path Flashcards
name the dz and its lesions
horse mm. azoturia, rhybdomylysis
- moist, swollen, dark red, hamorrhages
- hyaline degeneration and necrosis of skeletal mm.
- later fibrosis,atrophy, muscle pallor
- myoglobinuric nephrosis >> kidneys: dark-black
expalin the lesion and for what dz it is for
myoglobinuric nephrosis in azoturia
Azoturia (equine paralytic myoglobinuria; Monday
morning disease)
– sequelae
- death from cardiac and renal injury
- recovery and repeated episodes —> muscularatrophy
- recovery with muscular regeneration
Tying-up (setfast, acute rhabdomyolysis)
transient
– less severe form of azoturia
– mild rhabdomyolysis
examples of azoturia in cattle n dogs
Zebu type or “wild” cattle more prone
– associated with handling and transportation over long
distances in crowded railway trucks
in dogs (racing greyhounds)
– occurs rarely
– following intense muscular exertion
Capture myopathy
wild animals and birds
following capture and/or translocation over long
distances, chase, struggle*
Capture myopathy etiopathogenesis
pronounced acidosis
Capture myopathy lesions
*bilaterally symmetrical
*pale, edematous muscles
*muscle degeneration, hemorrhage, ruptured tendons
*myocardial injury –> death from congestive heart failure
Toxic Ionophores (monensin, salinomycin, narasin)
added to feeds for poultry and ruminants for
antibiotic and growth-enhancing effects
- equidae, ruminants, dogs, birds
-
susceptibility highest in horses
– coaccidental feeding within horse feed – accidental feeding
Ionophores (monensin, salinomycin, narasin) pathogenesis
ionophores facilitate movement of cations (Na+, Ca2+) across CMs leading to disruption of normal ionic
equilibrium
Ca2+ overload causes necrosis of skeletal and cardiac muscle
death from cardiovascular collapse/shock
Toxic Ionophores (monensin, salinomycin, narasin) lesions
-monophasic multifocal segmental necrosis
– pallor
– regeneration
– myocardial fibrosis
Toxic Lesions:
• segmental necrosis in skeletal and cardiac muscle
± calcification, regeneration, fibrosis
• hemorrhage and myonecrosis
• necrosis restricted to skeletal muscle in
mycotoxicosis
Electrolyte-related myopathies
– quarter horses and related breeds
– inherited: autosomal dominant
genetic mutation in sodium channel gene
Hyperkalemic periodic paralysis (HYPP) cs
laryngeal muscle dysfunction
• laryngospasms
trembling, weakness, collapse
metabolic acidosis
cardiotoxicity, pulmonary edema
HYPP pathogenesis
-delayed inactivaton of sodium channel activity
– uncontrolled sodium influxes into the cell
– altered voltage
– continuous myofiber electrical activity
– uncontrolled twitching
• muscle trembling, weakness and collapse
HYPP gross lesions
limited to prominent muscling
HYPP treatment
low-potassium diet;
diuresis
cs of Hypokalemia in cattle
profound weakness and recumbency
Hypokalemia in cattle etiology
- hypokalemia due to anorexia and ketosis
- glucocorticoids with high mineralocorticoid activities
• I/V administration of glucose or insulin
– insulin increases the flow of K+into cells
decreased muscle K+
• altered mitochondrial function andvasoconstriction (ischemia) → myofiber necrosis – hypokalemia →abnormal cardiac conduction
cs of Hypokalemia in cats
generalized weakness with ventriflexion of the neck
hypokalemia mechanism/pathogenesis
hyperpolarization of the cell membrane
2° excessive permeability to Na
decrease muscle K+–> interference with muscle cell function –> myofiber necrosis
• abnormal cardiac conduction
Hypokalemia in cats etiology
*abnormal skeletal muscle energy metabolism
- ischemia due to vasoconstriction
