Myasthenia gravis - Revision history

TLee430: The bullet points said patients are sensitive to succinylcholine. I changed it to say that they are resistant. I added that the ED95 of succinylcholine is 2.6 times normal (from Barash), not sure if thats really needed to be on there.

2022-07-17T11:57:57Z

The bullet points said patients are sensitive to succinylcholine. I changed it to say that they are resistant. I added that the ED95 of succinylcholine is 2.6 times normal (from Barash), not sure if thats really needed to be on there.

← Older revision		Revision as of 04:57, 17 July 2022
Line 7:		Line 7:
	🠕 sensitivity to nondepolarizing NMBs		🠕 sensitivity to nondepolarizing NMBs

	🠗 ~~sensitivity~~ to succinylcholine		🠗 resistant to succinylcholine

	Monitor for cholinergic symptoms		Monitor for cholinergic symptoms
Line 19:		Line 19:
	}}'''Myasthenia gravis''' is an autoimmune disease that produces antibodies against nicotinic acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction, leading to varying degrees of muscle weakness and fatigue and can affect ocular, bulbar (muscles involved in speech, chewing and swallowing), respiratory, and proximal skeletal muscles. Symptoms are worst at the end of the day or after exertion. Classification of myasthenia depends on whether the patient has only ocular or ocular and extraocular weakness.		}}'''Myasthenia gravis''' is an autoimmune disease that produces antibodies against nicotinic acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction, leading to varying degrees of muscle weakness and fatigue and can affect ocular, bulbar (muscles involved in speech, chewing and swallowing), respiratory, and proximal skeletal muscles. Symptoms are worst at the end of the day or after exertion. Classification of myasthenia depends on whether the patient has only ocular or ocular and extraocular weakness.

	==Anesthetic implications<!-- Briefly summarize the anesthetic implications of this comorbidity. --> ==		==Anesthetic implications<!-- Briefly summarize the anesthetic implications of this comorbidity. -->==

	===Preoperative optimization<!-- Describe how this comorbidity may influence preoperative evaluation and optimization of patients. -->===		===Preoperative optimization<!-- Describe how this comorbidity may influence preoperative evaluation and optimization of patients. -->===
Line 32:		Line 32:
	**Possibility of disrupting bowel anastomoses secondary to hyperperistalsis		**Possibility of disrupting bowel anastomoses secondary to hyperperistalsis
	**Cholinergic side effects including salivation, miosis, bradycardia		**Cholinergic side effects including salivation, miosis, bradycardia
	* IV pyridostigmine is 1/30 of the PO dose		*IV pyridostigmine is 1/30 of the PO dose

	====Labs and studies====		====Labs and studies====
Line 38:		Line 38:
	**If thymoma present, may be useful to characterize obstruction		**If thymoma present, may be useful to characterize obstruction

	====Premedication ====		====Premedication====
	*Consider pretreatment with metoclopramide or H2 blocker for aspiration prophylaxis		*Consider pretreatment with metoclopramide or H2 blocker for aspiration prophylaxis
	**Patients with involvement of respiratory or bulbar muscles are at higher risk for aspiration		**Patients with involvement of respiratory or bulbar muscles are at higher risk for aspiration
Line 44:		Line 44:
	*IVIG or plasma exchange can be used to improve symptoms of active flare for emergent cases		*IVIG or plasma exchange can be used to improve symptoms of active flare for emergent cases

