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Opt 637 CNS Exam 1
Dr Smith Lecture 4
101
Medical
Graduate
09/12/2011

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Cards

Term
What is the peak age of onset for myasthenia gravis?
Definition
There are two peak ages, ~20 and ~50-60
Term
What is seen in younger (~20) myasthenia gravis pt's?
Definition

hyperplasia of the thymus

 

Generally female

Term
What is seen in older myasthenia gravis pt's?
Definition

neoplasms of the thymus (thymoma)

 

No gender preference

Term
What is the first s/sx seen with myasthenia gravis?
Definition
EOM's are generally affected first
Term
What is a suspected reason that MG affects EOM's first?
Definition
Eyes and eyelids are the most active muscles in the body, so it seems reasonable they would be affected first.
Term
What is the main sx of myasthenia gravis?
Definition
muscle weakness and fatigability
Term
What are the main signs of MG?
Definition
EOM weakness

facial weakness that progresses through the day

dysphagia

limb weakness

respiratory weakness most feared complication
Term
What is the most feared complication of MG?
Definition
respiratory weakness
Term
How is MG diagnosed?
Definition
History and physical show increased muscle weakness/fatigue

Check for thyroid dysfunction, perhaps ANA

tensilon test

CT of chest (looking for Thymoma)

electromyography shows rapid decline in muscle AP and nerve stimulation
Term
What is the tensilon test?
Definition
A DDX for MG vs cholinergic crisis; edrophonium chloride, an ACH agonist is applied. In MG, muscle weakness will be reduced. If it is cholinergic crisis, muscles will get weaker. Have atropine on hand in case reversal is needed
Term
What is the ice test?
Definition
In myasthenia gravis, applying ice for a few minutes will reduce ptosis by ~2mm if positive
Term
What is Cogan's sign?
Definition
Eyelid 'twitch' where the lids overshoot the regular open position when opened.
Term
What should be kept on hand when doing the tensilon test?
Definition
atropine in case cholinergic crisis needs to be treated.
Term
What is the expected result for ANA test on MG pt's?
Definition
Generally positive
Term
What is used to treat MG?
Definition
Stop the ANA's with corticosteroids and immunosuppressive oral anti-cholinersterase agent Treat any thyroid dz thymectomy
Term
What is pyridostigmine?
Definition

oral anti-cholinesterase agent used to treat MG

 

Used to be first line, still used a lot but steroids are now DOC

Term
What is azathioprine?
Definition
ANA suppressor/ immunosuppressive
Term
When is a thymectomy recommended for MG tx?
Definition
When the drugs have failed to work
Term
What is epilepsy?
Definition
disorder with recurrent seizures
Term
Does a seizure indicate epilepsy?
Definition
Not necessarily. It must be a recurrent issue for it to be epilepsy
Term
What is an 'aura'?
Definition
A sense that a seizure is imminent in epilepsy pt's.
Term
When is an aura not seen in epilepsy?
Definition
If it is a full brain seizure, no warning will be sensed
Term
What is a postictal state?
Definition
post-seizure confusion that is common
Term
What is the pathology of a seizure?
Definition
abnormal neuronal discharge that disturbs cerebral function in a transient fashion
Term
What is a benign febrile convulsion?
Definition
2-4% of children between 3 mo and 5 yrs will have one. Usually preceded by a fever, and on first day of fever child will have a short seizure (minute or two up to 15 minutes)
Term
What is the risk for recurrence of benign febrile convulsions?
Definition
90% within 2 years
Term
At what point should a child having a seizure be taken to the hospital?
Definition
If seizure lasts 15 minutes, take to hospital. If seizure lasts 10 minutes, call 911 so that ambulance will arrive around the 15 min mark.
Term
When can benign febrile convulsions be indicative of epilepsy?
Definition
If there is family history, chances are elevated.
Term
What is a tx for benign febrile convulsions?
Definition
Give anti-pyretics to bring fever down
Term
Will anti-pyretics prevent benign febrile convulsions?
Definition
No
Term
What is the occurrence of idiopathic seizures?
Definition
75% of seizure disorders are idiopathic
Term
When do seizure disorders generally begin?
Definition
5-25 years
Term
What does a later onset of idiopathic seizure tend to indicate?
Definition
possibility of stroke, tumor, trauma, or systemic dz
Term
What is a common trauma that causes seizures?
Definition
head trauma
Term
What is the recurrence rate of idiopathic seizures?
Definition
30-70%
Term
What % of head trauma pts present with seizure?
Definition
2-5%
Term
If the seizure is in the first week since the head trauma, is it indicative of chronic disorder developing?
Definition
no
Term
What % of cerebral cortex stroke pt's produce seizures?
Definition
5-15%
Term
Are early seizures after a stroke indicative of chronic epilepsy?
Definition
no
Term
What are common causes of seizures?
Definition
mass lesions

