Neuro 3 Flashcards
Neurologic damage associated with B12 deficiency
subacute, combined degeneration of the posterior and lateral spinal columns.
Best lab test for B12 deficiency
High serum methylmalonic acid levels
Syringomyelia
disproportionate loss of pain and temperature sensation involving arms and hands. Causes damage to central white commissure.
Symptoms of ventral white commissure damage
loss of pain and temperature sensation bilaterally. Still have touch, vibration, and temperature
hydrocephalus
intracranial calcifications
chorioretinitis
in a newborn
Congenital toxoplasma infection. Why pregnant mothers should not handle cat litter
Myoclonic seizures
repetitive seizures consisting of brief, symmetric, muscular contraction with loss of body tone.
Seizures are precipitated by stress and sleep deprivation
First line drug of choice for myoclonic seizures
valproic acid
First line drug of choice for partial seizures (simple and complex)
carbamazepine
First line drug of choice for tonic-clonic seizures
phenytoin, carbamazepine, valproate
First line drug of choice for absence seizure
ethosuximide
second-> valproate
MOA of valproic acid
supresses abnormal electric activity in the cortex by affecting GABA and NMDA receptors as well as Na and K channels
signs of upper motor neuron lesion
hyperreflexia, spasticity, babinski sign
Gram positive rods with tumbling motility at room temperature
Listeria monocytogenes
Most common cause of listeria transmission in adults
refrigerated food
MOA of organophosphate poisioning
irreversible cholinesterase inhibitors. Elicit cholinergic stimulation that lasts until new cholinesterase can be synthesized
Treatment for organophosphate posioning
muscarinic antagonists (atropine) cholinesterase enzyme inhibitor (pralidoxime)
Symptoms of CNIII palsy
ptosis
downward and laterally deviated eye
impaired pupillary constriction and accommodation
diagonal diploplia
Most worrisome cause of CNIII palsy
enlarging intracranial aneurysm
Vision deficit caused by macular lesion
central scotoma: altered central vision surrounded by areas of normal vision
Causes of polyhydraminos
decreased fetal swallowing: fistula or anencephaly
increased urine output: anemia or twin-twin transfusion
MOA of buproprion
inhibits presynaptic reuptake of dopamine and norepinephrine (greater effect on dopamine)
Drugs that can cause seizures
buproprion clozapine- antipsychotic isoniazid- if given without B6 ciprofloxacin imipenem ---Higher risk in patients with previous seizures, anorexia, or bullemia---
Signs of lower motor neuron lesion
flaccid paralysis, areflexia, atrohpy, fasiculation
Where do you draw the line between upper motor neurons and lower motor neurons?
Above or below anterior horn
homonymous hemianopsia
visual field loss of half (vertically) of the same side of both eyes (left half of visual field of both eyes). Caused by optic tract lesion
Optic tract leison also associated with abnormal swinging flashlight test
Vitamin E deficiency mimics what inherited disorder?
Friedreich’s ataxia
Symptoms of Friedreich’s ataxia and vitamin E deficiency
ataxia, dysarthria, loss of both position and vibration sensation
Due to degeneration of spinocerebellar tracts, dorsal columns, and peripheral nerves
Antipsychotic side effects
Extrapyramidal:
- acute dystonic reaction (muscle contractions)
- akathisia (restlessness)
- Drug induced parkinsonism
Tardive dyskinesia (involuntary movements)
Neuroepileptic malignant syndrome: fever, rigidity, mental status changes, autonomic instability
Axonal reaction
changes in the body of a neuron after the axon has been damaged
Increased protein synthesis: enlarged, rounded cells, peripherally located nuclei, dispersed finely granular Nissl substance
Two classes of dopamine agonists used in Parkinson’s
ergot compounds- bromocriptine and pergolide
nonergot compounds- pramipexole and ropinrole
How does the abnormal huntingtin protein effect expression of other genes?
Prevents transcription via hypermethylation of histones
When do we draw the line between maternity blues and postpartum depression?
2 weeks
Treatment for toxoplasmosis
protozoan: treat with pyrimethamine and sulfadiazine
Second most common cause of brain lesion in AIDS patient?
primary central nercous system lymphoma, often associated with latent EBV infection
B cell lymphoma
Nerve that innervates posterior (extensor) compartment of the arm
radial
Radial nerve provides innervation to what part of the hand?
radial half or the dorsal hand
Median nerve supplies sensory innervation to what part of the hand
palmar and dorsal surfaces of the first 3 and 1/2 digits
What nerve is damaged by radial head subluxation
deep branch or radial nerve
Why is trazodone (antidepressent used for insominia) contraindicated in adolescent boys?
can cause priaprism
What nerve innervates the stapedius muscle?
What is the consequence of paralysis of this muscle?
Innervated by stapedius nerve (branch of CNVII)
paralysis causes increased sensitivity to sound
CNS side effect of levadopa?
Dopamine increases anxiety and agitation. Will not be decreased by addition of carbadopa, but worsened because more dopamine is available for the brain
MOA of morphine
binds to mu opioid receptors, activates potassium channels to increase efflux -> hyperpolarizes postsynaptic neurons and cease pain transmission
Signs of lesion to occipital lobe
homonymous hemianopia with macular sparing
Caused by PCA infarct
Recurrent lobar hemorrhage in elderly
cerebral amyloid angiopathy (amyloid deposited in arterial wall, weakens wall and predisposes it to rupture.
What genetic disorder is associated with bilateral acoustic neuromas?
NF-2, gene found on chromosome 22
Two immediate physical symptoms of marijuana use
rapid heart rate and conjunctival injection
How long is marijuana retained in tissues?
Lipophilic, can stay in tissues for up to 30 days
What structures can become compromised in transtentorial herniation?
Occulomotor nerve- fixed, dilated pupil
Posterior cerebral artery
Contralateral cerebral peduncle
Basilar artery- brainstem hemmorrhages
Phenytoin toxicities
- Ataxia and nystagmus
- gingival hyperplasia, coarsening of facial features, hirsutism
- megaloblastic anemia (messes with folate metabolism)
- Cyp450 inducer
- Teratogenic- fetal
Which atypical antipsychotic is most likely to cause Extrapyramidal symptoms
Risperidone
