Neuro Flashcards
Blind as a bat, mad as a hatter, red as a beet, hot as a hare, dry as a bone, the bowel and bladder lose their and the heart runs alone.
What kind of poisoning does this describe and how do you counteract it?
Atropine poisoning (competitive agonist of muscaric receptors–counters ‘rest and digest’)-similar type symptoms can occur when cutting down trees, b/c atropine comes from plant (Jimmy Weed).
Physostigmine-a reversible cholinesterase inhibitor.
ACh release from presynaptic terminal vesicles at the NMJ depends upon influx of extracellular ____________ at the presynaptic terminal?
Calcium. Influx of Ca2+ in the nerve terminal happens after neuronal depolarization and opening of VOLTAGE-GATED calcium channels.
Inability to form the membrane attack complex (C6-C9) will have recurring infections of what bacteria?
Neisseria species. (meningitis–high fever, chills, PETECHIAL SKIN RASH affected PALMS AND SOLES.
Treatment: IV Ceftriaxone for 2 weeks.
How does neisseria (meningococcal) enter into the body and infect?
Pili are responsible for epithelial attachment to the nasopharynx.
What branch of trigimenal nerve leaves the skull via the foramen ovale?
Foramen rotundum?
Foramen ovale: V3, mandibular (muscles of mastication–>masster, medial and lateral pterygoids, and the temporal is).
Formane rotundum: V2, maxillary
What are the most common causes of aseptic meningitis?
Aseptic–>non-bacterial
MCC of aseptic meningitis are enteroviruses (coxsackie, echo, polioviruses)
Enteroviruses are so named because they go through the fecal-oral route of entry.
Calcified cystic tumors in the head.
Cysts are filled with yellow, viscious fluids with cholesterol crystals. Keratin pearls may be seen.
Craniopharyngiomas–>come from Rathke’s pouch, just like the anterior pituitary does!
Cause headaches, growth problems and bitemporal hemianopia.
Patient faints when you put a speculum in their external auditory meatus. What nerve is causing this problem?
Vagus Nerve (X)–>This is vasovagal syncope.
Stimulate the vagus nerve and you stimulate parasympathetics (decreased HR and blood pressure).
Note: This would only occur due to stimulation of the POSTERIOR WALL, b/c most of the sensation of the canal is from CN V3 (mandibular branch of trigeminal).
Baby with blue eyes, fair skin, mousy odor.
What is the problem?
What enzyme is deficiency?
What do you need to supplement the diet with?
PKU:
Can’t do this–>
Phenylalanine to Tyrosine via Phenylalanine hydroxylase.
Don’t have PHENYLALANINE HYDROXYLASE.
Give these patients TYROSINE in their diet, and don’t give them PHENYLALANINE! The increased phenylalanine is what causes the neuro problems.
What enzyme deficiency will cause a build up of methlmalonyl CoA?
Methylmalonyl CoA ISOMERASE, which catalyzes the following reaction:
Methylmalonyl CoA—->Succinyl CoA (which can then enter the TCA cycle).
note: Methylmalonyl CoA occurs when there is catabolism of isoleucine, valine, threonin, methionine, cholesterole and odd-chain FA.
What does Waterhouse-Friderichsen syndrome refer to?
Meningococcal (Neisseria) sepsis that causes hemorrhagic destruction of the bilateral adrenal glands.
How do you determine the following on the mental status exam:
Orientation Comprehension Concentration Short-term memory Long-term memory Language Visual Spatial
Orientation: Providing name, location, and current date.
Comprehension: Following multistep commands
Concentration: Reciting months of the year backwards
STM: Recall three unrelated words after 5 minutes.
LTM: Providing details of significant life events.
Language: Writing a sensible sentence containing a non and a verb.
Visual spatial: Drawing a clock face.
What causes the neurologic pathology in Neimann Pck?
Sphingomyelinase deficiency-causes accumulations of the ceramde phospholipid sphingomyelin.
Characteristic changes of a neuron that include: shrinkage of cell body, EOSINOPHILIA of the cytoplasm, pyknosis of the nucleus and loss of Nissl substance (ribosomes).
Red neuron: irreversibly damaged neuron looks like this between 12-24 hours after insult.
Enlargement of hte cell body, eccentric nucleus, enlargement of the nucleolus, dispersion of nissl substance.
Loss of axon reaction.
How do you prevent a neonate from getting tetanus?
Make sure mom is immunized because she will pass IgG through the placenta and provide passive immunity to the neonate until he/she gets vaccine at 2 months of age.
Drug that makes you hostile, belligerent and possibly homicidal.
PCP (Phencyclidine)
Occlusion of what artery leads to: contralateral homonymous hemianopia with macular sparing?
Posterior cerebral artery:
Causes ischemic injury to the ipsilateral striate cortex.
If a person has a stroke in an area that causes completely loss of sensation on the contralateral side, where is the damage?
Thalamus: The VPL and VMP nuclei are damaged.
Lacunar infarcts are the result of small vessel lipohyalinosis and atherosclerosis involving penetrating vessels supplying the deep brain structures. What are risk factors for lacunar infarcts?
DM and uncontrolled hypertension.
Neurofibrillary tangles are seen in ________
alzheimers…along with amyloid plaques.
The only serotonin-releasing neurons in the CNS are found in the ___________ nuclei
Raphe…These neurons disseminate widely to synapse on numerous structures in the CNS.
Recurrent lobar hemorrhages in an elderly patient most likely result from ________ ________________ ____________.
Cerebral amyloid angiopathy.
