Part 38 Flashcards
Telltale sign of a seizure
If you grab hold of their arm it will NOT stop seizing
Ictal definition
Relating to or caused by stroke/seizure (during a seizure)
Post-ictal definition
Altered state of consciousness after seizure
New onset of seizures age 30 onward assume…
….tumor until proven otherwise
Tonic definition
Producing tone or contraction of muscles within seizure
Clonic definition
Alternating pattern of relaxation and contraction in muscles within seizure
Aura (seizures) definition
Distinctive visual or sensation warning sign typically predictive of an impending seizure episode
Epilepsy epidemiology
3.4 million americans, 1% of population, 50% of people with it develop by age of 25 but can get it at any time, twice as many with epilepsy who are 60 or older as children aged 10 or younger
Localized/partial epilepsy
Seizure located on one side or part of body initially that may evolve into entire body involvement (secondarily generalized), either simple (not lost consciousness) or complex (have change in state of consciousness)
Generalized seizures and their subclasses (5)
Seizure that occur over whole body symmetrically without local onset including several classes such as:
- tonic clonic (grand mal)
- absence (petit mal)
- myoclonic
- clonic
- atonic
70% of epiplepsy is ___, most common causes of provoked include the following (5)
idiopathic,
- head trauma
- infection
- brain tumor
- genetic anomalies
- prenatal disturbance of brain development
Seizures
Uncontrolled electrical activity in the brain resulting in physical convulsion and other manifestations in the body
Signs and symptoms of seizure (4)
- Fever (may be indicative of infectious etiology - febrile seizure)
- papilledema
- headache
- focal neurologic finding
Todd’s paralysis
Focal residual abnormality such as paralysis of one sided limb that may suggest post - focal onset of seizure
Seizure is not a ___, it is a ___
diagnosis, symptom
Focal seizures can progress if left untreated for a period of time to…
….generalized (secondary generalized)
Epilepsy
Recurrent seizures unrelated to fever or acute cerebral insult with no underlying provocation, generalized tonic-clonic characterized by rigidity (tonic phase) followed by repetitive clonic activity (of all extremities), may be accompanied by oral frothing, resp distress, cyanosis, incontinence, blackout, and convulsions
Psychogenic nonepipleptic seizures
Seizure activity characterized by sudden and time limited disturbances of motor, sensory, autonomic, cognitive, and/or emotional functions, mimics seizures but not associated with physiological CNS dysfunction (as measured on an EEG), tends to last longer than 2 min, pelvic thrust but no incontinence, can still communicate, forced eye closure, and no increase in prolactin levels (which is always seen in a true seizure)
Things that mimic seizures (4)
- syncope
- sleep disorders
- migraines
- TIA
Nonepileptic seizures (pseudoseizures)
More common in females that present with asynchronous movements, fluctuating course, extended duration, tight eye shuts, pelvic thrusting, etc. that shares distinct differences from a true seizure
Lennox gastaut syndrome triad of presentation
- developmental delay
- absence and tonic seizures
- slow spike wave discharges on EEG
Lennox gastaut syndrome
Infantile spasms onset 2-7 years
Complex partial seizures (psychomotor seizures)
Represents events of focal cerebral onset, characteristically manifests with variety of motor, sensory, or behavioral alterations, motor activity during complex partial seizure may remain focal
Juvenile myoclonic epilepsy
Recessive inherited epilepsy that is distinct in that it does not have a bad prognosis
Rhabdo and seizures
prolonged hours of seizing is concern
Febrile seizures
Most common in children, affect 3-5% of kids, does not indicate likelihood of developing seizures later in life, typically have tonic clonic motor activity lasting 1-2 min with rapid return to consciousness, tend to occur in conjugation with rapid rise in body temp
Atypical febrile seizure
Deviate from febrile seizure either by being prolonged exceeding 15 min, focal seizure manifestations, or multiple in the same febrile illness
Alcohol withdrawal seizures
Most commonly seen in alcohol dependent patients when sudden cessation, often precede other classic symptoms of withdrawal, untreated may progress to delirium tremens, most common 12-36 hrs after withdrawal, CT often considered for initial to rule out underlying process
