Neuro 5 Flashcards
What fetal abnormality can be seen in infants of mothers who take lithium during early pregnancy?
Ebstein’s anomaly: atrialized RV d/t downward displacement of tricuspid valve
What congenital anomaly is most likely to occur in pregnant pts who take valproate and why?
NTDs b/c valproate inhibits intestinal folic acid absorption
What 3 products are derived from POMC and what does this indicate?
B-endorphins, ACTH, and MSH - suggests there may be a close physiological relationship between stress axis and opioid system
What are 3 classic symptoms of pineal germinomas?
- precocious puberty: increased B-hDG
- obstructive hydrocephalus d/t compression of cerebral aqueduct
- Parinaud syndrome d/t compression of tectal area of the midbrain
Which hallucinogen presents with Sx of agitation, dissociation, hallucinations, violent behavior, and memory loss and PE findings of nystagmus and ataxia?
Phencyclidine
Which stimulant presents with Sx of euphoria, increased arousal, agitation, chest pain, headaches, and seizures and PE findings of tachycardia, hypertension, and mydriasis?
Cocaine
Which stimulant presents with Sx of agitation, psychosis, diaphoresis, and violent behavior with PE findings of tooth decay, HTN, tachycardia, and choreiform movements?
Methamphetamine
Which hallucinogen presents with Sx of visual hallucinations, depersonalization, euphoria, occasional dysphoria and panic and PE findings of mild tachycardia, milk HTN, and pt alert and oriented?
LSD
Which psychoactive drug presents with Sx of increased appetite, euphoria, slowed reflexes, and impaired time perception and PE findings of dry mouth, conjunctival injection, and mild tachycardia?
Marijuana
Which opioid analgesic presents wiht Sx of mild euphoria or lethargy to coma and PE findings of miosis, decreased respiratory rate, and decreased bowel sounds?
Heroin
What is the MOA of PCP?
hallucinogen that works as an NMDA antagonist leading ot excess release of excitatory NTs
Which vitamin deficiency leads to degeneration of spinocerebellar tracts, dorsal column of spinal cord, and peripheral nerves?
Vitamin E
Which vitamin deficiency presents with the triad of ataxia, confusion, and ophthalmoplegia?
Thiamine
What blood disorder causes acute abdominal pain, peripheral neuropathy, and hyponatremia?
acute intermittent porphyria
What disorder does severe vitamin E deficiency resemble?
Friedreich ataxia
What is the most common medical cause of excessive daytime sleepiness in the US?
obstructive sleep apnea
What are risk factors for obstructive sleep apnea?
obestiy, tonsillar hypertrophy, and hypothyroidism
What are Sx and PE findings of obstructive sleep apnea?
Sx: poor orophyrngeal tone leading to daytime sleepiness, morning headaches, and depression
PE: obesity and increased soft tissue in oropharynx
Which barbituate-like IV anesthetic agent is often used in surgery?
Thiopental
What is the cause of the short half life and rapid plasma decay of thipoental?
REDISTRIBUTION to other tissues throughout the body, such as skeletal muscle and adipose tissue
What is the course of CN III?
It exits the midbrain and courses between the PCA and superior cerebellar arteries
Aneurysm of which arteries can lead to a non-pupil sparing CN III palsy?
PCA or superior cerebellar a.
What type of injuries are GVE and GSE fibers of CN III susceptible to, respectively?
GVE: injury from compression (i.e. aneurysm and tumor) bc on outside of CN III
GSE: injury from ischemia (i.e. diabetes) bc on inside of CN III
A 34 yo swimmer presents with ear infection. While inspecting the pt, you insert a speculum into the external auditory meatus in close contact with its posterior wall. The pt faints during the procedure. Irritation of which of the following nerves was most likely induced?
CN IX - it does cutaneous innervation to the posterior part of the external auditory canal via small auricular branch and pt fainted d/t vasovagal syncope
What innervates most of the external auditory canal, including the external portion of the tympanic membrane?
auriculotemporal branch of CN V3
What innervates the inner surface of the tympanic membrane?
tympanic branch of CN IX
Ascending paralysis that starts a few weeks after an upper respiratory infection or GI infection is most likely d/t what infectious agent?
C. jejuni - Guillain-Barre syndrome
-acute demyelinating peripheral neuropathy
What is the pathogenesis of the ascending flaccid paralysis seen in Guillain-Barre syndrome?
Antibodies against the infectious agent cross-react with myelin of spinal roots and peripheral nerves which is accommpaned by an “endoneural inflammatory infiltrate” consisting of lymphocytes and macrophages
What is the pathogenesis of diabetic microangiopathy?
hyalinization of nerve arterioles leading to the narrowing of the arterial lumen and ischemic nerve injury
What disease is characterized by “endomysial” inflammatory infiltration that manifests with bilateral, symmetric weakness of proximal muscles?
Polymyositis
What is seen on light microscopy in Guillain-Barre syndrome?
segmental demyelination of peripheral nerves and endoneural inflammatory infiltrate
What is the difference between sublimation and altruism?
Sublimation converts negative emotions in to productivity, whereas altruism confers benefit others
What are 4 TCA drugs?
imipramine, doxepin, amitriptyline, and clomipramine
Why must TCAs be used with caution in pts who use them for short-term pain relief for painful diabetic neuropathy?
they may cause urinary retention d/t antagonism of central and peripheral muscarinic ACh receptors
What are classic Sx of mytonic muscular dystrophy?
