Neuro Flashcards
The vein that drains the upper eyelid drains directly into what dural venous sinus?
Superior ophthalmic vein drains directly into cavernous sinus
What structure does poliovirus infect?
Alpha motor neurons of the ventral horn of the spinal cord
What visual field defect is associated with Wernicke’s aphasia?
Upper quadrantic anopia because the dorsal radiations are also located in the temporal lobe
What cerebrovascular syndrome involves the hypoglossal nucleus and what artery is affected in this syndrome?
Medial medullary - anterior spinal artery
What are the two free-living amoeba that can infect the brain and what characterizes the populations they infect?
Naegleria fowleri - swimmers/divers
Acanthamoeba - immunosuppressed (HIV, diabetics, alcoholics)
What is torticollis and what drugs is it associated with?
Torticollis - involuntary twisting or deviation of the neck, neck pain, the presence of a sensory tick, and abnormal head posture
Associated with dopamine receptor blocking drugs like antipsychotics (e.g. fluphenazine, haloperidol) and other dopamine antagonists (e.g. metoclopromaide, prochlorperazine)
What are effective pharmacologic treatments for OCD?
- Tricyclic antidepressants (e.g. clomipramine)
2. Selective serotonin reuptake inhibitors (e.g. fluoxetine)
What are the characteristic findings of Friedreich ataxia?
Progressive ataxia and severe dysarthria with onset in childhood; other classic findings include loss of reflexes, spasticity, extensor plantar responses, and impaired vibration and position sense
What are the genetics of Friedreich ataxia?
Autosomal recessive with trinucleotide repeat of GAA expansion
What are symptoms associated with using PCP (phencyclidine)?
Disorientations, detachment, reckless behavior, impaired judgment, distortions of body image
What is the Moro reflex and when does it disappear?
Startling an infant can produce extension and abduction of the arms followed by flexion and adduction of the arms. This is a normal reflex that disappears sometime between 3 and 6 months.
What is the characteristic histologic finding in HIV encephalitis?
Multinucleated giant cells
Where are the opacifications in cataracts located?
Lens
Where are the two places of greatest neuronal degradation in ALS?
- Cerebral cortex (UMN)
2. Spinal cord anterior horn (LMN)
What muscle does the median nerve pass through as it crosses the elbow to the forearm?
Pronator teres
What is progressive supranuclear palsy?
Pathologic changes: widespread neuronal loss and gliosis in subcortical sites with sparing of cerebral and cerebellar cortices
Clinical presentation: Ophthalmoplegia, pseudobulbar palsy (dysarthric speech), axial dystonia, bradykinesia
Give the anatomic location of dopaminergic neurons that are lost in Parkinson’s.
Substantia nigra pars compact in the midbrain - between the cerebral peduncles and the midbrain tegmentum (part of the midbrain that is between the cerebral peduncles and the cerebral aqueduct)
What sort of signal seems to initiate multiple sclerosis?
CD4+ T lymphocytes that react against self myelin antigens secrete cytokines like interferon-gamma to activate macrophages which are then responsible for the demyelination
What is the most common LMN disease in infants and what part of the spinal cord is preferentially affected?
Werdnig Hoffman or infantile muscular spinal atrophy involves atrophy of the anterior or ventral horns
What is the first line treatment for someone with status epilepticus?
Benzodiazepines (e.g. lorazepam or diazepam)
The orbital floor is also the roof of what sinus?
Maxillary
What nerve goes through the foramen ovale?
Mandibular (V3) nerve
What nerve carries general somatic sensation from the anterior 2/3 of the tongue?
Mandibular (V3) nerve
How is herpesvirus transported into neuronal bodies? By what mediator?
Retrograde axonal transmission - mediated by dynein
What is confabulation and what disease process is associated with this symptom?
Patient unconsciously makes up explanations for events that would otherwise be inexplicable - different from lying because it happens in the context of memory loss
Confabulation is a key symptom in Wernicke-Korsakoff syndrome
What is a strong social history association with Wernicke-Korsakoff syndrome?
Chronic alcoholism
What distinguishes type I from type II Arnold Chiari malformations?
Type I - usually asymptomatic, herniation of cerebellar tonsils into foramen magnum
Type II - often presents with hydrocephalus and brainstem dysfunction, herniation of parts of the hindbrain/cerebellar vermis/4th ventricle
What does a cerebellar abscess look like on MRI and what is its most common cause?
Multilocular mass with ring-enhancing borders
Associated with otitis media
What is the classic presentation of Creutzfeld-Jacob disease?
Rapidly progressive dementia with some motor symptoms (startle myoclonus) and abnormal EEG activity
What are the most common bacterial causes of abscess in the brain?
Staph, strep, bacteroides
What is a myelomeningocele? The failure of what process embryologically can lead to it?
Herniation of the meninges and spinal cord through a defect in the posterior vertebra and skin
Caused by failure closure of the caudal neuropore
Describe the mechanism of benzodiazepines.
