S14C167 - Chronic Neurologic Disorders

Question 1

ALS

Answer 1

• progressive msc atrophy/weakness, spasticity, hyperreflexia, paralysis
• upper and lower motor neurons
• sensory and cognition spared
• mimickers: DM, dysproteinemia, thyroid/PTH dysfxn, B12 def, metal poisoning, vasculitis, CNS/SC tumor

Question 2

Myasthenia Gravis -MG

Answer 2

• autoimmune, muscle weakness/fatigue especially with repetitive movements, ptosis, dyspnea, dysarthria, dysphonia, worsen throughout day
• AChR antibodies cause msc weakness more often in proximal muscles (facial, bulbar)
• weakness improves with rest and requires long-term immunotherapy
• thymus abnormal in 75% of MG pts, removal helps
• DDx: lambert-eaton syndrome, meds (pcn, quinine, aminoglycosdie), botulinism, thyroid d/o
• Dx: EMG, AChR antibody testing,
• Tx: AChEsterase Inhibitors (neostigmine), thymectomy, steroids/AZP, PlEx, IVIG
• avoid parlaytics (succ)

Question 3

MG pts and missed dose pyridostigmine

Answer 3

• usualy dose is 60-90mg PO q4h
• if missed dose, double next dose
• if unable to take PO dose take 1/30th of IV dose (2-3mg), usualy IV dose is 0.5mg

Question 4

MG crisis

Answer 4

• myasthenia crisis (resp failure), test with edrophonium, if Sx improve then pt having crisis, not cholinergic OD
• edrophonium 1-2mg IV up to 10mg providing no cholinergic Sx
• if symptoms worsen iwth edro then cholinergic crisis present (fasciculations, resp depression, cholinergic Sx)

Question 5

MS

Answer 5

• CNS myelin dysfunction
• paresthesias, gait difficulty, extremity weakness, poor coordination, relapsing/remitting
• cerebral and spinal plaques form
• LE >UE
• optic neuritis is presenting complaint in 30% of MS, may cause RAPD (marcus gunn pupil)
• INO is very suggestive of MS (eye adduction and horizontal nystagmus)
• Dx: >2 areas of white matter pathoogy MRI
• DDx: SLE, lyme, neurosyphilis, HIV, GBS

Question 6

Marcus Gunn Pupil

Answer 6

-light shine onto affected eye causes pupil dilatation

Question 7

MS relapse

Answer 7

-occurs over several days, peaks at 1w then resolves over weeks/months

Question 8

MS Tx

Answer 8

-steroids, interferon, natalizumab

Question 9

Lambert-Eaton Myasthenic Syndrome

Answer 9

• fluctuating weakness/fatigue of proximal limb muscles
• may improve with repeated exercises
• c/o myalgias, muscle stiffness, paresthesias, metallic tastes, autonomic Sx (dry mouth)
• from p/q type VG Ca channel antibody
• associated with malignany, occurs in older men most often, assoc with SC lung Ca
• Tx: supportive, treat cancer, AZT, IVIG

Question 10

Parkinson’s Dz

Answer 10

• extrapyramidal mvmt d/o with resting tremor/cogwheel rigidity, bradykinesias/akinesias, impaired postural reflexes
• decreased dopaminergic receptors in substantia nigra, progressive, lewy bodies occur
• Dx: presence of TRAP - Tremor, cogwheel Rigidity, bradykinesia/Akinesia, impairment of Posture and equilibrium
• no definitive lab or imaging study for dx
• resting tremor improves with intentional mvmt

Question 11

Parkinson’s tx

Answer 11

• anticholinergics (benztropine)
• levodopa, amantadine, carbidopa
• dopaminergic OD/toxicity: cardiac dysrhythmias, orthostatic HoTN, dyskinesias, dystonias, nightmares, psychosis, dpn

Question 12

Polio

Answer 12

-enterovirus causes paralysis by destroying motor neurons, denervating muscles, atrophy
-postpolio syndrome is recurrence of Sx decades later (~30y)
-affects anterior horns therefore get proximal msc weakness LE>UE
-asymmetric flaccidity, absent DTR, fasciculations, max paralysis occurs w/in 5d, resolution w/in a year
-20% develop bulbar polio
Dx: CSF pleocytosis, CSF viral Cx, or rectal/throat polio virus Cx
DDx: GBS (more symmetric), mono, lyme, porphyria
Tx: supportive, lamotrigine for postpolio pts