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Neuro 4
Last few weeks of Neuro
51
Medical
Graduate
04/26/2010

Additional Medical Flashcards

 


 

Cards

Term
What are some conditions that can predispose a patient to Wenicke-Korsakoff syndrome?
Definition
  • Alcoholism (with dietary deficiency in thiamine)
  • Malignancy (gastric and esophageal cancers),
  • Hyperemesis gravidarum
  • Chronic dialysis
  • Bariatric surgery
Term
What is the clinical presentation of Wenicke-Korsakoff syndrome? The acute pathological? Subacute? Chronic?
Definition
  • Lateral rectus palsy, confabulation
  • Mamillary bodies with petechial hemorrhages (along with various other areas)
  • Rarefaction of the brain, vascular proliferation, macrophage infiltration; preservation of neuron (still reversible at this stage)
  • Can be irreversible damage; mamillary bodies shrunken, sunken and brown (due to hemosiderin)
Term
What is the normal intracranial pressure? What is the Monroe-Kellie doctrine?
Definition
10-15 mmHg; if there's an increase in brain mass, blood or CSF without a concomittant decrease, there will be an increase in ICP
Term
What is the primary treatment for increased ICP?
Definition
  • Surgical excavation of mass
  • Elevation of head (increase venous drainage)
  • Keep head straight (avoid neck compression)
  • Analgesia/sedation, osmotic diuresis (mannitol), CSF drainage
Term
What are the secondary maneuvers for the treatment of ICP?
Definition
  • Hyperventilation
  • Monitor jugular and venous sat.
  • Lobectomy or craniectomy
  • Barbiturate coma
  • Hypothermia, hyponatremia
Term
A trauma patient comes in with signs of trauma. What are some indications of cingulate/subfalcine herniation?
Definition
Demonstrate midline shift on imaging; observe symptoms indicative of anterior cerebral artery compression
Term
What is the mechanism of action for alcohol intoxication? How is it metabolized?
Definition
  • Mechanism of action
    • Binds to own site on GABA-a receptor (potentiates inhibition)
    • NMDA antagonist
    • Also binds to canniboid-1, opiate, glycine, ACh and 5-HT receptors
  • Metabolism
    • Metabolized by alcohol dehydrogenase (zero-order kinetics) to acetylaldehyde (causes hang-over effect)
    • Microsomal ethanol-oxidizing system, catalase
Term
What are the symptoms of alcohol withdrawal? How is withdrawal assessed?
Definition
  • Withdrawal signs
    • Peaks 2-3 days after last drink
    • Typically done by day 5-10
    • Tachycardia, HTN, diaphoresis, tremor seizure (generalized)
    • Rare event = delirium (delirium tremens), discernible by EEG
    • Hallucinations (in America, often pink elephants)
  • Clinical institute withdrawal assessment (CIWA)
    • Score >8, treat medically
    • Score >18, hospitalization
Term
What are the treatment options for alcohol dependence?
Definition
  • Disulfiram
    • Inhibits acetylaldehyde dehydrogenase (increasing circulating acetylaldehyde)
    • Severe "hang-over" immediately upon drinking
    • Can cross-react with other alcohols (perfume, mouth-wash), with heterogenous adverse effect
  • Naltrexone
    • Block opiate receptor, leading to decreased dopamine release from nucleus accumbens
    • Best results with family hx of alcoholism, with same sex parent affected
    • Get LFT's every 6 mo
  • Acomprosate
    • Metaborotropic glutamate receptor antagonist (works as glutamate modulator)
    • Deals with compensatory glutamate upregulation that occurs with GABA potentiation
Term
What are the important pharmocological and clinical distinctions between barbiturates and benzodiazepines?
Definition
  • Barbiturates control the degree of chloride channel at the GABA receptor. They are potentially fatal.
  • Benzos bind to the GABA receptor itself, controlling the frequency of chloride channel opening. Not fatal by itself, but fatal with alcohol
Term
What are the three opiate receptors?
Definition
  • Mu (site for morphine), used in supraspinal analgesia; causes respiratory depression, constipation, sedation, euphoria, miosis
  • Kappa, used for spinal anesthesia; causes sedation, dysphoria, psychomimetic
  • Delta, multiple functions

