Neuro 2 Flashcards
What disorder is characteristic of abdominal pain with neurologic manifestations, port wine urine upon stakding, no photosensitivity, and increased urinary ALA and porphogilinogen (PBG)?
acute intermittent porphyria
How do the manifestations of enzyme deficiency differ in the eraly vs. late steps of porphyrin synthesis?
deficiencies in early steps cause neuro abnormalities without photosensitivity, deficiencies in late steps cause photosensitivity
What are two agents in Tx of acute attacks of porphyria?
narcotics analgesics and meds that decrease the activity of ALA synthetase: glucose and IV heme preps
What is Rathke’s pouch (anterior pituitary) derived from?
surface ectoderm
What is the posterior pituitary, pineal gland, and retina derived from
neural tube
What event occurs during week 3 of embroygenesis and is initiated by the formation of the primitive streak?
gastrulation
What molecules will be deficienct in CSF analysis of narcoleptics?
hypocretin-1 (orexin-A) and hypocretin-2 (orexin-B) produced in lateral hypothalamus
What disease is 14-3-3 protein elevated in CSF?
Creutzfeldt-Jacob
What molecule will be decreased in CSF in pts with Parkinson?
homovanillic acid
What molecule will be decreased in CSF in pts with Alzheimer?
melatonin
What is characterized by conscious, brief episodes of sudden bilateral muscle tone loss precipitated by emotion such as laughter or joking or spontaneous, abnormal facial movements without emotional triggers?
Cataplexy
What is the difference between schizophrenia and schizophreniform disorder?
schizophreniform is between 1-6 mo. and schizophrenia is >6 mo.
Other than chronic repetitive stress, what other conditions is carpal tunnel associated with?
conditions associated with fluid retention (renal failure, hypothyroidism, pregnancy) and DM, acromegaly, and RA
What are pts with long history of hemodialysis at risk of?
deposition of B2-microglobulin (dialysis-associated amyloidosis)
What is the MOA of Entacapone?
It is a COMT inhibitor that primarily serves to increase the bioavailability of levodopa by inhibiting peripheral methylation and should only be used in combination with levodopa
What is the MOA of Selegiline?
It is an inhibitor of MAO-B which decreases central DA degradation.
What are two COMT inhibitors?
entacapone and tolacapone
What is the difference between entacapone and tolcapone? Which one is more toxic?
Entacapone inhibits peripheral methylation of L-dopa, tolcapone inhibits central and peripheral methylation and is associated wtih hepatotoxicity
What can lead to bilateral wedge-shaped bands of necrosis over the cerebral convexity and what do these regions correspond to?
ischemic hypoxic encephalopathy leading ot global cerebral ischemia of watershed infarcts of ACA-MCA and MCA-PCA
What is the pathogenesis of paraneoplastic syndromes?
tumor cells produce substances that induce an autoimmune reaction, such as paraneoplastic cerebellar degeneration
What is the most common cause of death in tricyclic antidepressant intoxication?
inhibition of fast Na+ channel conduciton, resulting in arrhythmias causing vfib or shock
What is the MOA of TCAs like amitryptiline?
inhibit reuptake of NE and 5-HT
Where do neurofibromas originate?
neurofibromas are tumors of Schwann cell which are derived from neural crest
What is the MOA of a monoamine oxidase inhibitor such as Phenelzine?
it is an antidepressant that works by irreversibly binding and inhibiting MAO A and B, resulting in decreased inactivation of 5-HT, NE, and DA which increases their levels
If a pt on phenelzine wants to switch t sertraline, why should you d/c for 2w before starting new med?
to regenerate enzymes back to normal levels for adequate normal NT metabolism
What is the MOA of Sertraline?
It is a SSRI that specifically increases serotonin
What is the genetic abnormality associated with Fragile X syndrome?
hypermethylation of FMR1 gene on the long arm of the X chromosome d/t increased CGG trinucleotide repeats
What is the most common side effect of SSRIs like sertrline?
sexual dysfunction
What are common SE of TCAs?