Potentiate GABA effects (agonist) by binding to chloride ion channels and increasing their conductance/frequency of opening
What artery is most commonly involved in an epidural hematoma and where is it located in the brain?
Middle meningeal artery in the middle cranial fossa
In visual processing, what is the difference between the temporo-occipital association cortex vs. parieto-occipital association cortex?
Temporo-occipital = the "what" Parieto-occipital = the "where"
What should you be suspicious of in a patient with neurologic symptoms presenting several days to weeks after a traumatic head injury?
Subdural hematoma
What are common clinical findings in a patient with sciatica?
MOTOR:
- Weakened extension of the thigh
- Loss of flexion of the knee
- Loss of function below the knee
SENSORY: pain/sensory loss on the posterior thigh, lateral leg, entire foot
What kind of drugs can precipitate an acute closure glaucoma?
Drugs with anticholinergic effects because muscarinic receptors on the pupillary constrictor muscle are blocked –> pupil dilates –> narrows or closes the angle in the anterior chamber of the eye
What are significant side effects of amitriptyline?
TCA with significant anticholinergic side effects
What is seen on biopsy of a toxoplasmosis lesion?
- Large, round encysted bradyzoites
2. Free, crescent-shaped tachyzoites
Why does severe retinopathy of prematurity occur and what is its signature finding on retinal exam?
Hypoxia stimulates vascular proliferation - major risk factors include prematurity and intensive oxygen treatment
Finding: white pupillary reflex
Through what structure does CSF flow out of the lateral ventricles?
Bilateral foramina of Monro
What is the mechanism of imipramine?
Tricyclic antidepressant that inhibits the reuptake of serotonin and norepinephrine
Describe the characteristic histologic appearance of an oligodendroglioma.
“Fried egg” cells - round nuclei with clear cytoplasm
What neurotransmitter is most important for induction of REM sleep?
Acetylcholine
How can altering the activity of pyruvate dehydrogenase mimic thiamine deficiency?
Pyruvate dehydrogenase uses a number of co-factors including TPP (from the vitamin thiamine) to convert pyruvate to acetyl-CoA
What characterizes benign essential tremor?
6-12 Hz tremor primarily affecting the arms
What are effective first-line treatments for essential tremor?
Propanolol (beta blocker) and primidone (barbiturate)
What virus infects oligodendrocytes?
JC virus –> PML
What is the most common viral encephalitis in the U.S. and where is it localized to in the brain?
HSV-1 localizes to the temporal lobe
What is the triad for normal pressure hydrocephalus?
Wacky (dementia), wet (urinary incontinence), wobbly (apraxic)
Contrast the typical location of a subarachnoid hemorrhage caused by a berry aneurysm vs. AVM.
Berry aneurysms are usually centered near the base of the brain whereas AVM’s typically involve the superficial or deep cerebral hemispheres.
What is the most common vector for viral encephalitis during the summer months?
Arthropods (mosquitoes)
What is the classic cause of chronic meningitis?
Tuberculosis (mycobacteria)
What drugs are the preferred treatment for withdrawal symptoms in a patient with liver disease?
Benzodiazepines that are metabolized through phase II processes - lorazepam, oxazepam, temazepam
Where do axons from the olfactory bulb go?
Piriform cortex
What encephalitis is measles associated with?
Subacute sclerosing panencephalitis - rare complication occurring years after measles infection consisting of personality change, seizures, myoclonus, ataxia, photosensitivity, ocular abnormalities, spasticity, coma
Where do the majority of intraparenchymal hemorrhages occur from?
Basal ganglia and internal capsule
What kind of drug is phenelzine?
MAO inhibitor
If on CT, you see a bleed that is crescent shaped, does not cross the midline, but extends across different suture lines, you should be suspicious of what?
Subdural hematoma
Which pharyngeal arches give rise to the vessels in the circle of Willis?
4 and 6
What supplies sensation for the anterior half of the external ear canal?
Auriculotemporal nerve
What happens in the gag reflex if you just lose the motor component (vagus nerve)?
When you stimulate the gag afferent limb (CN IX), you will not elicit a gag on the ipsilateral side but you should still see contralateral raising of the palate and uvula deviation to the contralateral side
What side effects do you expect to see with benztropine?
Benztropine is an antimuscarinic so it has anti-SLUDGE properties: cause decreased Salivation, Lacrimation, Urination, Defecation, GI motility, Emesis. Therefore for side effects, they cause xerostomia (dry mouth), tachycardia, bronchodilation, mydriasis, blurred vision, and fever.
What is the mechanism of action of sumatriptan?
5HT (1D/1B) agonist
What antidepressant is good for treating both Parkinson disease and depression?
Tricyclics (e.g. amitryptyline) because they have strong anticholinergic properties and Parkinson’s neurotransmitter imbalance comes from depleted dopamine/too much ACh.
What is the mechanism of action of typical antipsychotics?
D2 receptor antagonists
Aneurysm of which three arteries may compress the oculomotor nerve as it exits the brain stem?
Superior cerebellar artery, posterior cerebral artery, basilar artery
What neurotransmitter is important for the induction of REM sleep?