Delirium tremens and 2 treatments
Rapid onset of confusion following alcohol withdrawal, treated with valium or ativan (lorazapem)
Seizure diagnosis (4)
- Clinical assessment
- EEG
- CT
- Neurologic exam
Tuberous sclerosis vs von recklinghausen disease
Common type of neurocutaneous syndrome that is related to neurofibromatosis type I (which is von recklinghausen disease) clinically diagnosed by hypmelanotic macules as first manifestation followed by progression and eventual seizures but genetically distinct conditions
Classic triad of tuberous sclerosis
adenoma sebaceum, seizures, and developmental delay
common seizure triggers (6)
- missed medication (#1)
- stress/anxiety
- hormonal changes
- fatigue
- photosensitivity
- fever
Seizure treatment principles
Control frequency while limiting side effects, medication depends on etiology, acute management includes benzos, often require sedation
Absence (Petit mal) seizures
Generalized seizures with spells lasting up to 10 sec a piece and occurs dozens of times daily, patients have no recollection of events and will resume previous activity without any postictal symptoms
Classic EEG finding for absence seizures
3 cycle per second spike and waves
Status epilepticus
Seizure lasting longer than 30 min or occurrence of serial seizures from which there is no return to same level of consciousness as occurred prior to seizure, can be febrile, idiopathic, or symptomatic status
Treatment principles of status epilepticus (ABCDD)
Airway
Breating
Circulation (hypertension is normal finding)
Dextrostix (may be hypoglycemic)
Draw blood (get glucose, electrolytes, etc.)
Seizure episode treatment options (8)
- Lorazepem (ativan)
- diazepam (valium)
- phenobarbital in neonatal first line
- Phenytoin (dilantin) DOC, cannot be given IM
- mannitol (brain swelling)
- dexamethasone (same)
- Valproic acid (useful in treating generalized and artial seizure disorders)
- Ethosuximide (zarontin) DOC for absence epilepsy but other meds can make the condition worse
Not all initial, brief, uncomplicated seizures need to be…
….treated if no underlying pathology found, just treat underlying disorder (its possible to just have one)
Diagnostic studies for seizures (5)
- EEG with provocation testing
- MRI
- Metabolic panel
- Lumbar puncture
- EKG
Phenytoin ADR’s (4)
- gingival hyperplasia
- hirsutism
- lymphadenopathy
- hepatotoxicity
CT and MRI findings in seizure patients
- CT findings not visualized
- MRI present in 100% of cases, see streaky linear or wedge shaped lesions extending from ventricles
Potential complications of epilepsy (2)
- sudden unexpected death in epilepsy
- brain damage
Alternative treatment options for seizures (3)
- ketogenic diet
- lifestyle mods
- marijuana
Positive characteristics of new seizure meds (4)
- efficacy at least equal to older meds
- safer and more tolerated
- blood testing not necessary
- less drug interactions
Anticonvulsant withdrawal
Indicated only slowly after 2 years of seizure free activity in child with no underlying contributing neurological or systemic dz
Surgical treatment for seizures (3)
- Resection when foci can be isolated
- laser ablation
- vagal nerve stimulator inplantation
Safety issues for patients with epilepsy (4)
- Cannot drive for year after last seizure
- shouldn’t swim or bathe alone
- cooking should be monitored
- taking care of children can be challenging
Best anticonvulsant for pregnant women
Lamotrigine
Consciousness definition
State of awareness of self and environment, condition for which a person is capable of perceiving stimuli from the environment and respond appropriately, components include arousal (being awake mediated by reticular activating system) and awareness to sensations, emotions, and thoughts around us
System of consciousness has 2 principle functions
1) maintenance of waking state (arousal)
2) content of experience (awareness)
Components of “normal” waking consciousness (8)
- level of awareness
- content limitations
- attention
- controlled and automatic processes
- Perceptual and cognitive distortions
- emotional awareness
- self control
- time orientation
Clouding of consciousness
Very mild form of altered mental status in which patient has inattention and reduced wakefulness
Confusional state definition
