Week 2 Flashcards
Mets to the brain most commonly originate from what primary sites?
- melanoma
- RCC
- lungs
- breast
- GI (colon)
What is meningeal carcinomatosis?
a small cell carcinoma that has metastasized to the meninges of the brain and seeded the CSF
Diffuse gliomas are associated with a ___ mutation, while circumscribed ones are associated with a ___ mutation.
- diffuse: IDH1 or IDH2
- circumscribed: BRAF
How do mets to the brain typically appear on imaging?
- edematous
- at the grey/white interface
- well-circumscribed
What is the AMEN mnemonic?
a tool to recall the histologic features of grade II, III, and IV astrocytomas
- atypia
- mitoses
- endothelial proliferation
- necrosis
Which CNS tumor is associated with a p53 mutation?
diffuse astrocytoma
What is MGMT?
- a gene that encodes a DNA repair enzyme
- if methylated, it is non-functional and suggests a diffuse astrocytoma will respond to chemo
Pseudopalisading necrosis is a feature of what CNS tumor?
glioblastoma
What are the features of pilocytic astrocytoma?
- present in childhood
- cystic-solid lesion
- associated with NF-1
- common in cerebellum, 3rd ventricle, optic nerve
Which CNS tumor is always superficially located near the surface of the brain?
pleomorphic xanthoastrocytoma
What are the features of pleomorphic xanthoastrocytoma?
- adolescence
- cystic-solid
- located near surface
Which CNS tumor is characterized by calcifications, chicken wire vasculature, and perinuclear halos?
oligodendrocytomas
What is the clinical significance of 1p/19q?
codeletions suggest an oligodendrocytoma will be chemosensitive
Perivascular acellular regions called pseudorosettes are a feature of what CNS tumor?
ependymomas
Hyalnized vessels surrounded by mucin and then a layer of cells is characteristic histology for what CNS tumor?
myxopapillary ependymoma
Which CNS tumor is seen in adolescents with early onset epilepsy?
gangliomas
What are the features of gangliomas?
- early onset epilepsy
- calcifications
- neuronal/astrocytic morphology
- located in temporal lobe
Which CNS tumor stains for NeuN?
central neurocytoma
Which CNS tumor arises exclusively in the ventricle attached to the septum pallicidum near the foramen of monroe?
a central neurocytoma
Which tumor arises in the midline of the cerebellum?
medulloblastoma
What are the features of medulloblastoma?
- always arise in cerebellum, typically near midline
- neuroectodermal origin
- lots of mitoses
What tumor arises in fossa of children under the age of 5?
atypical teratoid rhabdoid tumor
What is a rhambdoid?
a cell with the nucleus displaced by the cytoplasm
NF-2 is associated with which CNS tumor?
meningioma
NF-1 is associated with which CNS tumor?
pilocytic astrocytoma
Which CNS tumor is sometimes hormonally active?
meningiomas
Psammoma bodies are a feature of what CNS tumor?
meningiomas
Which CNS tumor is associated with VHL?
hemangioblastomas
Which CNS tumor is lipid-rich?
hemangioblastomas
Meningiomas have what origin?
arachnoid
Whorl cells are a feature of what CNS tumor?
meningiomas
What is Brown Sequard syndrome?
a syndrome that mimics a hemisection of the spinal cord
Damage to the upper thoracic spinal cord will have what effect on the bladder?
it will often lead to spastic bladder
What virus commonly infects ependymal cells?
CMV
What are rosenthal fibers composed of?
heat shock proteins
Rosenthal fibers are a feature of what three disease?
- chronic gliosis
- pilocytic astrocytomas
- Alexander’s disease
The JC virus infects what glial cell population?
oligodendrocytes
Lewy bodies are a feature of what two disease?
- lewy body dementia
- parkinson’s
Granulovacuolar change is seen in what disease process?
