Ch. 15 Neuro Flashcards
What percent of strokes are ischemic vs hemorrhagic?
85% ischemic
15% hemorrhagic
What is the most common cause of stroke in the US?
thrombotic – results from clot formation at the site of an ulcerated atherosclerotic plaque
What are the two types of thrombotic strokes?
Lacunar - stroke of a small terminal vessel
Cortical
How is Cerebral Perfusion Pressure calculated?
CPP = MAP - ICP
What is the NIH Stroke Scale range?
0 to 42
What is amaurosis fugax?
transient monocular blindness from embolization of carotid plaque to the ophthalmic artery
How is TIA defined?
transient neurologic deficits lasting < 1 hour with no evidence of infarction on brain
imaging studies (MRI)
What is Wernicke aphasia?
receptive aphasia – an inability to comprehend language input; speech is fluent but disorganized
Where is Wernicke’s ares?
Temporal lobe
What is Broca aphasia?
expressive aphasia – inability to communicate verbally. Speech is halting and
produced with great effort
Where is Broca area?
frontal lobe
The hallmark of ________ circulation
stroke is crossed deficits (eg, sensory loss
on right side of face vs left side of body).
posterior
In hypertensive patient, where you are trying to lower BP to give TPA, which two medications are first line?
Labetalol, Nicardipine
What artery is implicated with:
Contralateral weakness of leg > arm and face with minimal sensory findings
Anterior cerebral artery
What artery is implicated with:
Contralateral weakness AND numbness of arm and face > leg
Middle cerebral artery (most common)
In a middle cerebral artery stroke you may see a gaze preference for which side?
Gaze preference toward size of infarct
What artery is implicated in clumsy hand–dysarthria syndrome?
Lacunar artery?
What artery is implicated if:
Contralateral visual field and light touch/pinprick deficit with minimal weakness
Posterior Cerebral Artery
What artery is implicated if:
Crossed deficits: ipsilateral cranial nerve deficits with contralateral weakness
Vertebrobasilar artery
What artery is implicated in “Locked in” syndrome?
(complete paralysis of voluntary muscles except eye movement; normal level of consciousness)
Basilar artery
What artery is implicated:
Sudden inability to walk or stand with
headache, vertigo, nausea/vomiting,
abnormal gait, CN abnormalities
Cerebellar artery
What glucose level is a contraindication to tPA?
> 400
What is the dose for tPA for stroke?
0.9 mg/kg with 10% given as bolus, remaining infused over 60 minutes.
Ex: 80 kg person: 72 mg total; 7.2 mg bolus, 64.8 mg infusion over remaining hour
If symptomatic intracranial hemorrhage (SICH) is confirmed with non-contrast CT, which thrombolytic and anti-platelet reversal agents should be considered?
FFP, platelets, cryoprecipitate
Aspirin should be given within ___ hours (unless thrombolysis candidate) for secondary stroke prevention.
48 hours
In secondary stroke prevention, what medications should be given if ASA allergy?
Clopidogrel (or ticlopidine)
Is routine seizure prophylaxis recommended in CVAs?
NO
What role does heparin have in CVAs?
No proven benefit in acute stroke
What is the ABCD^2 score used for?
predict likelihood of subsequent stroke within 2 days
What variables are included in ABCD^2 score to predict subsequent stroke in patients with TIA?
age >60y
BP >/= 140/90 mmHg
unilateral weakness (2 points)
speech disturbance without weakness
duration >/= 60 min (2 points)
Duration 10-59 min
Diabetes
What are the two categories of hemorrhagic stroke?
intracerebral hemorrhage and subarachnoid hemorrhage
What is the most common cause of ICH?
chronic hypertension
What are the 3 “B”s of increased ICP?
Bradycardia, BP increasing, bradypnea
What is mannitol dose for increased ICP?
0.25-2 g/kg IV of 15-25% solution over 30-60 minutes
If no clinical signs of increased ICP, what should target BP be?