More profound consciousness deficit that includes disorientation, bewilderment, and difficulty following commands
Delirium definition
An acute confusional state characterized by alternation of consciousness with reduced ability to focus, sustain, or shift attention
Drowsiness definition
State of consciousness where a person can be aroused by moderate stimuli but then drifts back to sleep
Lethargy definition
A state of consciousness of severe drowsiness in which a patient can be aroused by moderate stimuli with drowsiness between sleep states and then drifts back to sleep
Obtundation definition
A state of consciousness similar to lethargy where patient has lessened interest in environment*** and slowed response to stimulation, tending to sleep more than normal with drowsiness between sleep states
Stupor definition
State of consciousness where only vigorous and intense stimuli will arouse and individual, but when left undisturbed immediately relapse into unresponsive state
Coma definition
State of unarousable unresponsiveness
Minimially conscious state and an example
State related to coma with minimal but definite behavioral evidence of self or environmental awareness, with partial preservation of consciousness ex) following commands such as looking up or down
Vegetative state and example
State relating to coma where patient is able to be aroused but not aware** ex) Terri Schiavo case
Brain death definition
State related to coma considered death by neurological criteria, absence of brain stem reflexes, EEG showing no electrocerebral activity, may be kept alive by medical needs but even involuntary actions need to be performed by external influence
Ascending reticular activating system (ARAS)
Basic network of neurons originating in upper pons and midbrain integral to introducing and maintaining arousal, neurons project to diencephalon (thalamus and hypothalamus) and then to the cerebral cortex integral to awareness
5 causes of coma
- herniation syndrome and various trauma
- structural or brainstem lesions
- metabolic causes
- toxic syndromes (drug overdose)
- infection
Decorticate posturing, what its glasgow coma scale is, and what it indicates (3)
Presentation of stiff bent arms towards body and clenched fists with fingers bend and held on the chest with legs straight out (glasgow coma scale 3 in motor), indicating damage to cerebral hemispheres, midbrain, or thalamus
Decerebrate posturing what its glasgow coma scale is, and what it indicates (4)
Presentation of arms and legs held out straight, toes pointed downward, head and neck arched backwards, muscles tightened and held in rigidity (Glasgow coma scale 2 in motor), indicating brain stem damage, lesions or compression of midbrain, or lesions of cerebellum
Decerebrate posturing is often seen in ___ strokes
pontine
Common causes of metabolic induced coma and what is the most common? (11 of em, just list a few for christ sake)
- Hypoxia (most common)
- hypoglycemia
- hyperglycemia
- hypothyroidism
- CNS infection
- drugs
- hyperkalemia
- hyponatremia
- uremia
- hypocalcemia
- anemia
Asterixis
Tremor of the hand when the wrist is extended, sometimes said to resemble a bird flapping its wings, characterized by an inability to maintain a position upon manipulation by practitioner in already extended state (wave goodbye sign)
myoclonus and what is multifocal myoclonus suggestive of?
- Quick involuntary muscle jerk (hyperreflexia) characterized by practitioner pushing back on neutral state wrist or ankle and seeing jerking movement
- multifocal is strongly suggestive of metabolic coma
Pupils and vital signs with the various toxidromes (sympathomimetic, anticholinergic, hallucinogenic, opioid, sedative, cholinergic, serotonin syndrome)
Sympathomimetic - mydriasis and elevations and hyperactive bowel sounds
Anticholinergic - mydriasis and elevations
Hallucinogenic - mydriasis and elevations and hyperactive bowel sounds
Opioid - Miosis and depressions
Sedative - Miosis and depressions
Cholinergic - miosis and depressions but hyperactive bowel
Serotonin syndrome - Mydriasis and elevations
Common causes of infectious coma (4)
- Bacterial meningitis
- viral encephalitis
- syphilis
- malaria
Waterhouse-friderichsen syndrome
Adrenal failure due to bleeding into the adrenal glands most often infectious in origin caused by neisseria meningitidis
How does locked in syndrome differ from coma?
