Chronic autoimmune disorder. Antibodies destroy or block acetylcholine (ACh) receptors at the neuromuscular junction.

Ptosis (drooping eyelid), diplopia, facial weakness, dysphagia, dysphonia (voice impairment). Weakness worsens with activity.

Diagnostic for MG. IV edrophonium improves muscle strength (e.g., ptosis) for 5 minutes. Requires atropine at bedside.

Cholinesterase inhibitor (Mestinon). Increases ACh at NMJ. Give 30-45 minutes BEFORE meals for swallowing strength.

Too little ACh. Severe weakness, respiratory distress (dry). Often triggered by infection. Treat with IVIG or plasmapheresis.

Too much ACh. From overdose of pyridostigmine. Symptoms: salivation, lacrimation, bradycardia, bronchospasm (wet). Antidote: Atropine.

Eat at peak medication effect. Consume largest meal in morning. Sit upright, use soft foods, have suction available.

Weakness of intercostals/diaphragm can lead to respiratory failure. KEY SIGN: Inability to handle secretions/drooling.

Antibodies block acetylcholine (ACh) receptors at neuromuscular junction, preventing muscle contraction.

Repetitive Nerve Stimulation

Shows a decremental response: muscle action potentials decrease with repeated nerve stimulation.

Positive in 85-90% of generalized MG patients. Negative in some ocular MG or with MuSK antibodies.

75% of MG patients have thymic abnormalities (hyperplasia, thymoma). Thymectomy can improve symptoms, especially if thymoma present.

Medication Timing Critical

Pyridostigmine (Mestinon) given 30-45 minutes BEFORE meals to maximize strength for chewing and swallowing.

Myasthenic Crisis Precipitants

Infection (most common), surgery, stress, pregnancy, medications (aminoglycosides, beta-blockers, magnesium).

Cholinergic Crisis Symptoms

From too much ACh: SLUDGE (Salivation, Lacrimation, Urination, Diarrhea, GI upset, Emesis) + muscle fasciculations, bradycardia.

Atropine must be at bedside. IV edrophonium given; improvement in ptosis within 30-60 seconds confirms MG.

Removes circulating antibodies. Provides short-term improvement (days-weeks). Used for crisis or pre-op stabilization.

Modulates immune response. Alternative to plasmapheresis. Effects last weeks. Monitor for fluid overload, headache.

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Myasthenia Gravis

Question	Answer
Patho	Chronic autoimmune disorder. Antibodies destroy or block acetylcholine (ACh) receptors at the neuromuscular junction.
Key Symptoms	Ptosis (drooping eyelid), diplopia, facial weakness, dysphagia, dysphonia (voice impairment). Weakness worsens with activity.
Tensilon Test	Diagnostic for MG. IV edrophonium improves muscle strength (e.g., ptosis) for 5 minutes. Requires atropine at bedside.
Pyridostigmine	Cholinesterase inhibitor (Mestinon). Increases ACh at NMJ. Give 30-45 minutes BEFORE meals for swallowing strength.
Myasthenic Crisis	Too little ACh. Severe weakness, respiratory distress (dry). Often triggered by infection. Treat with IVIG or plasmapheresis.
Cholinergic Crisis	Too much ACh. From overdose of pyridostigmine. Symptoms: salivation, lacrimation, bradycardia, bronchospasm (wet). Antidote: Atropine.
Meal Planning	Eat at peak medication effect. Consume largest meal in morning. Sit upright, use soft foods, have suction available.
Respiratory	Weakness of intercostals/diaphragm can lead to respiratory failure. KEY SIGN: Inability to handle secretions/drooling.
Nuance	Antibodies block acetylcholine (ACh) receptors at neuromuscular junction, preventing muscle contraction.
Repetitive Nerve Stimulation	Shows a decremental response: muscle action potentials decrease with repeated nerve stimulation.
ACth Antibodies	Positive in 85-90% of generalized MG patients. Negative in some ocular MG or with MuSK antibodies.
Thymus Gland	75% of MG patients have thymic abnormalities (hyperplasia, thymoma). Thymectomy can improve symptoms, especially if thymoma present.
Medication Timing Critical	Pyridostigmine (Mestinon) given 30-45 minutes BEFORE meals to maximize strength for chewing and swallowing.
Myasthenic Crisis Precipitants	Infection (most common), surgery, stress, pregnancy, medications (aminoglycosides, beta-blockers, magnesium).
Cholinergic Crisis Symptoms	From too much ACh: SLUDGE (Salivation, Lacrimation, Urination, Diarrhea, GI upset, Emesis) + muscle fasciculations, bradycardia.
Test Procedure	Atropine must be at bedside. IV edrophonium given; improvement in ptosis within 30-60 seconds confirms MG.
Plasmapheresis	Removes circulating antibodies. Provides short-term improvement (days-weeks). Used for crisis or pre-op stabilization.
IVIG	Modulates immune response. Alternative to plasmapheresis. Effects last weeks. Monitor for fluid overload, headache.

Created by: Wasurenboh

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