- urinary retention (d/t anticholinergic effects)
- cardiac arrhtyhmias (quinidine effect)
- seizures in clomipramine and buproprion (d/t antihistaminic, antimuscarinic, and anesthetic)
- orthostatic hypotension (antagonism of a-adrenergics)
- sedation (antihistaminic effects)
What is the pathogenesis responsible for atypical/malignant phenylketonuria?
deficiency of dihydrobiopterin reductase which leads to deficiency of BH4 which is a cofactor for enzymes used for the synthesis of tyrosine, DOPA, serotonin, and NO
How does decreasd BH4 lead to increased prolactin
it deceases levels of DA
What is the MOA of timolol (and other nonselective BBs) to Tx glaucoma?
it diminishes the secretion of aqueous humor by the ciliary epithelium
What is the MOA of acetazolamide for glaucoma?
it is a carbonic anhydrase inhibitor that decreases aqueous humor secretion by the ciliary epithelium
How do prostaglandin F2a and cholinomimetics work?
they decrease intraocular pressure by increasing the outflow of the aqueous humor
-pilocarpine and carbachol cause miosis by promoting contraction of the sphincter of the iris which widens anterior chamber angle and makes the trabecular meshwork more accessible to outflow of aqueous humor
Describe the path of light through the eye
As light enters the eye, the retina generates a signal that is transmitted along the optic nerve bilaterally to the pretectal nucleus, located in the superior colliculus. From there, fibers project to hte ipsilateraly and contralateral Edinger-Westphal nuclei, with the decussating fibers traversing within the posterior commissure. The efferent fibers originate from parasympathetic pregangilonic neurons in the EW nucleus which then travel within CNIII to ciliary ganglion. They synapse on parasympathetic postganglionic neruons which in turn project fibers that innervate teh sphincter of the iris
What kind of dementia is associated with social disinhibition, speech abnormalities, and emotional flattening along with pronounced atrophy of the frontotemporal regions?
Pick disease
Where do most intracranial schwannomas occur and which cranial nerves are most commonly compressed?
cerebellopontine angle - compress CN V, VII, and VIII
What kind of brain tumor is found over the lateral hemispheric fissures and in the parasagittal aspect of the brain convexity with whorled pattern of cell growth and psammoma bodies?
Meningiomas
What disease is X-linked recessive, is deficient in a-galactosidase and accumulates ceramide trihexodside and presents with angiokeratomas, cardiac and renal involvment, and painful neuropathy?
Fabray disease
What disease is AR, deficient in B-glucocerebrosidase, accumulates glucocerebroside, and presents with macrophages that look crumpled, HSmegaly, pancytopenia, and severe bone and joint pain?
Gaucher disease
What disease is AR, deficient in a-L-iduronidase, accumulates dermatan and heparan sulfate, and presents with gargoylism, corneal clouding, hepatosplenimegaly, and developmental delay?
Hurler syndrome
What disease is XLR, deficient in iduronate sulfatase, accumulates dermatan adn heparan sulfate, but does not present with corneal clouding?
Hunter syndrome
What disease is AR, is deficient in sphingomyelinase, accumulates sphingomyelin, and presents with HSmegaly, cherry-red spot in macula, foam cells, and progressive neurodegeneration?
Niemann-Pick disease
What disease is AR, deficient in B-hexosaminidase A, accumulates GM2 ganglioside, and presents with cherry-red spot in macula, progressive neurodegeneration, and no HSmegaly?
Tay Sachs disease
What disease is AR, deficient in galactocerebrosidase, accumulates galactosyl-sphingosine and galactocerebroside, and presents with neurodegeneration and optic atrophy?
Krabbe disease
What disease is AR, deficient in arylsulfatase A, accumulates cerebroside sulfate, and presents with muscle wasting, dementia, and ataxia?
Metachromatic leukodystrophy
