16-2 CNS

q123456's version from 2016-06-01 18:44

CNS disease

Question Answer
hemispatial neglect
unilateral brain damage

associated with lesions of the right posterior parietal cortex, particularly the inferior parietal lobe (IPL) or temporoparietal junction (TPJ)

Such individuals with right-sided brain damage often fail to be aware of objects to their left, demonstrating neglect of leftward items.
parkinsonson disease treatmentlevodopa+carbidopa
SE: anxiety and agitaion
vitamin B6 increases the peripheral metabolism of levodopa>>>decrease its effectiveness
alzheimer's therapiesenhanced cholinergic neurotransmission (donepezil)
neuroprotection via antioxidants (vitamin E)
NMDA receptor antagonism (Memanitine)
trigeminal neuralgiacarbamazepine
essentia tremorthe first line treatment for essentia tremor: propranolol
pramipexoledopamine agonists have a chemical structural similar to the neurotransmitter dopamine and directly stimulate dopamine receptors.
ropiniroledopamine agonists have a chemical structural similar to the neurotransmitter dopamine and directly stimulate dopamine receptors.
bromocriptinedopamine agonists have a chemical structural similar to the neurotransmitter dopamine and directly stimulate dopamine receptors.
pergolidedopamine agonists have a chemical structural similar to the neurotransmitter dopamine and directly stimulate dopamine receptors.


Question Answer
epilepsypartial: carbamazepine
generalised seizures:
1) tonic–clonic: phenytoin, carbamazepine and valproate
2) absence: ethosuximide than valproate
3) myoclonic: valproate

status epilepticus:Status epilepticus: when a seizure lasts too long or when seizures occur close together and the person doesn't recover between seizures.
1) iv lorazepam
2) simultaneously load with phenytoin
3) if still seizing, start phenobarbital
4) still seizing, intubate and give general anesthesia
mechanisms of aciton of antiepileptic drugs1. Enhancement of GABA action (binds to GABAa receptors>>>facilitate the GABA mediated opening of Cl- channel

SE sedation
Primidone is an antiepileptic that is metabolized to phenobarbital and phenylethylmalonamide

clonazepam and diazepam: acute sezures
lorazepam used in treating status epilepticus
lorazepam and benzodiapines are also used for alcohol withdrawal syndrome (tremor, tachycardia, hypetension, hallucinations) KA37-4
used for insomnia
no tolerance and addiction, withdrawal symptoms is much lower than benzodiazepines.

***gamma-Aminobutyric acid (GABA) is the chief inhibitory neurotransmitter in the mammalian CNS. It plays the principal role in reducing neuronal excitability throughout the nervous system. In humans, GABA is also directly responsible for the regulation of muscle tone.

2. inhibits neuronal high frequency firing by reducing the ability of sodium channels to recover from inactivation>>>increase the refractory period.

the most widely used antiepileptic drugs
trigeminal neuralgia
1) agranulocytosis/aplastic anemia, CBC should be monitored regularly *** carbamazepine, clozapine, antithyroid drugs(propylthiouracil and methimazole)
2) p450 inducer
3) increase ADH secretion>>>SIADH ***lithium: ADH antagonist

SE: Lymphadenopathy, gingival hyperplasia

3. Inhibition of calcium channel function
ethosuximide used for absence seizure, fist line drug, SE: Skin rash (stevens-johnson sndrome)

4) inhibiton of sodium and calcium channel function
valproate used for all types of seizures including absence,tonic clonic and myoclonic seizure, also manic episodes, SE: Hepatotoxicity

5) new drugs: lamotrigine: SE: Skin rash (stevens-johnson sndrome)

Antipsychotics and antidepression

Question Answer
serotoninrelease by neurons in the raphe nuclei of the brainstem
serotonin syndromee.g SSRIs+MAO inhibitors, hyperreflex, vomiting/diarrhea, agitation/confusion

SSRIs+MAO inhibitors
SSRIs +tricyclic antidepressants
SSRIs+linezolid (antibiotics for vancoycin resistant enterococcus and methicillin resistant S aureus)
5-HT (serotonin)tryptophan
1) interstine: carcinoid syndrome increase GI motility>>>diarrhea/vomiting (SSRI's SE: diarrhea/vomiting)
2) platelet: platlet aggregation
3) midbrain: control appetite, sleep and mood
serotonin degradation: monoamine oxidase (MAO)>>>5-HIAA>>>urine
MAO inhibitors: phenelzine and selegiline (MAO-B inhibitor)
function: migraine/carcinoid syndroe/mood disordrs/anxiety