Acetylcholine
In sensorineural hearing loss, what is damaged?
Hair cells of the organ of Corti
What is the time frame for an epidural hematoma?
1 - 48 hours
What nerve root mediates the Achilles tendon reflex?
S1
What are the two types of local anesthetics?
Esters - have only one I in their spelling
Amides - have 2 I’s in their spelling
How can altering the activity of pyruvate dehydrogenase mimic thiamine deficiency?
Pyruvate dehydrogenase uses a number of co-factors including TPP (from the vitamin thiamine) to convert pyruvate to acetyl-CoA
What is the first line treatment for a seizure in which someone remains unconscious for more than 30 minutes (status epilepticus)?
Benzodiazepines
What syndrome might a family history of retinal angiomas suggest?
Von Hippel-Lindau disease
What aside from toxoplasmosis can cause multicentric ring-enhancing mass lesions in the brain and meninges?
CNS lymphoma
What do pseudounipolar cells of the spinal and cranial nerve ganglia derive from?
Neural crest cells
What nerve mediates hip abduction?
Superior gluteal nerve
What kind of bleed does a ruptured berry aneurysm cause?
Subarachnoid hemorrhage
What disease is marked by wasting of muscles of the anterior compartment of the leg, foot drop, and pes cavus (high-arched feet)?
Charcot-Marie Tooth
What nerve is most commonly affected in Charcot-Marie Tooth?
Deep peroneal nerve
What is a life-threatening complication of reactivated herpes zoster (shingles) in AIDS patients?
Multifocal encephalitis
What syndrome causes:
- vertigo, nystagmus, nausea, vomiting (vestibular nuclei)
- ipsilateral cerebellar signs (inferior cerebellar peduncle)
- dysphagia and dysphonia (nucleus ambiguus)
- loss of pain and temperature in ipsilateral face and contralateral body (spinal tract and nucleus of trigeminal nerve)
- Horner syndrome (descending hypothalamics)
Lateral medullary or Wallenberg’s (PICA occlusion)
What disease does deficiency of arylsulfatase A (cerebroside sulfatase) result in?
Metachromatic leukodystrophy
What tends to cause a subarachnoid hemorrhage that centers over one of the hemispheres?
AVM
Which streptococcus can cause meningitis?
Pneumococcus
How can we prevent a newborn from getting group B strep from a mother with the infection?
Give the mother IV ampicillin during labor
What does a 6-7 year old child presenting with changes in personality, behavior, memory, myoclonic jerks, blindness, and spasticity likely have if there is a history of measles?
Subacute sclerosing panencephalitis
What type of tumor can cause a vertical gaze palsy by compressing the vertical gaze center in the tectum of the midbrain?
Pinealoma
What cranial nerve passes by the superior cerebellar artery?
Oculomotor
Why is tooth enamel organ likely to appear on histological examination of a craniopharyngioma?
Craniopharyngiomas are derived from Rathke’s pouch (oral ectoderm)
Microscopically, which brain tumor forms a whorling pattern?
Meningioma
How do you treat an essential tremor?
Beta blocker
What is the diagnosis for progressive bilateral tremors of the upper extremity without other neurological symptoms?
Essential tremor
When does the Moro reflex normally disappear?
3 - 6 months
What disease is suggested by large abnormal oligodendrocytes with eosinophilic inclusions?
PML because JC virus infects oligodendrocytes
What tumor is associated with bitemporal hemianopsia?
Pituitary adenoma (prolactinoma)
How does Group B Strep test on the CAMP test?
Positive
What nerve passes through the greater sciatic foramen?
Superior gluteal
What is the Cushing response or reflex (hypertension, bradycardia, irregular breathing) in a trauma in response to?
Increased intracranial pressure
What are the two main effects of amphetamines?
- Induce dopamine release (important for reward/reinforcing effects of these drugs)
- Induce norepinephrine release (responsible for systemic side effects like HTN)
Presentation: Hemiparesis and loss of tactile/proprioception/vibration sense on the same side of the body, tongue deviates to the opposite side
Diagnosis?
Medial medullary syndrome - infarction of the anterior spinal artery
What should you be suspicious of in a child with infection symptoms with white spots on the buccal mucosa?
Measles (white spots on the buccal mucosa = Koplik spots)
What do you see histologically with measles?
Syncytia (common in all members of paramyxoviridae) - formed from the fusion of the infected cells
What type of seizure is characterized by sudden loss of postural tone that lasts only a few seconds?
Atonic
What is cyclobenzaprine?
Tricyclic amine salt used as a spasmolytic with antimuscarinic side effects similar to TCA’s
What is the underlying pathophysiologic process in Guillain Barre?
Autoimmune attack on the myelin of peripheral nerves
What brain cancer occurs in the cerebral hemispheres and has a histologic finding of clear cells with round nuclei?
Oligodendroglioma (they have “fried egg” cells on histology)
What branch of the trigeminal nerve supplies the upper lip?
V2
What organisms cause temporal lobe abscess?
Staph, strep, bacteroides
Meningitis caused by gram-positive in pairs and short chains. What is the organism?
