Myasthenia gravis during pregnancy

Myasthenia Gravis during pregnancy

Ahmed Alaa el dinAssistant Lecturer of OB/GYN

High Risk Pregnancy UnitCairo University

Items to be discussed in this talk

• What is Myasthenia Gravis?• Incidence• Etiology• Clinical presentation• Examination • Investigations• Clinical classification• Life threatening presentations• Management• Myasthenia Gravis AND pregnancy• Trivia



What is Myasthenia Gravis?

• MYO = MUSCLE• ASTHENIA = WEAKNESS• GRAVIS = SEVERE

Myasthenia Gravis =

Severe Muscle Weakness

What is Myasthenia Gravis?

• MG is an autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatigue.



Incidence

• 1 in 7’500 • Mainly affects females• Age: 20 – 30 years



Etiology

• Autoimmune:IgG vs Acetyl choline receptors (AChR)diminished end-plate action potential weak muscle contractions



Clinical presentation

• The characteristic feature is Fatigability• Initially intermittent symptoms: EYE• Within 1 year: Generalized (85%)• Remissions and Exacerbations

Clinical presentation

• Eye: Diplopia - Ptosis (Early, Common, Symmetrical or Assymetrical)

• Bulbar: Dysphagia – Dysarthria• Face: Difficult smiling & chewing• Respiratory: Dyspnea• Limb: Weakness – Gait• Heart: Not affected



Examination

• Muscle strength: Weakness• Deep tendon reflexes: Normal• Associated autoimmune diseases: SLE,

RA, DM, Thyroid



Investigations

• Edrophonium test: THERAPEUTIC TEST Cholinesterase inhibitor ↑ available ACh Clinical improvement occurs in 10-60 sec and lasts for approximately 10 min

• Anti-AChR antibody: MOST SPECIFIC Sensitivity: 80-95% except ocular MG (50%)

• EMG• Pulmonary function tests• CT or MRI: Thymoma (75%)• Screen for other autoimmune diseases



Classification

• Class I: Eye muscle weakness only• Class II: Eye muscle weakness + mild

weakness of other muscles• Class III: Eye muscle weakness +

moderate weakness of other muscles• Class IV: Eye muscle weakness +

severe weakness of other muscles OR need for nasogastric feeding• Class V: Intubation needed to maintain

airway



Life threatening presentations

Crises may be precipitated by:• Systemic diseases• Concurrent infections • Emotional upset

Life threatening presentations

• Myasthenic crises: severe muscle weakness, inability to swallow, and respiratory muscle paralysis

• Refractory crises:the same symptoms but unresponsive to the usual therapy

• Cholinergic crises: excessive cholinergic medication leads to nausea, vomiting, muscle weakness, abdominal pain, and diarrhea.



Management

• Medications• Plasmapharesis• Surgery

Management


Medications

• Anti-choline esterase:- Neostigmine and Pyridostigmine - Action: slowing cholinesterase that degrades

acetylcholine in the motor end plate becomes present longer to stimulate its receptor improve muscle function

- Dose & Administration: Start with a low dose, e.g. 3 x 20 mg pyridostigmine, and increase until the desired result is achieved. If taken 30 minutes before a meal, symptoms will be mild during eating. - Side effects: Perspiration and diarrhea- Toxicity: Cholinergic crises (D.D. Myasthenic crisis)

Medications

• Immunosuppressives:- Corticosteroids e.g. Prednisone- Azathioprine- Cyclosporin- Mycophenolate- Cyclophosphamide for refractory cases• Immunoglobulin therapy:- 0.4 gm/kg/day for 5 days• Pulse steroid: - Methylprednisolone

Myasthenic crisisOR

Before surgery

Management


Plasmapharesis

- Effective- Expensive

For:- Myasthenic crisis- Before surgery

Management


Surgery

Thymectomy For:Thymoma OR Thymic hyperplasia (75%)



Myasthenia Gravis AND Pregnancy

• Effect of pregnancy on MG.• Effect of MG on pregnancy & labor.

• Pre-conceptional management.• Antenatal management.• Management during delivery.• Postpartum management




Effect of pregnancy on MG

• Unpredictable: Worsens, improves or unchanged.

• Risks: Exacerbation, Crises, Respiratory complications necessitating ventilation, Death

• Most dangerous in 1st ∆




Effect of MG on pregnancy

• Maternal:- Pre-eclampsia (Immunological theory) ?- Hydramnios ?- Prolonged 2nd stage (Can’t bear down)- ↑ C.S.• Fetal:- IUGR- PTL- Miscarriage & Still birth- Neonatal MG (10-20%)


• Effect of pregnancy on MG.• Effect of MG on pregnancy.


Pre-conceptional management

• Counselling about risks (maternal-fetal)• Pregnancy better avoided during 1st year• Pregnancy better postponed till a

period of remission• Review medications• Consider thymectomy before pregnancy




Antenatal management

• Team: OB/GYN + Neurologist + ……• Frequent hospitalization• Rest: Physical - Mental• Medications:- Pyridostigmine: (Class C)- Corticosteroids: especially if in remission- Immunosuppressants: Azathioprine , Others - IV Ig • Plasmapharesis: BUT avoid ↓ BP & ↓ volemia• Drugs to be avoided: Narcotics, Muscle relaxants, MgSO4,

Aminoglycosides• Fetal surveillance




Management during delivery

• Time: according to obstetric indication• Route: according to obstetric indication• Oxytocin: allowed• Epidural & Regional analgesia: allowed• Drugs to be avoided: Narcotics, Muscle

relaxants for GA, MgSO4, Aminoglycosides• 2nd stage: Forceps




Postpartum management

• Revise medications: doses• Newborn:- 85% have antibodies- 10 – 20% have symptoms• Weak cry, poor suckling and respiratory

distress• Temporary: resolves within 2 to 6 weeks• Treatment: parenteral neostigmine or small

doses of edrophonium



Trivia

Celebreties diagnosed with MG

Trivia “ Celebreties diagnosed with MG”


• Aristotle Onassis (Business man)



• Paris Hilton (Actress)



• Amitabh Bachchan (Actor)



• Sleepy (Cartoon character)

THANK YOU

Health & Medicine

Myasthenia gravis during pregnancy