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86 Cards in this Set
- Front
- Back
1 in 1000 persons has ______, which could be primary or secondary, secondary or peripheral
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dysautonomia
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Intraoperatively, dysautonomia is characterized by _____ responses to many physiological and pharmacologic stimuli.
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paradoxical
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What diseases can cause primary autonomic failure?
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- MSA (multiple system atrophy)
- shy-drager - parkinsons - lewy body dementia - autoimmune ganglionic neuropathy - familial dysautonomia - purre autonomic failure - dopa beta hydroxylase deficiency |
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What are the causes of secondary autonomic failure?
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- afferent baroreceptor failure
- DM - spinal cord injury |
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Proper functioning of the ANS requires intant ____ and ____ limbs.
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afferent and efferent
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What do afferent neurons do?
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detect changes in BP and temp, communicate these changes centrally
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What is afferent neuron dysfunction associated with?
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- labile HTN (baroreflex failure) particularly during postop period after endarterectomy or other neck surgeries affecting carotid sinus nerve
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What do efferent neurons do?
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engage effectors to perturb or restore homeostasis
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Abnormalities of central autonomic pathways such as in pts with ____, or efferent effector systems as in pts with ________, _______, or any combination thereof all can lead to clinical autonomic failure and _______.
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MSA,
pure autonomic failure, pts with dopamine beta hydroxylase deficiency, orthostatic hypotension |
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Which pts are the most vulernable to the complex and interacting responses to drugs and perturbations that occur during anesthesia?
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MSA
extremely low BP upright, extremely high BP supine |
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What are the hallmarks of autonomic dysfunction?
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1. orthostatic hypotension (at least 20/10 decr over 3 min in standing position)
2. major BP changes to trivial stimuli (DECR w standing, eating, hyprventilation, straining/valsalva, fever/heat, exercise, dehydration; INCR w lying supine, water ingestion, hypoventilation, abdominal binding, caffiene, t-berg) - urinary bladder dysfunction (Retention), ED, GI immotility, supine natriuresis |
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BP changes in autonombic dysfunction may be as great as...
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100/50!
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Supine HTN
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- >50% dysautonomic pts get severe HTN SBP <200 when supine
-supine natriuresis leads to orthostatic hypotension, accentuating HD lability - possibly caused by residual sympathetic tone causing incr peripheral vascular resistance (Despite generally low NE and renin activity) |
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What is denervation hypersensitivity?
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- pts w MSA, Shy-Drager/Autonomic failure have very LOW baseline NE/renin levels, fail to incr baseline plasma NE when challenged
- decr/absent neural traffic --> adrenergic receptor upregulation in vascular endothelium --> more dramatic in peripheral vs central dysautonomic dz. |
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The ______ tests several components of the baroreflex arc.
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valsalva maneuver
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The increases in intrathoracic pressure seen during valsalva _______ stroke volume and BP.
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increases
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The valsalva will cause a _____ in BP and CO due to diminished ______ and reflex _____.
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decrease, venous return, tachycardia
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What happens when dysautonomics release their valsalva?
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BP overshoots d/t incr peripheral vascular resistance and CO
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In autonomic dz, the HR changes in phase 2 are _______, and phase 4 and BP are _______.
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attenuated/absent,
accentuated |
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How is the valsalva maneuver test performed?
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- blow through closed mouthpiece w tiny leakage hole (16 gage)
- maintain 40 mmHg approx 15 sec - 4 phases |
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What is the effect of hyperventilation in dysautonomic pts?
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- yields sympathetic response during deep and rapid breathing for 30 sec to counteract systemic vasodilation induced hypocapnea
- significant decr in BP indicates failure/dysfunction |
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Multiple System Atrophy (MSA)
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- primary dysautonomic dz
- rare, severe, SYNUCLEIOPATHY characterzied by alpha-synuclein protein aggregation in neural glia and cytoplasm - degen./dysfcn of various CENTRAL AND PERIPHERAL NS structures - develop multiple features: parkinsonism, cerebellar dysfcn, pyramidal signs |
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How is MSA distinguished from Parkinsons?
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- presence of assymetric resting tremor
- poor response to levodopa - rapidly progressive |
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This is a subset of MSA characterized by degeneration of locus ceruleus, intermediolateral column of spinal cord, and PNS
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Shy Drager
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What is the diagnostic hallmark of Shy Drager?
