: Liver: Hepatitis, necrosuppurative, random and multifocal, acute, severe, with colonies of bacilli, Holstein, bovine. 

 

ETIOLOGIC DIAGNOSIS: Clostridial hepatitis

 

CAUSE: Clostridium haemolyticum (formerly C. novyi type D)

 

CONDITION: Bacillary hemoglobinuria (BH)

 

SYNONYMS: Red water disease, Infectious icterohemoglobinuria 

 

GENERAL DISCUSSION: 

• C. hemolyticum is a gram-positive, spore forming, anaerobic bacillus measuring 1 x 7 um and is commonly found in soil of areas with poorly drained pastures and alkaline pH (most often in Gulf Coast and Western states in the US)
• BH is an acute, often fatal, endemic disease of cattle and sheep most often tied to liver fluke migration (Fasciola hepatica); often seasonal (Summer, early Autumn)
  • Occurs primarily where Fasciola hepatica is abundant
• Other causes of hepatic ischemia allowing sporulation of C. haemolyticum (and therefore BH) include: hepatic necrosis due to Fusobacterium necrophrum secondary to rumenitis, liver damage secondary to Cysticercus tenuicollis, incidental vascular disorders such as telangectasia, and other causes of reduced liver perfusion
• C. haemolyticum produces a single major toxin, hemolytic beta toxin (phospholipase C), that causes massive intravascular hemolysis and cellular necrosis through destruction of hepatocyte and erythrocyte cell membranes
• High mortality; death results from severe toxemia and hypoxia
• Typically affects animals in good nutritional condition, over one year of age

 

PATHOGENESIS:

• Route of spread from ingestion to liver hypothesized: spores ingested with contaminated feed/soil > may enter small intestine through enterocytes, M cells or macrophages > spread to liver via portal vein 
• Once in liver: spores phagocytized by Kupffer cells and remain latent > liver damage (e.g. fluke migration through liver and in intrahepatic veins) >thrombosis, ischemia, infarction within hepatic parenchyma > decreased oxygen tension > germination of spores > production of exotoxin - hemolytic beta toxin (phospholipase C) by vegetative bacteria > hepatocellular necrosis and thrombosis> vascular damage > toxemia > intravascular hemolysis

 

TYPICAL CLINICAL FINDINGS:

• Most commonly, cattle found dead without clinical signs
• Acute, severe anemia, hemoglobinemia, and hemoglobinuria (from intravascular hemolysis)
• In peracute disease: loss of appetite, cessation of rumination, defecation, and lactation, fever, lethargy, anorexia, decreased production, hematochezia, tachycardia, tachypnea, abdominal pain, brisket edema

 

TYPICAL GROSS FINDINGS:

• Large (often single) distinct, well demarcated foci of hepatic necrosis surrounded by an intensely hyperemic zone

• Lesions are larger than those of black disease and usually single

• “Port wine” urine in bladder
• Kidneys: Petechiae and hemoglobin-stained kidneys, speckled red/brown by hemoglobin
• Fibrin may be observed on surface of pleura, peritoneum, pericardium; dry, fibrinohemorrhagic peritonitis in some cases

 

TYPICAL LIGHT MICROSCOPIC FINDINGS:

• Hepatic necrosis, often focally extensive and in a single location (less commonly multifocal)
  • Thrombosis of hepatic venules (more common) and portal vein branches with infarction – secondary to necrosis 
• Thrombi in hepatic venules, intestines, and other abdominal organs (secondary to exotoxin induced necrosis)
• Bacilli present singly or in short chains and have distinctive bulging subterminal spores; most often seen at margin of lesion
• +/- evidence of trematode migration (fluke pigment)

 

ADDITIONAL DIAGNOSTIC TESTS:

• PCR on frozen liver is preferred method
• PCR on FFPE can be attempted (target short fragments of beta toxin gene)
• IHC does not discriminate between C. novyi type B and C. haemolyticum
• Can be difficult to differentiate from postmortem growth on H&E / impression smears since these organisms are part of normal flora

