Myasthenia gravis - Revision history

Danbot: Strip excess bold

2026-03-22T09:26:38Z

Strip excess bold

Danbot: Add MedicationDose SMW entries for IVIG and pyridostigmine; doses verified against neurology guidelines

2026-03-20T17:56:05Z

Add MedicationDose SMW entries for IVIG and pyridostigmine; doses verified against neurology guidelines

← Older revision		Revision as of 17:56, 20 March 2026
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	*Suspected precipitant (infection, medication change, non-adherence)		*Suspected precipitant (infection, medication change, non-adherence)
	*Prior crisis history and treatments (PLEX vs IVIG preference, thymectomy status)		*Prior crisis history and treatments (PLEX vs IVIG preference, thymectomy status)


			==Medication Dosing==
			===Myasthenic Crisis===
			*{{MedicationDose\|drug=IVIG\|dose=0.4 g/kg/day x5 days (or 1 g/kg/day x2 days)\|route=IV\|context=Immunomodulatory therapy for crisis\|indication=Myasthenia gravis\|population=Adult\|notes=Alternative to plasmapheresis; preferred if sepsis or hemodynamic instability}}

			===Outpatient/Symptomatic===
			*{{MedicationDose\|drug=Pyridostigmine\|dose=60 mg QID (titrate to effect)\|route=PO\|context=Acetylcholinesterase inhibitor (symptomatic)\|indication=Myasthenia gravis\|population=Adult\|notes=Provides symptomatic relief; does not alter disease course}}

	==See Also==		==See Also==

Ostermayer at 23:25, 28 February 2026

2026-02-28T23:25:51Z

Show changes

Ostermayer at 04:14, 27 February 2026

2026-02-27T04:14:55Z

← Older revision		Revision as of 04:14, 27 February 2026
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	*FEV		*FEV
	*Negative inspiratory force (NIF) (normal is -80 to -100; respiratory support is indicated for -20 to 0)		*Negative inspiratory force (NIF) (normal is -80 to -100; respiratory support is indicated for -20 to 0)
			i.e. values closer to zero indicate weaker inspiratory effort
	*Ability to handle secretions		*Ability to handle secretions

Rossdonaldson1: /* General Medications */

2024-04-17T17:37:22Z

General Medications

← Older revision		Revision as of 17:37, 17 April 2024
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	**Effect lasts 15-20 days		**Effect lasts 15-20 days

	===~~General~~ Medications===		===Other Medications===
	''[[Pyridostigmine]] and [[neostigmine]] primarily used for symptomatic relief but does not alter course of crisis<ref>Wendell LC and Levine JM. Myasthenic Crisis. Neurohospitalist. 2011 Jan; 1(1): 16–22.</ref>. Consider avoiding in ICU ventilated patients, as these may increase secretions. Continued use of these meds also prevents assessment of other treatment modalities and can increase muscle weakness if used in excess''		''[[Pyridostigmine]] and [[neostigmine]] primarily used for symptomatic relief but does not alter course of crisis<ref>Wendell LC and Levine JM. Myasthenic Crisis. Neurohospitalist. 2011 Jan; 1(1): 16–22.</ref>. Consider avoiding in ICU ventilated patients, as these may increase secretions. Continued use of these meds also prevents assessment of other treatment modalities and can increase muscle weakness if used in excess''
	*[[Pyridostigmine]]: Titrate up to find the lowest effective dose		*[[Pyridostigmine]]: Titrate up to find the lowest effective dose

Rossdonaldson1: /* Management */

2024-04-17T17:36:31Z

Management

← Older revision		Revision as of 17:36, 17 April 2024
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	===Myasthenic Crisis===		===Myasthenic Crisis===
	*Acetylcholinesterase inhibitors are discontinued to avoid excessive bronchial secretions		*Acetylcholinesterase inhibitors are discontinued to avoid excessive bronchial secretions
	*[[Intubation]]		*[[Intubation]] (if needed)
	**If possible avoid depolarizing AND non-depolarizing agents		**If possible avoid depolarizing AND non-depolarizing agents
	**If patient requires paralysis use non-depolarizing agent at smaller dose		**If patient requires paralysis use non-depolarizing agent at smaller dose
	**If must use depolarizing agents, will need higher doses		**If must use depolarizing agents, will need higher doses
	*IVIG ~~and plasmapheresis~~		*[[IVIG]]
			**0.4 g/kg/day for 5 days
			**Effect lasts 30-45 days
			*[[Plasmapheresis]]
			**Effect lasts 15-20 days