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ANS degeneration evidenced by orthostatic hypotension, urinary/bowel retention, impotence
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In Shy Drager, the intermediolateral cell column exists at vertebral levels ____ thru ____ and mediates the entire sympathetic innervation of the body, but the nucleus resides in the _____.
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T1-L2,
medulla |
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What secondary dysautonomic dzs can cause afferent baroreflex failure?
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- trauma, surgical trauma (carotid endarterectomy), carotid body tumor, glomus tumor on head/neck, brainstem stroke, cranial nerve damage s/p radiation therapy
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Acute afferent baroreflex failure resembles _____ more than autonomic failure. SBP swings to _____ can occur with seemingly normal stimuli.
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pheochromocytoma,
as high as 320 |
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What is Parkinsonian cardiac autonomic disorder?
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- severe depletion of dopaminergic neurons of the nigrostriatal system --> movement disorder
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How do you provide a "Thoughtful anesthetic" during dysautonomia?
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- understand impact of decr ANS activity on CV responses to events such as changes in body position, positive airway pressure, and acute blood loss (during surgery)
- choose pharm agents w consideration for CV impact |
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How can you ensure HD stability for dysautonomic pts during surgery?
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- preop hydration (preinduction fluid bolus)
- maintain euvolemia - maintain current meds, dont be afraid to treat VS fluctuations - check multiple pre-induction BPs (BP normal in sitting, take BP 1,3,5 min after supination to expose instability) |
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Inpatient _____ will worsen orthostatic changes during general anesthesia in dysautonomic pts.
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deconditioning
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In pts with autonomic dysfcn, any structural lesion of the adrenergic pathways can cause ______. These pts can tolerate lower standing BPs without dizziness/collapse, probably because....
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orthostatic hypotension,
cerebral blood flow preserved from autoregulation |
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In MSA, autoregulation of CBF seems to be preserved down to a SBP of ____, well below the _____ at which autoregulation fails in normal subjects.
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60, 80
still treat hypotension rapidly! |
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Should you be aggressive in controlling orthostatic fluctuations?
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yes! fix promptly
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Hypotension and vasodilation without signs of autonomic compensation require...
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vigilance!
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What can you do to treat hypotension during orthostatic fluctuations?
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head up or down maneuvers
responsive to phenylephrine (sensitive to low doses, esp. in peripheral dysautonomia) |
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Supine HTN may require treatment, but avoid _____.
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long-acting agents
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Carefully dosed precedex, NTG, and nicardipine are better choices for dysautonomic HTN than...
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labetalol or hydralazine
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Liver blood flow in dysautonomics is ____ and ____ Dependent, which may affect hepatically cleared drugs.
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posture and pressure
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Plasma levels of ______ infusion can reach toxic levels depending on a dysautonomic pts position.
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lidocaine
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Which pressors have the greatest effect in dysautonomics?
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phenylephrine, norepi, and vasopressin
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What are the airway complications associated with dysautonomic pts?
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- assume GI motility issues until proven otherwise (RSI)
- in MSA, may display muscle rigidity, vocal cord paralysis, and central resp dysregulation --> complicates intubation and post op ventilation - additional postop risk for obstruction, aspiration and hypoventilation |
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When does orthostatic hypotension become less of an issue during general?
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after positioning is complete
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Anesthesia can suppress any residual _____ neural traffic in dysautonomic pts, disturbing crucial counterregulatory compensation in the face of surgical trauma.
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sympathetic
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The loss of CV reflexes predispose autonomic pts to...
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- dramatic BP changes in response to rapid volume status changes (fluid bolus and blood loss)
- HR may stay fixed in spite of BP changes - a-line, flow-trac |
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How can you adjust your ventilator to optimize hemodynamics in dysautonomics?
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- positive pressure ventilation often elicits sympathetic response, but doesnt in these pts -- consider baseline effect of venous return and CO
- minimize PEEP bc it inhibits venous return - goal to keep CO2 normal, hypoCO2 causes hypotension, hyperCO2 causes HTN |
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What are the goals of temperature regulation intraoperatively for dysautonomics?