Alzheimer’s
What are alzheimer type II astrocytes?
an abnormal astrocyte that appears in those with hepatic or metabolic encephalopathy
What are Hirano bodies composed of?
actin
Bunina bodies are a feature of what disease?
ALS
What is transsynaptic degeneration?
a type of Wallerian degeneration in which a nerve cell atrophies due to loss of afferent input
Negri bodies are associated with what disease?
rabies
What are corpora amylacea?
age-related degenerative change seen near the surface of the brain composed of ubiquitinated heat shock proteins
Which glial cell lays down scar tissue in the CNS?
astrocytes
What are gemistocytes?
expanded astrocytes
What is considered an acute sensorimotor deficit? Subacute? Chronic?
- acute: less than four weeks
- subacute: four to eight weeks
- chronic: more than eight weeks
Diabetic peripheral neuropathy is associated with what pattern of numbness?
“stocking-glove” aka length dependent
What peripheral neuropathy is often preceded by a flu-like illness?
Guillain-Barre
What are the four primary causes of mononeuropathy multiplex?
- leprosy
- vasculitis
- hereditary
- lyme disease
What are axonotmetic, neuropraxic, and neurotmetic injuries?
- axonotmetic: axon transected but surrounding CT intact
- neuropraxic: crush injury, ischemia, demyelination
- neurotmetic: irrecoverable transection of axon and CT
Inflammatory demyelinating polyneuropathies are typically characterized by what kind of weakness?
proximal
What are the two most significant length-dependent neuropathies?
diabetes and CSPN
What is the classic cold-dependent patterned neuropathy?
leprosy
What is cryptogenic sensory polyneuropathy?
a length dependent neuropathy of unknown cause
Chronic inflammatory demyelinating polyneuropathy is best treated with what?
corticosteroids
Onion bulbing is a feature of what sort of peripheral neuropathy?
segmental demyelination
The corneal reflex is mediated by what nerves?
CN V and VII
The knee jerk reflex is mediated by what spinal nerve?
L4
Motor units are recruited in what order?
smallest to largest
How is the ventral horn organized?
lower motor neurons that innervate more distal muscles are located more laterally
What muscles will demonstrate an inverse stretch reflex?
spastic or rigid muscles
How does a spinal cord injury affect an individual’s flexion reflex?
the reflex becomes exaggerated and can even become paired with bladder or bowel evacuation
Describe the circuitry of the inverse stretch reflex.
- stretch of spastic/rigid muscle puts tension on the GTO
- Ib afferents synapse onto an inhibitory interneuron
- that interneuron inhibits the alpha motor neuron of the stretched muscle
What reflex complements the flexion reflex?
the crossed extensor reflex
What NT is present at the neuromuscular junction?
acetylcholine
The femoral nerve mediates what deep tendon reflex?
the knee jerk
The stretch reflex is mediated by the ___ sensory receptor while the inverse stretch reflex is mediated by the ___ sensory receptor.
- stretch: muscle spindle
- inverse: GTO
Where do muscle spindle Ia afferents project?
- homonymous and heternymous alpha motor neurons
- spinocerebellar neurons in Clarke’s column
- the dorsal column
What is muscle rigidity?
- sustained contraction at rest
- increased tonic stretch reflex
- increased stiffness
What is muscle spasticity?
- no contract at rest
- increased phasic stretch reflex
- resistance to stretch proportion to velocity of stretch
What is the cremasteric reflex?
- stroke the medial upper thigh
- scrotal elevation
- L1/L2
What is myasthenia gravis?
a disease in which Abs are directed against AChRs like those at the NMJ
What is a Jendrassik maneuver?
a procedure used to heighten a person’s stretch reflex
How do Ia muscle spindle afferents differe from type II?
Ia sense both length and velocity while II only sense length
What is reciprocal innervation?
contraction of a muscle is accompanied by inhibition of its antagonist
Clonus is a feature of what kind of muscle disorder?
spasticity
In what order are motor units recruited by an external electrical stimulation?
larger units first
