In: Nursing
Mary Collins, a 35-year-old woman, is admitted to the emergency department with shortness of breath, difficulty swallowing, and a drooping eyelid on the left side. The physician on duty suspects that she is suffering from myasthenia gravis and orders atropine 0.6 mg in the intravenous (IV) form followed by neostigmine 1.5 mg IV.
Following the administration of neostigmine, Ms. Collins is able to swallow and breathe more effectively.
Why has Mrs. Collins’ breathing improved, and why is she now able to swallow?
MYASTHENIA GRAVIS - it is an autoimmune disorder characterized by skeletal muscle weakness. Weakness in this disease worsens after period of activity.
✓ symptoms -
• skeletal muscle weakness
•drooping of eyelids
• difficulty in swallowing
• shortness of breath
• impaired speech
ROLE OF NEOSTIGMINE IN MYASTHENIA GRAVIS-
✓ ACETYLCHOLINE is a neurotransmitter released at motor nerve endings.
✓ ACETYLCHOLINESTERASE is an enzyme ,present at synaptic cleft , which metabolize acetylcholine into choline and acetic acid.
✓ NEOSTIGMINE IS AN ACETYLCHOLINESTERASE INHIBITOR.
✓ mechanism of action -
Neostigmine blocks acetylcholinesterase at synaptic cleft -->acetylcholinesterase can no longer metabolize acetylcholine --> acetylcholine concentration increase at neuromuscular junction --> increased neuromuscular transmission --> improved muscle strength.
IT IS VERY CRUCIAL TO MONITOR THE DOSAGE OF NEOSTIGMINE BECAUSE OVERDOSE MAY CAUSE BRONCHOCONSTRICTION.