	===General Medications===		===General Medications===
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	*[[Neostigmine]]		*[[Neostigmine]]
	**0.5mg IV		**0.5mg IV
	[[Prednisolone]]: If symptomatic despite Pyridostigmine. Monitor diabetes mellitus.		*[[Prednisolone]]: If symptomatic despite Pyridostigmine. Monitor diabetes mellitus.
	*Ocular myasthenia gravis		**Ocular myasthenia gravis
	**Start 5 mg on alternate days for three doses and increase by 5 mg every three doses until symptoms improve.		***Start 5 mg on alternate days for three doses and increase by 5 mg every three doses until symptoms improve.
	**The maximum dose is 50 mg on alternate days or 0.75 mg/kg/alternate day		***The maximum dose is 50 mg on alternate days or 0.75 mg/kg/alternate day
	*Generalized myasthenia gravis		**Generalized myasthenia gravis
	**Start 10 mg on alternate days for three doses and increase by 10 mg every three doses until symptoms improve.		***Start 10 mg on alternate days for three doses and increase by 10 mg every three doses until symptoms improve.
	**Maximum dose is 100 mg alternate days or 1.5 mg/kg		***Maximum dose is 100 mg alternate days or 1.5 mg/kg
	~~[[Plasmapheresis]]~~
	*Effect lasts 15-20 days
	~~[[IVIG]]~~
	*0.4 g/kg/day for 5 days
	*Effect lasts 30-45 days

	==Disposition==		==Disposition==

Rossdonaldson1: /* Evaluation */

2024-04-17T16:37:51Z

Evaluation

← Older revision		Revision as of 16:37, 17 April 2024
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	[[File:Tumor Thymoma1.jpg\|thumb\|A chest CT-scan showing a thymoma (red circle).]]		[[File:Tumor Thymoma1.jpg\|thumb\|A chest CT-scan showing a thymoma (red circle).]]
	===Workup===		===Workup===
			====ED Workup====
			Always evaluate:<ref>Emergency Medicine Practice -- Weakness: A systemic approach to acute non-traumatic neurologic and neuromuscular causes Dec 2002</ref>
			*Tidal volume
			*Forced Vital capacity (normal is >25cc/kg in MG)
			*FEV
			*Negative inspiratory force (NIF) (normal is -80 to -100; respiratory support is indicated for -20 to 0)
			*Ability to handle secretions

			====Neuro Workup====
	The following may be considered for neurologic workup, but are not typically indicated in the ED:<ref>Myasthenia gravis: Association of British Neurologists’ management guidelines [https://pn.bmj.com/content/15/3/199]</ref>		The following may be considered for neurologic workup, but are not typically indicated in the ED:<ref>Myasthenia gravis: Association of British Neurologists’ management guidelines [https://pn.bmj.com/content/15/3/199]</ref>
	*ACh-R antibody testing: first-line investigation. Indication for thymectomy if < 45 years.		*ACh-R antibody testing: first-line investigation. Indication for thymectomy if < 45 years.

Rossdonaldson1: /* Management */

2024-04-17T16:37:00Z

Management

← Older revision		Revision as of 16:37, 17 April 2024
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	==Management==		==Management==
	~~Always evaluate:<ref>Emergency Medicine Practice -- Weakness: A systemic approach to acute non-traumatic neurologic and neuromuscular causes Dec 2002<~~/~~ref>~~		;Avoid medications that can cause/worsen exacerbations (see Background), including [[magnesium]] (which can cause [[respiratory failure]])
	*~~Tidal volume~~		===Myasthenic Crisis===
	*~~Forced Vital capacity (normal is >25cc/kg in MG)~~		*Acetylcholinesterase inhibitors are discontinued to avoid excessive bronchial secretions
	*~~FEV~~		*[[Intubation]]
	*~~Negative inspiratory force (NIF) (normal is~~ -~~80 to -100; respiratory support is indicated for -20 to 0)~~		**If possible avoid depolarizing AND non-depolarizing agents
	*~~Ability to handle secretions~~		**If patient requires paralysis use non-depolarizing agent at smaller dose
			**If must use depolarizing agents, will need higher doses
			*IVIG and plasmapheresis

