Neurological diaseases exam 3 Flashcards
Cerebral blood flow is modulated by: (5)
CMR
CPP (MAP- ICP)
PaCO2
PaO2
drugs, intracranial pathologies
What is normal CBF?
50 mL/100g brain tissue per minute
750 mL/min
15% of CO
What does the intracranial and spinal vault contain?
How much volume does brain tissue, intracranial blood and CSF have combined?
IC and spinal vault contains neural tissue (brain + spinal cord) blood and CSF. Is enclosed by dura matter and bone
-1200-1500 mL (ICP 5-15 mmHg)
What is the monro kellie hypothesis?
Any increase in one component of intracranial volume must be offset by a decrease in an other component to prevent an elevated ICP
How do homeostatic mechanisms support CCP?
Homeostatic mechanisms can increase MAP to support CPP despite increases in ICP, but eventually these compensatory mechanisms fail, result in cerebral ischemia
What do meningeal barriers separate?
Meningeal barriers separate the falx cerebri and tentorium cerebelli
Intracranial vault is compartmentalized
What is the falx cerebri?
What is the tentorium cerebelli?
falx cerebri- dura that ceperates 2 cerebral hemispheres
tentorium cerebelli: dura that lies the rostral to the cerebellum and marks the border between the supratentorial and infratentorial spaces
increases in the contents of one region causes increase in ICP and contents can herniate
What is subfalcine herniation?
Herniation of hemispheric contents under the falx cerebri; typically, compressing branches of the anterior cerebral artery, creating a midline shift
What is transtentorial herniation?
Herniation of the supratentorial contents past the tentorium cerebelli, causing brainstem compression in a rostral to caudal direction. This leads to AMS, defects in gaze and ocular reflexes, hemodynamic and respiratory compromise, and death
What is uncal herniation?
a subtype of transtentorial herniation, where the uncus (medial portion of temporal lobe) herniates over the tentorium cerebelli. This results in ipsilateral oculomotor nerve dysfunction
Sx: pupillary dilatation, ptosis, and lateral deviation of the affected eye, brainstem compression and death
What causes herniation of the cerebellar tonsils?
What are the s/s?
Elevated infratentorial pressure, causes the cerebellar structures to herniate through foramen magnum
Sx: medullary dysfunction, cardiorespiratory instability and subsequently death
Label the herniation
- subfalcine:
- transtentorial
- cerebellar contents thru foramen magnum
- traumatic event causing herniation out of cranial cavity–> displacement of bone tissue
What are some causes of ICP
Tumors bc of their size and cause edema in surrounding tissue. They also can obstruct CSF flow (tumors in third ventricle)
-intracranial hematomas
-blood in CSF–> leads to obstruction of CSF reabsorbtion
-infections (meningitis, encephalitis)
What are some methods (8) to decrease ICP?
How do they work?
- Elevation of the head: encourages jugular venous outflow
- Hyperventilation: lowers PaC02
- CSF drainage: external ventricular drain (EVD)
- Hyperosmotic drugs: increase osmolarity, drawing fluid across BBB
- Diuretics: induce systemic hypovolemia
- Corticosteroids: decrease swelling and enhance the integrity of the BBB
- Cerebral vasoconstricting anesthetics (propofol): decrease CMR02 and CBF
- Surgical decompression
What to do during neurological assessment?
- Look at patients’ history, symptoms, and baseline neuro-deficits
- Review imaging and available neurological testing results
- Review the patients’ current drugs and treatments
- Evaluate the potential risks/benefits of various anesthetic options to determine the most appropriate plan of care
- Implement pre-op measures that may help optimize the patients’ condition prior to anesthesia
- Provide clear pre-op documentation of the factors above, and have a rational for chosen anesthetic plan
What is multiple sclerosis and who’s at risk?
- Progressive, autoimmune demyelination of central nerve fibers
- Rx factors: Female, 1st deg relative, epstein barr-V, other autoimmune disorders, smoking
What triggers MS? (3)
What are the s/s
stress, elevated temps and postpartum period
s/s: motor weakness, sensory disorders, visual impairment and autonomic instability.
Symtoms vary based on site of demyelination
What are some preanesthetic considerations for MS?