Consciousness is preserved even though patient cannot move muscles they can voluntary blink and move vertical eyes, can still perceive and detect the environment
How does Akinetic mutism differ from coma?
A lack of motor response in awake individual where a patient cannot move or speak
How does Psychogenic unresponsiveness differ from coma?
It is a prolonged motionless dissociative attack with absent or reduced response to external stimuli despite no activity cessation on an EEG, likely in response to trauma
Initial evaluation and history of suspected coma patient (6)
- history from witnesses
- old charts or medical bracelets
- abrupt, gradual, or fluctuating?
- preceding focal signs and symptoms (transient visual symptoms indicate ischemia!)?
- recent illness?
- drug use/abuse?
Cherry red skin in suspected coma patient is associated with…
…carbon monoxide poisoning
Osler’s nodes
Painful purple nodules on palms and soles seen in bacterial endocarditis
Neurologic exam on a suspected coma patient
- Level of consciousness: (Glasgow coma scale)
- Motor responses (muscle tone, reflexes, posturing)
- Brainstem reflexes (pupillary light, corneal reflexes)
Glasgow coma scale does not include ____ in coma assessment while FOUR score does making it slightly better
Brainstem reflexes
Glasgow coma scale definition and ranges
Grades severity of coma according to 3 categories of responsiveness excluding the brainstem, with a score of 3 being worst and 15 being best, 13 or higher indicates mild brain injury, 9-12 indicates moderate, 8 or less is severe
FOUR score definition and ranges
4 component exam to grade severity of coma, including eye, motor, brainstem**, and respiratory, lower the score the greater the severity of coma, has better biostatistical properties than glasgow coma scale in terms of sensitivity, specificity, accuracy, and positive predictive value
FOUR score <6 predicts…
….expected death
Pinpoint pupils is indicative of ____, significant asymmetric pupillary response is indicative of ____ or ___, unreactive midsized pupils indicates ___ or ___
Pontine lesion, brainstem involvement, ruptured aneurysm, drugs, death
Vestibule-ocular reflex
Detects an intact brainstem, if when turning patients head, eyes remain facing forward, they have an intact brainstem, but if eye turns with the head then brainstem is damaged
Caloric reflex test
Intact brainstem reflex test, cold water placed in the ear causes eyes to move toward the same ear in normal response, warm water placed in the ear causes the eyes to move away from the ear in normal response
Things to give in suspected coma patient (4), things to order in suspected coma patient (6)
- Glucose IV
- thiamine
- naloxone (counteract narcotic OD)
- O2
- Non contrast CT
- EKG
- TSH
- CBC
- blood culture
- EEG
Lumbar puncture is indicated if these 2 things are present (suspicion of meningitis)
- elevated or depressed temp
- nuchal rigidity
Status epilepticus abortion drug choices in order of first choice to third
- IV lorazepam
- IV dilantin or valproic acid
- IV phenobarbital
Confirmatory test for brain death
Blood flow perfusion on MR scintigraphy
Cardinal feature of metabolic coma
-symmetrical nature of neurologic deficits, such as symmetric pupils that appear abnormal but constrict with light
Glasgow coma scale criteria
- Eye opening (1-4) (4 is spontaneous)
- Best verbal response (1-5) (5 is oriented)
- Best motor response (1-6) (6 is obeys commands)
Confusion
A problem with coherent thinking, characterized by confused patients unable to think with normal speed, clarity, or coherence, an essential component of delirium
Acute confusion state
Refers to acute state of altered consciousness with disordered attention, diminished speed, clarity, and coherence of thought. Delirium is a special type of confusional state
Delirium definition
An acute confusional state associated with varying picture of agitation, hallucinations, convulsions, tremor, delusions, and inability to sleep. Often also has psychomotor behavioral disturbances such as hypoactivity/hyperactivity, variable emotional disturbances, and similar symptoms to dementia