Streptococcus pneumoniae
What enzyme is thiamine a cofactor for?
Pyruvate dehydrogenase
What is the difference between superficial vs. deep peroneal nerves?
Deep peroneal nerve - foot drop, more anterior compartment (associated with lead poisoning)
Superficial peroneal nerve - eversion, more lateral compartment
What is neurosyphiilis?
Late sequela of syphilitic infection (5 - 20 years later) with mental deterioration that eventually leads to general paralysis with mutism and incontinence
Mnemonic: PARESIS Personality Affect Reflexes (hyperactive) Eyes (Argyll Robertson) Sensorium defects Intellectual decline Speech deficiency
Why are Alzheimer patients at increased risk of hemorrhage?
Cerebral amyloid angiopathy makes vessel weak and prone to rupture
What virus infects oligodendrocytes?
JC virus
When a patient cannot adduct the eye, how do you differentiate between an MLF lesion vs. a CN III lesion?
Check convergence. Someone with a CN III lesion will not be able to converge whereas someone with an MLF lesion can converge and only has a problem with conjugate movements.
Can also check to see if the pupillary reflexes are intact (should be intact in MLF but impaired with CN III lesion)
What is the role of the enzyme PNMT (phenylethanolamine-N-methyltransferase)?
Converts norepinephrine into epinephrine
What are the functions of CN IX?
- Salivation (parotid gland)
- Taste and tactile sensation for posterior 1/3 of the tongue
- Tactile sensation from external ear, pharynx, middle ear, auditory
- Input from carotid sinus/body
- Motor efferents to stylpharyngeus muscle
What atrophies in Friedreich ataxia?
Spinal cord, dorsal root ganglia, and to a lesser extent the cerebellum
What are tertiary syphilitic granulomas (gummas) made of?
Modified (epithelioid) macrophages
What should you be wary of in treating patients with Klebsiella infection (think associated social history and potential complications)?
Watch out for withdrawal symptoms from alcoholism - treat with benzodiazepines (specifically LOT: lorazepam oxazepam, temazepam)
Patient with neurological symptoms that cannot be explained by one focal lesion - suspect what?
Multiple sclerosis
What does MS show on MRI?
Scattered, peri-ventricular lesions (caused by oligodendrocyte depletion)
What is it called when someone has double vision walking down stairs and what does it indicate?
Vertical diplopia - trochlear nerve palsy
Overuse of what vitamin can lead to intracranial hypertension, skin changes, hepatosplenomegaly?
Vitamin A
Contrast Guillain Barre vs. polymyositis in terms of endoneural vs endomysial inflammatory infiltration.
Guillain Barre - endoneural
Polymyositis - endomysial
What is the best way to prevent neonatal tetanus?
Vaccinate mom with tetanus toxoid during pregnancy
Calcified cystic mass with thick brownish cholesterol-rich fluid inside. Accompanied by headaches and visual changes. Diagnosis?
Craniopharyngioma
What are enteroviruses?
Picornaviruses except for rhinovirus (rhinovirus is the only one that isn’t transmitted fecal-oral)
What is often the cause of aseptic meningitis?
Enteroviruses (Polio, Echo, Coxsackie)
Why should you be careful to use TCA’s in patients with BPH?
Anticholinergic properties may cause urinary retention
“Foamy histiocytes” filled with sphingomyelin accumulate in the liver, skin, and spleen in what disease?
Niemann-Pick
In the U.S., the majority of overdose deaths are caused by what drugs?
Prescription drugs - in particular opioids
If a child has very high levels of arginine (associated with spastic paresis of his lower extremities and choreoathetoid movements), what enzyme deficiency are you suspicious of?
Arginase - the enzyme that normally produces urea and ornithine from arginine
Describe the defect in maple syrup urine disease.
Defect in alpha-keto acid dehydrogenase leading to an inability to degrade branched chain amino acids (e.g. leucine, isoleucine, valine)
What is the difference between schizoaffective disorder and bipolar disorder with psychotic features?
Schizoaffective must have a period of at least 2 weeks of psychotic symptoms without mood symptoms
Describe latent period effect.
The initial steps in pathogenesis and/or exposure to a risk factor sometimes occur years before clinical manifestations of a disease are evident
Describe the relationship between narcolepsy and cataplexy.
Cataplexy is one of the symptoms/manifestations of narcolepsy
On PE you see small, irregularly shaped pupils that do not react with light but do constrict with accommodation. What is this finding and what is it indicative of?
Argyll-Robertson pupil; indicative of tabes dorsalis
What should patients taking levadopa be cautious of taking in addition?
B6 (found in most multivitamins) because it increases the peripheral metabolism of levadopa which decreases its effectiveness
In Wernicke-Korsakoff syndrome, what defect is permanent even once thiamine is repleted?
Memory loss
What is the significant of blotchy red muscle fibers on Gomori trichome stain?
Mitochondrial myopathies
What is believed to be the underlying mechanism in the alteration of gene expression in Huntington disease?
