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271

Local anesthetics

Amides are lidocaine, mepivacaine, bupivacaine. Esters are procain, cocaine, tetracaine.

272

Mech of local anesthetics

Block Na+ channels (inner portion) and preferentially bind to activated ones. Tertiary amines penetrate membrane uncharged, then after charge, bind ions.

273

Factors affecting the effectiveness of local anesthetics?

It's hard for charged, alkaline anesthetics to get into infected (acidic) tissue. Order of nerve blockade small diameter > large diameter. Then myelinated > unmyelinated. Lose pain, temp, touch, then pressure. Can give with vasoconstrictors like epi to enhance local action via dec bleeding and dec. systemic conc.

274

Local anesthetic toxicity

CNS excitation, CV tox (bupivacaine), HTN, hypotension, arrhythmias (cocaine)

275

Basic overview of paralytics

Used for surgery or mech ventilation. Selective for motor nicotinic receptors. Depolarizing vs. nondepolarizing = agonist vs. competetive antagonist

276

Succinylcholine

Strong ACh receptor agonist -> sustained depolarization and prevents muscle ctx. Complications - hyperCa, hyperK, malignant hyperthermia. Phase 1 block is prolonged depol. w/ no antidote. Phase 2 block is repolarized but AChR desensitized and req. cholinesterase inhibitors. Patients with hyperK (crush/burn, denervating injuries, myopathies) -> depolarizing agents

277

Dantrolene

Ryanodine receptor. Prevents release of Ca2+ from SR in skeletal muscle. Used for malignant hyperthermia and NMS.

278

Parkinsons drugs

BALSA = Bromocriptine, Amantadine, Levodopa, Selegiline, Antimuscarinics.

279

Selegeline

MAO-B inhibitor that prevents DA breakdown (MAO-B prefers to breakdown DA > NE and 5-HT). Other DA breakdown inhibitors are COMT inhibitors (entacapone and tolcapone)

280

Benztropine

Curbs excess cholinergic activity in Parkinsons as an antimuscarinic.

281

Memantine

Alzheimer's drug. NMDA receptor antagonist. Tox includes dizziness, confusion, hallucinations

282

AChE inhibitors for Alzheimer's

Donepezil, galantamine, rivastigmine.

283

HD drugs

Haloperidol (DA receptor antagonist). Inhibitors of vesicular monoamine transporter (VMAT) - tetrabenazine and reserpine.

284

Sumatriptan

5-Ht1b/1d agonist. Inhibits treigeminal n. activation and prevents vasoactive peptide release. t1/2 <2hrs. Used for acute migraines and cluster headaches. Tox = coronary vasospasm CONTRA = CAD or Prinzmetal angina

285

Myotonic muscular dystrophy

Myotonia = slow relaxation of muscles. Difficulty loosening one's grip. AD. CTG (myotonia-protein kinase). Anticipation. Cataracts. Atrophy of type 1> type 2.

286

Meniere's disease

Increased volume of endolymph. Tinnitus, vertigo, hearing loss is sensorineural (Weber will lateralize to HEALTHY side)

287

Fluorinated anesthetics effect on CV, Resp, Cerebral blood flow, Kidney, hepatic blood flow?

Myocardial depression leads to decreased CO. Hypotension. Respiratory depressant (dec. TV and minute ventilation -> hypercapnea and dec. mucociliary clearance). Halothane and sevolurane have bronchodilation prop's - asthma. Decreased vascular resistance -> increased cerebral blood flow -> ICP. Dec. GFR, increased renal vascular resistance, and decreased RPF. Decreased hepatic blood flow.

288

How does solubility of anesthetic in peripheral tissues effect anesthetic concentration?

If peripheral tissue solubility is high (AV gradient high), then it takes more anesthesia to saturate the blood and the brain.

289

How does pulmonary ventilation rate affect anesthetic concentration?

Rise of gas tension in alveoli is proportional to the rate AND depth of respiration.

290

How does the blood/gas partition coefficient affect the action of anesthetics?

Higher blood/gas partition coefficient means highly SOLUBLE --> blood saturates slowly leading to delayed rise in partial pressure -> increasing onset of time. (e.g. halothane)

291

MS path

Plaques. Demyelination w/ relative preservation of axons. Accumulation of lipid-laden macrophages. Astrocytosis. Infiltration by lymphocytes and mononuclear cells.

292

Pheochromocytoma

PNET tumor of chromatin cells of sympathetic nervous system (90% from adrenal medulla).

293

HD location

AD 100% penetrance. Loss of neurons in caudate nucleus and putamen (striatum). STN lesion = hemiballismus.

294

Side effects for 1st gen antipsychotics?

Generally, low-potency (Chlorpromazine and thioridazine) have more non-neuro SE's (sedation, Antichol, orthostatic hypotension). High-potency (haloperidol, fluphenazine) will have EPS - acute dystonia, akathisia, parkinsonism.

295

Congenital torticollis

Etio - birth trauma or malposition of head in utero -> SCM injury and fibrosis. Develops by wk 2-4. Head tilted toward AFFECTED side with CHIN pointed AWAY. Good prognosis. Tx = conservative and stretching

296

Alcoholic cerebellar degeneration

Chronic thiamine deficiency. Gait ataxia, truncal instability, intention tremor. Atrophy of anterior lobes and cerebellar vermis.

297

Two ways that tumors increase ICP?

Blockage. Breakdown of the BBB.

298

How does NPH lead to urinary incontinence?

Disrupts paraventricular fibers from cortex which normally inhibit the SACRAL micturition center (responsible for bladder contraction and found in S2-S4 level)

299

Causes of exacerbations of myasthenia gravis?

(1) Myasthenic crisis 2/2 not enough Ach in cleft (e.g. not enough drug). Dx with edrophonium improvement. (2) Cholinergic crisis 2/2 TOO much Ach -> refractory muslce. Dx with no improvement with edrophonium.

300

Neuroblastoma

Most common extra cranial cancer of children. Found in any neural crest deviated. Associated with N-myc. Paraneoplastic syndrome includes opsoclonus and myoclonus. Often see increased excretion of catecholamines in urine.