- difficulty loosening a grip after a handshake or inability to release the doorknob
- cataracts, frontal balding, and gonadal atrophy
What is the genetic basis behind myotonic dystrophy?
abnormal CTG repeat that codes for a myotonia-protein kinase leading ot anticipation
What is seen on light microscopy of myotonic dystrophy?
atrophy of Type 1 muscle fibers
How is the Dx of tetanus made?
Clinically
-baed on Hx of penetrating wound in a pt who has not been vaccinated and clinical signs such as trismus, risus sardonicus, msucel spasrm, etc.
What biochemical process undergoes ATP-dependent attachment to other proteins and labeling them for degradation - such as antigen processing, muscle wasting, cell cycle regulation, DNA repair, and disposal of misfolded proteins and regulatory enzymes?
Ubiquitin
Impairment of what biochemical process can contribute to development of neurodegenerative disorders such as Parkinson and Alzheimer?
ubiquitin-proteasome system
What is the effect of fluorinated anesthetics on the brain?
It leads to an increase in cerebral blood flow which can result in increased ICP
What are the effects if inhalation anesthetics on the heart, lungs, liver, and kidney?
heart: myocardial depression and hypotension
lungs: respiratory depression
kidney: decreased GFR, increased renal vascular resistance, and decreased renal plasma flow
liver: decreased hepatic flow
What are the two classes of DA agonists and what do they stimulate?
- ergot compounds: bromocriptine and pergolide
2. nonergot compounds: pramipexole and ropinirole
How does amantadine work to alleviate Parkinson Sx?
It is an indirect and direct dopaminergic agent and enhances effects of endogenous dopamine bc thought to have some anticholinergic properties
What is the action of selegiline for PD?
it is a MAO-B and decreases central DA degradation
- MAO-B is present in the brain; therefore selegiline prevents degradation of DA in the brain
- it delays clinical progression of PD
What is the MOA of COMT inhibitors and dopa decarboxylase inhibitors?
both decrease breakdown of levodopa in peripheral tissues and increase the amount available to cross the BBB
How do anticholinergics play a role in alleviated Parkinson Sx?
Trihexyphenidyl and benztropin inhibit central muscarinic receptors which treats drug-induced Parkinsonism and pts with tremors
What is the MOA of reserpine?
it inhibits DA entry into presynaptic vesicles, causing a chemical sympathectomy which reduces BP and HR
What is the MOA of guanethedine?
It is an adrenergic neuron blocker that inhibits NE release
How do BBs aid in acute Tx of myocardial ischemia and what is an important AE?
BBs reduce BP and cardiac work; but when nonselective agents are used, bronchoconstriction may be seen
What is a major cause of morbidity and mortality 4-12 days after a subarachnoid hemorrhage and how will the pt present?
vasopasm - will present with weakness in one arm and leg
What med is prescribed to prevent vasospasm after subarachnoid hemorrhage?
Nimodipine - selective CCB
What is the most dangerous complication of SAH and how will it present?
rebleeding: sudden development of a severe headache, severe N&V, change in consciousness, appearance of new neurologic deficits
What is the drug of choice for alcohol withdrawal?
long0acting BZs, like diazepam or chlordiazepoxide
What is the MOA of baclofen?
GABAb agnost used for spastic conditions
What do signs of pain with ocular movement and decreased vision indicate?
optic neuritis
What is intention tremor a sign of?
cerebellar dysfucntion
What condition is optic neuritis and cerebellar dysfucntion commonly seen together?
MS
What are the 3 most important mitochondrial myopathies?
- myoclonic epilepsy with ragged red fibers (MERRF)
- Leber optic neuropathy (blindness)
- mitochondrial encephalopathy with stroke-like episodes and lactic acidosis (MELAS)
Why are ragged red muscle fibers seen in mitochondrial diseases?
abnormal mitochondira accumulate under the sarcolemma
What are signs of common peroneal nerve injury and where does it occur?
signs: foot drop and high-stepping gait
location: trauma to leg near head of the fibula
Branched-chain ketoacid dehydrogenase catalyzes decarboxylation of a-ketoacid derivatives of which aas?
leucine, isoleucine, and valine
What is an AR disorder of tyrosine degradation caused by a deficiency of homogentisic acid oxidase leading to connective tissue hyperpigmentation and degenerative joint disease?
Alkaptonuria
What are two causes of PKU?
deficiency of phenylalanine hydroxylase or its cofacter tetrahydrobiopterin
What structures may be hypopigmented in PKU?
skin, hair, eyes, and catecholaminergic brain nuclei (substantia nigra, locus ceruleus, and vagal nucleus dorsalis)
What CNS tumor has Homer-Wright rosettes?
medulloblastoma
What is the triad of Wernicke syndrome?
ophthamoplegia, ataxia, and confusion
What are 3 enzymes that thiamine serves as a cofactor for?
- pyruvate dehydrogenase
- a-ketoglutarate dehydrogenase
- transketolase
How can thiamine deficiency be diagnosed?
measuring erythrocyte transketolase activity
What are 5 CYP450 inducers?
- carbamazepine
- phenobarbital
- phenytoin
- rifampin
- Griseofulvin
What are 7 CYP450 inhibitors?
- cimetidine
- ciprofloxacin
- erythromycin
- azole antifungals
- grapefruit juice
- isoniazid
- ritonavir (protease inhibitors)
Korsakoff syndrome is associated with damage to which nuclei?
anterior and dorsomedial thalamic nuclei –> results in confabulation
What are 4 disorder associated with trinucleotide repeats and anticipation?
Huntington, Fragile X, myotonic dystrophy, and Friedreich ataxia
