Neurodegenerative Diseases and Myasthenia Gravis

Degenerative Diseases

• Characterized by progressive neuronal death, multifactorial
• Examples include multiple sclerosis and myasthenia gravis

Myasthenia Gravis

• Autoimmune-mediated neuromuscular disorder
• More common in women, incidence peaks in 20s and 30s
• Etiology unknown, but genetic factors play a role
• Most patients demonstrate antibodies to acetylcholine receptor
• Seronegative patients often have antibodies to muscle-specific tyrosine kinase (MuSK)
• Cardinal features: weakness, easy fatigability, preserved DTR
• Cranial muscles: diplopia and ptosis

Multiple Sclerosis

• Characterized by immune-mediated focal or patchy destruction of myelin sheaths
• Inflammatory response and demyelination
• Classic findings: sensory loss, visual symptoms, weakness
• Genetic and environmental factors, including exposure to bacteria and viruses
• 4 Clinical Types: relapsing-remitting, secondary progressive, primary progressive, and progressive-relapsing
• Relapsing-remitting MS: 90% of affected individuals, unpredictable recurrent episodes of neurological dysfunction
• Secondary progressive MS: relapsing disease that begins to pursue a progressive downhill course after each relapse

Arteriovenous Malformations

• Rare in pregnancy
• Congenital focal abnormal conglomerations of dilated arteries and veins
• Lack capillaries and have arteriovenous shunting
• When AVMs bleed, half do so into the subarachnoid space, half are intraparenchymal with subarachnoid extension
• Mode of delivery: cesarean delivery, high risk of recurrent hemorrhage from an unresected or inoperable lesion

Diagnosis and Management

• MRI: superior diagnostic test for demyelinating diseases
• Cerebrospinal fluid analysis: characteristic multifocal white-matter plaques
• Treatment of subarachnoid hemorrhage: bed rest, analgesia, neurological monitoring, and strict blood pressure control
• Early repair after the sentinel hemorrhage is recommended