160/90
If clinical signs of increased ICP exist, consider ICP monitoring with what goal for CPP?
60-80 mmHg
What is the difference between simple partial seizures and complex partial seizures?
Simple partial = brief event WITHOUT alteration of consciousness
complex partial = impairment of consciousness and +postictal state
What is a secondary generalized seizure?
partial seizure that spreads to both hemispheres
(eg generalized seizure preceded by aura or unilateral motor symptoms)
What is a secondary generalized seizure?
partial seizure that spreads to both hemispheres
(eg generalized seizure preceded by aura or unilateral motor symptoms)
What are the two types of nonconvulsive seizures?
absence or petit mal
What is seen on EEG during nonconvulsive seizures?
brief 3Hz, spike and wave discharges on EEG
what is another name for convulsive seizures?
Grand mal
What are the different types of convulsive (grand mal) seizures? List 5
clonic
tonic
tonic-clonic
myoclonic
atonic
What is Todd paralysis?
Focal paralysis, typically following a generalized seizure usually lasts 1-2 hours but may last 1-2 days
How is status epilepticus defined?
Seizure lasting ≥ 5 minutes
or
≥ 2 discrete seizures without a complete recovery in between the events
If seizure due to alcoholism is suspected, which two things should be given (besides benzos)?
thiamine and glucose
What are two possible side effects of phenytoin administration?
hypotension and cardiac dysrhythmias (due to its propylene glycol diluent)
What is the difference between phenytoin and fosphenytoin?
fosphenytoin is the water soluble prodrug of phenytoin (with better side effect profile)
what is the onset of action of phenytoin and fosphenytoin?
10-30 minutes
What are possible side effects of phenobarbibtal?
sedation, respiratory depression, and hypotension
What is the onset of action of phenobarbital?
15-30 minutes
What should be given for seizures in pregnancy?
Magnesium sulfate, if eclamptic
Otherwise, discuss with neuro and OB – risk of seizures is likely much worse than risk of teratogenicity
What should be given if seizure is suspected to be due to isoniazid overdose or gyromitrin toxin (mushroom)?
Pyridoxine (Vitamin B6)
What is the most common bacteria implicated in meningitis?
streptococcus pneumoniae
(gram positive diplococci)
In meningitis in ages >60 years old, what organism should be considered and covered with antibiotics?
Listeria monocytogenes
(gram-POSITIVE rod)
cover with Ampicillin
What are the three most common organisms implicated in meningitis in those <1 month old?
Group B strep
E coli
L monocytogenes
What are the three most common causes of meningitis following neurosurgical procedure or head trauma?
S pneumoniae
Staph aureus
Pseudomonas aeruginosa
What is the most common viral cause of meningitis and what season is it most common?
Enterovirus
summer months
Which 2 organisms should always be considered as cause for meningitis in immunocompromised?
Fungal (eg cryptococcus)
Parasitic (eg Toxoplasma gondii)
What are some noninfectious causes of meningitis?
SLE
Drug induced
Carcinomatosis
Sarcoidosis
Behcet disease
What does bacterial meningitis typically start?
nasopharyngeal colonization –> hematogenous spread –> CNS infection
Meningitis due to fungi typically spread from what source?
Pulmonary
What do you call the following physical exam finding?
Position the patient with hips and knees flexed. Extend the knees. Flexion of neck or pain in neck is positive sign.
Kernig sign
What do you call the following sign?
Neck flexion results in flexion at hips (neck sign) or passive flexion of hip on one side results in contralateral hip flexion (contralateral sign).
Brudzinski sign
What three concomitant infections should you look out for in suspected meningitis?
Sinusitis, otitis, pneumonia
When is a Head CT recommended BEFORE LP in suspected meningitis?
- patients >60 years old
- immunocompromised (eg HIV)
- History of CNS disease (stroke, mass lesions, or head trauma)
- New onset seizures within 1 week
- Marked CNS depression, papilledema, or focal neuro deficits
What are the 3 contraindications to LP?
