Chronic Neurologic Disorders CH 234

Chronic Neurologic Disorders CH 234 November 3, 2009

Amyotrophic Lateral Sclerosis • Aka ALS or Lou Gehrig disease • Rapidly progressive muscle atrophy and weakness • Degeneration of both upper and lower motor neurons • Causing varying degrees of spasticity, hyper-reflexia, and muscle paralysis • Sensory and cognitive function is usu. Spared • Progressive respiratory muscle weakness • 50% die in 3 yrs of diagnosis

ALS in the ED • Acute respiratory failure: may need intubated (ABG not reliable tool to assess impending failure) • Aspiration pneumonia • Choking episodes • Trauma from extremity weakness

Myasthenia Gravis • Autoimmune disease • Acetylcholine receptor antibodies impair receptor fxn • “great imitator” • General weakness, esp proximal muscle groups • Ptosis and diplopia first and later dysphagia • Symptoms worse with prolonged use, improves with rest • Usu. no sensory, reflex or cerebellar deficit

Myasthenia Gravis • Myasthenic crisis: respiratory failure from weakness • May be drug induced or related to a thymoma • Dx with edrophonium chloride, EMG and serum studies • Tx is with cholinergic inhibitor such as pyridostigmine (do not miss doses) • Most significant ED complication is need for intubation • Avoid depolarizing or nondepolarizing paralytic agents as they persist in the system 3x as long

Tensilon Test • Determines disease exacerbation vs excessive cholingeric drug therapy • Epdrophonium (tensilon) is given. If the patient has resolution of weakness, then it is considered a positive test and due to exacerbation • Negative if muscle fasciculations, resp depression or cholingeric symptoms occur with Tensilon • A positive result should be followed with longer acting Neostigime

Multiple Sclerosis • Motor, sensory, visual, and cerebellar dysfunction caused by CNS myelin destruction • May be relapsing remitting, relapsing progressive or chronically progressive • Seen most commonly in women in 20-30 who live in the north and are white • Diagnosed by MRI (multiple plaques on brain and spinal cord that may resolve and reform in other areas), LP and clinical signs/symptoms

Multiple Sclerosis • Optic neuritis is presenting sx in 30% • Symptoms may worsen with heat • Plethora of signs including gait disturbance, weakness, incontinence, dementia, vertigo,etc • High dose methylprednisolone shortens exacerbations • Long term therapy by neurology with interferon-B and immunosuppressive meds

Lambert-Eaton Myasthenic Syndrome • Autoimmune disorder causes fluctuating weakness and fatigue esp of the proximal limb muscles • Show improvement with sustained or repeated exercise, Lambert sign • c/o myalgias, muscle stiffness, paresthesia, metallic tase and muscarinic insufficiency (dry mouth) • Assoc with older men who smoke and have lung CA • Supportive tx

Parkinson Disease • Chronic neurodegernerative disease • Extrapyramidal movement disorder: resting tremor, cogwheel rigidity, bradykinesias or akinesia and impaired postural reflexes • Reduced number of functional dopaminergic receptors in substantia nigra with presence of Lewy bodies • Tx with anticholinergics; levodopa or carbidopa; and dopamine receptor agonists ie bromocriptine

Polio Myelitis and Postpolio Syndrome • Neurotropicenterovirus that causes paralysis through motor neuron destruction, muscle denervation, and atrophy • 80% are asymptomatic, 1-2% get major illness with neurologic abnl • Most will resolve in 1 yr but 20% will develop bulbar polio (speech, swallowing, facial muscle, and extraocular muscle dysfunction) • Postpolio syndrome ~30yrs after the initial and affects muscles/joints intially spared • Consider polio if acute febrile illness, aseptic meningitis and asymmetric flaccid paralysis with loss of reflexes and normal sensation

Sources • Tintinalli’s 6th edition

Chronic Neurologic Disorders CH 234