Myotonic-Muscular Dystrophy

Question 1

DMD: cardiac

Answer 1

• heart atrophies and degenerates

- dec. contractility, papillary muscle dysfunction leads to MR

Question 2

DMD: pulmonary

Answer 2

• dec. ability to cough, dec respiratory reserve, dec. ability to handle secretions
• predisposed to PNA

Question 3

Myotonic dystrophy

Answer 3

• audosomal dominant, symptons in 2nd-3rd decades of life

- prolonged muscle contraction and delayed muscle relaxation following stimulation

Question 4

myotonic dystrophy: symptoms

Answer 4

• atrophy and weakness

- usu. facial, pharyngeal, sternocleidomastoid

Question 5

myotonia dystrophica

Answer 5

• most common and most serious, 3rd decade
• respiratory muscle weakness
• cardiac anomalies: cardiomyopathy, cardiac dysrhythmia, cardiac conduction abnormalities

Question 6

myotonia congenita

Answer 6

• at birth
• skeletal muscle involvement, other organs usu spared
• respond to quinine

Question 7

paramyotonia

Answer 7

-rarest and mildest symptoms (only develop when have a cold)

Question 8

myotonia dystrophica: volatiles

Answer 8

• myocardial depression aggravates myopathy

- also worsens cardiac conduction defects–RBBB or sudden 3rd degree heart block

Question 9

myotonia dystrophica: nm blockers

Answer 9

• succs causes sustained muscle contraction and hyperkalemia (in MG–causes unreliable relaxation)
• nondepolarizers-increased sensitivity (as with myasthenia gravis, myasthenic syndrome, muscular dystrophy)
• anticholinesterases that reverse nondepolarizing block precipitates myotonia

Question 10

myotonia dystrophica: extubation criteria

Answer 10

• can have restrictive lung disease 2/2 muscle weakness

- extreme sensitivity to barbiturates, opioids, benzs

Question 11

IV regional/local infiltration/spinal

Answer 11

• very effective because anesthetic goes directly to muscle
• spinal does not ensure relaxation–sustained contraction can occur
• infiltration with quinine, tocanide, mexiletine can also alleviate symptoms
• also true for MD

Question 12

gastric motility

Answer 12

• motility is decreased

- full stomach precautions, RSI

Question 13

muscular dystrophy

Answer 13

• x-linked disease
• painless atrophy and degeneration of muscles
• pseudohypertrophy: fatty infiltration causes skeletal muscles to enlarge
• kyphoscoliosis
• death between 15-25 yo 2/2 CHF, PNA

Question 14

MD and NM blockers

Answer 14

• succs: causes sustained contraction and hyperkalemia–succs is membrane active depolarizing agent (in MG–unreliable relaxation)
• inc sensto nondepolarizers
• anticholinesterases to reverse nondepolarizing block might precipitate myotonia