neurodegenerative & seizure disorders Flashcards
Neurodegenerative disorders: characterized by what and caused by what 3 possible things?
Characterized by progressive loss of neuronal function in the CNS
Cause of disease thought to involve heredity, autoimmunity, & environmental factors
what is a tremor?
an unintentional (involuntary), rhythmical alternating movement that may affect the muscles of any part of the body. -caused by the rapid alternating contraction and relaxation of muscles and is a common symptom of diseases of the nervous system
what is chorea?
A term that is used to refer to rapid, jerky, involuntary movements of the limbs or face that characterize several different disorders of the nervous system
what are tics?
Sudden uncoordinated abnormal movements that occur repetitively especially seen in the face and head.
Can be suppressed voluntarily for short periods.
what population does parkinsons affect?
Onset usually between age 40 & 70, with peak onset in sixth decade
Slightly more common in men
what are the 4 Cardinal Signs of parkinsons?
- Rigidity: An increased basal muscle tone, inability to initiate movements
- Bradykinesia: Difficulty initiating movement & once initiated movement is slow
- Tremor: This occurs primarily at rest and improves with intention
- Postural/gait instability
what are the 4 secondary signs of parkinsons?
- As disease advances often get decline in cognitive function too but the hallmark of the disease is the movement disorder
- Autonomic dysfunction
- Speech disturbances
- Micrographia
pathophys of parkinsonism
For optimal control and coordination of movement need a balance between dopamine and acetylcholine in basal ganglia.
parkinsons–>excess of Ach and deficiency of dopamine= problems in the ability to control movement
(substantia nigra not making dopamine… no dopamine going to straitum…where it usually inhibits NTs)
what are the two goals of parkinsons drugs?
restore dopaminergic activity (b/c dopamine reduced) and/or balance excess Ach w/ anti-cholinergic/anti-muscarinic
When inhibiting dopa decarboxylase with carbidopa, another system is activated to metabolize dopamine…
-what do we need to counter-act this?
COMT Inhibiting COMT enzyme: Reduced accumulation of 3-O-methyldopa Prolong the action of levodopa Increase levodopa’s bioavailability
7 treatment principles for parkinsons
- Treatment based on symptoms – no treatment currently prevents progression
- Tailor treatment to the individual
- Early Disease can be managed with exercise and lifestyle interventions
- Medications can be delayed in younger patients and start when there is an impact on quality of life
- Several classes of medications can be used simultaneously
- Drug initiation for mild symptoms include:
MAO-B inhibitors, amantadine, or anticholinergics - As disease progresses, eventually levodopa or dopamine agonist is required
Younger patients (<65) dopamine agonist are preferred to reduce motor complications
Older patients (>65) levodopa/carbidopa tolerated better
parkinsons is a ____ deficit resultant from _____ loss in the _____that provides innervation to the straitum
dopaminergic
neuronal loss
substantia nigra
all parkinsons pt will eventually need what kind of medications?
dopaminerigic
what is the most effective medication for parkinsons?
levodopa (w/ carbidopa)
drug- induced parkinsonism: drugs? characterized by?
Haloperidol, metoclopramide, and the phenothiazines cause Parkinsonism b/c they antagonize dopamine receptors.
Characterized by:
Symptoms within 3 months of starting the neuroleptic
Related to dose of neuroleptic given, the higher the dose, more likely the symptoms
treatment for drug-induced parkinsonism?
decrease dose & usually better in a few weeks, if need to can use antimuscarinics
Don’t use levodopa does not help & can cause psychosis
what is a seizure? what can it be a result of?
episode of abnormal electrical activity in the brain that causes involuntary movements, sensations or thoughts
Can be a result of:
Head trauma, stroke, brain tumors, hypoxia, hypoglycemia, fever, chronic alcohol withdrawal
what qualifies it as epilepsy?
At least 2 unprovoked seizures occurring > 24 hours apart
what are focal seizures and what are the three types?
Limited to 1 cerebral hemisphere of the brain
1.Simple partial seizure: no alteration of consciousness
May be referred to as aura - can lead to complex or tonic-clonic
2.Complex partial seizure: altered consciousness, automatisms, behavioral changes
3. Secondarily generalized seizure: seizure becomes generalized and is accompanied by loss of consciousness
what are general seizures and what are the two types?