- Coagulopathy (relative): INR > 1.5, Platelets <50k (<20k = absolute)
- infection at skin puncture site (absolute)
- Increased ICP or trauma to lumbar vertebrae
What is normal opening pressure for LP?
5-20 cm H2O
What are normal leukocyte levels for CSF?
</=5
What is a normal CSF protein level?
20-45
What is normal glucose for CSF?
50-80% or 60-70% of serum level
How does the LP opening pressure change in bacterial meningitis?
elevated
How does the LP opening pressure change in viral meningitis?
normal or slightly elevated
What is the typical CSF leukocyte count in bacterial meningitis?
> /= 500 leuks/mm3
What is the typical CSF leukocyte count in bacterial meningitis?
100-500 leuks/mm3
What is the CSF %neutrophil count in bacterial meningitis?
> 80%
What is the CSF %neutrophil count in bacterial meningitis?
<50%
What is the CSF protein level in bacterial meningitis?
> 200
What is the CSF protein level in bacterial meningitis?
<200
What is the CSF glucose level in bacterial meningitis?
</=40% or <50% of serum
What is the CSF glucose level in viral meningitis?
usually normal
What is the CSF glucose level in fungal meningitis?
<50%
What is the CSF protein level in fungal meningitis?
> 200
What is the CSF %neutrophil level in fungal meningitis?
<50%
What is the CSF leukocyte count in fungal meningitis?
10-500
What is the LP opening pressure in fungal meningitis?
elevated
CSF gram stain with gram positive diplococci suggests what organism?
pneumonoccocus
CSF gram stain with gram negative diplococci suggests what organism?
meningococcus
CSF gram stain with small pleomorphic gram negative coccobacilli suggests what organism?
H influenzae
CSF gram stain with gram positive rods and coccobacilli suggests what organism?
listeria
What immediate empiric antibiotics should be given if meningitis suspected?
Vancomycin 1gIV
Ceftriaxone or Cefotaxime 2g IV
+/- Ampicillin if neonate, >60 yrs old, debilitated, or alcoholic
+/- Metronidazole if concern for extension from sinusitis or otitis
Giving antibiotics before LP will not decrease ability to detect organism in CSF fluid if LP performed
within ___ hours and antigen assays are utilized
2
Should steroids be given for meningitis?
YES– Appears to decrease morbidity and mortality in adults with bacterial meningitis (especially S pneumoniae) and children with H influenzae
meningitis.
What is the dose for steroids for meningitis?
Dexamethasone 0.15 mg/kg IV 15 minutes before or concurrent with the first dose of antibiotics, repeat every 4-6 hours (max 10 mg in adults).
What is the treatment for viral meningitis?
no specific treatment unless herpes simplex meningitis – then acyclovir
If neisseria meningitidis or H influenzae type b is identified as cause for meningitis, what should close contacts be treated with?
rifampin (4 doses 10 mg/kg q12h) is recommended
once bacterial organism is identified.
Alternatively, ciprofloxacin can be used (500 mg PO single dose).
What is the most common cause of encephalitis?
viruses - majority of cases
Arbovirus and HSV = most common
What is the diagnostic imaging of choice for encephalitis?
MRI with contrast
(CT with contrast is alternative but is less sensitive)
What is the empiric treatment for encephalitis where HSV or HZV are suspected?
Acyclovir 10mg/kg IV q8h
What is the empiric treatment for encephalitis where cytomegalovirus is suspected?
Ganciclovir
What are the 3 mechanisms of spread that cause brain abscesses?
- Contiguous infection of middle ear, sinus, or teeth
- Neurosurgery or penetrating trauma
- Hematogenous spread
How does a brain abscess appear of MRI/CT with contrast?
ring-enhancing lesions
What is the empiric treatment for brain abscesses with no obvious source?
Vancomycin + ceftriaxone or cefotaxime +
metronidazole
What is the most common cause of secondary seizures in the developing world?
