Neuro Flashcards
Why is there so much variability in the expression of mitochondrial diseases?
normal and abnormal diseases are randomly distributed between daughter cells in mitosis (heteroplasmy)
Name three mitochondrial syndromes
- Leber hereditary optic neuropathy
- Myoclonic epilepsy with ragged-red fibers
- mitochondrial encephalomyopathy with lactic acidosis and stroke like episodes (MELAS)
child cognitive impairment behavioral problems mild anemia lives in old house
lead poisioning
Enzymes most sensitive to lead inhibition
delta-aminolevulinate dyhydrase and ferrochelatase (zinc containing)
Causes delta-ALA and proroporphyrin IX to accumulate, decreased production of heme
Pathway that N. meningitidis uses to colonize CNS:
Nasopharynx-> mucosal epithelium -> bloodstream -> choroid plexus ->CNS via BBB
Location of Foramen of Monro
between lateral ventricles and third ventricle
Location of cerebral aqueduct
between third ventricle and fourth ventricle
Openings between fourth ventricle and subarachnoid space:
lateral foramina of Luschka and medial foramen of Magendie
How does CSF return to venous circulation
arachnoid villi
Noncommunicating hydrocephalus
caused by obstruction of CSF flow
Communicating hydrocephalus
blockage of subarachnoid space, not within brain or brainstem
from fibrosis following inflammation
Normal pressure hydrocephalus
CSF is not absorbed by arachnoid villi
Hydrocephalus ex vacuo
Increased CSF volume occurring in conditions of brain atrohpy
Psuedotumor cerebri
increased intracranial pressure in overweight young women. Related to decreased CSF outflow at arachnoid villi
Causes of progressively weakening diaphragmatic contractions (intact phrenic nerve stimulation)
NMJ pathology (myasthenia gravis) or rapid diaphragmatic muscle fatigue (restrictive lung disease)
fever and muscle rigidity after surgery under general anathesia
tachycardia, hypertension, hyperkalemia, myoglobinemia
Malignant hyperthermia. Caused by excess free calcium in the cytoplasm of muscle fibers (defect in ryanodine receptor). Ramps of action of sarcoplasmic reuptake of Ca (ATP dependent-> generates heat)
What drug is used to reverse malignant hyperthermia?
Dantrolene- muscle relaxant that acts of ryanodine receptors preventing further release of Ca into the cytoplasm.
Tetrodotoxin
neurotoxin in pufferfish. Binds to voltage gate sodium channels in nerve and cardiac tissue, preventing depolarization
Most common symptoms of MS
optic neuritis
internuclear opthalmoplegia
sensory deficits
Worsen with heat exposure
Enzyme deficiency in Niemann-Pick
sphingomyelinase
Urinary incontinence
ataxic gait
dementia
Normal pressure hydrocephalus (wacky, wobbly, wet)
CT findings in normal pressure hydrocephalus
symmetric dilitation of ventriculi
Light reflex findings when one optic nerve is damaged
Light in effected eye will not cause contstriction of either pupil (optic nerve can’t carry info away)
Light in unaffected eye will cause constriction of both pupils (occulomotor nerves still function)
What happens at sites of irreversible neuron injury?
Astrocytosis (glial cells that form scar that compensates for volume loss)
Which vitamins are fat soluble?
ADEK
Which vitamin deficiency causes neuromuscular disease and hemolytic anemia?
Vitamin E (functions to protect fatty acids from oxidation. Deficiency allows damage to neurons and RBCs)
Cerebellar ataxia
Telangectasia
increased risk of sinopulmonary infections
ataxia telangiectasia:
AR
defect in ATM (DNA repair) gene
Causes IgA deficiency
Function of kinesin
transport of neurotransmitter containing secretory vesicles to synaptic terminals
Spastic rigidity
hyperreflexia
paresis
Upper motor neuron lesions. Can be located in corticospinal tract, internal capsule (posterior limb), and primary motor cortex.
hemiballism
wild, flinging movements of the extremities on one side (contralateral to lesion) of the body. Occurs due to damage of the subthalamic nucleus (part of basal ganglia)
What comprises the wall of a cerebral cystic cavity?
astrocytes (gliosis)
Cause of neonatal tetanus
infected umbilical stump
When can a child get their first tetanus vaccine?
Two months
What molecules are derived from POMC?
beta-endorphins
ACTH
MSH
How does tetanospasmin (tetanus toxin) travel through the body?
motor neuron (retrograde transport) -> spinal cord-> inhibition of inhibitory interneurons -> unregulated firing on primary motor neurons
Two brain tumors that arise in the cerebellum
pilocytic astrocytomas and medullobastomas
tumor composed of sheets of small cells with basophilic nuclei and scant cytoplasm (small, round, blue). Abundant mitoses
Primitive neuroendocrine tumors. Include Medullobastomas
Amniocentesis findings in neural tube defect
High Alpha-fetoprotein and acetylcholinesterase.
Confusion/apathy/inattentiveness
ataxia
opthalmoplegia (horizontal nystagmus)
damage to mamillary bodies
Wernicke encephalopathy
Caused by glucose infusion in a patient with a thiamine deficiency
flu-like prodrome agitation disorientation pharyngospasm photophobia followed by flaccid paralysis Exposure to wild mammals
Rabies encephalitis
How do rabies viruses bind to cells?
Bind to nicotinic acetylcholine receptors
Signs of acute Vitamin A toxicity
nausea
vomiting
vertigo
blurred vision
Signs of chronic Vitamin A toxicity
alopecia dry skin hyperlipidemia hepatotoxicity HSM visual difficulties intracranial hypertension
Signs of niacin deficiency
3D’s of pellagra: dementia, dermatitis, diarrhea
Schizophrenic symptoms lasting 1-6 months
Schizophreniform disorder
Substance that causes the most overdose deaths in the US
Opioid analgesics
Vertical diploplia
Double vision when looking towards the nose. USually caused by palsy of trochlear nerve (CNIV)
Total sensory loss on one side of the body (no motor dysfunction)
Contralateral thalamic syndrome
Cause of lacunar infarcts
small vessel lipohyalinosis and atherosclerosis involving penetrating vessels supplying deep brain structures
Risk factors for lacunar infarcts
DM and uncontrolled hypertension
Stimulus for release of acetylcholine into NMJ
Calcium influx into nerve terminal
Blotchy red fiber on Gomori trichrome stain
mitochondrial myopathies. Because abnormal mitochondria accumulate under the sarcolemma
Tumor at cerebellopontine angle
S-100 positive
around cranial nerve (especially VIII)
Schannoma
What two types of cancers are S-100 positive
Schwannoma and Melanoma
