14. Neuromuscular Disease

Question 1

neuropathy

Answer 1

damage or disease involving fibers of the nervous system. may affect sensation, movement, gland or organ function.

Question 2

myopathy

Answer 2

a muscular disease[1] in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness.

Question 3

neuromuscular junction

Answer 3

connects the nervous system to the muscular system via synapses between efferent nerve fibers and muscle fibers, also known as muscle cells.

Question 4

“dying back” neuropathy

Answer 4

neuropathy affecting distal neurons first; toxins or metabolic deficiencies can affect longest nerve fibers first because longer nerve fibers require more energy to maintain functin, and because there is a greater opportunity to injure a longer nerver fiber

Question 5

Wallerian degeneration

Answer 5

a process that results when a nerve fiber is cut or crushed, in which the part of the axon separated from the neuron’s cell body degenerates distal to the injury

Question 6

epineurium

Answer 6

The epineurium is the outermost layer of dense irregular connective tissue surrounding a peripheral nerve.[1] It usually surrounds multiple nerve fascicles as well as blood vessels which supply the nerve. Smaller branches of these blood vessels penetrate into the perineurium.

Question 7

perineurium

Answer 7

In the peripheral nervous system, nerve fibers are each wrapped in a protective sheath known as the endoneurium. These are bundled together into groups known as fascicles, each surrounded by a protective sheath known as the perineurium

Question 8

endoneurium

Answer 8

The endoneurium is a layer of delicate connective tissue made up of endoneurial cells that encloses the myelin sheath of a spinal cord nerve fiber.

Question 9

schwann cells

Answer 9

glial cells of the PNS

Question 10

entrapment neuropathy

Answer 10

compression of a nerve resulting in myelin disruption. could be due to mechanical abnormalities or swelling of tissues

Question 11

where is a common site for an entrapment neuropathy?

Answer 11

carpal tunnel

Question 12

lateral femoral cutaneous neuropathy

Answer 12

aka meralgia paresthetica, entrapment between ilium and inguinal ligament.

Question 13

other sites of compression neuropathies?

Answer 13

ulnar passing behind the epicondyle, deep branch of the ulnar passing wrist, radial nerve at spiral groove of upper arm, peroneal nerve at head of fibula, lateral femoral cutaneous.

Question 14

what nerves make up the lateral femoral cutaneous?

Answer 14

L2, L3

Question 15

what is a result of lateral femoral cutaneous entrapment?

Answer 15

numbness, burning pain on lateral thigh.

Question 16

polyneuropathy

Answer 16

Polyneuropathy is a serious, unpredictable, occasionally progressive, and life threatening neurological disorder[1] that occurs when many nerves throughout the body malfunction simultaneously.

Question 17

Charcot Marie Tooth disease

Answer 17

Charcot–Marie–Tooth disease (CMT), also known as Charcot–Marie–Tooth neuropathy, is a genetically and clinically heterogeneous group of inherited disorders of the peripheral nervous system characterised by progressive loss of muscle tissue and touch sensation across various parts of the body.

Question 18

Lambert-Eaton myasthenic syndrome: cause?

Answer 18

due to antibodies against the VG calcium channels in the terminals of motor nerves. Ca entry into these terminals is needed for release of Ach. produces weakness, diminished reflexes and autonomic dysfunction

Question 19

paraneoplastic sx

Answer 19

associated with cancer. consequence of cancer being in body but not directly related to local cancer cells.

Question 20

example of a paraneoplastic sx?

Answer 20

Cushing’s, Lambert-Eaton

Question 21

myasthenia gravis

Answer 21

autoimmune sx in which antibodies exist against the Ach receptor. means that nerve is unable to activate the muscle.

Question 22

nerve conduction studies do what?

Answer 22

evaluate the speed of nerve conduction and amount of nerve signal that gets through. can test both sensory and motor.

Question 23

electromyography

Answer 23

assesses electrical activity of muscle fibers, evaluates health of muscles, can detect muscle fibers that have been denervated.

Question 24

large peripheral nerve fibers convey what?

Answer 24

localized touch, pressure, vibration, joint pressure sense

Question 25

small nerve fibers convey what?

Answer 25

pain, touch, temp, autonomic

Question 26

what are a few causes of polyneuropathy?

Answer 26

infection, diabetes, nutritional prob, alcohol, toxins, meds, hereditary, inflammatory

Question 27

what is a hereditary cause of polyneuropathy

Answer 27

Charcot-Marie Tooth

Question 28

with polyneuropathy, what reflex is detected early

Answer 28

ankle jerk reflex

Question 29

what is a common pattern of polyneuropathy?

Answer 29

distal, symmetrical sensory loss (stocking/glove)

Question 30

a few causes of myopathies?

Answer 30

metabolic, infectious, inflammatory, genetic, drug, toxin

Question 31

myopathies usually result in what?

Answer 31

proximal and symmetrical weakness (hip, shoulder) and then move on to more distal muscles

Question 32

reflexes in myopathies?

Answer 32

reflexes are preseved until very late in disease

Question 33

sensation in myopathies?

Answer 33

no sensory loss. muscles may be tender/cramp

Question 34

myasthenia gravis: most commonly what population?

Answer 34

young females, old males

Question 35

myasthenia: sx?

Answer 35

fatigued muscles, due to damage to Ach receptors by antibody

Question 36

myasthenia: how affect resp?

Answer 36

may affect diaphragm, other resp muscles

Question 37

MG: treatmetn?

Answer 37

AchE inhibitors, immunosuppressives

Question 38

Lambert-Eaton: weakness where?

Answer 38

hip girdle muscles, decr patellar reflexes

Question 39

Lambert-Eaton: cause

Answer 39

sometimes small cell cancer, can also be idiopathic

Question 40

Lambert-Eaton: strength pattern

Answer 40

strength increases with sustained contraction