Hypermethylation of histones
Symmetric degeneration of both dorsal columns and corticospinal tracts (ascending AND descending) is suggestive of what pathology?
B12 deficiency - subacute combined degeneration
Contrast the eye findings in use of thioridazine vs. chlorpromazine.
Thioridazine - retinal deposits
Chlorpromazine - corneal deposits
Most of the toxic effects from infection with Neisseria meningitidis comes from what?
Outer membrane lipooligosaccharide - analogous to LPS
What is the major cause of lacunar infarcts?
Hypertensive arteriosclerosis of small penetrating arterioles
How would you treat TCA-associated cardiac abnormalities?
Sodium bicarbonate
What is tetrodotoxin?
Pufferfish poison that binds to voltage-gated sodium channels and inhibits the influx of sodium
What is used for prenatal diagnoses of neural tube defects?
Elevated alpha fetal protein and acetylcholinesterase levels (they leak out from fetal cerebrospinal fluid in the case of NTD)
How is cryptococcus neoformans diagnosed?
India ink stain - the background is stained while the organism remains transparent
What is the main treatment for cryptococcus neoformans?
Amphotericin B and flucytosine
How is listeria eliminated from the body?
Cell-mediated immunity (macrophage activation and killing)
Where does rabies virus bind?
Acetylcholine receptors
Presentation: fever, severe agitation, disorientation, hallucinations, light sensitivity, dysphagia, excessive salivation - diagnosis?
Rabies
Where is Broca’s area located?
Inferior frontal gyrus of the dominant lobe
Baby with diaper that smells like burnt sugar - diagnosis?
Maple syrup urine disease - defective breakdown of branched chain amino acids (leucine, isoleucine, valine)
Branched chain alpha ketoacid dehydrogenase, pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase all require which 5 cofactors?
Mnemonic: tender loving care for nancy
Thiamine pyrophosphate Lipoate Coenzyme A FAD NAD
How do we treat orotic aciduria?
Supplementation with uridine (which can be converted to UMP and go on to make pyrimidines)
The FDA requires periodic monitoring of what with administration of clozapine?
WBC count because of the risk of agranulocytosis (the other important side effect is seizure)
Where is urea’s nitrogen derived from?
NH3 and asparatate
How can Horner’s syndrome affect the arm/forearm?
Can compress the ipsilateral brachial plexus leading to weakness and/or sensation deficits in the ipsilateral arm and forearm
Presentation: Mental retardation, facial deformities and macroorchidism - diagnosis?
Fragile X syndrome
What lab test is uniformly elevated in patients with temporal arteritis?
ESR
Most sympathetic output to the viscera involves a 2 neuron system that ultimately synapses on what kind of receptor?
Noradrenergic
What are the two exceptions to the typical set up of sympathetic output?
- Adrenal glands - directly innervated by the preganglionic neuron which secretes ACh
- Sweat glands - 2 neuron system that both use ACh
What drug is indicated for patients that suffer from both tonic-clonic and absence seizures?
Valproate
Autopsy of the brain: bilateral wedge-shaped bands of necrosis seen over cerebral convexity - diagnosis?
Hypoxic encephalopathy (from ischemia)
Presentation: Child with difficulty walking, frequent respiratory infections, and cultured cells showing a high rate of radiation induced genetic mutation. Diagnosis?
Ataxia-telangiectasia
What would you see with ataxia-telangiectasia in the brain?
Cerebellar atrophy
What immune deficiency predisposes someone to getting Neisseria infections?
Inability to form membrane attack complex - deficiency of complement
Presentation: Abdominal pain, neuropsychiatric manifestations, color change in urine upon standing - diagnosis?
Acute intermittent porphyria
What are 2 treatments for the acute intermittent porphyria?
Glucose and IV heme
How does glucose help acute intermittent porphyria?
Represses ALA synthase activity
What accumulates in Tay Sach’s disease?
GM2 ganglioside (cell membrane glycolipid)
What is the primary site of entry for cryptococcus neoformans?
Lungs
Kyphoscoliosis, foot abnormalities, heart failure, and neurologic symptoms should make you suspicious of what inherited disorder?
Friedrich ataxia
What infectious organism is associated with Guillain Barre?
Campylobacter jejuni
What drug has a similar mechanism of action as benzodiazepines but a much lower risk of tolerance dependence?
Zolpidem
What vitamin deficiency closely resembles Friedrich ataxia in how it causes degeneration of spinocerebellar tracts, dorsal columns, and peripheral nerves?
Vitamin E
Foci of hemorrhage and necrosis in the mamillary bodies and periaqueductal gray matter in an alcoholic on autopsy are suggestive of what?
Thiamine deficiency
What test can be used to look for thiamine deficiency?
Erythrocyte transketolase activity - thiamine is a cofactor for transketolase, pyruvate dehydrogenase, and alpha ketoglutarate dehydrogenase
What is the difference between schizophreniform and schizophrenia?
Schizophreniform - symptoms for 1 to 6 months vs. schizophrenia - more than 6 months
What is the equation to calculate a 95% confidence interval?
