Myasthenia Gravis
Plasmapheresis
- Goal is to improve muscle strength -Insertion in a large bone dual lumen Cath -Blood id moved through arterial lumen and circulated through the plasmapheresis machine which removes antibodies that block AChR function.
MG Actions
-Adm medications 30 mins to 1 hr before activities and eating -Elevate HOB with eating or drinking -Establish communication methods with client -Plan meals at medication peaks -Offer soft foods and thickened liquids -Plan for rest periods between ADLs
Medications that are contraindicated in MG
-Antibiotics -Calcium channel blockers -D-penicillamine -Magnesium
Causes of Myasthenia Gravis
-Autoimmune disease -Thymus gland tumor/ hyperplasia -Ace onset 20-40 yrs in women -60-80 yrs in men
MG Assessment
-Breathing and respiratory effort -Vital capacity measurements -Nutritional intake -I & O -Daily weight -Dysarthris- nasal quality r/t CNs -Dysohagia- weakness of oropharyngeal muscles
Cyclophosphamide (Cytoxan)
-Chemotherapeutic agent -Allows the clients endogenous stem cells ti repopulate the immune system with new lymphocytes -Reboots the immune system
Diagnostic test for Mysthenia Gravis
-Edrophonium test ( Tensilon test) temp -Serum antibiotics -CT/ MRI -EMG -Repetitivr Nerve Stim & EMG showing dec response
Arterial Blood Gases
-In client with MG, it is important to carefully monitor vital capacity measurements. -Pulse oximetry is not helpful in determining respirations - Because of weakness of diaphragm & intercostal muscles -Client retains CO2 and the provider need to obtain and ____________ to assess CO2.
Thymectomy
-Is performed in the first 3 yrs of diagnosis & less than 65 yrs - Medications Neo and IV med is required to maintain muscle strength and respiratory function
Myasthenic Crisis
-Medical emergency- ICU -Cause by a bacterial or viral infection -Causes weakness of Respiratory or Bulbar muscles -S/S- Tachycardia , Flaccid muscles, pale, cool skin -Usually last for 2 weeks
Treatment for Myasthenia Gravis
-No cure -Adm pyridostigmine *30 mins to an 1 hr before meals to improve chewing/ swallowing -Late meds: -Immunglobulin & Plasmapheresis -Thymectomy -ST & dietitian liquids or eternal feeding -Monitor vital capacity. Plus ox not helpful due to diaphragm weakness retains CO2. Need ABG's to assess CO2
Symptoms of Myasthenia Gravis
-Ptosis, muscle weakness, double vision, difficulty swallowing - Bulbar symtoms- the first to appear in 16 % of MG cliens. *CN IX (glossopharyngeal)- swallowing *CN X (Vagus) organs, head,neck, thoracic, abd cavities *CN XI (Spinal accessory) controls movenment of the head, neck,and shoulders *CN XII ( Hypoglossal)- Controls tongue movement
Side effects of Pyridostigmine & Neostigmine
-Pyridostigmine is to be given at night before sleep -Stomach cramps -Diarrhea -Increased secretions -Nausea -Bradycardia -Muscle twitches
MG Diet
-Risk for aspiration -Language pathologist -Registered dietitian -Thickened liquids or enteral tube feeling
Neostigmine (Prostigmin)
-Short acting AChE inhibitor -Adm IV when client oral route is not available -S/S- Bradycardia & Cardiac dyrhythmia -Monitor IV site for patency -IV neostigmine is 1 mg = 60 mg pyridostigmine -Stop oral Pyridostigmine 1 hr before stoping IV drug
MG Teaching
-Wear Medical bracelet -Keep meds with them at all times -Avoid public places to prevent colds & flu -Get vaccines to prevent Flu & Pneumonia -Don't take OTC meds without checking with HCP first - Inform client & family about Myasthenia Gravis Foundation of America
Pyridostigmine is an anticholinesterase medication that will help improve muscle strength. It is important the patient has maximum muscle strength while eating for the chewing and swallowing process. Therefore, the medication should be given 1 hour before the patient eats because this medication peaks (has the maximum effect) at approximately 1 hour after administration. How does the medication improve muscle strength? It does this by preventing the breakdown of acetylcholine. Remember the nicotinic acetylcholine receptors are damaged and the patient needs as much acetylcholine as possible to prevent muscle weakness. Therefore, this medication will allow more acetylcholine to be used...hence improving muscle strength.
A patient with myasthenia gravis will be eating lunch at 1200. It is now 1000 and the patient is scheduled to take Pyridostigmine. At what time should you administer this medication so the patient will have the maximum benefit of this medication?