meningitis or encephalitis

hypoglycemia

uremia

HIV encephalopathy
Term
What is the level of hypoglycemia that will cause a seizre?
Definition
60-115 mg/dL is normal, but below 20-30 mg/dL can cause seizure
Term
When is seizure seen w/ uremia?
Definition
in some cases where uremia occurs rapidly
Term
What are systemic disorders that cause seizures?
Definition
drug overdose

drug withdrawal
Term
What drug overdoses can cause seizures?
Definition
antidepressants
anti-psychotics

cocaine

insulin

lidocaine

methylxanthines
Term
When can drug withdrawal cause seizures?
Definition
Within 48 hrs of EtOH cessation or reduction

Sedatives
Term
What are large and small seizures called?
Definition
Tonic-Clonic (grand mal)

absence seizures (petit mal)
Term
What are partial seizures?
Definition
single side of brain affected, so only left temporal lobe, or vice versa
Term
What is a complex seizure?
Definition
both sides of brain affected
Term
What is seen in the tonic phase of a tonic-clonic seizure?
Definition
lose consciousness almost instantaneously

are not breathing

cyanosis due to lack of O2

contraction of masticatory muscles

extension of extremities and opishotonus

tonic contraction of limbs for 10-30 seconds

May be brief cry right before
Term
What is the clonic phase?
Definition
Alternate muscle contractions and relaxation

symmetric limb-jerking for 30-60 seconds

lack of swallowing so frothing of mouth may be seen

ventilation efforts return after tonic phase

jerking will become less frequent until movements cease

incontinence (loss of sphincter control)

may remain unconscious for 30 minutes

pt will be really tired afterward
Term
What should people do when observing a person with seizures?
Definition
try to protect the head, keep them from hitting it on things
Term
What is seen in the recovery phase of a tonic-clonic seizure?
Definition
postictal confusion w/ headache

May take 30 minutes to return to full orientation

pupil reflexes are normal throughout

hemiparesis during the postictal period (Todd's paralysis)

important to distinguish the condition from a stroke
Term
What is status epilepticus?
Definition
seizure continues indefinitely, full consciousness not restored between episodes

may cause permanent brain damage
Term
What can cause permanent brain damage in status epilepticus?
Definition
hyperpyrexia (T > 106*F)

circulatory collapse

excitotoxic neuronal damage
Term
What are absence (petit mal) seizures?
Definition
childhood seizures that often disappear in 20's

brief loss of consciousness (5-10 seconds) without loss of postural tone

blinking or head turning may be seen

full orientation follows cessation of seizures

often caused by hyperventilation
Term
How can absence seizures be induced?
Definition
hyperventilation
Term
What is a tonic seizure?
Definition
no clonic phase after tonic phase
Term
What is a clonic seizure?
Definition
a loss of consciousness and clonic jerking without tonic phase
Term
What is a hypnic jerk?
Definition
A myoclonic jerk while falling asleep.
Term
What was Dr Smith's updated report on how to handle a seizure in a patient.
Definition
Keep person on the ground, remove clothing from neck, clear area, turn head to side, cushion the head, allow person to rest afterward. Be aware of concussion from the fall. Provide transportation back to home. Call an ambulance if the seizure lasts more than 5 minutes or if it is the person's first seizure
Term
What are simple partial seizures?
Definition
Unilateral temporal lobe seizure

May proceed into a tonic-clonic seizure

consciousness is generally preserved with memory of the event intact
Term
What is a Jacksonian March?
Definition
clonic movements that spread to contiguous regions of motor cortex
Term
What is piloerection? Where may they be seen?
Definition
Hair standing on end, sometimes seen in partial seizures
Term
What kind of seizure maintains consciousness and memory of the event is retained?
Definition
simple partial seizures
Term
What is a complex partial seizure?
Definition
Motor activity of oral, face, and neck movements

Usually involves both temporal lobes or medial frontal lobes

Consciousness is impaired, but not lost

No memory of event

May become frightened
Term
What kind of seizure is more likely to proceed into a tonic-clonic seizure in children than in adults?
Definition
Complex partial seizures
Term
How is epilepsy diagnosed?
Definition
EEG reveals abnormal spikes, though a normal EEG does not exclude epilepsy dx
Term
When is an MRI or CT used to dx epilepsy?
Definition
If the pt begins their seizures after age 25 or if they have focal seizures
Term
What is a pseudoseizure?
Definition
No tonic phase

