Pathology: Skeletal Muscle L3

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Questions and Answers

What is the primary cause of "Sweeny" in horses?

Bacterial infection of the suprascapular nerve
Nutritional deficiency leading to muscle atrophy
Compression of the suprascapular nerve due to lack of protection (correct)
Autoimmune attack on skeletal muscles

What is the characteristic gross lesion associated with "Sweeny"?

Diffuse hemorrhagic necrosis of muscle fibers
Purulent abscesses within the supraspinatus muscle
Atrophy of the supraspinatus and infraspinatus muscles with a prominent scapular spine (correct)
Enlarged suprascapular nerve with fibrotic adhesions

Damage to which nerve leads to atrophy of the left cricoarytenoideus dorsalis muscle?

Phrenic nerve
Vagus nerve
Left recurrent laryngeal nerve (correct)
Glossopharyngeal nerve

What is a likely clinical consequence of laryngeal paralysis?

Respiratory stridor and difficulty breathing (B) Signup and view all the answers

Muscular dystrophy is characterized by:

Chronic polyphasic myocyte degeneration & necrosis with hypertrophy, atrophy, and fibrosis (B) Signup and view all the answers

Muscular dystrophy is caused by a mutation in which gene?

Dystrophin (B) Signup and view all the answers

What is the mode of inheritance for muscular dystrophy?

X-linked (C) Signup and view all the answers

What are clinical signs of muscular dystrophy?

Exercise intolerance, generalized muscle weakness, excessive drooling, and difficulty eating (B) Signup and view all the answers

Hyperkalemic Periodic Paralysis (HYPP) is caused by a mutation in which gene?

Sodium channel gene (SCN4A) (B) Signup and view all the answers

What is the primary pathophysiological mechanism of HYPP?

Prolonged action potential due to a defective sodium channel, leading to hyperkalemia and muscle spasms (C) Signup and view all the answers

What are common clinical signs of HYPP?

Muscle spasms and collapse (A) Signup and view all the answers

How is HYPP diagnosed?

DNA test (C) Signup and view all the answers

What is the recommended management for horses with HYPP?

Hypokalemic diet and refraining from breeding affected animals (B) Signup and view all the answers

What is the genetic mutation associated with Equine Polysaccharide Storage Myopathy (PSSM)?

Mutation in glycogen synthase I (GYS1) gene (B) Signup and view all the answers

How does Clostridium botulinum toxin cause paralysis?

By inhibiting acetylcholine (Ach) release at the neuromuscular junction (C) Signup and view all the answers

What is the primary route of Clostridium tetani neurotoxin entry into the body?

Deep penetrating wounds (C) Signup and view all the answers

What is a hallmark clinical sign of tetanus in affected animals?

Lockjaw and a protruded third eyelid (B) Signup and view all the answers

How does the tetanus neurotoxin cause prolonged muscle contractions?

By blocking the release of glycine and GABA from inhibitory neurons (A) Signup and view all the answers

What is the primary difference between congenital and acquired myasthenia gravis?

Congenital is due to defective neuromuscular junctions, while acquired is an autoimmune disorder against acetylcholine receptors (C) Signup and view all the answers

Which of the following electrolyte imbalances can cause severe muscular clinical signs?

Hypokalemia in cats and hypocalcemia in cattle (B) Signup and view all the answers

Which endocrine disorder is associated with muscle atrophy and weakness in horses, particularly affecting type 2 muscle fibers?

Pituitary Pars Intermedia Dysfunction (PPID) (C) Signup and view all the answers

Flashcards

Cause of "Sweeny" in horses?

Compression of the suprascapular nerve due to lack of protection.

Gross lesion of "Sweeny"?

Atrophy of the supraspinatus and infraspinatus muscles with a prominent scapular spine.