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- lose ability to sweat or vasoconstrict in reponse to temp change, complicating temp regulation already impaired under anesthesia
- hyperthermia --> hypotension d/t vasodilation - hypothermia can persist without autnomic compensation (Esp DM) - may have postop fever |
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Hypotension from spinal anesthetic is typically ______ but easily _____. Therefore, its important to consider ____ effect on hemodynamic status prior to initiating regional.
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exaggerated, treated,
positioning's |
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For autonomics receiving regional, ___ and ____ Trump technique.
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euvolemia and vigilant monitoring
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PREOP AUTONOMIC DYSFCN CONSIDERATIONS
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- Ortho hypotension with or without supine HTN
- possible gastroparesis and aspiration risk (RSI) - awareness of blood volume status and prep for blood tx PRN - preinduction fluid bolus |
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INTRAOP DYSAUTONOMIC ANESTHESIA CONSIDERATIONS
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- GA vs RA mostly equivocal
- hyper/hypo thermia both pose risks - positioning may significantly affect Hemodynamics - if severe supine HTN, use NTG, reverse t-berg, precedex, pronation - suddent volume changes pos or neg will yield dramatic HD changes - avoid pneumoperitoneum - pressors may be exaggerated or blunted - replete electrolytes |
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POSTOP DYSAUTONOMIC ANESTHESIA CONSIDERATIONS
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- anticipate volume changes and observe closely
- ensure adequate blood volume to avoid orthostatic events - ensure maint of normothermia - ileus exacerbated by opioids - restart home meds before D/C |
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Glomus tumors
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- neuroendocrine tumor appears in head and neck
- originates in tissue along carotid, aorta, glossphopharyngeal nerve, middle ear (location dictates s/s) - may be secretory (NE - pheomimetic, cholecystekinin - postop ileus, serotonin/kallikrein - carcinodimimetic) |
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Unlike pheochromocytomas, glomus tumors do not secrete ____ because they lack the ___ necessary to convert NE to ___. Administration of ______ may be used preop to lower BP and facilitate volume expansion in pts with incr serum NE.
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epi, transferase, epi, phenoxybenzamine or prazosin
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Secretion of ____ by the duodenal and intestinal mucosa is stimulated by protein or fat rich ____ entering the duodenum. It then inhibits gastric ____ and _____ and mediates digestion in the duodenum.
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CCK, chyme,
emptying and acid secretion, |
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Which is inappropriate as an initial treatment for HTN d/t neuroendocrine tumor in prep for surgical removal?
nitroprusside, metoprolol, phenoxybenzamine, doxazosin? |
metoprolol -- want to lower SVR before vasodilating
bc decr myocardial contractility in the setting of incr SVR will result in heart failure! (always lower SVR prior to beta blockade) |
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When prepping pt for general anesthesia to resect a carcinoid tumor, which drug should be selcted and why?
- thiopental - vecuronium - atracurium - morphine |
vecuronium (no histamine release)
carcinoid tumors often release histamine, so avoid histamine -releasing drugs |
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What is the care plan for a glomus tumor pt?
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- standard monitors, A-Line, large bore IVs, possible central line (Consider tumor location)
- anticipate hyper/hypotension, ensure euvolemia - pheomimetic glomus tumor: Na nitroprusside, phentolamine, nicardipine, mag, clevidipine, vasopressin - carcinoid glomus tumor: octreotide (100 mcg/hr) - intraop: incr VAE risk (monitor w precordial doppler/echo, etco2), avoid NMB if surgeon monitoring facial nerves |
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Idiopathic facial nerve palsy (bell's palsy)
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- rapid paralysis of muscles innervated by facial nerve
- presumed to be inflammation and edema of facial nerve, most often in facial canal of temporal bone - viral inflammatory mechanism (HSV) may be cause - surgical decompression (in severe bell's, trauma) |
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Bell's Palsy pts are likely to be on which medication?
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prednisone
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Facial nerve palsy has been described following placement of ____ to treat ______.
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blood patch, PDPH
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Trigeminal Neuralgia (Tic Delaroux)
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- brief intense unilateral face pain triggered by sensory stimuli to ipsilateral side of face
- likely caused by nerve root compression by abnormal blood vessel |
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What is the drug of choice for trigeminal neuralgia?