5 Key characteristics that define delirium
1) distrubance in attention and awareness
2) short period of time development change from baseline and tends to fluctuate
3) disturbance in cognition such as memory deficit or disorientation
4) cannot be explained by another pre-existing condition (such as dementia)
5) evidence from history/PE/lab findings indicate a causal factor
3 types of altered memory seen in delirium
1) Retrograde (past)
2) antegrade (create new memories)
3) confabulation (misinterpretation or fabrication)
Nearly __% of older medical patients experience delirium at some point during hospitalization, with even higher rates in surgical patients
0.3
Delirium vs dementia
Delirium affects mainly attention, vs dementia affects mainly memory
Delirium vs dementia onset
Sudden with definitive beginning vs gradual with unknown beginning
Delirium vs dementia duration
Days to weeks vs permanent
Delirium vs dementia cause
Almost always 2nd to a acute condition vs chronic brain disorder
Delirium vs dementia course
Reversible usually vs slowly progressive
Delirium vs dementia effect at night
Both usually worsen
Delirium vs dementia attention
Greatly impaired vs unimpaired until end stage
Delirium vs dementia language use
Slow and incoherent and inappropriate vs sometimes difficutly to finding right word
Delirium vs dementia memory
Varies vs lost especially for recent events
Delirium vs dementia medical attention
Immediate vs required but less urgent
Most common causes of delirium (6)
- Drugs/toxins
- infections
- metabolic derangement
- brain disorders (seizures, head injury)
- systemic organ failure
- physical trauma (burn, hypothermia)
Dementia is or is not a cause of delirium?
is NOT a cause of delirium
Stroke is or is not a cause of delirium?
is typically
Sun downing
A type of delirium, occurs because with less light, broken routine, many unfamiliar faces, a person may not be able to cognitively compensate when their brain is already compromised such as an alzheimer’s patient resulting in a delirious state worsened in the evening
Common causes of post operative delirium (3)
- use of pre op and post op meds
- intraoperative events such as hypoxia or hypotension
- pre-existing unrecognized alcohol or drug use
The bed side chat
A conversation with a patient assessing attentiveness, degree of arousal, etc. by asking them simple questions part of the neurological exam
Confusion Assessment Method (CAM)
A supplemental type of assessment used in patients who there is concern for delirium, not commonly used and not necessarily standard
Neuroimaging is rarely positive following a neurological exam of a patient with ___ findings
non-focal
Differential diagnosis of delirium (4)
- depression
- schizophrenia/psychosis
- dementia
- malingering (faking it to get out of work or obligations)
Delirium treatment (5)
- Room near a nursing station allows for greater observation and socialization
- social visits
- avoidance or minimizing restraints (posey bed cover like at porter or pillowcase tying of extremities like something we’d do at a sleepover)
- haldol (haloperidol) antipsychotic
- Ativan (lorazepam) benzos
Delirium treatment (haldol and ativan) ADR’s (3)
- dystonia
- torsades de pointes
- anticholinergic effects
The only cranial nerve covered in dura mater and technically part of the CNS opposed to the PNS
CN II (optic nerve)
T4 dermatome corresponds to…. T10 corresponds to…
Nipple line, umbilicus line
Peripheral neuropathy definition
Pathology or abnormality affecting the nerves of the PNS specifically including mono (focal involvement of single nerve) or poyneuropathies (affecting many peripheral nerves and often symmetric)
Carpal tunnel syndrome is an example of a ___ neuropathy
Mono
Diabetic neuropathy is an example of a ___ neuropathy
Poly
Mononeuropathy multipex
Simultaneous or sequential non-symmetrical involvement of varying nerves and is not progression of a single neuropathy (for example peroneal nerve and median nerve compression occurring at the same time) sometimes due to same underlying cause other times randomly co-occurring
Peripheral neuropathy predisposing factors (8)