- decreased dietary intake of K+
• increased urinary excretion of K+
following chronic renal disease
- 2º to GIT disease or inappropriate fluid therapy
- hyperthyroidism: increases activity of Na-K-ATPase
Hypokalemia lesions in cats
myofiber necrosis
• ± chronic interstitial nephritis
myofiber necrosis
• ± chronic interstitial nephritis
lesions of hypokalemia in cats
Hypernatremia in cats mechanism
- pathogenesis
- lesions
increased muscle Na+ →abnormal energy metabolism
increased Na+ in blood → vasoconstriction →ischemia
lesions: myofiber necrosis and regeneration
profound muscle weakness, neurologic signs,
hemolytic anemia
Hypophosphatemia in cattle
etiology of hypophosphotemia
dietary, vomiting, diarrhea
electrolyte imbalance: hypercortisolism,
renal disease, diuretics
lesions of Hypophosphatemia in cattle
myocardial and skeletal muscle necrosis
• ischemic necrosis secondary to recumbency
malignant hyperthermia, PSE pork, “herztod”, back
muscle necrosis
Porcine stress syndrome (PSS)
inherited
• Landrace, Pietran, Hampshire, Yorkshire, Poland
China
– life-threatening, hypermetabolic syndrome
– also seen in dog, horse
Porcine stress syndrome (PSS) pathoetiology
– respiratory and metabolic acidosis
– myoglobinemia, hyperkalemia, high blood lactate
– hyperthermia
– cardiovascular collapse >> death
causes of Porcine stress syndrome (PSS)
stresses
fighting
exercise
crowding
transport
handling
overheating
slaughter
halothane anesthesia
Porcine stress syndrome (PSS) pathogenesis
congenital enzyme deficiency.defect in uptake, storage, and release of Ca2.high intracellular Ca.increased glycolysis
build up of lactate
increased body heat
hypercontraction and denaturation →necrosis
movement of intracellular water into interstitium–wet, exudative muscles
Porcine stress syndrome (PSS) lesions
usually type II fibers affected
back muscle necrosis, edema
pale, soft and exudative (PSE)
pulmonary edema, hydrothorax, ascites
pale, soft and exudative (PSE)
PSS LESIONS
pulmonary edema, hydrothorax, ascites
PSS LESIONS
- DZ
- LESIONS
- SPP
- PATHOGENESIS
- PSS
- BACK MUSCLE NECROSIS, EDEMA.
- SOFT PALE N EXUDATIVE
- PULMONARY EDEMA, HYDROTHORAX,ASCITES
* PIGS
* POOR INTRACELLULARCAREGULATION
* INFLUX OF CA INTO THE CELL
* INCREASED GLYCOLYSIS
* HYPERCONTRACTABILITY LEADING TO NECROSIS
* HEAT PRODUCTION
* INFLUX OF INTRACELLULAR WATER
Compartment syndrome PATHOGENESIS
ISCHEMIC MYOPATHY
muscular expansion →vascular compression
ischemia →infarction
Compartment syndrome IN CHICKEN
Deep pectoral myopathy
• turkey, chicken
• exertion
↓
• vigorous flapping of
wings
↓
• necrosis of muscles
(supracoracoid)
ischemic necrosis of ventral and limb muscles following prolonged recumbency
- DZ
- RECUMBENCY
DOWNER’S SYNDROME
Downer syndrome pathogenesis
prostration(exhaustion)
- muscle injury
- edema
- compression → venous occlusion
- ischemia → injury
ischemia/degeneration/fibrosis (pale)
• congestion/hemorrhage /myoglobin (red)
LESIONS OFDowner syndrome
Equine post-anesthetic hypotensive myopathy
- cs
- lesions
- sequela
occurs in 3-6% of anesthetic cases
– muscle swelling with lameness
– paresis with renal failure and shock
– sequelae: permanent loss of muscle function
Equine post-anesthetic hypotensive myopathy sequelae
permanent loss of muscle function
acute degenerative myopathy due to severe trauma to a muscle group
Muscle crush syndrome
Muscle crush syndrome PATHOGENESIS N SYNDROME
similar to Downer syndrome
vascular occlusion
• ischemia →degeneration and necrosis of muscles
Aortic-iliac thromboembolism in cats and horses
CS OF HYPOTHYROIDISM IN MM.
