Myasthenia Gravis in Children

00:01 Let's switch to Myasthenia Gravis.

00:04 Many students think of Gravis as an adult disease.

00:07 But there are absolutely, rarely pediatric variants both in the newborn period and later on in childhood.

00:16 Myasthenia Gravis of the newborn it presents as a chronic muscle weakness with fatigability.

00:23 This is an autoimmune attack of antibodies against the Acetylcholine receptors in the post synaptic muscle.

00:30 In newborn disease, this is often because the mother has Myasthenia Gravis.

00:35 So mothers with Myasthenia Gravis have transplacental migration of their immunoglobulin or IgG which is direct against Neuromuscular injuctions.

00:45 This crosses the placenta and then attacks the infants neuro muscular injuction.

00:50 Infants may be sick for several weeks before they resolve as immunoglobulins can persist for a long time in the child after transplacental migration from the mother.

01:02 Patients present with fatigable weakness and they may have ocular muscle problems.

01:08 This is common especially early in disease. So they have a disconjugate gaze.

01:13 They can also have Ptosis and they often have diplopia.

01:18 Diplopia is not going to be a complaint that a child is going to have.

01:22 But you will see the disconjugate gaze.

01:24 Older children, who are already developing Myasthenia Gravis because they are having their own autoimmune event, will complain of Diplopia.

01:31 Myasthenia Gravis is caused by antibodies directed against the acetyl-choline receptor.

01:38 And these antibodies can absolutely be measured.

01:41 So the diagnosis is made by simply checking for the auto antibodies.

01:45 However, false negatives can occur.

01:47 And in cases where we suspect Myasthenia Gravis, we can do nerve conduction studies to make that diagnosis more definitively.

01:55 Another definitive way to make the diagnosis is to do the Tensilon test.

02:00 Remember, tensilon is effective because in patients with Myasthenia Gravis, tensilon will prevent the reuptake of the acetyl-choline and will cause a transient increase of Acetyl-choline in the Neuromuscularinjunction.

02:17 As a result, the patient should have a transient loss of symptoms.

02:21 The provision of tensilon should make the patient essentially improve immediately.

02:26 Treatment of Myasthenia Gravis involves providing Acetyl-cholinesterase inhibitors.

02:32 such as pyridostigmine.

02:33 These prevent the breakdown of acetyl-choline breakdown in the neuromuscularjunction and improve neuromuscular signalling.

02:41 Additionally, patients can have immunosupression to prevent the auto antibodies.

02:46 Prednisone is our mainstay therapy.

02:49 IVIG and plasmaphoresis can also be used to prevent those immunoglobulin from attacking the neuromuscularjunction.

02:58 Thymectomy is not recommended in children the way it is in adults.

03:03 In adults that can be curative.

03:04 But in children the thymus is crtically important for the developing of T-cells.

03:09 The thymus is actively involved in developing those T-cells throughout childhood.

03:13 So, we will not due thymectomy on prepubertal children.

03:18 That is all I have to talk to you today about this problem.

03:21 New Entry 51