- Diabetes
- peripheral arterial disease
- HTN
- hypercholesterolemia
- tobacco/alcohol use
- Genetic conditions
- nutritional deficit
- iatrogenic (such as surgery positioning)
Peripheral neuropathy epidemiology
Males equal to females, risk increases with age
PNS disorders symptoms (3)
- weakness
- parasthesia/dysesthesia (burning, numbness, pins and needles)
- autonomic dysfunction
Typical presentation of a patient with chronic peripheral neuropathy description
-my feet are asleep especially at night (brain has nothing else to focus on) and sometimes have shooting tingling pain coming up the legs that has been going on a while in both legs over past few months (subacute)
Cranial neuropathies signs and symptoms are specific to…
….the sensation and motor function (remember pneumonic to know which CN’s do which) of that specific nerve
Some say money matters…
Sensory I Sensory II Motor III Motor IV Sensory V1 Sensory V2 Both V3 Motor VI Both VII Sensory VIII Both IX Both X Motor XI Motor XII
Degenerative disk disease definition
Tear of intervertebral disk that rips the annulus fibrosis allowing the nucleus pulposis to protrude out most often laterally and potentially compress spinal nerve roots that also exit laterally either from sharp trauma or extended deterioration over time
Degenerative disk disease presentation (4)
- Low back pain
- sensory disturbance
- weakness
- unilateral specific location
Diabetic amyotrophy definition
Subacute onset, very painful, dermatomal sensory deficit with a protracted course over 2 to 3 months that resembles a disk herniation but imaging is unremarkable typically occurring in prolonged hyperglycemic states
Diabetic amyotrophy treatment (1)
Steroids to decrease inflammation and monitoring blood glucose
Herpes zoster infection (REMEMBER the name of the causative agent)
Shingles, caused by varicella zoster virus that resides in nerve roots and erupts sporadically and is triggered by stress or immunocompromise appearing with dermatomal vesicular rash with severe pain
Post herpetic neuralgia
Pain lingering from herpes zoster infection that lasts for months or years after
Herpes zoster treatment (2)
Antiviral medication and chronic pain management
Brachial plexopathy in infant
Occurs during childbirth when a shoulder gets caught on the pubic symphisis of the mother while the baby’s head is pulled
Cervical or brachial plexopathy etiologies (3)
- trauma
- malignancies
- idiopathic
Brachial/lumbar plexitis
A subacute, severe pain sensory disturbance and weakness with a many month course of the brachial/lumbar plexus impacting multiple nerves downstream from where these nerves move
Electromyography and nerve conduction velocity tests can confirm…
These tests are typically second to what studies?
….multiple nerve root involvement indicating plexitis being the cause of a peripheral neuropathy
-Negative imaging studies
Brachial/lumbar plexitis treatment (3)
- steroids
- pain management
- surgery
Upper motor neurons tend to be ___ to the lower motor neuron preventing ____ (seen if destroyed).
If a lower motor neuron is destroyed then tend to see ____
inhibitory, spasticity, flaccid paralysis or fasciculations (but no strong contractions)
Median nerve neuropathy/carpal tunnel syndrome
Typically an overuse syndrome from swelling associated with tendonitis seeing dysethesias, parasthesias, and weakness in digits I through radial aspect of digit IV and and palm
Ulnar nerve neuropathy
Usually an overuse syndrome most noticable with repetitive flexion/extension of the arm, due to stretch or compression in cubital tunnel or from compression due to resting on a surface, sensory deficits tend to affect digit V and ulnar aspect of digit IV, as well as ulnar claw hand
Median neuropathy/carpal tunnel syndrome treatment (3)
- activity modification
- splint
- surgery
Ulnar nerve neuropathy treatment (1)
-surgical decompression
Peroneal nerve compression
Usually from compression or ischemia of the nerve typically in pt’s who habitually cross legs or have knee/leg trauma, symptoms include foot drop (lack of dorsiflexion) and sensory loss in lateral aspect of foot and shin