This is where B-amyloid is deposited int he arterial wall, resulting ina weak wall and predisposition to rupture. It is associated iwth advanced age and not related to systemic amyloidosis. RECURRENT HEMORRHAGIC STROKE is the most common presentation of cerebral amyloid angioapathy. Unlike cerebral hemorrahges from hypertension, amyloid-associated strokes are less severe. They are usually in the cerebral hemispheres (LOBAR STROKES) and involve smaller areas of brain parenchyma.
Gram + coagulase negative staphylococcus can cause meningitis. What is the most important virulence factor this organism can have?
Staph. epidermidis: BIOFILMS
What else will you see with the following symptoms:
- Kyphoscoliosis
- Pes Cavus (high instep)
- Lower extremity ataxia
Hypertrophic Cardiomyopathy
This is Friederch ataxia, an autosomal recessive condition where the posterior columns of the spinocerebellar tracts of the spinal cord show degeneration. Children ages 5-15.
The number of NEW cases of a disease per year divided by the total population at risk.
Incidence.
The number of persons with a disease/total population at a SPECIFIC POINT IN TIME.
Prevalence
Morphine is an analgesic which can be injected into the epidural space for long-lasting analgesia. How does morphine help terminate pain at the spinal level?
When morphine binds mu receptors, it causes G-protein coupled activation of potassium channels to INCREASE POTASSIUM EFFLUX. This leads to HYPERPOLARIZATION OF post synaptic neurons and termination of pain transmission.
Hydrocephalus (enlargement of ventricles, intracranial calcifications, and CHORIORETINITIS form the class triad of ___________________ in neonates.
Congenital toxoplasmosis-acqured in urtero via the placenta.
Expecting mothers, avoid cat feces.
Viral meningitis is typically caused by what type of viruses?
Enteroviruses (fecal-oral)
Like: Coxsackie, Echo and Polio
Chronic thiamine (B1) deficiency leads to the diminished ability of cerebral cells to utilize glucose. The mechanism is decreased function of the enzymes that use vitamin B1 cofactor (pyruvate dehydrogenase, alpha=detoglutarate, and one other one). How do you diagnose thiamine deficiency?
Erythrocyte transketolase activity. (which the third enzyme it is a cofactor for).
Note: An increase in erythrocyte trasnketolase levels after thiamine infusion is diagnostic for thiamine deficiency.
Acute hypoxic and/or complete ischemic injury in most organs results in coagulative necrosis of hte parenchymal cells. However, kn the brain, such injury produces a focal of ________________ necrosis that occurs within 10 days of the infarction.
Liquefactive…
Eventually, the infarcted CNS tissue is replaced with a cystic astroglial scar.
Note: Fibrinoid necrosis - vasculitidies
Caseous necrosis = tb
Non-enzymatic fat necrosis = local trauma to adipose tissue
Congenital abnormality associated with the anti-epileptic valproate.
Meningocele: Valproate inhibits intestinal folic acid absorption.
What never is damaged:
Right leg numbness. Lifts right foot high than left when walking, and right foot slaps to the ground with each step. Unable to EVERT the right foot.
Common peroneal: most injured nerve in the leg. Starts in popliteal fossa and then courses laterally into the antior compartment of the leg, passing superfically around the head and neck of fibula.
Lesion causes plantarflexed and inverted goo!
How does KETAMINE block OPIOID tolerance?
Morphine tolerance is thought to come from glutamate binding to NMDA receptors, activing them. Ketamine is an NMDA receptor blocker, which will keep glutamate off of that shit.
The NF-1 autosomal dominant or recessive?
DOMINANT, with high penetrance.
YOu get: cafe’-au-lait spots, neurofibromas, optic nerve gliomas (lisch nodues are pigmed hamartomas of the irus and are asymptomatic.
Hypothalamic nucleus responsible for circadian rhythem
Suprachiastmatic
Hypothalamic nuclei responsible for satiety.
Ventro medial: lesion here leads to growing ventrally and medially)!
Note: This nuclei is stimulated by leptin, so leptin = satiety.
Lateral hypothalamic nuclei is response of _________.
Hunger: lesion leads to anorexia.
Lateral nuclei is INHIBITED by leptin. leptin inhibits hunger.
Anterior nuclei of hypothalamus mediates __________
head dissipation via parasympathetics.
Anterior turns on the A/C.
Destruction leads to hypothermia.
What part of the hypothalamus is responsible for secreting dopamine (thus inhibiting prolactin) and also secreting GHRH and GnRH?
Arcuate nuclei
Part of hypothalamus that releases ADH, Corticotropin-releasing hormone, oxytocin and thyrotropin-releasing hormone secretion.
Paraventricular
What does the supraoptic nuclei of the hypothalamus secrete?
ADH and Oxytocin: Sends it down to the posterior pituiary
What will the glucose, WBC, and protein levels be like for viral vs bacterial meningitis?
Bacterial:
Low Glucose
High Protein
High WBC with neutrophil predominance
Viral:
Normal
Protein slightly elevated
WBC count: Lymphocytic predominance
What is the most common cause of bacterial meningitis in adults of all ages?
What does it look like on microscopy?
Strep pneumo: Gram + cocci in pairs, lancet-shaped.
Strep pneumo is the leading cause of community-acquried pneumonia, otitis media, and meningitis in adults. S. pneuoniae appears on gram stain as lancet-shaped, gram+ cocci in pairs.
Bean-shaped gram - cocci in pairs
Neisseria meningitits: occurs in army barracks, college dorms, etc.
Mechanism of lorazapam.
Benzos, barbituates and alcohol all three bind to the different components of the GABA1 receptor and facilitate the inhibitory action of GABA in the CNS.
Specifically, benzos bind GABAa and stimulate the influx of choloride ions into the neurons. It INCREASES THE FREQUENCY OF THE ION CHANNEL OPENING.