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anticonvulsant carbamazepine
also use baclofen and lamotrigine |
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For trigeminal neuralgia pts, you should anticipate ____ during nerve fiber destruction, and _____ from anticonvulsant therapy.
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hypertension,
hepatic enzyme induction |
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Glossopharyngeal neuralgia
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- episodes of intense pain in throat, neck, tongue and ear
- severe brady and cardiac syncope reflecting activation of motor nucleus of vagus - hypotension - seizures d/t cerebral ischemia and possible cardiac arrest |
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What is the anesthetic mgmt for glossopharyngeal neuralgia?
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- antimuscarinic prior to laryngoscopy
- LTA prior to intubation - anticipate hypovolemia and CV abberations intraop - have trancutaneous/venous pacer ready - potential for vocal cord paralysis from surgical trauma may precipitate obstruction after extubation |
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Charcot-Marie Tooth Dz (CMT1A, Chuck Mantooth Dz)
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- most comon 1:2500 inheritied chronic motor/sensory neuropathy
- distal skeletal muscle weakness, wasting loss of tendon reflexes - presents mid-teen yrs |
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Charcot Marie Tooth Dz does not cause ____ but has risks with ___ Administration.
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MH, succ
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Brachial plexus neuropathy (AKA idiopathic brachial neuritis, parsonage-turner syndrome, shoulder-girdle syndrome)
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- inflammatory/immune patho
- acute onset - initial severe pain in upper arm, followed by patchy paresis of skeletal muscles innervated by brachial nerve |
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What is the anesthesia consideration for brachial plexus neuropathy?
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autoimmune neuropathies may be provoked from surgical stress
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Guillain Barre Syndrome (acute idiopathic polyneuritis)
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- sudden onset of skeletal muscle weakness/paralysis that manifests initially in legs and spreads cephalad over ensuing days to arms, trunk, and face
- serious cases involve intercostal and pharyngeal muscle weakness impairing ventilation - may resolve spontaneously |
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What are the anesthesia considerations for chronic cases of guillain barre syndrome?
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- anticipate autonomic lability
- adrenergic and cholinergic receptor upregulation - controlled airway - avoid succ! |
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DM is commonly associated with ______. The longer the hyperglycemia/ hypoinsulinemia is sustained, the greater the extent of _____.
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peripheral polyneuropathy,
neuropathy |
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Nerve conduction velocity _____ secondary to hyperglycemia.
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slows
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Hyperglycemia induces _____ proinsulin producing bone marrow derived cells that travel to the PNS, where they fuse with ____ Cells and ____ neurons, causing neuronal dysfunction and death.
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fusogenic, schwann cells and dorsal root ganglion neuron
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_____ is a key anesthetic consideration for pts with diabetic polyneuropathy.
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positioning
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The peripheral nerves of pts with DM are more vulnerable to _____ due to compression or stretch injury often despite padding and positioning during these periods.
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ischemia
document and get informed consent! |
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What is the most clinically significant type of diabetic neuropathy?
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diabetic autonomic neuropathy
complex, multifactorial patho |
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DM autonomic neuropathy is more common in...
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poorly controlled long-standing diabetics
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____ Stress from hyperglycemia initiates a cascade of cellular mayhem, resulting in....
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oxidative stress,
results in direct nerve damage and microcirculation damage |
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What are the factors involved in the deveopment of DM autonomic neuropathy?
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hyperglycemia causes:
- incr free radicals - decr NO - incr protein kinase C - decr Na-K ATPase |
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S/S of diabetic neuropathy that can be identified on assessment?
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- loss of HR variability w deep breathing (early sign)
- resting tachy (late parasymp destruction) - exercise intolerance - orthostatic hypotension - QT abnormalities (predispose to torsaades!) - HTN - silent ischemia/infarct - CV instability intraop |
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For pts with _____, its not what you use but how you use it with drugs.
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diabetic autonomic neuropathy
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For diabetic autonomic neuropathy, you should expect and anticipate...
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post induction hypotension (MAP decr 30) -- esp in pts taking ACEIs! (-prils)
stimulation w laryngoscopy wont always fix this, give small amts of phenylephrine PRN |
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What are the induction techniques for diabetic autonomic neuropathy?
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higher fi02 60%
get preinduction rhythm strip cardiac style induction (high opioid, low IV agent, low IA, a-line PRN) |