Note: all G-coupled receptors

Term
What are signs and symptoms of opiate withdrawal? What are some important considerations when dealing with a patient going through withdrawal?
Definition
  • Diarrhea, rhinorrhea, abdominal cramping, vomiting, malaise, dysphoria, myalgia
  • Withdrawal is non-lethal, but addicts have lower tolerance for pain/discomfort due to diminished endorphin function
Term
What are the treatments for opiate dependence?
Definition
  • Naltrexone
    • Long acting opiate blockade with an antagonist
    • Compliance is big problem, except for medical professionals
    • Blockade of endogenous opiates in these patients 
  • Methadone
    • Long acting opiate blockade with an agonist
    • Typically given PO, QD
    • Can safely be on maintenance for years to prevent withdrawal and cravings
    • Tight federal regulation
    • Takes weeks to months to detox from it b/c long t ½
    • Ppl on methadone maintenance - More alert than general population!!
  • Buprenorphine
    • Partial agonist
    • Mechanism of action: Opiate agonist up to a certain level of tolerance, then is an antagonist.
    • Ceiling effect, so can’t OD
    • Metabolized By cytochrome 450 3A4, so a lot of interaction potential (benzo, TCA, eryththromycin, nifedipine, HIV protease inhibitors).
    • No street value
  • Suboxone
    • Buprenorphine + naloxone
Term
Which opiates are capable of evading standard drug screens? Which effects of opiates do not induce tolerance?
Definition
  1. The synthetics (meperidone, methodone, propoxyphene, fentanyl)
  2. Miosis and constipation (users develop tolerance to euphoria; typically drug seek to avoid withdrawal)
Term
What are the three components of the Glasgow score? What are important considerations when using the score?
Definition

Not linear; <8 is classified as severe traumatic brain injury; doesn't give complete picture

  • Eye opening (spontaneously, in response to voice, pain, or none)
  • Verbal response (oriented x3, semi-lucid sentences, inappropriate words, incomprehensible sounds, or none)
  • Motor response (to command, localization of pain, withdraws from pain, flexion, extension, none)
Term
What is the pathological consequence of B12 deficiency? What is the molecular etiology? How does it manifest microscopically?
Definition
  1. Sub-acute combined degeneration (degeneration of the posterior cords), generally at the thoracic level, leading to parathesia and loss of proprioception.
  2. Loss of myelin basic protein, limiting myelin maintenance
  3. Vacuolization in spinal cords with macrophages in the area (otherwise, vacuolization = artifact)
Term
How does carbon monoxide poison present pathologically? Clinically? Which part of the brain is it most likely to affect?
Definition
  1. Petechial hemorrhages in the brain (cherry red coloration) with massive edema
  2. Headache, dizziness, impaired hearing and vision, confusion, convulsion, coma, cardio-respiratory failure
  3. Globus pallidus (iron-rich), anterior vessels
Term
What are the major secondary infections implicated in CNS malformation?
Definition

TORCH

 

  1. Toxoplasmosis
  2. "Other"
  3. Rubella
  4. Cytomegalovirus
  5. Herpes/HIV

 

Term
What are the major consequences of fetal alcohol syndrome? At what point in fetal development can it occur?
Definition
Micro(en)cephaly; typically during the period of growth and proliferation (5 weeks to 6 months)
Term
At what stage of development can neural tube defects occur? How common are they? What diagnostic test is used for screening?
Definition

  1. Days 16-28
  2. 1/500
  3. Alpha fetoprotein

Term
What is craniorachischisis? At what period of development can it occur?
Definition
Opening in both the anterior and posterior neuropores; occurs on day 22
Term
Define anencephaly. What pathological features are present?
Definition

Absence or hypoplasia of the skull vault, typically incompatible with life >1 week. Due to failure in anterior neural fold formation. 