Mean +/- 1.96 * SD/sqrt(n)
What is the equation to calculate a 99% confidence interval?
Mean +/- 2.58 * SD/sqrt(n)
What is the best way to prevent vertical transmission of tetanus?
Vaccination of young adults - mom will then have IgG against tetanus which will be passed on to the infant through the placenta
What is the point of edrophonium test?
For myasthenia gravis if you give edrophonium and it works, it means the patient is being undertreated. If it doesn’t work, it suggests the patient is having a cholinergic crisis.
What is the incidence of a disease?
Number of NEW cases per year divided by total population at risk
Why is there variable severity in mitochondrial diseases?
Heteroplasmy - random distribution of normal and mutated mitochondria between daughter cells during mitosis
How is delusional disorder different from schizophrenia?
Delusional disorder usually involves a single overriding delusion that is non-bizarre (unlikely but theoretically possible delusion). These patients can function without significant impairment in day to day life.
Presentation: infant without prenatal care born to a homeless mother has shrill crying, tremor, rhinorrhea, sneezing, and diarrhea - diagnosis?
Opiate withdrawal
What is the treatment for opiate withdrawal in a neonate?
Opium solution
What does cryptococcus neoformans look like on CSF?
Round or oval budding yeast
How does neisseria meningitidis gain access to the blood stream?
Pharynx –> blood –> choroid plexus –> meninges
Methylmalonic acidemia results from a defect in what reaction?
The isomerization of methylmalonic coA to succinyl coA
What enzyme is upregulated in Lesch Nyan syndrome?
PRPP amidotransferase in order to increase de novo purine synthesis because of the increase in substrate (PRPP) since in Lesch Nyan syndrome, you have a deficit in the enzyme HGPRT which results in failure of purine salvage.
How does a muscarinic agonist produce vasodilation?
Promotes endothelial cells to release NO (EDRF) –> activates guanylate cyclase –> increased cGMP –> activates Ca pump –> Ca efflux –> vascular smooth muscle wall relaxation
Psamomma bodies are characteristic of which brain tumor?
Meningioma
Presentation: Aggression, nystagmus, ataxia, agitation, disorientation, confusion - what drug did this person take?
PCP
What is the main difference between low potency and high potency antipsychotics?
Low potency - more likely to cause non-neurologic side effects (sedation, anticholinergic, orthostatic hypertension) vs. high potency - more likely to cause extrapyramidal side effects (dystonia, akathisia, parkinsonism)
What injury typically causes weak wrist extension but no sensory deficits?
Radial head subluxation - damages the deep part of the radial nerve
What is the difference between mass lesion at the cerebellopontine angle vs. Meniere’s disease?
Cerebellopontine angle - symptoms would be constant vs. Meniere’s disease - symptoms come and go in episodes
What nerve root is involved with pain in the posterior thigh and leg as well as diminuition of the ankle jerk reflex?
S1
What part of the brain is first damaged in global cerebral ischemia?
Hippocampus
What cranial nerve does transtentorial herniation affect?
Oculomotor
Ornithine transport into the mitochondria is essential for what process?
Formation of urea
What cranial nerve arises at the level of the middle cerebellar peduncle (you can see the connection between the cerebellum and the brain stem)?
Trigeminal
Hypertensive crisis after eating certain foods on an antidepressant med should make you think of?
MAO inhibitor - anything containing tyramine (e.g. wine and cheese party)
Why is coadministration of an SSRI and MAOI contraindicated?
Could result in really high levels of serotonin since SSRI inhibits its reuptake while MAOI inhibits its degradation - wait 2 weeks after discontinuing an MAOI before starting SSRI for enzyme levels to readjust since MAOI binds irreversibly and enzyme levels increase in response to the drug
What 2 enzymes does lead inactivate?
ALAD and ferrochelatase
Which receptor does naloxone have the greatest affinity for?
Mu
What is the problem in Meniere’s disease?
Defective resorption of endolymph causes an increased volume of endolymph in the inner ear
What brain tumor is associated with paralysis of upward gaze?
Parinaud syndrome is associated with brain germinomas which are typically tumors of the pineal gland
Total sensory loss on the contralateral side of the body is indicative of what?
Thalamic syndrome - no motor deficits but proprioception is profoundly affected so patient is very subject to falls
Does bulimia nervosa necessarily have a purging component?
No - the patient can exhibit other compensatory behaviors for binge eating (e.g. intense exercise, diet, or fasting)
What is the mechanism of action of ethosuxamide?
Blocks T type calcium channels
What is the mechanism of action of phenytoin, carbamazepine, valproic acid?
Inhibits neuronal high-frequency firing by reducing ability of Na channels to recover from inactivation
Which antidepressant does NOT have sexual side effects?
Bupropion
When treating cholinergic crisis with atropine, what effects do we still need to worry about?
Muscle paralysis because atropine only blocks muscarinic receptors and cholinergic crisis also has some nicotinic effects (this is why we give pralidoxime)
At what point in the action potential is K conductance greatest?