-consider PFT if respiratory compromise
-CBC, BMP, +/- liver function tests (LFT if on dantrolene and azathioprine)
-pre op steroids (pay attention to glucose and electrolytes)
-temp managment (trigger for MS)
How is MS managed?
There is no cure. Managed w corticosteroids, immune modulaters and targeted antibodies (IgG)
What med to avoid during MS?
Avoid succ! may induce hyperkalemia (upregulated N-ach receptors)
GA, RA, and peripheral nerve blocks are acceptable
What is myasenthia gravis?
Which nerves are susceptible?
-autoimmune, antibodies are gerenated against N-Ach receptors at skeletal motor endplate.
-cranial nerves are susceptible
S/S of myasenthia gravis
ocular symptoms are common (diplopia, ptosis) and there is bulbar involvement (laryngreal and pharyngeal weakness) aspiration risk!)
-thymic-hyperplasia is common! 90% improve after thymectomy
What exacebate MG?
What is treatment of MG?
-exarcabated by exercise, pain, insomnia, infection and surgery
-Ach-E inhibitors (Pyridostigmine), immunosuppressive agents, steroids, plasmapheresis, IVIG
Preanesthetic considerations for MG
-PFT, optimize respiratory function
-reduce paralytic dosage to avoid weakness
-caution w opoids to avoid respiratory compromise
-AchE inhibitors may prolong succ and ester LA
-Pre op steroids
Labs for MG patients?
What are MG patients increased risk of post op?
-* Labs: CBC, BMP, +/-LFT (LFT if on Azathioprine)
-pay attention to glucose and electrolytes d/t steroids
-counsel pts on increased risk for post op resp support and ventilation until fully recovered from anesthesia
What is Eaton-Lambert Syndrome?
-disorder causing the development of autoantibodies against VG calcium channels.
-Reduced Ca++ influx into presypnaptic Ca+ channels causes reduced Ach release at NMJ
What are the s/s for ELS?
-s/s progressive limb girdle weakness, dysautonomia, oculobulbar palsy
What is the treatment for Eaton Lambert?
What are 60% cases associated with?
Treatment: selective K+ channel blocker “3-4 diaminopyridine”, Ach-E inhibtors, immunologics (azathioprine), steroids, plasmapheresis, IVIG
-60% cases related to small cell carcinoma
What to caution with ELS patients?
-Caution with paralytic and opioid dosing
-they are very sensitive to nondepolarizing NMB (more than MG patients) and depolarizing NMB
Caution with opioid dosing
Regional > GA
Might also need post op vent!
What is muscular dystrophy?
- Hereditary disorder of muscle fiber degeneration caused by breakdown of the dystrophin-glycoprotein complex, leads to myonecrosis, fibrosis, and skeletal muscle membrane permeability. 6 types of MD.
What is the most common and severe form of muscular dystrophy?
Duchenne MD, occurs only in boys 2-5 y/o. wheelchar bound 8-10 y/o. Lifespan 25 y/o dt pulm complications
S/S of muscular dystrophy
Common lab finding?
- Sx: progressive muscle wasting without motor/sensory abnormalities, kyphoscoliosis, long bone fragility, respiratory weakness, frequent pneumonia, EKG changes
-elevated serum creatine kinase seen caused by muscle wasting
What should you obtain prior to surgery for muscular dystrophy?
CBC, BMP, PFT, CK and preop EKG and echocardiogram (evaluate for cardiomyopathy)
What meds to avoid in muscular dystrophy and why?
Avoid succ and volatile anesthetics! They can lead to hypermetabolic syndrome (can lead to rhabdo, hyperkalemia, vfib and cardiac arrest
What meds are acceptable to use during surgery for muscular dystrophy?
-consider low dose rocuronium and TIVA for GA
-RA> GA
Have MH cart ready w dantrolene!
What is myotonia?
prolonged contraction after muscle stimulation; seen in several disorders
Myotonic dystrophy is the most common type of myotonia.
What are the s/s?
What heart condition is common?
onset 20-30’s
-s/s: wasting in face, masseter, pretibial muscles. Can also affect pharyngeal, laryngea and diaphgramatic muscles.
-20% have mitral valve prolapse
What is myotonia congenita?
- milder form of myotonia; involves the skeletal muscles.
What is central core disease?
What are the symptoms?
-Central core muscles lack mitochondrial enzymes.
