MS, MG, MD Flashcards
Both d/t weakness; can both be considered disorders of nerve conduction; autoimmune, lymphocytes
MS & MG
Wrap around the axon of a neuron, insulating it, and forming the myelin sheath
Schwann cells
Similar function as Schwann cells, insulating neuronal axons and forming a myelin sheath; only found in the CNS while Schwann cells are only in PNS
Oligodendrocytes
Supporting cell found in the CNS; form a spider like network and facilitate nutrient extraction from the blood supply and disposal of cellular waste products
Astrocytes
Exclusive to CNS, circulate through the nervous system helping with immunity by destroying bacteria or dead cells
Microglial cells
Line areas of the NS that have CSF and thees cells help circulate the fluid
Ependymal cells
Autoimmune disease? which causes inflammatory demyelination of CNS (no specific antibody found); Demyelination of axons reducers neurons ability to function
Multiple sclerosis
Inflammation-> demyelination-> axonal degeneration
Multiple sclerosis
Shows response to tx w/ immunomodulating rx
Multiple sclerosis
Disruption of BBB; Rx that block T cell movement into CSF improve the sx/s of this
Multiple sclerosis
Sx/s= weakness, fatigue, numbness, tingling, unsteadiness in a limb, spastic paraparesis; retrobulbar neuritis/ optic neuritis (blurred/dimmed vision, blind spots, pain w/ eye movement, HA, sudden color blindness, impaired night vision, impaired contrast sensitivity, diplopia); disequilibrium/vertigo, pain, sphincter disturbance
Multiple Sclerosis (sxs very vague!)
Relapses and remissions; onset between 15-50; optic neuritis; Lhermitte’s sign (person flexes neck and get a shock like pain down their spine); Internuclear ophthalmoplegia; fatigue, Uhthoff’s phenomenon (symptoms worsened in HOT environments)
Multiple sclerosis
Dx: must show 2 or more DIFFERENT areas in central areas of white matter affected at DIFFERENT times
Multiple sclerosis
Test of choice to dx clinically suspected MS=
MRI
Lesion is the cerebral or spinal plaque-discrete region of demyelination with initially preserved axon; found in the periventricular, juxtacortical, infratentorial and/or spinal cord
Multiple sclerosis
Dx: increased Gadolinium enhancement may indicate acute lesion (often asymptomatic)
Multiple sclerosis
Lumbar puncture may have mild lymphocytosis, may have IgG in CSF; albumin in CSF indicated disruption of BBB; Presence of oligoclonal bands (series of distinct bands found in the immunoglobulin of the CSF) is highly suggestive
Multiple sclerosis
Type of MS; an initial episode then months/years before new systems emerge or previous symptoms return; cycle can lead to incomplete remissions and progressive disability with weakness, spasticity, ataxia of limbs, impaired vision and urinary incontinence; physical findings= optic atrophy, nystagmus, dysarthria, pyramidal/sensory/cerebellar deficits in one or multiple limbs; Uhthoff’s phenomenon!
Relapsing-remitting MS (RRMS)
NO CURE; tx aimed at improving quality of life and limiting disability; acute attached tx with glucocorticoids (methylprednisolone)
Multiple sclerosis
First drugs that were available for MS; cytokine that modulates immune responsiveness
Interferons
Disease modifying therapy for MS, CIS=
injection therapy w/ interferon beta or glatiramer
Disease modifying therapy for RRMS-“convenience” approach=
oral therapy with dimethyl fumarate or teriflunomide
Disease modifying therapy for RRMS-“efficacy” approach=
infusion therapy with natalizumab
Problem at the synapse, rather than the myelin sheath:
Myasthenia gravis
autoimmune disease; uncommon; MC disease of neuromuscular transmission; Ab against nicotinic AchR at NMJ; some Ab impair ability of Ach to bind to AchR, other Ab destroy AchR
Myasthenia gravis
Also, Ab against MuSK (muscarinic tyrosine kinase); MuSK proteins mediate clustering of AchR during NMJ formation and associated with AchR maintenance; Ocular and generalized manifestations
Myasthenia gravis
Up to 75% of pts have thyme abnormalities
Myasthenia Gravis
Organ located in the upper anterior portion of the chest cavity just behind the sternum; main function is to roved an area for T lymphocyte maturation; vital in protecting against autoimmunity
Thymus
Commonly associated with facial symptoms, ptosis, diplopia, bulbar muscle weakness, expressionless face, neck muscles; May progress DOWN to respiratory muscles, limb weakness
Myasthenia Gravis
Fatiguability of muscles; may have frank ptosis on exam, slack jaw; The simpson test; Cogan lid twitch sign
Myasthenia Gravis
Short-acting AchE inhibitor; c/i in pts with cardiac disease or asthma; may proceed increased salivation or adnominal cramping, symptomatic bradycardia or bronchospasm
Tensilon test
Have circulating Ab against nicotinic AchR
Myasthenia gravis
Most pts with Seropositive, have timid abnormalities, especially AchR-Ab
Myasthenia gravis
Includes electrophysiologic testing: repetitive nerve stimulation studies; single fiber EMG
Myasthenia gravis
Respiratory weakness may lead to respiratory failure; can occur spontaneously during active phase of disease or be precipitated by surgery, infection, medications or tapering of immunosuppression;
Myasthenia gravis: CRISIS
Inherited disorders causing progressive muscle weakness and atrophy d/t a genetic defect; common theme of muscle weakness; some forms cause cardiac dysfunction and cognitive deficits
Muscular dystrophies
Defective gene on X chromosome responsible for producing dystrophin (a protein that protects muscles); a dystrophin deficit leads to enzymatic muscle breakdown; occurs in males; Sx/s start centrally (trunk) and spread to legs first; elevations in CK
Duchenne muscular dystrophy (DMD)
Those affected make SOME dystrophin; defective gene on X chromosome responsible for producing dystrophin; occurs in males
Becker muscular dystrophy
Can occur in M/F; muscle weakness usually begins in arms in teen years, then progresses to legs and face; CLASSIC TRIAD (contractors of elbows, ankle plantar flexors and spine early; later onset of humeroperoneal weakness, & cardiac abnormalities)
Emery-Dreifuss Muscular dystrophy
MC form of MD (in whites); M/F; 2 genetic subtypes; muscle stiffness, inability to relax muscles after contraction; affects different body systems causing muscle loss and weakness-facial muscles, arms, legs, also cardiac complications, cataracts, abnormal intellectual functioning, excessive daytime somnolence
Myotonic dystrophy
Multiple subtypes (>20); affects shoulder girdle and/or hip girdle; tx focused on stretching to prevent contractures
Limb-girdle MD