	===Medications===		===General Medications===
	''[[Pyridostigmine]] and [[neostigmine]] primarily used for symptomatic relief but does not alter course of crisis<ref>Wendell LC and Levine JM. Myasthenic Crisis. Neurohospitalist. 2011 Jan; 1(1): 16–22.</ref>. Consider avoiding in ICU ventilated patients, as these may increase secretions. Continued use of these meds also prevents assessment of other treatment modalities and can increase muscle weakness if used in excess''		''[[Pyridostigmine]] and [[neostigmine]] primarily used for symptomatic relief but does not alter course of crisis<ref>Wendell LC and Levine JM. Myasthenic Crisis. Neurohospitalist. 2011 Jan; 1(1): 16–22.</ref>. Consider avoiding in ICU ventilated patients, as these may increase secretions. Continued use of these meds also prevents assessment of other treatment modalities and can increase muscle weakness if used in excess''
	*[[Pyridostigmine]]: Titrate up to find the lowest effective dose		*[[Pyridostigmine]]: Titrate up to find the lowest effective dose
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	*0.4 g/kg/day for 5 days		*0.4 g/kg/day for 5 days
	*Effect lasts 30-45 days		*Effect lasts 30-45 days
	~~[[Avoid magnesium]]~~
	*Can induce respiratory failure

	~~In '''Myasthenic Crisis''' :~~
	*Acetylcholinesterase inhibitors are discontinued to avoid excessive bronchial secretions
	*[[Intubation]]
	**If possible avoid depolarizing AND non-depolarizing agents
	**If patient requires paralysis use non-depolarizing agent at smaller dose
	**If must use depolarizing agents, will need higher doses
	*IVIG and plasmapheresis

	==Disposition==		==Disposition==

Rossdonaldson1: /* Evaluation */

2024-04-17T16:28:39Z

Evaluation

@@ Line 41: / Line 41: @@
 [[File:Myasthenia gravis ptosis reversal.jpg|thumb|Right partial ptosis (left picture) with left lid showing compensatory pseudo lid retraction because of equal innervation of the levator palpabrae superioris (Hering's law of equal innervation): Right picture: after an edrophonium test, note the improvement in ptosis.]]
 [[File:Tumor Thymoma1.jpg|thumb|A chest CT-scan showing a thymoma (red circle).]]
-*Prolonged upward gaze test<ref>Ptosis in myasthenia gravis: Extended fatigue and recovery bedside test. Klaus V. Toyka. Neurology Oct 2006, 67 (8) 1524.</ref>
+===Workup===
-**Have the patient gaze upward at examiner's finger for 30 seconds
+The following may be considered for neurologic workup, but are not typically indicated in the ED:<ref>Myasthenia gravis: Association of British Neurologists’ management guidelines [https://pn.bmj.com/content/15/3/199]</ref>
 *ACh-R antibody testing: first-line investigation. Indication for thymectomy if < 45 years.
 **MuSK antibody testing: for patients negative for ACh-R antibodies
@@ Line 58: / Line 50: @@
 *Thymus scanning: All patients with suspected myasthenia, irrespective of distribution (ocular/generalised) or serology (seropositive/negative), should undergo thymus imaging. The modality (CT or MRI) should be decided locally.
 *Edrophonium/Tensilon test
 ==Management==

