Food Animal Thrombocytopenia and Vascular Disease

Hemostasis is composed of what TWO interrelated components?

Coagulation and fibrosis

Hemarthrosis, suffusive hemorrhage, hematomas, body cavity hemorrhage, epistaxis, melena, and hematuria are all generalities of —-.

Coagulopathy

Petechia, hyphema, melena, hematuria, prolonged bleeding, ecchymoses, and epistaxis are all generalities of —-.

Thrombopathy

Name at least FIVE of the seven common causes of thrombocytopenia in food animals and indicate which two are most common.

1. BVDV

2. Bracken fern

3. DIC (most common)

4. Septic mastitis/metritis/endotoxemia (most common)

5. Salmonellosis

6. Lymphosarcoma

7. ITP

Irrespective of etiology, thrombocytopenia has what THREE causes?

1. Shortened platelet lifespan (increase platelet destruction)

2. Ineffective platelet production

3. Platelet sequestration

What is the normal range of platelets?

192,000-892,000

Thrombocytopenia typically has ——- platelets, but clinical signs of hemorrhage are more likely at —— platelets.

<100,000

<10,000

What isolates of BVDV are associated with induced thrombocytopenia?

Type 2

What are the THREE major clinical signs of BVDV-induced thrombocytopenia?

1. Bloody diarrhea

2. Epistaxis

3. Severe leukopenia/neutropenia

What cell are platelets from?

Where do these cells reside?

Megakaryocytes

Bone marrow

What organism is associated with bracken fern toxicosis?

Pteridium aquilinium

What is the toxic principle of bracken fern toxicosis?

Ptaquiloside

Name FOUR major clinical signs of bracken fern toxicosis.

1. Enzootic hematuria

2. Bladder cancer

3. Bone marrow suppression (thrombocytopenia)

4. Widespread hemorrhage

What is the most common form of hemostatic dysfunction in large animals?

DIC

True or False: DIC has many different causes and can be localized or systemic. It often presents as metritis, mastitis, and salmonellosis.

True!

DIC involves widespread —- deposition in the microcirculation.

Fibrin

Why is DIC considered a dynamic disease? (2)

1. Ischemic damage to tissue/organs

2. Hemorrhagic diathesis (consume coags; hyperactive fibrinolysis)

DIC is dependent upon rate of —- generation, the adequacy of —-, and the function of the ————- system.

Thrombin

Fibrinolysis

Mononuclear-phagocyte system

What are the FOUR areas likely to become ischemic with DIC?

1. Renal (oliguria/azotemia/ileus)

2. Pulmonary (tachypnea/hypoxemia)

3. Digital (laminitis)

4. Cerebral

What is the major area likely to become hemorrhagic with DIC?

GI (melena)

True or False: Petechia and ecchymoses is characteristic of DIC and life-threatening hemorrhage is rare in ruminants with DIC.

True!

What are FOUR major lab findings consistent with DIC?

1. Decreased platelets

2. Increased PT

3. Increased APTT

4. Decreased antithrombin

What lab value in the coag cascade is not reliable in food animals?

FDPs

What are FOUR treatments for DIC?

1. ID/treat primary disorder

2. IV fluids (help with ischemia)

3. NSAIDs (Banamine)

4. Plasma

What drug class is contraindicated in DIC?

Steroids

What causes moldy sweet clover toxicosis?

Ingestion of moldy sweet clover hay/silage (no shit)

What is the active toxin in moldy sweet clover toxicosis?

Dicoumarol

True or False: Natural coumarins are present in sweet clover and converted to dicoumarol, leading to improper curing and mold formation.

True!

What are the THREE main clinical signs of moldy sweet clover toxicosis?

1. Epistaxis

2. Melena

3. SQ hematomas

What are the THREE most likely regions to develop a SQ hematoma with sweet clover toxicosis?

Brisket, tuber coxae, carpi (points of trauma)

True or False: SQ hematomas in moldy sweet clover toxicosis is not hot or painful.

True!

What toxicosis is moldy sweet clover identical to in dogs?

What factors, then, are involved?

Warfarin

2, 7, 9, and 10 babyyyyyyy

Moldy sweet clover toxicosis causes disease in cattle —— days after ingestion.

2-7 days

What THREE ways is moldy sweet clover toxicosis diagnosed?

1. Bloodwork (prolonged PT and normal platelets)

2. Absence of fever/anorexia

3. History of ingestion

What are the THREE major treatments for moldy sweet clover toxicosis?

1. Discontinued use of contaminated feed

2. Vitamin K1 (1.1-3.3 mg/kg IM: rapid)

3. Plasma/blood transfusion

___: inflammation and necrosis of blood vessel walls

Vasculitis

True or False: Vasculitis is typically a secondary manifestation of a primary infectious, toxic, or neoplastic disorder.

True!

What are the THREE major causes of vasculitis in cattle?

1. Histophilus somni (TEME)

2. Bluetongue

3. Malignant catarrhal fever

What is the major cause of vasculitis in small ruminants?

Bluetongue

What are the TWO major causes of vasculitis in swine?

1. Greasy pig disease

2. Erysipelas

What are the FOUR general signs of vasculitis?

1. Demarcated areas of dermal/SQ edema

2. Hyperemia

3. Petechiae/ecchymoses

4. Ulceration of mucus membranes

What is an Orbivirus from Reoviridae that is related to Epizootic Hemorrhagic Disease of Deer?

Bluetongue Virus

Bluetongue virus is born from an —— vector, namely —————-.

Arthropod

Culicoides variipennis (midge)

The overall seroprevalence of Bluetongue in the US is —-%.

18%

What are the TWO types of clinical disease associated with Bluetongue?

1. Vasculitic (cyanosis of tongue)

2. Reproductive form

True or False: Clinical disease of Bluetongue is rare in cattle and 2-10% of cattle infected with BTV will develop clinical disease.

True!

True or False: Bluetongue is abortogenic/teratogenic.

True!

What are the THREE major clinical signs of Bluetongue?

1. Fever

2. Edema

3. Cyanotic tongue

What is the pathophysiology of Bluetongue?

Virus infects vascular endothelium -> vasculitis/edema and necrosis of epithelial and mucosal surface

When is Culicoides variipennis most prevalent?

Midsummer to early fall

True or False: Bluetongue virus in US closely mirrors the prevalence of the vector, Culicoides variipennis, and is the most important mode of transmission.

True!

True or False: Animal-animal transmission maintains the endemic state of Bluetongue.

False! Animal-animal transmission is INCAPABLE of maintaining the endemic state of Bluetongue.

What is one major contributing factor involving cattle with Bluetongue prevalence?

Overwintering

What are the FIVE major diagnostics used for Bluetongue?

1. Gross pathology

2. Histo

3. Serology

4. Virus isolation

5. PCR

What is conisdered the best serologic test for Bluetongue and is the official test for import to Canada?

Competitive ELISA