Lateral femoral cutaneous nerve compression/meralgia paresthetica
Compression of lateral femoral cutaneous nerve at the waist (inguinal canal) common in obese, weightlifters, post partum, or hip surgery patients, often idiopathic, sees parasthesias/hyperesthesia’s in anterior lateral thigh
Lateral femoral cutaneous nerve compression/meralgia paresthetica has sensory involvement but…
…NO MOTOR involvement
Posterior tibial nerve compression/tarsal tunnel syndrome
Least common among compressive mononeuropathies, causes pain and sensory disturbance at the medial aspect of foot and angle due to compression at the tarsal tunnel (medial ankle)
Polyneuropathies
Slow onset, progressive, begining in lower distal extremities and spreading proximally eventually to upper extremities type of neuropathy that can involve combos of sensory, motor, and autonomic fibers and have symptoms in all 3
Guillain barre syndrome/acute inflammatory demyelinating polyradiculoneuropathy definition and how is it diagnosed
Often occurring few weeks post viral illness, is a rapidly progressing ascending sensory loss and motor weakness, also involves autonomic involvement (heart, temp, pupils), diagnosed clinically but confirmed by CSF analysis and slow nerve conduction studies
Guillain barre syndrome pathophysiology
Theorized to be antibody mediated attack of the myelin on nerve roots and peripheral axons resulting in radicular symptoms
Diagnostic studies for guillain barre syndrome (3)
- CSF analysis (lumbar puncture
- EKG
- breathing capacity
Guillain barre syndrome treatment (4)
- IV IG
- Plasmapheresis (plasma replacement)
- Respiratory support
- DVT prophylaxis
Chronic inflammatory demyelinating polyradiculoneuropathy
Chronic form of guillan barre syndrome that presents as either a relapse or one that does slowly progresses regardless of treatment
Charcot marie tooth disease/hereditary sensory motor neuropathy
Genetic sensory motor neuropathy disease usually beginning at early age characterized by high arched foot, hammer toes, intrinsic hand and foot muscle atrophy, and sensory loss
2 ways antiseizure drugs work
1) act on neurons within a focus to reduce excessive rate of discharge
2) drugs can prevent propagation of seizure activity from a focus to other brain regions
5 primary mechs thru which anti seizure medications work
1) suppression of Na+ influx
2) suppression of Ca2+ influx at T type calcium channels
3) Enhancing activity of GABA
4) Antagonism of glutamate (which is excitatory neurotransmitter)
5) Promotion of K+ efflux
Therapeutic goal of antiseizure meds
Reduce seizures to extent that enable patient to live normal or near normal life, may not be possible without intolerable side effects so may have to balance
Treatment with antiseizure meds requires matching the proper medication with…
….specific seizure disorder
Antiepileptic drug treatment timeline protocol
Begin initial therapy, should it fail try 2nd and 3rd options alone then try combo, once one is selected, need trial period to determine effectiveness (pt should not drive or do other activities that are hazardous during this time)
Epilepsy therapy needs this common practice
Monitoring plasma drug levels
Withdrawal of antiseizure medications
Because some forms of epilepsy undergo spontaneous remission at some point discontinuation must be considered, no firm guidelines are indicated but most important rule is that withdrawal must be done slowly tapering the dosage down to prevent status epilepticus. If on multi drug regimen, taper off each drug sequentially
Cause of 50% of treatment failures in patients that are withdrawing from antiepileptic drugs
Nonadherance to medication therapy (patient compliance)
Suicide risk with antiepileptics (3)
- only some antiepileptic drugs raise risk
- risk linked more to illness than the medication
- suicide attempts are quite rare but should require monitoring
Antiepileptic drug ADR’s (2)
- suicidality
- reduced bone density
Antiepileptic drug interactions (1)
-contraceptive failure when on PO contraceptives
Antiepileptic drugs are indicated in pregnancy at low dose because….