Neurocysticercosis (CNS T solium larvae
infection – from eating undercooked pork)
What is the treatment for Neurocysticercosis (CNS T solium larvae infection)?
Antiparasitic agents (praziquantel and albendazole).
The majority of shunt infections present within _______ (time period) of placement).
within 6 months
(50% within 2 weeks).
Which two organisms are most commonly implicated in intracranial shunt infections?
■ Staphylococcus epidermidis (50%)
■ S aureus
What percentage of SAH have a completely normal neuro exam?
50%
What is the Hunt and Hess classification?
The Hunt and Hess scale is a grading system used to classify the severity of a subarachnoid hemorrhage based on the patient’s clinical condition. The scale ranges from a score of 1 to 5. It is used as a predictor of prognosis/outcome with a higher grade correlating to a lower survival rate.
How sensitive is a noncon Head CT for identifying SAH?
Symptoms < 24 hours = sensitivity > 90%-95% (controversial, some sources cite 98% within 12 hours). Increasing evidence that the sensitivity
of CT within the first 6 hours after a minor SAH approaches 100%.
Symptoms for 1 week = sensitivity < 50%.
What is the gold standard for diagnosing SAH if CT negative?
Xanthochromia (via spectrophotometry, NOT naked eye) ≥ 12 hours after onset of headache
In SAH, what should BP goal be?
Control BP (MAP < 130).
What medication has been shown to prevent vasospasm and ischemic stroke?
(initiate within 4 days of symptom onset)
Nimodipine PO
What is a subdural hygroma?
Collection of blood-tinged fluid in dural space of uncertain etiology; tends to follow trauma; on CT fluid density is same as CSF; surgical evaluation is needed, if symptomatic
What is the most common cause of brain tumor?
metastases from lung or breast carcinoma
What should steroids be considered for brain mets?
if edema is present on imaging or if severe symptoms
What is the diagnosis criteria for Temporal arteritis?
3 of 5 criteria:
■ Age > 50
■ New onset localized headache
■ Temporal artery tenderness or decreased pulse
■ Erythrocyte sedimentation rate > 50 mm/h
■ Refer urgently for temporal artery biopsy to confirm diagnosis if highly suspicious
What is the treatment for Temporal Arteritis?
Immediate high dose steroids: Prednisone 40-80 mg/d
NSAIDs for pain relief
What is a complication of temporal arteritis?
loss of vision due to ischemic optic neuritis
What is idiopathic intracranial hypertension also known as?
Pseudotumor cerebri
What are risk factors for idiopathic intracranial hypertension (aka pesudotumor cerebri)?
young obese female
oral contraceptives
vitamin A
chronic steroid use
tetracyclines
and thyroid disorders
What are signs/symptoms of idiopathic intracranial hypertension (aka pesudotumor cerebri)?
■ Long-standing headache ± visual disturbances and nausea/vomiting.
■ Visual loss may occur.
■ Eye findings may include papilledema, loss of peripheral vision, and CN VI palsy.
How is idiopathic intracranial hypertension (aka pesudotumor cerebri) diagnosed?
increased intracranial pressure (> 25 cm H2O) with
normal CSF evaluation
(Head CT may show small ventricles and an enlarged cisterna magna)
When diagnosing idiopathic intracranial hypertension (aka pesudotumor cerebri), what test should be done/what should be excluded?
Consider magnetic resonance venography (MRV) for evaluation of cerebral venous thrombosis
What is the treatment for idiopathic intracranial hypertension (aka pesudotumor cerebri)?
Acetazolamide (decreases CSF formation) +/- furosemid
When are steroids and/or therapeutic LP indicated for idiopathic intracranial hypertension (aka pesudotumor cerebri)?
In the setting of acute vision loss at temporizing measure until surgical intervention
What is the treatment for refractory idiopathic intracranial hypertension (aka pesudotumor cerebri)?
Optic nerve sheath fenestration or shunt placement
What are the most common causes of stroke in patients <45 years old?
internal carotid and vertebral artery dissection
(usually due to trauma or injury)