27. Lower Motor Neuron Disease

Question 1

What are the signs of LMN disease?

Answer 1

paresis or paralysis, decreased muscle tone (flaccidity), decreased segmental spinal reflexes.
Dysphonia, dysphagia, increased fatiguability, exercise intolerance and regurgitation secondary to megaesophagus.
Hypoventilation with severe weakness of intercostal muscles and diaphragm + sometimes laryngeal dysfunction.

Question 2

MOA of tick paralysis

Answer 2

Holocyclotoxin is thought to impair Act release at the NMJ by blocking Ca2+ influx at the axon terminal.

Question 3

T or F:
dogs appear to be resistant to the North American form.

Answer 3

F. Cats are, not dogs.

Question 4

MOA of botulism

Answer 4

Botulism neurotoxin rapidly and irreversibly binds to neuronal surface receptors on nerve terminals, is internalised and prevents synaptic release of ACh at the NMJ causing flaccid paralysis.

Question 5

MOA of acquired Myasthenia Gravis

Answer 5

immune-mediated disease in which antibodies are formed against the nicotinic receptors on the postsynaptic membrane of the NMJ.

Question 6

What is the most common mediastinal neoplasia associated with MG?

Answer 6

Thymoma