…considered less risk of harm (although some evidence exists of lowered IQ’s) to the fetus than if the mother has a seizure
Phenytoin (dilantin) function, mech of action, pharmacokinetics, ADR’s (5), therapeutic range
- Broad spectrum antiseizure agent, active against partial seizures as well as tonic clonic seizures, no longer drug of choice because of ADR’s and interactions
- Stabilizes membranes by decreasing Na+ conductance during high frequency repetitive firing exerting effect only when neuronal activity is abnormally high allowing normal conductance of AP in CNS but halting seizure activity
- Has sharp rise beyond therapeutic range making pharmacokinetics difficult to balance
- CNS sedation (dizziness, visual disturbances, cognitive impairment) at high supratherapeutic levels, gingival hyperplasia, skin rash, cardiac arrhythmia when given IV too fast, teratogen
- between 10-20 ug/mL in plasma
Fetal hydantoin syndrome
Growth deficiency in pregnancy causing cranofacial distortion, positional deformities of limbs, and impaired neurodevelopment seen in pregnant women who take phenytoin
Phenobarbital function, mech of action, therapeutic uses (all except one), ADR’s (3), interactions (2)
- Can reduce seizures without causing sedation
- Binds to GABA receptors enhancing GABA activity at the receptor resulting in potentiation of inhibitory effects of GABA
- Effective against all types of epilepsy except absence seizures
- Drowsiness, depression, toxicity
- CNS depressants, induction of drug metabolizing enzymes decreasing effects of other drugs such as oral contraceptives
Primidone (Mysoline) function
Active against all major seizure disorders with exception of absence seizures, very similar to phenobarbital
Carbamazepine (tegretol) function, mech of action, therapeutic uses (3), ADR’s (5), drug interactions (4)
- effective against all forms of epilepsy except absence seizures
- Appears to act by delaying recovery of inactivated Na+ channels
- Epilepsy, trigeminal/glossopharyngeal neuralgia, bipolar disorder
- CNS minimal effects (unlike phenytoin), leukopenia, aplastic anemia, dermatologic rxns, birth defects
- induction of drug metabolizing enzymes, phenytoin, phenobarbital, grapefruit juice
Ethosuximide (zarontin) mech of action, indication (1), ADR’s (1)
- suppresses neurons in hypothalamus responsible for generating absence seizures thru inhibition of ca2+ influx thru T channels
- Only used for absence seizures
- devoid of significant ADR’s
Valproic acid (depakene) and divalproex sodium (depakote) mech of action, therapeutic uses (3), ADR’s (4), drug interactions (2)
- suppress high frequency neuronal firing thru blockade of na+ channels
- used to widely treat all seizures, treat bipolar disorder, treat migraine
- GI upset, hepatotoxicity, teratogenic category D (may cause fetal abnormalities but may be used if only thing that controls seizure in mother), pancreatitis
- phenobarbital and phenytoin
Clonazepam (Klonopin) mech of action, function (2)
- Benzodiazepine that does not suppress abnormal excitability wihtin seizure focus thought to be due to enhancement of GABA
- used to treat different kinds of seizures and sleep
Oxcarbazepine (trileptal) therapeutic uses (3), ADR’s (1)
- monotherapy or adjunctive in treatment of partial seizures, bipolar, and neuropathic pain
- Less severe than carbamezapine
Lamotrigine (lamictal) mech of action, function, ADR’s (2)
- regulates release of glutamate and aspartate which are excitatory neurotransmitters
- used in adjunctive therapy for seizures
- rash, suicidal thoughts
Gabapentin neurontin) function, mech of action, dosing
- adjunctive therapy for partial seizures with and without secondary generalization in patients >3 years old
- analog of GABA that enhances release rather than binding directly to GABA receptors
- must be titrated upward
Pregabalin (lyrica) function and ADR’s (3)
- Analog of GABA similar to gabapentin used in neuropathic pain as alternative to gabapentin
- weight gain, dizziness, reproductive adverse effects in men AND women
Levetiracetam (keppra) mech of action, therapeutic uses (1)
- unknown
- adjunctive therapy for partial or direct treatment for other types of seizures
Topirimate (topamax) therapeutic uses, mech of action, ADR’s (3)
- tonic clonic seizures
- 4 major mechanisms
- difficulty concentrating, drowsiness, dizziness
Antiseizure med that affects K+ efflux
Ezogabine (potiga)
Diazepam function, ADR (1)
- First line choice in seizure convulsion abortion in 90% of patients, effects are short lived and must be administered in repeated doses
- IV venous thrombosis
Lorazepam (aivan)/valium function
-Preferred to diazepam for seizure convulsion abortion because has longer duration up to 72 hours meaning follow up with long acting drug may be unecessary unlike diazepam