5-HT1 agonist:
buspirone(anxiety): anxiety: benzodiazepines, buspirone and SSRIs
needs several weeks following the beginning of treatment
minimal hypnotic effects (no sedation)

5-HT3 antagonists: ondansetron, tropisetron (antiemetic drugs)

5-HT2/3 antagonist: mirtazapine(antidepressants)
drugs for migraineacute attack: triptan(5-HT1 agonists)
3)inhibition of prolactin secretion (anti psychotic drugs>>>lactation)
first generation
high potency: haloperidol, trifluoperazine, fluphenazine-extrapyramidal symptoms
low potency: thioridazine, chlorpromazine-anticholinergic, antihistamine and alfa blockade effects

thioridazine: retinitis pigmentosa>>>impaired vision

block dopamine D2 receptor

1 Fat diposits
2 hyperprolactinemia>>>galactorrhea
3 extrapyramidal system:
1) acute dystonic reaction: sudden onset sustained muscle contractions

2) akathisia: restlessness with inability to sit still, treatment:propranolol (also used to treat benigh essential tremor)

3) durg induced parkinsonism:tremor, rigidity, bradykinesia, masked facies. treatment: benztropine effects of antipsychotic drugs. however, benztropine induces constipation, dry mouth and blurred vision.

tardive dyskinesia: upregulation of dopamine receptors

antimuscarinic-dry mouth constipation
anti-histamine receptors-sedation
second generation
block 5-HT2, dopamine, a and H1 receptors.

A receptor antagonism

improve the negative symptoms of schizophrenia

clozapine: is used against ‘negative’ features.
SE: agranulocytosis so Blood count is monitored weekly

risperidone and olanzapine: are used if extrapyramidalsymptoms are troublesome
benzodiazepines1)binds to GABA receptors>>>increase the affinity of GABA for the receptor>>>increase the frequence of Cl- channel opening.
2)drugs of choice in the treatment of alcohol withdrawal and anxiety
3)Inhibit anxiety and muscle tone.
5)SE: sedation (can not be used with alcohol, barbiturates, neuroeptics and 1st generation antihistamines)
Antidepressant drugs

MAO inhibitors

increase ADH production>>>SIADH>>>hyponatremia
All types of antidepressant drug appear to take at least 2
weeks to produce any perceived beneficial effects

antidepressants induce mania in bipolar disorder

1) selective serotonin reuptake inhibitors (SSRIs)
fluoxetine (used for OCD)
SE:loss of libido. In combination with MAOIs, SSRIs can cause a ‘serotonin syndrome’

2)inhibits serotonin reuptake
SE: priapism (painful erection) >>>contraindicated for use in adolescent boys

3) inhibition of noradrenaline and 5-HT reuptake.

a) tricyclic antidepressants:
imipramine, amitriptyline, clomipramine (used for OCD)
1 anti histamine receptor: sedation
2 NE and 5-HT reuptake: serzures and tremors
3 cardiac fast sodium channels (phase 0 myocardial depolarization is prolonged)>>>prolonged QRS complex>>> arrhythmias>>>treatment:NaHCO3
4 anti-alfa-1: vasodilation>>>hypotension
5 anti-muscarinic: atropine like (tachycardia, dilated pupils, flushing, hyperthermia, urinary retention (no urine))

b) venlafaxine

4)MAO inhibitor
at least 2 weeks after discountinuing phenelzine before starting the new drugs, why? during this washout interval to allow sertraline therapy to be initiated safely.

MAO: monoamine oxidase
phenelzine, selegiline KA26-33
SE:"cheese reactions" hypertensive crises on food intake

5)noradrenaline (dopamine and NE) reuptake inhibitors:
SE: Seizures if high doses, contraindicated in patients with a seizure disorder and bulimia or anorexia nervosa

fluoxetin (sexual performance)>>>bupropion (seizure)