Originate at one point, but rapidly engages hemispheres of the brain
generalized motor and generalized nonmotor
what are the 4 types of general motor seizures?
- Tonic-clonic (grand mal): increase muscle tone followed by spasms of muscle contraction and relaxation
- Tonic: flexion/extension phases
- Atonic: sudden loss of all muscle tone
- Myoclonic: brief, rhythmic, jerking spasms of entire body
what are the two types of general nonmotor seizures ?
1.Absence (Typical/Atypical): brief loss of consciousness, minor muscle twitches and eye blinking
Typical – abrupt onset with altered consciousness
Atypical- gradual onset with altered consciousness
2.Myoclonic Absence: brief, rhythmic, jerking spasms of entire body
what do we known about unknown onset seizures?
Can appear like focal or generalized seizures
Unable to determine origination
what are the 4 steps to diagnosing a seizure disorder ?
Neurologic examination (head, vision, cranial nerves, motor function, cerebellar function, and sensory function)
Laboratory tests
Because metabolic causes of seizures are common- serum glucose, electrolytes, calcium, and renal function tests are needed
Electroencephalograms
MRI - technique of choice for epilepsy diagnosis
drugs for acute/ status epilepticus
Diazepam (Valium)
Lorazepam (Ativan)
Fosphenytoin (Cerebyx)
Phenobarbital (Luminal)
drug of choice for focal seizures
Carbamazepine
Lamotrigine
Levetiracetam
Oxcarbazepine
drug of choice for generalized motor
Lamotrigine Levetiracetam Valproate Carbamazepine Oxcarbazepine
drug of choice for general nonmotor absence
Ethosuximide
Valproic acid
drug of choice for generalized nonmotor myotonic absence
Lamotrigine
Levetiracetam
Valproic acid
what is status epilespy?
When patients experience recurrent episodes of tonic-clonic seizures without regaining consciousness or normal muscle movement between episodes or any seizure that last more than 20 minutes
-life threatening and longterm consquences
treatment for status epilepsy?
Basic life support first (ABCs). This involves supporting respirations, BP and getting rid of acidosis
Also need IV anticonvulsants meds
-Benzodiazepines
- Fosphenytoin (phenytoin w/ less ADRs)
benzodiazepenes for status epilepticus
Diazepam or lorazepam give IVP
Intravenous push (IVP) means directly from syringe into vein
IVP faster, more toxic than IV drip
Benzodiazepines given like this can suppress or stop respirations or affect heart & need to be ready to support
anticonvulsants for status epilepticus
Urgent Medications
When giving benzodiazepines - effect wears off in 30-40 minutes. Usually need to give another drug soon after benzos so seizures don’t start again once benzos wear off.
Options: phenytoin, fosphenytoin, phenobarbital
If fosphenytoin ineffective can try phenobarbital, next step is general anesthesia
General anesthetics = midazolam & propofol
why are serum conc levels important for anticonvulsant drugs?
With older drugs there is relatively well established relationships between blood levels and therapeutic effects
Carbamazepine, phenobarbital, phenytoin, valproic acid
what three anti-convulsants are teratogens? how does this happen?
Phenytoin, phenobarbital and carbamazepine all associated with specific syndromes of multiple birth abnormalities
all 3 are enzyme inducers
what 5 anti-convulsant drugs should we monitor in elderly populations b/c of d/c pharmokinetics?
Carbamazepine - decreased clearance
Phenytoin – decreased protein binding, esp. if decreased renal function
Valproic acid – decreased protein binding
Diazepam – increased half-life
Lamotrigine – decreased clearance
what 3 anti-convulsant drugs do we need to monitor for Suicidality?
Gabapentin, lamotrigine, oxcarbazepine
what anti-convulsants increase the risk of osteoporosis?
Inducers – phenytoin, carbamazepine, phenobarbital- may increase risk of osteoporosis
what is the withdrawal effect regarding seizure medications?
When stopping seizure meds there is a risk of increased seizure frequency and severity of seizures.
rules for medication discontinuation of seizure meds?
Often try to stop meds once seizure free for 2-5 years
General dose reduction:
Barbiturates and benzodiazepines take longest to stop
Epilepsy is considered resolved in those who have remained seizure free for 10 years with no medications for the last 5 years.