Rossdonaldson1 at 16:26, 17 April 2024

2024-04-17T16:26:03Z

@@ Line 49: / Line 49: @@
 {{Myasthenic vs cholinergic crisis}}
 ===Investigations<ref>Myasthenia gravis: Association of British Neurologists’ management guidelines [https://pn.bmj.com/content/15/3/199]</ref>===
@@ Line 66: / Line 58: @@
 *Thymus scanning: All patients with suspected myasthenia, irrespective of distribution (ocular/generalised) or serology (seropositive/negative), should undergo thymus imaging. The modality (CT or MRI) should be decided locally.
 *Edrophonium/Tensilon test
 ===Medications===

← Older revision		Revision as of 09:26, 22 March 2026
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	===Precipitants of Myasthenic Crisis===		===Precipitants of Myasthenic Crisis===
	Identify and treat the trigger in every crisis presentation:<ref name="Roper"/><ref name="emcrit"/>		Identify and treat the trigger in every crisis presentation:<ref name="Roper"/><ref name="emcrit"/>
	*~~'''~~Infection~~'''~~ (most common cause, >30–40% of crises; respiratory infections #1, aspiration pneumonitis #2)		*Infection (most common cause, >30–40% of crises; respiratory infections #1, aspiration pneumonitis #2)
	*Medication changes (see above; also includes tapering or abrupt discontinuation of immunosuppressants)		*Medication changes (see above; also includes tapering or abrupt discontinuation of immunosuppressants)
	*Non-adherence with pyridostigmine or immunosuppressants		*Non-adherence with pyridostigmine or immunosuppressants
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	===ED Workup===		===ED Workup===
	Always evaluate respiratory function serially (q2hr or more frequently if deteriorating):<ref>Emergency Medicine Practice -- Weakness: A systemic approach to acute non-traumatic neurologic and neuromuscular causes Dec 2002</ref><ref name="Wendell"/>		Always evaluate respiratory function serially (q2hr or more frequently if deteriorating):<ref>Emergency Medicine Practice -- Weakness: A systemic approach to acute non-traumatic neurologic and neuromuscular causes Dec 2002</ref><ref name="Wendell"/>
	*~~'''~~Forced Vital Capacity (FVC)~~'''~~: normal ≥60 mL/kg; <20 mL/kg indicates impending respiratory failure		*Forced Vital Capacity (FVC): normal ≥60 mL/kg; <20 mL/kg indicates impending respiratory failure
	*~~'''~~Negative Inspiratory Force (NIF)~~'''~~: normal is −80 to −100 cmH₂O; values closer to 0 indicate weaker effort		*Negative Inspiratory Force (NIF): normal is −80 to −100 cmH₂O; values closer to 0 indicate weaker effort
	*~~'''~~Tidal volume~~'''~~		*Tidal volume
	*~~'''~~Ability to handle secretions~~'''~~		*Ability to handle secretions
	*Continuous capnography (best early indicator of ventilatory deterioration)<ref name="NUEM">Management of Myasthenia Crisis in the ED — NUEM Blog. https://www.nuemblog.com/blog/myasthenia 2019.</ref>		*Continuous capnography (best early indicator of ventilatory deterioration)<ref name="NUEM">Management of Myasthenia Crisis in the ED — NUEM Blog. https://www.nuemblog.com/blog/myasthenia 2019.</ref>

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	===Bedside Tests===		===Bedside Tests===
	*~~'''~~Prolonged upward gaze test~~'''~~<ref>Toyka KV. Ptosis in myasthenia gravis: Extended fatigue and recovery bedside test. Neurology Oct 2006, 67(8):1524.</ref>		*Prolonged upward gaze test<ref>Toyka KV. Ptosis in myasthenia gravis: Extended fatigue and recovery bedside test. Neurology Oct 2006, 67(8):1524.</ref>
	**Have the patient gaze upward at examiner's finger for 30–60 seconds		**Have the patient gaze upward at examiner's finger for 30–60 seconds
	**Diplopia or ptosis that develops is suggestive of MG		**Diplopia or ptosis that develops is suggestive of MG
	*~~'''~~Ice Pack Test~~'''~~ (high specificity for MG)		*Ice Pack Test (high specificity for MG)
	**Place ice-pack on closed eyes for 2 mins; positive if ptosis decreases by ≥2 mm		**Place ice-pack on closed eyes for 2 mins; positive if ptosis decreases by ≥2 mm
	*~~'''~~Single breath count test~~'''~~		*Single breath count test
	**Have patient take a deep breath and count aloud as high as possible; <20 suggests respiratory compromise		**Have patient take a deep breath and count aloud as high as possible; <20 suggests respiratory compromise