 

	Hct	Plasma color	Urine Color	RBC’s in urine sediment
Myoglobinuria	WRI	Clear	Pink	No
Hemoglobinuria	Decreased	Pink	Pink	No
Hematuria	WRI	Clear	Pink	Yes

 

 

DIFFERENTIAL DIAGNOSIS: 

• Black disease (Clostridium novyi, usually type B), also known as infectious necrotic hepatitis, occurs mostly in sheep and cattle, occasionally in horses and pigs; however, pathogenesis very similar to bacillary hemoglobinuria

• Hepatic necrosis (immature fluke migration) > decreased oxygen tension > germination of dormant spores > toxin production
• Produces alpha toxin (related to toxins produced by C. difficile and C. sordelli) and beta toxin (phospholipase C, a lecithinase, the necrotizing and hemolytic toxin)
• The subcutis of dead animals is dark colored / black secondary to venous congestion (hence the name)
• The liver may show both the hemorrhagic lesions of acute fascioliasis as well as circular yellow-white areas of necrosis surrounded by hyperemia
• Bacteria often at leading margin of lesion admixed with infiltrating neutrophils
• Hepatic lesions are smaller than those of bacillary hemoglobinuria and usually multiple

• Acute leptospirosis causes intravascular hemolytic anemia and hemoglobinuria
• Hypophosphatemic hemolytic anemia (postparturient hemoglobinuria): This is common in dairy cows 3 to 8 weeks following parturition; erythrocytes require phosphorus for the synthesis of ATP (Embden-Meyerhof pathway), which is essential for membrane function and integrity
• Babesia bovis (Texas or red water fever): Fever, intravascular hemolysis, hemoglobinuria; intracytoplasmic paired pyriform protozoa 
• Hemolytic anemia associated with Brassica sp. (rape or kale): Anemia results from dimethyl disulfide produced by ruminal bacteria from plant breakdown.
• Bracken fern (enzootic hematuria): Hemorrhagic cystitis; neoplasia in chronic cases
• Other bacteria: C. perfringens, E. coli
• Oxidants: Acetaminophen, copper, onions, propylene glycol, red maple, phenothiazine
• Immune mediated: Autoimmune hemolytic anemia (horses, cattle) 

 

COMPARATIVE PATHOLOGY:

• Primarily a disease of cattle; also reported in sheep, pigs, horses, and elk
• Wapiti: Infection associated with giant liver fluke infection

 

References: 

1. Cullen JM, Stalker MJ. Liver and Biliary System. In: Maxie MG, ed. Jubb, Kennedy & Palmer's Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier; 2016:316317. 
2. Howerth EW, Nemeth NM, Ryser-Degiorgis MP. Cervidae. In: Terio KA, McAloose D, St. Leger J, eds. Pathology of Wildlife and Zoo Animals. London, UK: Academic Press; 2018:164-165. 
3. Navarro MA, Uzal FA. Pathobiology and diagnosis of clostridial hepatitis in animals. J Vet Diagn Invest. 2020; 32(2): 192-202.
4. Stanton JB, Zachary JF. Mechanisms of Microbial Infections. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 7th ed. St. Louis, MO: Elsevier; 2022:210. 
5. Stockham SL, Scott MA. Fundamentals of Veterinary Clinical Pathology. 2nd ed. Hoboken, NJ: Wiley; 2013:176, 182-183.
6. Valli VEOT, Kiupel M, Bienzle D, Wood RD. Hematopoietic System. In: Maxie MG, ed. Jubb, Kennedy & Palmer's Pathology of Domestic Animals. Vol 3. 6th ed. St. Louis, MO: Elsevier; 2016:126. 
7. Van Wettere AJ, Brown DL. Hepatobiliary System and Exocrine. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 7th ed. St. Louis, MO: Elsevier; 2022:519,530. 

 

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