AAN - Miastenia Gravis

Question 1

Qual o objetivo do tratamento da MG?

Answer 1

MMS:Thepatienthasnosymptomsorfunctional limitations from MG but has some weakness on examination of some muscles. This class recognizes that some patients who otherwise meet the definition of remission have mild weakness. CTCAE grade 1 medication side effects: asymptomatic or only mild symptoms; intervention not indicated.

Question 2

Qual a definição de remissão em MG?

Answer 2

The patient has no symptoms or signs of MG. Weakness of eyelid closure is accepted, but there is no weakness of any other muscle on careful examination. Patients taking cholinesterase inhibitors (ChEIs) every day with reasonable evidencetosupportsymptomaticbenefitaretherefore excluded from this category.

Question 3

Qual a definição de MG ocular?

Answer 3

Anyocularmuscle weakness. May have weakness of eye closure. Strength in all other facial, bulbar, and limb muscles is normal. (It is recognized that some patients report fatigue when strength testing is normal. The physician should use clinical judgment in attributing fatigue to generalized MG in the absence of objective nonocular weakness).

Question 4

Qual a definição de crise miastenica?

Answer 4

Worsening of myasthenic weakness requiring intubation or noninvasive ventilation to avoid intubation, except when these measures are employed during routine postoperative management (the use of a feeding tube without intubation places the patient

Question 5

Qual a definição de miastenia gravis refrataria?

Answer 5

PIS3 is unchanged or worse after corticosteroids and at least 2 other IS agents, used in adequate doses for an adequate duration, withpersistentsymptomsorsideeffectsthatlimit functioning, as defined by patient and physician

Question 6

Qual deve ser o tratamento sintomático da miastenia gravis?

Answer 6

Pyridostigmine should be part of the initial treatment in most patients with MG. Pyridostigmine dose should be adjusted as needed based on symptoms.The abilitytodiscontinue pyridostigminecan be an indicator that the patient has met treatment goals and may guide the tapering of other therapies. Corticosteroids or IS therapy should be used in all patientswithMGwhohavenotmettreatmentgoals after an adequate trial of pyridostigmine

Question 7

Qual a imunoterapia no tratamento da miastenia gravis?

Answer 7

A nonsteroidal IS agent should be used alone when corticosteroids are contraindicated or refused. A nonsteroidal IS agent should be used initially in conjunction with corticosteroids when the risk of steroid side effects is high based on medical comorbidities. A nonsteroidal IS agent should be added to corticosteroids when: a. Steroid side effects, deemed significant by the patient or the treating physician, develop; b. Response to an adequate trial (table e-1) of corticosteroids is inadequate; or c. The corticosteroid dose cannot be reduced due to symptom relapse.
Nonsteroidal IS agents that can be used in MG include azathioprine, cyclosporine, mycophenolate mofetil, methotrexate, and tacrolimus. The following factors should be considered in selecting among these agents: a. There is widespread variation in practice with respect to choice of IS agent since there is little literature comparing them. b. Expert consensus and some RCT evidence support the use of azathioprine as a first-line IS agent in MG. c. Evidence from RCTs supports the use of cyclosporine in MG, but potential serious adverse effects and drug interactions limit its use. d. Although available RCT evidence does not supporttheuseofmycophenolateandtacrolimusin MG, both are widely used, and one or both are recommendedinseveralnationalMGtreatment guidelines.

Question 8

Quais as condutas na miastenia gravis refrataria?

Answer 8

Patients with refractory MG should be referred to a physician or a center with expertise in management of MG. In addition to the previously mentioned IS agents, the following therapies may also be used in refractory MG: a. Chronic IVIg and chronic PLEX (see IVIg and PLEX, no. 6); b.Cyclophosphamide; c. Rituximab, for which evidence of efficacy is building, but for which formal consensus could not be reached.

Question 9

Como manejar os imunossupressores na miastenia gravis?

Answer 9

For nonsteroidal IS agents, once treatment goals have been achieved and maintained for 6 monthsto2years,theISdoseshouldbetapered slowly to the minimal effective amount. Dosage adjustmentsshouldbemadenomorefrequently than every 3–6 months (table e-1).
Tapering of IS drugs is associated with risk of relapse, which may necessitate upward adjustments in dose. The risk of relapse is higher in patientswhoaresymptomatic,orafterrapidtaper. d. It is usually necessary to maintain some immunosuppression for many years, sometimes for life.

Question 10

Quais os usos de IVIG e PLEX na MG?

Answer 10

1. PLEX and IVIg are appropriately used as shortterm treatments in patients with MG with lifethreatening signs such as respiratory insufficiency or dysphagia; in preparation for surgery in patients with significant bulbar dysfunction; when a rapid response to treatment is needed; when other treatments are insufficiently effective; and prior to beginning corticosteroids if deemed necessary to prevent or minimize exacerbations. 2. The choice between PLEX and IVIg depends on individual patient factors (e.g., PLEX cannot be usedinpatientswithsepsisandIVIgcannotbeused in renal failure) and on the availability of each. 3. IVIg and PLEX are probably equally effective in the treatment of severe generalized MG. 4. The efficacy of IVIg is less certain in milder MG or in ocular MG. 5. PLEX may be more effective than IVIg in MuSKMG. 6. The use of IVIg as maintenance therapy can be consideredforpatientswithrefractoryMGorforthosein whom IS agents are relatively contraindicated.