May be a warning before the attac occurs

Shouting or obscene utterances during apparent loss of consciousness

No postictal confusion

No seizure activity seen on EEG during episode

clonic phase consists of wild thrashing where they do not hurt themselves
Term
What are the tx basics for epilepsy?
Definition
Block glycolysis

Alter ionic transport

Enhance GABA activity

Decrease glutamateric transmission/activity
Term
What is an excitatory neurotransmitter that is targeted in epilepsy tx?
Definition
glutamate
Term
What is an inhibitory neurotransmitter that is increased in epilepsy tx?
Definition
GABA
Term
What is a ketogenic diet?
Definition
glycolysis blocking diet that may help control epilepsy
Term
What is phenytoin (dilantin)?
Definition
First line drug for epilepsy

Alters ionic transport

Blocks sodium channels
Term
What is an ocular SE of phenytoin?
Definition
nystagmus
Term
What is carbamazepine?
Definition
epilepsy drug that blocks sodium channels

First choice for children with epilepsy
Term
What is topiramate?
Definition
Used to treat epilepsy or strong headaches
Term
What are the ocular SE of topiramate?
Definition
Causes swelling of the ciliary body

increase in myopia

angle closure glaucoma
Term
How is topiramate induced glaucoma treated?
Definition
Use atropine if lens has moved forward
Term
What is phenobarbitol?
Definition
Only used for epilepsy in children

Mechanism unknown
Term
What are common secondary drugs for tx of epilepsy?
Definition
Valproic acid

gabapentin

lamotrigine

felbamate
Term
What is lamotrigine?
Definition
Ca++ channel blocking drug

Reduces depression

Also treats epilepsy
Term
What is felbamate?
Definition
Caused aplastic anemia, but for many was the only drug that controls their epilepsy, so still on the market despite the risks
Term
What drugs are used to treat new seizures (petit mal)?
Definition
Ethosuximide (Zarontin); May cause skin rashes

Valproic acid (Depakote)
Term
What drugs are used for partial seizures?
Definition
Tiagabine

Topiramate

Vigabatrin

Ezogabine
Term
What is tiagabine?
Definition
GABA uptake blocker used to treat partial seizures
Term
What is Vigabatrin?
Definition
Used to treat partial seizures through GABA uptake inhibition

May cause permanent peripheral vision loss
Term
What is Ezogabine (Potiga)?
Definition
Treats partial seizures

Stabilizes K+ channels (Keeps them open)

May cause urinary retention
Term
When are epilepsy drug regimens changed?
Definition
If recurrent seizure activity is not controlled by first drug, though control with a single drug usually possible
Term
What are the SE of anti-convulsants?
Definition
Blood dyscrasias: aplastic anemia and increased bleeding time

GO TO SLIDE 72 IN CNS XL FILE AND FINISH THIS SLIDE
Term
What are surgical procedures used to treat epilepsy?
Definition
Excision of epileptogenic zone assuming it can be identified and it is not vital for neurologic function

Usually in the temporal lobe
Term
What is the success rate of epilepsy excision procedures?
Definition
>75% are seizure free after 5 years
Term
What are SE of epilepsy excision procedures?
Definition
decrease in verbal recall memory in 33% of pts
Term
What epilepsy pt's are the best candidates for surgery?
Definition
Pt's who experience more than one type of aura
Term
What is corpus callosotomy?
Definition
Cut the corpus collosum --> disconnect the two hemispheres

Only used for pt's with uncontrolled seizures?
Term
What is a hemispherectomy?
Definition
Remove on hemisphere of brain in severe eleptogenic lesions involving most or all of one hemisphere.
Term
What are SE of hemispherectomy's?
Definition
permanent hemiplegia

hemisensory loss

hemianopsia
Term
What is left vagus nerver stimulation used for?
Definition
Treating partial seizures

Stimulator in chest programmed to give 30 sec stimulationq 5 minutes

Pt waves a wand over sensor in chest during aura
Term
What is the reduction in seizures for left vagus nerve stimulation pt's?
Definition
30-50% of pt's have a 50% reduction in seizure frequency --> decreased need for meds
Term
What is a thymoma?
Definition
Tumor of the thymus gland
Term
What is a myasthenic crisis?
Definition
Inability to breath due to MG
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