L16: Muscle Diseases Of Ruminants (Mallicote) Flashcards Preview

Ruminant Medicine Spring 2016 > L16: Muscle Diseases Of Ruminants (Mallicote) > Flashcards

Flashcards in L16: Muscle Diseases Of Ruminants (Mallicote) Deck (34)
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1
Q

Inflammatory muscular diseases

A
Clostridial myositis
Protozoal infection (Sarcocystis)
2
Q

Etiology of clostridial myositis

A
  • anaerobic, spore-forming bacteria
  • requires CREATION OF anaerobic conditions**
  • initial entry routes: inoculation or ingestion of spores
3
Q

Organism that causes blackleg

A

Clostridium chauvoei

4
Q

Organism that causes gas gangrene

A

C. Perfringens

5
Q

Risk factors for clostridial myositis

A
  • may occur repeatedly at same locale
  • C. Chauvoei assoc. with warmer months
  • C. Sordelli assoc. with older feedlot cattle
  • wound infections: C. Perfringens, C. Septicum, C. Novyi
  • sheep/goats: shearing, tail docking, dehorning
  • IM injections
  • parturition
  • fighting rams
  • shearing, docking, castration
  • rapidly growing animals on high nutrition plane
6
Q

Pathogenesis of Clostridium

A

After ingestion/inhalation, spores disseminate to muscle. They can be vegetative until anaerobic conditions created (ie. Via trauma) –> proliferation of bacteria –> exotoxins released –> muscle damage, systemic effects

7
Q

CS of clostridial myositis (peracute)

A
  • sudden death may be only finding

- peracute bacterial proliferation

8
Q

CS of longer (protracted) course of clostridial myositis

A
  • fever
  • tachypnea
  • tachycardia
  • lameness +/- swelling at site of infection
  • swelling is hot, painful, fluctuant, malodorous sanguinous fluid, +/- draining, areas can be cold to touch
  • very high rate of mortality
  • cattle down, sheep reluctant to move
9
Q

Clin path of clostridial myositis

A
  • severe hemoconcentration and dehydration
  • normal to increased WBC with L shift
  • muscle enzymes inconsistent
10
Q

Dx of clostridial myositis**

A

1) Hx, CS
2) Isolation of organism from live animal:
- smear: large G+ rods
- FA
- culture of fluid/muscle (won’t help patient directly)
3) Post-mortem:
- gross pathology: crepitus, bloody fluid, rancid butter odor
- IFA or direct smear

11
Q

Tx of clostridial myositis

A

-prognosis extremely poor
-penicillins** prevent further proliferation
anti-inflammatories
incision/drainage, flush w/ H2O2
-supportive care
-must convert anaerobic env. To aerobic env.!

12
Q

Prevention of clostridial myositis

A
  • investigate potential sources of injury
  • minimize chute trauma
  • counsel clients
  • passive Ab in calves is protective
  • multivalent vaccines starting at 4 mo.: 7 or 8-way for cattle
  • small ruminant vaccine
13
Q

Sarcocystis cruzi

A

-protozoa that encysts in muscle and can cause neuro dz

14
Q

White Muscle Disease etiology

A
  • affects most rapidly growing calves, lambs, kids

- more common in areas with selenium deficient soil, poor quality forage

15
Q

Role of selenium

A
  • protection from oxidation injury

- important for muscle cell membrane integrity

16
Q

Vitamin E role

A

Protects from superoxide damage

17
Q

Pathophys. Of white muscle dz

A

-lipid peroxidation of muscle membrane –> diffuse muscle degeneration

18
Q

2 forms of white muscle disease

A

Skeletal

Cardiac

19
Q

CS of skeletal form of white muscle dz

A

-stiffness, weakness, recumbency
-pain, m. Tremors
+/- resp. Signs (fx of muscles required for respiration affected)

20
Q

CS of cardiac form of white muscle dz

A
  • heart murmurs
  • pulm. Edema
  • sudden depression, death
21
Q

Clin path of White Muscle Disease

A

Myoglobinuria
Increased CK, AST, LDH
Plasma Vitamin E

22
Q

White Muscle Disease on histology

A

-necrotic muscle fibers surrounded by macs

23
Q

Tx of White Muscle Disease

A
  • Selenium preparations
  • Vitamin E
  • Antioxidants (ie. Vit. C, N-acetyl cystein)
  • supportive care (ie. Abx if risk of pneumonia)
  • find root of the problem
24
Q

Toxic myopathies

A

Gossypol (feed additive)
Senna (Cassia)
Tremetol-containing plants (rayless goldenrod, white snakeroot)
Ionophores (monensin, lasalocid)

25
Q

Etiology of gossypol

A
  • comes from cottonseed meal
  • toxic to monogastrics and pre-ruminants
  • causes peritoneal, pericardial, and pleural fluid accumulation; myocardial necrosis, liver damage
26
Q

ionophores

A

Anti-coccidial and growth-promoting feed additives

  • causes cardiac and skeletal m. Necrosis
  • CS relate to cardiac dysfx
27
Q

Predisposing conditions to traumatic myopathy

A
  • metabolic dz
  • neuro dz
  • recumbency
28
Q

Dx of traumatic myopathy (rhabdomyolysis)

A
  • firm musculature in acute period
  • myoglobinuria
  • CK values >5000
  • elevated AST (more useful with chronic recumbency and previous m. Trauma; longer half-life than CK)
29
Q

Tx of traumatic myopathy

A
  • resolve underlying cause**
  • fluids
  • NSAIDs
  • vit. E/Sel (anti-oxidants)
  • nursing care
30
Q

Inherited myopathies

A

Phosphorylase deficiency: Charolais cattle
Myofiber hyperplasia: Belgian blues
Myotonia congenita: fainting goats

31
Q

Etiology of phosphorylase deficiency

A
  • mutation in charolais
  • exercise intolerance/collapse
  • serum CK elevated
  • genetic screening
32
Q

Etiology of myofiber hyperplasia

A
  • inherited mutation of type 2B muscle fibers
  • more likely to have elso heel, dystocia, jaw deformities
  • belgian blues
33
Q

Etiology of myotonia congenita

A
  • tetanic m. Contractions when startled
  • delay in m. Cell relaxation (interruption of Cl channels in muscle cells)
  • autosomal dominant w/ incomplete penetrance
34
Q

Types of muscular diseases

A
Inflammatory
Nutritional
Toxic
Traumatic 
Inherited