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	*'''Intubation''' (if needed)—favor elective intubation over emergent<ref name="Wendell"/>		*'''Intubation''' (if needed)—favor elective intubation over emergent<ref name="Wendell"/>
	**If possible, intubate without paralytic agents (use adequate sedation alone)		**If possible, intubate without paralytic agents (use adequate sedation alone)
	**If paralysis is required, ~~'''~~use a nondepolarizing agent at reduced dose~~'''~~ (preferred):		**If paralysis is required, use a nondepolarizing agent at reduced dose (preferred):
	***~~'''~~Rocuronium 0.5–0.6 mg/kg~~'''~~ (roughly half the standard dose)<ref name="Poremba">Poremba M. UMEM Educational Pearls: Myasthenia Gravis and Neuromuscular Blockers. University of Maryland. 2023.</ref><ref name="roccase">Billups K et al. Extreme Paralysis Following Rocuronium Administration in a Myasthenia Gravis Patient. West J Emerg Med. 2023;24(4):735-738.</ref>		***Rocuronium 0.5–0.6 mg/kg (roughly half the standard dose)<ref name="Poremba">Poremba M. UMEM Educational Pearls: Myasthenia Gravis and Neuromuscular Blockers. University of Maryland. 2023.</ref><ref name="roccase">Billups K et al. Extreme Paralysis Following Rocuronium Administration in a Myasthenia Gravis Patient. West J Emerg Med. 2023;24(4):735-738.</ref>
	***MG patients are extremely sensitive to nondepolarizing agents—standard doses can cause prolonged paralysis (case reports of >4 hours)<ref name="roccase"/>		***MG patients are extremely sensitive to nondepolarizing agents—standard doses can cause prolonged paralysis (case reports of >4 hours)<ref name="roccase"/>
	***'''Sugammadex''' can reverse rocuronium/vecuronium (dose 2–4 mg/kg, or 16 mg/kg for immediate reversal); have available<ref>StatPearls: Anesthesia for Patients With Myasthenia Gravis. 2025.</ref>		***'''Sugammadex''' can reverse rocuronium/vecuronium (dose 2–4 mg/kg, or 16 mg/kg for immediate reversal); have available<ref>StatPearls: Anesthesia for Patients With Myasthenia Gravis. 2025.</ref>
	**If depolarizing agents must be used:		**If depolarizing agents must be used:
	***~~'''~~Succinylcholine 1.5–2.0 mg/kg~~'''~~ (roughly double the standard dose)<ref name="Levitan">Levitan R. Safety of succinylcholine in myasthenia gravis. Ann Emerg Med. 2005;45(2):225-226.</ref>		***Succinylcholine 1.5–2.0 mg/kg (roughly double the standard dose)<ref name="Levitan">Levitan R. Safety of succinylcholine in myasthenia gravis. Ann Emerg Med. 2005;45(2):225-226.</ref>
	***MG patients are ~~'''~~resistant~~'''~~ to succinylcholine (fewer functional AChRs); may require up to 2.6× normal dose		***MG patients are resistant to succinylcholine (fewer functional AChRs); may require up to 2.6× normal dose
	***Not contraindicated in MG (unlike other neuromuscular diseases, no risk of hyperkalemia from receptor upregulation)<ref name="Levitan"/>		***Not contraindicated in MG (unlike other neuromuscular diseases, no risk of hyperkalemia from receptor upregulation)<ref name="Levitan"/>
	***Response may be unpredictable; avoid defasciculating dose of nondepolarizer		***Response may be unpredictable; avoid defasciculating dose of nondepolarizer
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	====Pharmacologic Management in Crisis====		====Pharmacologic Management in Crisis====
	*~~'''~~Discontinue acetylcholinesterase inhibitors~~'''~~ (pyridostigmine/neostigmine) to reduce bronchial secretions<ref name="Wendell"/>		*Discontinue acetylcholinesterase inhibitors (pyridostigmine/neostigmine) to reduce bronchial secretions<ref name="Wendell"/>