During repolarization (NOT at the overshoot)
What 2 opioid side effects are resistant to tolerance?
Miosis and constipation
What is propionic acid?
Intermediate in the catabolism of branched chain amino acids
How does a beta blocker help in the treatment of chronic glaucoma?
Targets the ciliary epithelium to produce less aqueous humor
What 2 drugs are both anticonvulsants AND mood stabilizers?
Valproic acid and carbamazepine - valproic is preferred for absence, generalized tonic-clonic, and myoclonic seizures
What antiepileptic drug is metabolized to phenobarbital and phenylethylmalonamide?
Primidone
What is the function of N-acetylglutamate in the urea cycle?
Required as an essential activator of carbamoyl phosphate synthase I (enzyme) in the first step of the urea cycle
What are the two causes of polyhydramnios?
- Decreased fetal swallowing (GI obstruction, intestinal atresia, or anencephaly)
- Increased fetal urination
Child with bilateral lens subluxation (dislocated lens) - suspicious of?
Homocystinuria
What is phenelzine?
MAO inhibitor
What do we use MAO inhibitors for?
Atypical depression - characterized by mood reactivity meaning a person with atypical depression will have improvement in mood to something positive
What distinguished buspirone in terms of its side effect profile?
Minimal to no hypnotic, sedative, or euphoric effects
question 10
come back
What is the main virulence mechanism of staphylococcus epidermidis?
Common cause of foreign body infection because of its ability to produce adherent biofilm - extracellular polysaccharide matrix
How is the diagnosis of tetanus made?
Clinical suspicion (history and physical) - there is no serum toxin assay or antibody test and blood cultures are often unsuccessful in isolating the organism
Abnormal slow relaxation of muscles, frontal balding, gonadal atrophy?
Myotonic dystrophy - autosomal dominant disorder
Patients with narcolepsy have decreased levels of which hormones?
Hypocretin-1 and 2
What is chlorpheniramine and what is its major side effect?
Anti-histamine - causes sedation
Stimulation of what receptor causes mydriasis?
Alpha 1
What is entacapone?
COMT inhibitor that helps prevent peripheral metabolism of L-DOPA (given with levodopa for treatment of Parkinson’s)
Presentation: Dilated pupils, yawning, piloerection, lacrimation, hyperactive bowel sounds - withdrawal from what?
Opioids (e.g. heroin)
Why is methadone a good treatment for heroin abusers?
Long half life means that it is able to suppress withdrawal symptoms well
What three drugs can cause lithium toxicity due to their effect on the kidney?
NSAIDs, thiazides, ACE inhibitors
What is selegiline?
Inhibitor of MAO type B
What is the most common cause of bacterial meningitis in adults?
Strep pneumo
Before alanine can be converted to glucose, its amino group is transferred to what?
Alpha-ketoglutarate
What is pentazocine?
Partial opioid agonist
Why are benzodiazepines associated with increased risk of falls?
Daytime drowsiness
Describe the mechanism of action of paraneoplastic syndrome.
Often tumor cells producing substances that induce an autoimmune reaction and cause damage and degeneration of healthy organs and tissues
What is the main treatment for homocystinuria?
Vitamin B6 (pyridoxine)
Are alprazolam, triazolam, oxazepam short/medium/long acting benzo’s (correlate with severity of side effects)?
Short - less side effects
Are estazolam, lorazepam, temazepam short/medium/long acting benzo’s (correlate with severity of side effects)?
Medium - moderate side effects
Are chlordiazepoxide, clorazepate, diazepam, flurazepam short/medium/long acting benzo’s (correlate with severity of side effects)?
Long - more severe side effects
What cofactor is necessary for the conversion of oxaloacetate to acetate?
B6 (pyridoxine) - necessary cofactor for transamination and decarboxylation of amino acids
Thiamine deficiency most affects what neural structure?
Mamillary body (on a sagittal section, looks like it’s under the hippocampus)
Restlessness, agitation, dysphagia progressing to coma following an exposure to bats should make you suspicious of?
Rabies
What is prophylaxis for rabies?
Killed vaccine
What organism produces botulinum toxin?
Clostridium botulinum
What distinguishes clostridia?
Produce spores
Crescent shaped mass on CT is suggestive of?
Subdural hematoma
What is ruptured in a subdural hematoma?
Bridging veins
The onset of action of a gas anesthetic depends on what?
Its solubility in the blood (blood/gas partition coefficient)
If a gas anesthetic has high blood/gas partition coefficient, does it have a quicker or slower onset of action?
Slower because it takes more to saturate the blood (more soluble in blood) and you have to saturate the blood before it will move into brain tissue
At what age should a child be able to copy simple shapes?
Age 3
What other cerebellar tumor affects children aside from pilocytic astrocytoma?
Medulloblastoma
How do we distinguish pilocytic astrocytoma from medulloblastoma?
Histology
Pilocytic astrocytoma - Rosenthal fibers
Medulloblastoma - sheets of small cells with deeply basophilic nuclei and scant cytoplasm with abundant mitoses
What is the unconscious manifestation of neurologic symptoms when pathophysiological explanations for the symptoms cannot be found (typically in women and accompanied by life stressor)?