Mycophenolate mofetil
Acts in B and T cells to inhibit inosine monophosphate (IMP) dehydrogenase-->decreased GMP in de novo purine synth-->decreased DNA synth in B and T cells-->decreased prolif of B and T cells Use = immunosuppressant in transplant pts, also for autoimmune disorders
Positive
An edrophonium injection temporarily improves the condition when the client is in myasthenic crisis ( _______ edrophonium test)
Negative
An edrophonium injection temporarily worsens the condition when a client is in cholinergic crisis ( _____ edrophonium test).
Cholinergic Crisis
Caused by excessive medication -S/S- Bradycardia, fasciculation (muscle twitches) sweating, pallor, excessive secretions, small pupils
-Chocking, aspiration -Respiratory failure -Cholinergic Crisis -MysthenicvCrisis
Myasthenia Gravis Complications
Nicotinic acetylcholine; muscle weakness the nicotinic acetylcholine receptors are attacked by antibodies created by the immune system (hence why this disease is considered autoimmune) or antibodies are inhibiting the function of muscle-specific kinase (which is a receptor tyrosine kinase that helps with maintaining and building the neuromuscular junction). Either way this leads to the neurotransmitter acetylcholine from being able to communicate with the muscle fiber to make it contract.
Myasthenia gravis occurs when antibodies attack the __________ receptors at the neuromuscular junction leading to ____________.
The answers are A, C, D, E, F (restlessness from hypoxia, which is experienced with respiratory failure),
Select all the signs and symptoms below that can present in myasthenia gravis: A. Respiratory failure B. Increased salivation C. Diplopia D. Ptosis E. Slurred speech F. Restlessness G. Mask-like appearance of looking sleepy H. Difficulty swallowing
The patient experiences improved muscle strength. During a Tensilon test Edrophonium is administered. This medication prevents the breakdown of acetylcholine, which will allow more of the neurotransmitter acetylcholine to be present at the neuromuscular junction....hence IMPROVING muscle strength IF myasthenia gravis is present. Therefore, if a patient with MG is given this medication they will have improved muscle strength.
The neurologist is conducting a Tensilon test (Edrophonium) at the bedside of a patient who is experiencing unexplained muscle weakness, double vision, difficulty breathing, and ptosis. Which findings after the administration of Edrophonium would represent the patient has myasthenia gravis?
The answer is C. Clients with MG have weak muscles and this can include the muscles that are used for chewing and swallowing. The patient should choose meal options that require the least amount of chewing and that are easy to swallow. Option C is a thick type of soup and the mashed potatoes are soft....both are very easy to eat and swallow compared to the other options.
Which meal option would be the most appropriate for a patient with myasthenia gravis? A. Roasted potatoes and cubed steak B. Hamburger with baked fries C. Clam chowder with mashed potatoes D. Fresh veggie tray with sliced cheese cubes
Remember patienbecause they've received too much of their anticholinesterase medications (example Pyridostigmine). However, on the other hand, patients who have received insufficient amount of their anticholinesterase medication or have experienced an illness/stress/surgery are most likely to experience a myasthenia crisis. Both conditions will lead to muscle weakness and respiratory failure but from different causes, which is why a Tensilon test is used to help differentiate between the two conditions.
Which patient below is MOST at risk for developing a cholinergic crisis?
The answer is B. Patients with MG tend to have the best muscle strength in the morning after sleeping or resting rather than at the end of the day....the muscles are tired from being used and the muscle become weaker as the day progresses etc. Therefore any rigorous activities are best performed in the morning or after the patient has rested.
You're a home health nurse providing care to a patient with myasthenia gravis. Today you plan on helping the patient with bathing and exercising. When would be the best time to visit the patient to help these tasks? A. Mid-afternoon B. Morning C. Evening D. Before bedtime
Behind the sternum in between the lungs
You're educating a patient about the pathophysiology of myasthenia gravis. While explaining the involvement of the thymus gland, the patient asks you where the thymus gland is located. You state it is located?
Atropine will help reverse the effects of the drug given during a Tensilon test, which is Edrophonium, in case an emergency arises. Edrophonium is a short-acting cholinergic drug, while atropine is an anticholinergic.
You're preparing to help the neurologist with conducting a Tensilon test. Which antidote will you have on hand in case of an emergency?
The answer is B. These medications are not used to treat MG, but ANTIcholinesterase medications (like Pyridostigmine) are used to treat this condition.
You're providing teaching to a group of patients with myasthenia gravis. Which of the following is not a treatment option for this condition? A. Plasmapheresis B. Cholinesterase medications C. Thymectomy D. Corticosteroids
Apheresis process
________is to remove whole blood, the desired component removed, and the remaining portion of blood returned to the donor/patient.)