	**Exception: if patient is NOT intubated, continue home pyridostigmine—abrupt cessation can worsen crisis<ref name="emcrit"/>		**Exception: if patient is NOT intubated, continue home pyridostigmine—abrupt cessation can worsen crisis<ref name="emcrit"/>
	**Restart pyridostigmine as patient approaches extubation		**Restart pyridostigmine as patient approaches extubation
	*~~'''~~Plasmapheresis (PLEX)~~'''~~ — generally preferred in crisis for faster onset<ref name="emcrit"/>		*Plasmapheresis (PLEX) — generally preferred in crisis for faster onset<ref name="emcrit"/>
	**Usually improvement by 2nd–3rd session		**Usually improvement by 2nd–3rd session
	**Effect lasts 15–20 days		**Effect lasts 15–20 days
	**Contraindicated in sepsis, hemodynamic instability		**Contraindicated in sepsis, hemodynamic instability
	**Requires central venous access		**Requires central venous access
	*~~'''~~[[IVIG]]~~'''~~		*[[IVIG]]
	**0.4 g/kg/day for 5 days (total 2 g/kg)		**0.4 g/kg/day for 5 days (total 2 g/kg)
	**Effect lasts 30–45 days		**Effect lasts 30–45 days
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	====Corticosteroids in Crisis====		====Corticosteroids in Crisis====
	*~~'''~~Use with caution in the acute setting~~'''~~<ref name="emcrit"/>		*Use with caution in the acute setting<ref name="emcrit"/>
	**Steroid initiation can ''cause'' transient worsening (in ~50% of patients), typically 5–10 days after initiation		**Steroid initiation can ''cause'' transient worsening (in ~50% of patients), typically 5–10 days after initiation
	**Generally defer initiation until after PLEX/IVIG has been started and patient is stabilized		**Generally defer initiation until after PLEX/IVIG has been started and patient is stabilized
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	===Outpatient / Non-Crisis Management===		===Outpatient / Non-Crisis Management===
	''[[Pyridostigmine]] and [[neostigmine]] provide symptomatic relief but do not alter the course of crisis<ref name="Wendell"/>. Consider avoiding in ICU ventilated patients due to increased secretions.''		''[[Pyridostigmine]] and [[neostigmine]] provide symptomatic relief but do not alter the course of crisis<ref name="Wendell"/>. Consider avoiding in ICU ventilated patients due to increased secretions.''
	*~~'''~~[[Pyridostigmine]]~~'''~~: Titrate up to find the lowest effective dose		*[[Pyridostigmine]]: Titrate up to find the lowest effective dose
	**Initially 30 mg four times daily for 2–4 days		**Initially 30 mg four times daily for 2–4 days
	**Then 60 mg (1 tablet) four times daily for 5 days and experiment with timing		**Then 60 mg (1 tablet) four times daily for 5 days and experiment with timing
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	**If patient's usual dose has been missed the next dose is usually doubled		**If patient's usual dose has been missed the next dose is usually doubled
	**IV route: 1/30th of the PO dose (2–3 mg) by slow IV infusion		**IV route: 1/30th of the PO dose (2–3 mg) by slow IV infusion
	*~~'''~~[[Neostigmine]]~~'''~~		*[[Neostigmine]]
	**0.5 mg IV		**0.5 mg IV
	*~~'''~~[[Prednisolone]]~~'''~~: If symptomatic despite pyridostigmine. Monitor for diabetes mellitus.		*[[Prednisolone]]: If symptomatic despite pyridostigmine. Monitor for diabetes mellitus.
	**''Ocular myasthenia gravis''		**''Ocular myasthenia gravis''
	***Start 5 mg on alternate days for three doses, increase by 5 mg every three doses until symptoms improve		***Start 5 mg on alternate days for three doses, increase by 5 mg every three doses until symptoms improve