- generalized weakness
- atrophy and
- megaesophagus
PATHOGENESIS OF HYPOTHYROIDISM IN MM.
decreased thyroid hormone →affects muscle
metabolism → myofiber weakness and atrophy
peripheral neuropathy (axonal degeneration) and damage to motor nerves → denervation atrophy
LESIONS OF HYPOTHYROIDISM
selective atrophy of type II fibers
Hypercortisolism
- sc
- lesions
- pathogenesis
– Cushingoid pseudomyotonia
– weakness followed by muscle atrophy (type II fibers)
– increased cortisol production or iatrogenic XS
• peripheral neuropathy →denervation atrophy with
regeneration
LESIONS OF HYPERCORTICOTISM
- muscle atrophy, degeneration and necrosis
- bilateral adrenocortical hyperplasia
- +/- tumor (in the pituitary gland or adrenal gland)
myofiber necrosis and regeneration in cats
hypernatremia
the type of inflamation caused by bacteria on mm.
hemorrhagic
necrotizing
granulomatous
the type of inflammation caused by protozoa on mm.
gangrenous
type of inflammation caused by viruses on mm.
necrotic
type of inflammation caused by helminths
on mm
suppurative
the type of inflammation which is immune mediated
granulomatous
type of mm. inflammation which is idipathic
eosinophilic
most serious systemic viral infections are capable of
producing
what type of necrosis lesion
scattered foci of muscle necrosis
viruses that causes mm. inflamation( necrosis)
canine distemper
feline panleukemia
porcine encephal;opathy
hog cholera
FMV
bluetongue
newcastle
inflammatory dz which are immune mediated
- dog
- horse
dog: masticatory myositis and polymyositis
horse: purpura hemorrhagic
inflammatory dz which is immune mediated
iosinophilic myositis in rumminants
Bacterial myositis lesions
- hemorrhage
- supperative
Clostridium sp in ruminants
haemorrhagic myositis
blackleg
dz caused by clostridium sp. in horses,ruminants and pigs
malignant edema
pathogenesis of clostriium
– activation of spores → proliferation of bacilli →toxin
production →vascular damage →edema, hemorrhage,
necrosis, myositis, emphysema
Hemorrhagic myositis
blackleg (ruminants); Clostridium chauvoei
lesions of Hemorrhagic myositis
usually in the large muscles of pectoral and pelvic
girdles
• heart, tongue, diaphragm masticatory muscles may
also be involved
- dark red and wet (“wet stage”)
- black, dry, spongy (“dry stage”)
- crepitant
- sweetish to rancid odor
which dz causes this lesions
• dark red and wet (“wet stage”)
– blackleg (ruminants); Clostridium chauvoei
Hemorrhagic myositis
which dz causes this lesions
black, dry, spongy (“dry stage”)
– blackleg (ruminants); Clostridium chauvoei
Hemorrhagic myositis
- dz
- lesions
- type of microb
- Hemorrhagic myositis
- – blackleg (ruminants)
- wet stage–>dark red n wet
- dry stage–>black,dry spogy
clostridium chauvoei
other lesions of black leg
- endocarditis
- fibrinohemorrhagic pleuritis
malignant edema causes
– Clostridium septicum,
Clostridium perfringens
malignant edema (horses, ruminants, swine) lesions
severe edema
- formation of bubbles of gas
- hemorrhage → dark brown to black muscles
- discoloration of the overlying skin
- coldness of the affected part
- dz
- etiology
- cs
malignant edema
clostridium
- gas gangrene
- severe edema
- hemorrhage
- discoloration of the overlying skin
- coldness of the affected parts
Eosinophilic myositis Etiology
sarcocystosis
• immunologic injury (autoimmune reaction against
type IIc fibers of masticatory muscles)
• idiopathic
– Eosinophilic myositis of ruminants
idiopathic
hypersensitivity to Sarcocystis infection?