 

Area cerebrovasculosa present (mass of disorganiced tissue)

Term
Define encephalocele. What are some potential sequelae?
Definition
Failure of the fusion of the posterior skull, leading to neural tube/brain herniation. Might be vision impairment due to occipital lobe involvement.
Term
What are the major types of spina bifida?
Definition

 

  • Meningocele - sac containing meninges, but not spinal cord
  • Myelomeningocele - sac containing meninges AND spinal cord
  • Spina Bifida Occulta - malformed spinal arches, no herniation
  • Congenital dermal sinus - connection between skin and subarachnoid space

 

Term
During your ob/gyn rotation, you observe the live birth of a baby with cyclopia. While this is a rare live birth, it apparently occurs 1/250 conceptions, and can also manifest as a baby with cleft lip or proboscis. What would you expect to see on gross pathology? Which genes/chromosomes predispose to this condition?
Definition

Failure of the prosencephaly (forebrain) to form. No midline, one hemisphere.

 

Chromosome 13 and genes of the Sonic Hedgehog pathway (as well as cholesterol inhibitors, which modify SHH)

Term
On autopsy of a child, you notice the brain is perfectly smooth. What is the name of this defect? What are some alternative forms? What gene is likely mutated in this child?
Definition
  1. Lissencephaly, type I (due to failure in migration @ month 3-4)
  2. Lessencephaly type II (cobblestone appearance)
  3. Doublecortin (microtubule binding protein)
Term
What is the effect of doublecortin in males? Females?
Definition
  • Males - lissencephaly (smooth brain)
  • Females - subcortical band hetertopias (double cortex)
Term
You observe a delivery. You observe the baby has a shallow posterior fossa. Further work-up suggests hydrocephalus and tonsillar herniation, as well as myelomeningocele at the sacrum. What is the most likely diagnosis?
Definition
Arnold-Chiari Malformation, Type II
Term
A child is brought in for autopsy, with a positive history for enlarged head, increased ICP, hypotonia and seizures. The most discernible feature is  a large cystic dilatation of the fourth ventricle. What is the most likely diagnosis? What are some other pathological features? What disorder can it occur in?
Definition

  • Dandy-Walker malformation
  • Enlarged posterior fossa, a/hypoplasia of the cerebellar vermis, agenesis of corpus callosum, aqueductal stenosis
  • Seen in lissencephaly type II

Term
What is the difference between Chiari Type I and Type II?
Definition
Type I is just cerebellar herniation, but is associated with syringomyelia (dilation of the syrinx/central canal)
Term
When does syringomyelia manifest? How does is present clinically?
Definition
Congenital, but often present in 20's or 30's with loss of pain and termperature sensation. If in cervical cord, can cause atrophy in the intrincis muscles of hand.
Term
What is the theorized cause of porencephaly?
Definition

Damage to the circulation of the major arteries in week 18-27 (equivalent of a fetal stroke), causing a migration disorder and pore formation.

 

Congenital hemiplegia, retardation, seizures and spasticity ensue.

Term
What are the watershed territories of the fetal brain? What is the most common ischemic insult in infants?
Definition
White matter; periventricular leukomalacia (causes spastic motor dysfunction)
Term
What is the most common type of intracranial hemorrhage in the premature baby? How common are they? What are some risk factors?
Definition

 

  • Germinal matrix (area where new cells are formed, next to ventricle). Vessels are compromised due to incomplete formation of basal lamina.
  • 40-50% in infants born <26 weeks, 20% in infants 25-32 weeks, <5% in normal births
  • Respiratory distress, congenital heart disease, coagulopathy

 

Term
What is the first-line treatment of narcolepsy?
Definition

Modafinil

 

Catoplexy is treated with SNRI's (venlafaxine), TCA's and atomoxetine

Term
What is the treatment for periodic leg movement of sleep?
Definition
DA antagonist (ropinarole)
Term
How are epidural hemoatomas distrinct from subdural on CT?
Definition
Epidural = lens shaped (respects boundaries of sutures), subdural = crescent shaped
Term
What are the initial sources of damage from gunshot wounds to the head? Secondary? What are important issues to monitor?
Definition

  1. Cavitation and coning
  2. Edema, hemorrhage and increased ICP
  3. Intracranial hemorrhage, traumatic aneurysm, infection. Increased risk of seizures

Term
What is the theorized cause of diffuse axonal injury? What are the histological and radiological features?
Definition

Intertial damage generate shearing force on cranium on abrupt acceleration/deceleration. MRI shows small hemorrhagic contusions. 