Proximal muscle weakness & scoliosis
rare
What triggers myotonias and what is the treatment?
Myotonias are triggered by stress & cold temps
Tx: No cure. Sx managed w/Quinine, Procainamide, Steroids
What to assess for in myotonia?
What are they at risk for?
-Assess breath and heart sounds
-Risk for aspiration and high risk for endocrine abnormalities (thyroid and glyucose levels)
-Risk for risk for post op respiratory weakness and also high aspiration risk
What to avoid in myotonia patients?
Caution with what meds?
What to do to avoid flareups during surgery?
-Avoid succ d/t fasciculations (can trigger myotonia)
-Caution w opioids to avoid respiratory depression
-Keep them warm to avoid flareups
What are the 3 major dementia syndromes?
What meds are they usually on?
- Alzhemiers (70%), vascular dementia (25%), parkinsons 5%
- AchE-I, MAOI’s, psych meds; meds may affect anesthetic
What are dementia patients at risk for post op?
High risk for post op delirium (consider TIVA); RA preferred (dt low opoid requirment)
What meds to avoid for parkinsons’ patients? (4)
What med do you continue?
-Avoid reglan, phenothiazine butyrophenones
-Avoid demerol if on MAIO
-continue PO levodopa to avoid unstable extrapyramidal effect such as chest wall rigidity
What is parkinsons disease?
Degeneration of dopaminergic fibers of basal ganglia; extrapyramidal motor neurons are overstimulated
Dopamine regulates the extrapyramidal motor system, which is stimulated by Ach
Parkinsons triad of symptoms
skeletal muscle tremor, rigidity, akinesia
other: pill rolling,” facial rigidity, slurred speech, difficulty swallowing, respiratory difficulty, depression & dementia
What to disable before surgery in Parkinsons pateints?
What settings are recommended for cautery?
***** Deep brain stimulators may need to be disabled to avoid interaction w/cautery
* If cautery used, bipolar recommended as it reduces scattering of electro-currant
What are common s/s for brain tumors?
high ICP, papilledema, headache, AMS, mobility impairment, vomiting, autonomic dysfunction, seizures
Types of tumors
Whare are gliomas?
-gliomas: primary tumor, least agressive astrocytoma (found in young adults and new onset sezires)
What are pilocytic astrocytomas?
-pilocytic astrocytoma: common in children and young adults, mostly benign
What do anaplastic astrocytoma evolve to?
Anaplastic astrocytoma are poorly differentiated and usually evolve into gliobllastoma multiforme– these have a high mortality; require surgery and chemo and are very deadly
Where do meningiomas arise from?
-Meningiomas are usually benign and arise from sura or arachnoid tissue.
-Good prognosis w surgical resection!
What are pituatary adenomas; what is the treatment?
Pituatary adenomas are noncancerous; transsphenoidal or open crani is usually curative
What are acoustic neuromas?
Acoustic neuromas are usually benign schwannomas involving the vestibular component of CN VIII within auditory canal. Good prognosis w resection & radiation
What does radiation damage cause?
What do patients with brain tumors present with in regards to vital signs
radiation damage may cause lethargy and AMS
-Present w autonomic dysfunction; which may manifest on EKG, labile HR and BP
What meds are brain tumor patients on?
-Pt are often on steroids to minimze cerebral edema (monitor glucose levels)
-Also on anticonvulsants (especially w supratentorial lesions; closer to motor cortex)
What meds are usually used with brain tumor patients?
-preop steroids and antiseizure meds per surgeon
-Mannitol used to reduce ICP and volume
What are clinical features for occluded ACA?
What are clinical features for occluded MCA?
ACA: contralateral leg weakness
MCA: contralateral hemiparesis and hemisensory deficit, aphasia in the dominant hemisphere and contralateral visual field defect
What are clinical features for occluded PCA?
What are clinical features for occluded penetrating arteries?
PCA: contralateral visual field defect, contralateral hemiparesis.
Penetrating arteries: contralateral hemiparesis, contralateral hemisensory deficits
What are clinical features for occluded basiliar artery?
What are the clinical features for occluded vertebral artery
BA: oculomotor deficits and or ataxia w crossed sensory and motor deficits
VA: lower cranial nerve deficits and or ataxia w crossed sensory deficits
What are 5 causes of ischemic strokes?