	==== Associated comorbidities====		====Associated comorbidities====
	*Thymoma		*Thymoma
	* Diabetes mellitus		*Diabetes mellitus
	*Thyroid disorders		*Thyroid disorders
	*Systemic lupus erythematosus		*Systemic lupus erythematosus
Line 55:		Line 55:
	====Neuromuscular blockade====		====Neuromuscular blockade====
	Patients with myasthenia gravis are:		Patients with myasthenia gravis are:
	* More sensitive to nondepolarizing neuromuscular blockers		*More sensitive to nondepolarizing neuromuscular blockers
	*Resistant to succinylcholine		*Resistant to succinylcholine
	** At increased risk for developing phase II neuromuscular block, particularly with repeat doses of succinylcholine		**At increased risk for developing phase II neuromuscular block, particularly with repeat doses of succinylcholine
			**ED95 is 2.6 times normal in these patients.<ref>{{Cite book\|last=Barash\|first=Paul\|title=Clinical Anesthesia\|publisher=Wolters Kluwer\|year=2017\|isbn=978-1-4963-3700-9\|location=Philadelphia, PA\|pages=1067}}</ref>
	*In patients taking an acetylcholinesterase inhibitor for myasthenia management, cholinergic crisis is possible if acetylcholinesterase inhibitor is used for neuromuscular blockade reversal		*In patients taking an acetylcholinesterase inhibitor for myasthenia management, cholinergic crisis is possible if acetylcholinesterase inhibitor is used for neuromuscular blockade reversal

	==== Airway management ====		====Airway management====

	* Consider increased aspiration risk if bulbar symptoms are present		*Consider increased aspiration risk if bulbar symptoms are present
	* If thymoma present, may cause anterior mediastinal mass effect		*If thymoma present, may cause anterior mediastinal mass effect

	====Other medications====		====Other medications====

Chris.Rishel at 01:59, 22 February 2022

2022-02-22T01:59:15Z

← Older revision		Revision as of 18:59, 21 February 2022
Line 36:		Line 36:
	====Labs and studies====		====Labs and studies====
	*PFTs may be helpful to establish baseline respiratory function		*PFTs may be helpful to establish baseline respiratory function
	**If thymoma present, may be ~~of particular use~~ to characterize ~~any related~~ obstruction		**If thymoma present, may be useful to characterize obstruction

	====Premedication ====		====Premedication ====
Line 59:		Line 59:
	** At increased risk for developing phase II neuromuscular block, particularly with repeat doses of succinylcholine		** At increased risk for developing phase II neuromuscular block, particularly with repeat doses of succinylcholine
	*In patients taking an acetylcholinesterase inhibitor for myasthenia management, cholinergic crisis is possible if acetylcholinesterase inhibitor is used for neuromuscular blockade reversal		*In patients taking an acetylcholinesterase inhibitor for myasthenia management, cholinergic crisis is possible if acetylcholinesterase inhibitor is used for neuromuscular blockade reversal

			==== Airway management ====

			* Consider increased aspiration risk if bulbar symptoms are present
			* If thymoma present, may cause anterior mediastinal mass effect

	====Other medications====		====Other medications====

Chris.Rishel at 01:56, 22 February 2022

2022-02-22T01:56:22Z

← Older revision		Revision as of 18:56, 21 February 2022
Line 17:		Line 17:
	\| image =		\| image =
	\| caption =		\| caption =
	}}		}}'''Myasthenia gravis''' is an autoimmune disease that produces antibodies against nicotinic acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction, leading to varying degrees of muscle weakness and fatigue and can affect ocular, bulbar (muscles involved in speech, chewing and swallowing), respiratory, and proximal skeletal muscles. Symptoms are worst at the end of the day or after exertion. Classification of myasthenia depends on whether the patient has only ocular or ocular and extraocular weakness.

	'''Myasthenia gravis''' is an autoimmune disease that produces antibodies against nicotinic acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction, leading to varying degrees of muscle weakness and fatigue and can affect ocular, bulbar (muscles involved in speech, chewing and swallowing), respiratory, and proximal skeletal muscles. Symptoms are worst at the end of the day or after exertion. Classification of myasthenia depends on whether the patient has only ocular or ocular and extraocular weakness.