***Atypical antiderpessants:
a2 antagonist and 5-HT2/3 receptor antagonist: mirtazapine
block NE reuptake: maprotiline
inhibit serotonin reuptake: trazodone
dopamine and NE reuptake inhibitor: bupropion (smoking cessation) KA36-43 SE Seizures in patients with bulimia or anorexia nervosa
lithiummood stabilizer for bipolar disorder

hypothyroidism>>>bradycardia, weight gain, dry skin, hair loss and constipation
ADH antagonist>>>causes nephrogenic diabetes insipidus by impairing aquaporin 2 waterchannels ,reducing response to vasopression

lithium>>>ebstein's anomaly in infants>>>decreased volume of the right ventricle and atrialization of the right ventricle
narcolepsysodium oxybate: prevention of cateplexy
modafinil:inhibits dopamine reuptake>>>increase extracellular dopamine levels in the caudate, putamen and nucleus accumbens


Question Answer
acute stress disorderdisturbance lasting less than 1 month ***post traumatic stress disorder>1 month
dysthymic disorder>2 years
major degression>2 weeks, guilt, appetite disorder, suicidality and sleep disorder
anorexia nervosaLow BMI, amenorrhea,
bulimia nervosaNormal BMI, irregular menses
acute manic therapylithium/valproate/carbamazepine/olanzapien(atypical antipsycholtic)
schizoaffective disease mood symptoms
schizophreniform disorder >1 month <6 months
Narcolepsy3 times weekly for 3 months
somatization disorderhigh use of medical resoursees
hypochondriasishealth anxiety or illness anxiety disorder, refers to worry about having a serious illness.
body dysmorphic disorder believe their body is pathologically flawed in fact it it not
factitious disorder in order to receive medical attension
malingering in order to receive disability benefits
conversion disorderAcute,
Conversion disorder signs and symptoms appear with no underlying physical cause, and you can't control them.
facilitaion encourage
mature ego defensesaltruism, humor, sublimation and suppression
displacementsomeone who is frustrated by his boss at work may go home and kick the dog
identificaitonwithout being aware that he is copying his teacher, a resident physician assumes a similar mode of dress and manner with patients.
projectionAttributing one's thoughts or impulses to another person
rationalizationmaking excuses
reaction formationwhen a person feels an urge to do or say something and then actually does or says something that is effectively the opposite of what they really want. It also appears as a defense against a feared social punishment.
regressionwhere a person returns to a child state to escape the present. ... Regression is one of Anna Freud's original defense mechanisms.
repressionexclusion from conscious ness of painful or unacceptable mommories
passive aggression


Question Answer
a 24 year old man is brought to the ER in deep coma. he is cyanotic and unresponsive to painful stimuli. his temperatre is 36.7C, blood pressure is 100/60 mmHg, pulse is 100/min, and respirations are 4/min. his pupils are constricted and poorly responsive to light. resuscitation efforts are initiated and several minutes later the patient regains consciousness and states that he want to go home. the drug used to treat this patient has the greatest affinity to which of the following receptors?Mu.
ketamine is a NMDA receptor antagonistglutamate binds to NMDA receptor>>>increase phospharylation of opioid receptors>>>morphine tolerance.
used for pain and treating heroin addiction
amphetamines and methylphenidatehyperactivity disorder

amphetamine toxicity
a 25 year old man, 106/mm, 39.4C, mydriasis, diaphoresis and agitation, delusions of persecution, ideas of reference and feelings of omnipotence.
treatment: diazepam ammonium chloride (acidify the urine and hasten amphetamine excretion)
methamphetaminecause the release of dopamine, NE and serotonin
drug abuse KA26/46
naloxoneopioid receptor antagonist used for treating opioid intoxication or overdosee.
great affinity for mu receptors
physical dependence
respiratory and cardiac depression
reduced GI motilty
pentazocinecompetitively inhibit mu receptors and produce antagonistic effects reduing opioid analgesic effects.
DiphenoxylateBinds to mu opiate receptor in the gastrointestinal tract and slows motility.
morphine causecontraction of SM cells in the sphincter of oddi>>>constriction and spasm>>>increase bile duct pressures>>>biliary colic
antagonism of M3 Glands/contraction of gut, bladder and bronch/miosis/accommodation
vareniclinebinds to nicotinic acetylcholone receptor, partial agonist of the receptor >>>reduce the symptoms of nicotine withdrawal


Question Answer
PCP hallucinogen, violent behavior, nystagmus
cocainestimulant, mydriasis
heroinopioid, dry mouth , miosis, constipation and depression
heroin suppress ventilation>>>respiratory acidosis
marijuanaconjunctive injection