  1. Corpus callosum lesions
  2. Dorsolateral brainstem lesion 
  3. Axonal retraction balls

Term
What is a promising sign that a patient with spinal cord injury is capable of recovery? What are major chronic complications?
Definition

Surgical intervention can be therapeutic if minimal function is still present below the lesion

  • Pneumonia
  • DVT
  • Decubitus (bed sore)
  • UTI (from catheter)

Term
What is the major mechanism of action of amphetamines? What are some clinical features of abuse? What is unique about methamphetamine?
Definition

  • Massive release of dopamine, serotonin and catecholamine, with partial reuptake inhibition
  • Bruxisms (teeth grinding), psychosis similar to those found in mania or schizophrenia
  • Crosses BBB faster and increase half life

Term
What is the mechanism of action of caffeine? Which populations should be wary about using it?
Definition

Adenosine receptor antagonist in basal ganglia, modulating dopamine levels.

 

Pregnant women and women nursing should minimize amount they use (increased half-life in babies and in pregnant women)

Term
Which recreational drug is associated with increased risk of a specific type of cancer?
Definition
Nitrites (poppers) associated with Karposi's sarcoma (also seen in AIDs patients)
Term
When you come in for your regular teeth cleaning, you notice your dentist is acting strange. He forgets your name and seems to have difficulty manipulating his instruments. What is the mechanism of action for the drug he is likely abusing? Are the affects reversible?
Definition
Nitrous oxide releases endorphins and acts as a partial reuptake inhibitor. Can be reversed by B12 administration.
Term
A baby in the delivery unit is stuporous, with extreme hypertonia. You notice it is prone to shrill cries and poor suckling. After a session of phototherapy, the baby is entirely well. What is the most likely pathology? 
Definition
High bilirubin; yellow staining is observed in the nuclear groups (basal ganglia, hippocampus, brain stem, etc.), with eosinophilic degeneration of neurons
Term

What is the general pathological picture for metabolic diseases? Match the deficiency with the following disorders:

  • Hurler's 
  • GM2 gangliosidosis (Tay-Sachs)
  • Neuronal ceroid lipofuscinosis
  • Pompe's disease

Definition

Neurons are "ballooned", generally seen with megaencephaly (englarged brain). Due to deficient degradation of waste product.

  • Deficiency in iduronidase, causing accumulation of dermatan and hepran sulfate ("gargoyle" features, short stature, coarse face, corneal clouding, etc.)
  • Deficiency in hexosaminidase, causing accumulation of ganglioside (a lipid)
  • Accumulation of autofluorescent protein, with various ages of onset
  • Deficiency in acid maltase, leading to accumulation of glycogen. Multi-organ dysfunction (cardiomegaly, macroglossa, hepatomegaly)

Term
What gene is responsible for the pathology seen in Wilson's disease? What are the clinical presentations? Gross and microscopic pathology?
Definition

 

  • ATP7b (metabolizes copper into ceruloplasm, allowing for biliary excretion); build up of copper in the liver spills out systemically
  • Clinical presentation
    • Liver failure
    • Wing beating tremors, dysarthria, dysphonia, dysphagia
    • Gait abnormalities
    • Seizures
    • Psychological pathology (schizophrenia, manic depressive, psychosis)
    • Kayser-Fleischer rings in cornea
  • Definitive diagnosis is made by liver biopsy (macronodular cirrhosis), disease targets putamen
Treatable with dietary modification and copper chelation

 

Term
How can one measure if the eardrum is intact, or if there is fluid behind it?
Definition
Acoustic impedance; a stiff eardrum, or a torn one, will both have flat tympanograms
Term
What are the beneficial properties of earwax?
Definition
Sticky (acts as primary defense), hydrophobic (prevents water from entering), acidic / contain lysozyme (antimicrobial/fungal)
Term
Which organisms are the frequent sources of acute otitis externa?
Definition
Pseudomonas and Staphylococci; Pseudomonas is especially dangerous in diabetes
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