	==Anesthetic implications<!-- Briefly summarize the anesthetic implications of this comorbidity. --> ==		==Anesthetic implications<!-- Briefly summarize the anesthetic implications of this comorbidity. --> ==

Chris.Rishel: Major reorganization and addition of content

2022-02-22T01:56:10Z

Major reorganization and addition of content

Show changes

Oliviamsutton at 16:58, 7 December 2021

2021-12-07T16:58:49Z

← Older revision		Revision as of 09:58, 7 December 2021
Line 55:		Line 55:

	== Diagnosis<!-- Describe how this comorbidity is diagnosed. --> ==		== Diagnosis<!-- Describe how this comorbidity is diagnosed. --> ==
			Not to be confused with [[congenital myasthenic syndromes]] (CMS) or [[Lambert-Eaton syndrome]]

	== Treatment<!-- Summarize the treatment of this comorbidity. Add subsections as needed. --> ==		== Treatment<!-- Summarize the treatment of this comorbidity. Add subsections as needed. --> ==

Oliviamsutton: Created page with "{{Infobox comorbidity | other_names = Myasthenia | anesthetic_relevance = High | anesthetic_management = | specialty = | signs_symptoms = | diagnosis = | treatment = | im..."

2021-12-07T15:31:28Z

Created page with "{{Infobox comorbidity | other_names = Myasthenia | anesthetic_relevance = High | anesthetic_management = | specialty = | signs_symptoms = | diagnosis = | treatment = | im..."

New page

{{Infobox comorbidity
| other_names = Myasthenia
| anesthetic_relevance = High
| anesthetic_management =
| specialty =
| signs_symptoms =
| diagnosis =
| treatment =
| image =
| caption =
}}

Myasthenia gravis is an autoimmune disease that attacks post-synaptic nicotinic acetylcholine receptors at the NMJ, leading to varying degrees of muscle weakness and fatigue and can affect ocular, bulbar (muscles involved in speech, chewing and swallowing), respiratory, and proximal skeletal muscles. Symptoms are worst at the end of the day or after exertion. Classification of myasthenia depends on whether the patient has only ocular or ocular and non-ocular weakness.

== Anesthetic implications ==

=== Preoperative optimization ===

**

* A steroid listed on a patient’s medication profile indicates a higher risk and elective procedures should be postponed if possible.
* Patients with involvement of respiratory or bulbar muscles tend to have a higher risk for aspiration so pretreatment with metoclopramide or H2 blockers may be helpful. Some MG patients are sensitive to respiratory depressants and premedication with opioids, BZDs, or barbiturates should be considered carefully or not at all.
* IVIG or plasma exchange can be used in emergent cases.
* Diseases associated with MG include DM, thyroid disorders, SLE and RA.
* Patients with MG are resistant to succinylcholine and are exquisitely sensitive to non-depolarizing NMBs.
* Patients should take their morning dose of acetylcholinesterase inhibitor though doing so may result in:
** Altered patient drug requirements following surgery
** Increased vagal reflexes
** Possibility of disrupting bowel anastomoses secondary to hyperperistalsis
** Significant side effects including salivation, miosis, bradycardia and even cholinergic crisis if given NMB reversal

=== Intraoperative management ===

* Of note, IV pyridostigmine is 1/30 of the PO dose.

=== Postoperative management ===

* Extubation: performed on awake patients and hopefully close to his/her baseline status. Reinstitute anticholinesterase medication, either by IV infusion or by reimplementation of the patient’s oral regimen.
* Leventhal Criteria: Predictive risk factors for post-operative ventilation support:
** Disease duration > 6yrs
** Concomitant pulmonary disease
** Peak inspiratory pressure < -25 cmH2O
** Vital capacity < 40 mL/kg (or <2.9L)
** Pyridostigmine dose > 750 mg/d

* Other indicators include preoperative use of steroids, and previous episode of respiratory failure.
* Drugs to avoid: Calcium Channel blockers, Magnesium, Aminoglycoside antibiotics as all of these may contribute to muscle weakness
* Post-Op Bed: Patients should be monitored in either a ICU or step-down unit but NOT to a conventional surgical ward.

== Related surgical procedures ==

== Pathophysiology ==

== Signs and symptoms ==

== Diagnosis ==

== Treatment ==

=== Medication ===

=== Surgery ===

=== Prognosis ===

== Epidemiology ==

== References ==
[[Category:Comorbidities]]