E2: Muscle Diseases Flashcards
Serum CK offers remarkable sensitivity as aan indicator of __________.
Myonecrosis (of heart and skeletal muscle)
What is the expected CK range for a horse that has just begun training or in response to moderate exercise?
400-500 IU/L
Which enzyme, CK or AST, rises more slowly in response to myonecrosis?
AST
What does it indicate if AST is increased in conjunction with decreasing or normal CK activity? What is CK remains elevated?
Myonecrosis has occured but is not continuing
CK remaining elevated = ongoing myonecrosis
What does a poitive Hemastic test n the absence of hemolysis or RBCs in urine suggest?
Myoglobinuria
In the exercise challenge test, a horse should be kept at a constant slow trot for ____ minutes. When must you take the sample?
15 minutes
4-6 hours after exercise (not immediately!)
What is a normal result for a healthy host post- Exercise challenge test? What result indicates exertional rhabdomyolysis?
Normal: Rarely >3x CK
Abnormal: >5x CK
What will a electromyography of a healthy horse show? What about a horse with muscle abnormalities?
Normal: little to no spontaneous electrical activity until muscles contract
Abnormal: spontaneous electrical activity
Electromyography (EMG) and __________ are used to classigy the disease Neuropathic or Myopathic.
Nerve conduction velocity (NCV)
What element isused in nuclear scintigraphy to ID some forms of muscle damage?
Technetium 99m methylene diphosphonate (MDP)
On US, does muscle fiber disruption appear hyper- or hypoechoic? How does increased connective tissue or loss of muscle cell mass look?
Hypoechoic
Hyperechoic
Responses to ____ and ______ are used to diagnose recurrent exertional rhabdomyolysis and susceptibility to malignant hypethermia.
Caffeine
Halothane
Complete denervation of a muscle results in a >50% loss of muscle mass within ______ weeks.
2-3
What nerve is damaged in a horse with Sweeney?
Suprascapular
T/F: A QH sire who is heterozygous for HYPP who is bred with a mare who is lacking the trait has a 1/4 chance of having offspring with HYPP.
True
It is autosomal dominant genetic disorder
(QHs, American Paint, Appaloosas, and QH crossbreeds)
At what age do clinical signs usually begin in a horse with HYPP?
2-3 yrs
Why can alfalfa hay, soybean meal, and molasses trigger HYPP?
High in potassium
T/F: During a HYPP episode, CK will be greatly elevated.
False
CK shows no change or only modest increase during episodic fasciulations and weakness.
In a horse with HYPP, where does sweating and muscle fascilation commonly occur?
Flanks
Neck
Shoulders
How do you control HYPP longterm? How do you treat a horse wtih recurrent episodes?
Longterm: Diet
Acute: Acetazolamide, Hydrochlorothiazide
What type of tick infestation cause sintermittent painful muscle cramps that are not associated with exercise? Will CK levels be elevated?
Otobius megnini
Yes, CK will be elevated 4k-17k IU/L
IM injections of ______ ______ can trigger ______ myonecrosis.
Flunixin meglumine
Clostridial
How do you make a definitive diagnosis of clostridial myonecrosis? (What samples would you need and what tests would you run)
Aspirates from affected tissue - direct smear exxam + fluorescent antibody testing + anaerobic bacterial culture
The toxins from this species of clostridium are thr most potent and myonecrosis caused by this organism is fatal.
C. sordelli