Conversion disorder
What is tetrahydrobiopterin used for?
Cofactor in the synthesis of tyrosine, dopa, serotonin, and nitric oxide
What does a high arteriovenous concentration gradient tell you about the rate of onset of an anesthetic?
Slow because high arteriovenous concentration means high tissue solubility (which is why the venous concentration is lower) meaning you need more of the drug to saturate the blood so that it can then go to brain tissue
What is the major determinant of virulence in E. coli strains that cause meningitis in infants?
K1 capsular antigen - protects the bacteria during hematogenous spread so it can reach the meninges
What do we use cholinomimetics to treat?
Non-obstructive urinary retention, paralytic ileus, glaucoma
What in the brain will stain for lipids?
Microglia that come and break down myelin
How do penicillins and cephalosporins work?
Irreversible binding to penicillin-binding proteins such as transpeptidases
What are neurofibromas derived from?
Schwann cells (neural crest)
Characterize nicotinic vs. muscarinic vs. adrenergic receptors.
Nicotinic - ligand gated ion channels
Adrenergic and muscarinic - G coupled protein receptors
What is the most common cause of intraparenchymal hemorrhage?
Hypertension - through the formation of small Charcot-Bouchard pseudoaneurysms in the small arterioles that penetrate the basal ganglia and thalami
Empty bottle of pills with presentation of confusion, agitation, tremor, tachycardia, hypertension, clonus, hyperreflexia, hyperthermia, diaphoresis?
Serotonin syndrome
What do we use to treat serotonin syndrome?
Cyproheptadine - antihistamine with antiserotonergic properties
What is the precursor of serotonin?
Tryptophan
What are pramipexole and ropinirole?
Non-ergot compounds that are dopamine agonists (used in the treatment of Parkinson’s)
What is the function of pili for meningococcus?
Attachment to epithelia of oro and nasopharynx
Hydrocephalus, intracranial calcifications, chorioretinitis in an infant?
Congenital toxoplasmosis
What antibiotic can cause serotonin syndrome?
Linezolid
What enzyme is deficient in atypical PKU?
Dihydrobiopterin reductase - cofactor for tyrosine hydroxylase (which converts tyrosine to DOPA)
What drug is given to prevent the recurrence of seizures in status epilepticus?
Phenytoin
What is the mechanism of action of phenytoin (what other drugs have a similar mechanism)?
Decrease sodium current in cortical neurons (similar to carbamazepine and lamotrigine)
Where is the lesion if it produces contralateral homonymous hemianopia and Marcus Gunn pupil in the contralateral eye?
Optic tract
What is malformation?
Intrinsic developmental abnormality
What is disruption?
Secondary breakdown of previously normal tissue or structure
What is holoprosencephaly an example of?
Malformation
What do second generation (atypical) antipsychotics treat in schizophrenia that first generation do not?
Negative symptoms - 2nd generation treat both positive and negative vs. 1st generation only treat positive
Clozapine, risperidone, olanzapine, quetiapine are examples of what?
Atypical antipsychotics
Which vitamin deficiency in CF patient presents with neurologic symptoms (decreased proprioception and hyporeflexia in lower extremities) and hemolytic anemia?
Vitamin E
Recurrent lobar hemorrhages in an elderly patient suggests what underlying pathology?
Cerebral amyloid angiopathy
Which antiepileptic is associated with generalized lymphadenopathy as a side effect?
Phenytoin
What generation is fexofenadine?
2nd generation antihistamine
What generation is chlorpheniramine?
1st generation antihistamine
Is rifampin a cyp450 inducer or inhibitor?
Inducer
What are the cyp450 inducers?
Mnemonic: Chronic alcoholic Mona steals phen-phen and never refuses greasy carbs.
Chronic alcohol use Modafinil St. John's wort Phenytoin Phenobarbital Nevirapine Rifampin Griseofulvin Carbamazepine
What are the cyp450 inhibitors?
Mnemonic: A cute gentlemen cipped iced grapefruit juice quickly and kept munching on soft cinnamon rolls
Acute alcohol Ciprofloxacine Isoniazid Grapefruit juice Quinidine Amiodarone Ketoconazole Macrolides Sulfonamides Cimetidine Ritonavir
What sensory divisions does CN IX cover?
Posterior 1/3 of the tongue, tonsillar region, upper pharynx, carotid body, carotid sinus, inner surface of tympanic membrane, Eustachian tube
Cerebellar hemangioblastoma with congenital cysts of liver, kidney, and/or pancreas is suggestive of what?
vHL
What drug is used as chemoprophylaxis for meningococcal meningitis?
Rifampin
Hypothyroidism is a major side effect of what psych drug?
Lithium
Neuron with shrunken nuclei, no detectable Nissl substance, intensely eosinophilic cytoplasm?
Red neuron - irreversible injury
Describe the mechanism of action of botulinum toxin.
Blocks the presynaptic exocytosis of ACh vesicles