- Large artery atherosclerosis (carotid stenosis)
- Small vessel occlusion (lacunar stroke)
- Cardioaortic embolic ( emboli from atrial fibrillation)
- Other etiology (stroke due to hypercoagulable states or vasculopathies)
- Undetermined etiology
What is ischemic CVA treatment?
-PO aspirin
-IV or IA TPA (when specific criteria is met; <4.5 hr from symptoms)
-thrombectomy
-revascularization
2 most reliable predictors of outcomes for hemorrhagic stroke?
Treartment depends on ____
blood volume and change in LOC
Tx depends on severity
What is conservative treatment for hemorrhagic stroke?
Surgical treatment involves what
-Conservative tx is centered on the reduction of ICP, BP control, seizure precations, and vigilant monitoring
-surgical tx involves hematoma evacuation
If someone is on a new anticoagulant, they can’t have elective cases for how long?
3 months
High risk patients for CVA that pause ____ will need _____ to bridge the gap.
Pause **long acting AC ** (warfarin) will need short acting AC (LMWH, IV heparin)
What do you assess preop for cerebrovascular disease patients?
Assess orientation, bilateral grip strenght and LE strenght
Ask for h/a, tinnitus, vision/memory issues and bathroom issues
Why are majority of cerebral aneurysms undiagnosed?
What are risk factors ?
-Most cerebral aneurysms are not diagnosed before rupture bc only 1/3 patients show symptoms.
Risk factors: HTN, smoking, female, oral contraceptives, cocaine
S/S for cerebral aneurysm?
H/A, photophobia, confusion, hemiparesis, coma
Intervention should be performed within _____ of rupture for best outcomes
Preanesthesia considerations for cerebral aneurysms include:
within 72 h!
preanesthesia considerations include CT angio, EKG, Echo, CBC,BMP, Type and cross w blood on hold, BP control and mannitol
What are post SAH patients at risk for?
What is the triple H therapy?
Risk for vasospasm 3-15 days post SAH
Hypertension, Hypervolemia, Hemodilution
Free Hgb triggers inflammatory mediators which reduce NO and inc endothelin 1, leads to vasoconstriction
Intervention treatments for post SAH vasospams are?
balloon dilation and direct injection of vasodilators relieve the spasm
What is arteriovenous malformation
Arterial to venous connection w/o intervening capillaries
Creates an area of high flow, low resistance shunting
Majority are supratentorial
sx: mass effects to hemorrhage
What is the treatment for AVM ?
Tx: radiation, angio-guided embolization, surgical resection (higher mortality)
Chiari Malformation: cerebellum displacement
Type 1 is downward displacement of _____.
Type 2 is downward displacement of _____ _____ and is associated w/ myelomeningocele
cerebellum
cerebellar vermis
Chiari
Type 3 is rare; occipital _____ with downward cerebellar displacement
Type 4: cerebellar hypoplasia w/o displacement of _____ _____ contents. (Not compatible w life)
encephalocele
posterior fossa
What is tuberous sclerosis aka bourneville disease
Autosomal dominant disease causing benign hematomas, angiofibromas, and other malformations that can occur anywhere in the body
Often involves co-existing tumors of face,oropharnyx, heart, lungs, liver &kidneys
And cortical tumors and giant cell astrocytoma in brain
What is von hippel lindau disease?
What disorder do they present with
Benign tumors of the CNS, eyes, adrenals, pancreas and kidneys
May present w/ pheochromocytoma
Anesthesia considerations for Neurofibromatosis
Anesthesia considerations account for increased ICP, airway issues, scoliosis, possibility of pheochromocytoma
-avoid neuroaxial d/t tumors
tumors on nerves! no cure
Hydrocephalus treatment
VP shunt: drain placed in ventricle of the brain andempties into peritoneum, high failure rate
ETV: catheter placed into the lateral ventricle that drains into the peritoneal space, right atrium, or more rarely the pleural space
Surgical treatment for cerebral aneurysm include ? (3)
Coiling, steering and trapping/bypass (for large aneurysm)
Neurosurgeon on standby in case of rupture
What is the aneurysm grading scale for prognosis
Hunt and Hess
Phenytoin, tegretol and barbs are ______ _____
Enzyme inducers; likely required higher dose of hepatic cleared medications
