When Things Go Wrong (55b, 66b - 77b, 79b) Flashcards
Which genetic mutation is implicated in familial ALS?
C9orf7
- Causes hexanucleotide repeat in chromosome 9
- Autosomal dominant inheritance
What are the EMG findings of small-fiber neuropathy?
None!
- EMG is normal
- Only detects abnormalities in large (A-alpha, A-beta) fibers
- Need to do skin biopsy
This can be super frustrating for patients if they are in pain, and the doctor says its in their head!
Describe the classic pattern of diabetic neuropathy
Is this characteristic of axonal or demyelinating neuropathy?
Glove and stocking pattern: characteristic pattern of numbness is one in which the distal portions of the nerves are first affected, the so-called “stocking-glove” pattern.
Axonal neuropathy
Which area of the cerebellum is damaged?
- Ataxia of the arm and leg
- Disorders of motor planning
Intermediate cerebellar hemispheres
Which area of the brain relays the major output pathway from the basal ganglia?
Ventral thalamus
Also releays major output from the cerebellum
Remember, the output nuclei of the basal ganglia are the substantia nigra pars compacta and the internal segment of globus pallidus
What are the goals of management for hemorrhagic stroke?
How is this accomplished?
- Prevent expansion of the hematoma
- Prevent compression of vital brain structures
Accomplished by:
- Lower blood pressure
- Secure ruptured vessel
- Give platelets + anticoagulants
How do you differentiate between benign essential tremor and Parkinsonism?
- Benign essential tremor
- Faster than Parkinsonism tremor
- Worse with anxiety, fatigue, temperature extremes
- Better with alcohol, sleep
- May be symmetric or asymmetric
- Parkinsonism
- Rest/pill-rolling tremor (4-6 Hz)
Typical acute CNS demyelinating symptoms include all of the following except?
- Optic neuritis
- Partial myelitis
- Abrupt onset of hemiparesis
- Double vision
- Balance impairment
c. Abrupt onset of hemiparesis
* Attacks take >1 day to develop in MS
What is the managment of primary CNS lymphoma?
- Chemotherapy (methotrexate)
- Radiation (whole brain)
- Corticosteroids can decrease edema initially, but disease will recur if other treatments are not used
Basal ganglia, direct pathway
- Receptor:
- Signals to:
- Promotes or inhibits movement?
Basal ganglia, direct pathway
- Receptor: D1 dopamine receptor
- Signals to: Globus pallidus internal segment, substantia nigra reticulata
- Promotes or inhibits movement: promotes movement
On a SPECT scan, what would you expect to see in a patient with Parkinson’s disease?
- Parkinson’s Disease = period-shaped substantia nigra
- Not normal; image B
- Not Parkinson’s Disease = comma shaped
- Normal; image A
- Patient may still have parkinsonism, but look for different etiology
A large cyst with an “enhancing mural nodule” on MRI is most likely which kind of brain tumor?
Pliocytic astrocytoma
- Usually cerebellar
- Histology will show rosenthal fibers
-
pilocytic astrocytoma (Grade 1) occurs in both children and adults most commonly in the cerebellum
- can be seen in association w/ Neurofibromatosis Type 1 (NF1)
- Macroscopic Findings: well circumscribed, often cystic
- Microscopic Findings: biphasic appearance w/ both compact and loose areas, has pink/red accumulations called Rosenthal fibers (which are only seen in slow growing lesions)
Which tracts are involved in ALS?
Corticospinal and corticobulbar
How do we test for small fiber neuropathy?
- Skin biopsy
- QSART (a fancy sweat test)
- If sweating is reduced or it takes too long, indicates autonomic dysfunction
HSV-1 is associated with [meningitis/encephalitis]
HSV-2 is associated with [meningitis/encephalitis]
HSV-1 is associated with encephalitis (frontotemporal)
HSV-2 is associated with meningitis
HSV-1 generally causes worse outcomes; causes acute necrosis
How will agenesis of the corpus callosum affect intelligence, if there are no other structural brain abnormalities?
Intelligence is likely to be normal
What is myoclonus?
Brief, lightning-like muscle jerks
- Not rhythmic
- Parkinsonism tremor is rhythmic/predictable
- Most common = asterixis
- Quick flap of the hand
Which of the mechanisms is not considered to be a pathologic feature of multiple sclerosis ?
- Innate immune activation
- Axon damage due to metabolic stress
- Loss of Schwann cells
- Elaboration of increased sodium channels in demyelinated axons
c. Loss of Schwann cells
- Demyelination in MS is due to autoreactive lymphocytes and inflammation
- Will affect white AND grey matter
Which tumors are associated with “chicken wire vasculature” and “fried egg appearance”
Oligodendroglioma
A patient presents with headache is worst in the morning but diappears during the day, recurring the next day
The headache is worse with head shaking and the valsalva maneuver
They have been increasing in frequency and severity
What are you most concerned for?
Brain tumor
- Classic brain tumor headache = signs of increased intracranial pressure
Will Parkinson’s disease be symmetric or asymmetric at onset?
Asymmetric
Which tumor is associated with pseudo-rosettes and true rosettes?
Ependymoma
An infant is admitted to the NICU after imaging reveals bilaterally hypoplastic optic nerves, absent septum pellucidum, and thin corpus callosum.
What is the most likely diagnosis?
What screening tests should be ordered?
Septo-optic dysplasia
Order glucose monitoring screen and endocrine function tests
- Failure of midline prosencephalic structures
- 2/3 of the following confirm diagnosis:
- Optic nerve hypoplasia
- Pituitary defects
- Midline brain defects
A-alpha fibers are [motor/sensory]
A-beta fibers are [motor/sensory]
A-alpha fibers are motor
A-beta fibers are sensory
What is the treatment for acute-onset Guillain-Barre Syndrome?
- Plasmapharesis + IVIG
Steroids do not work!!
What is the acute treatment for cluster headache?
100% oxygen face mask at 7 L/min, in a seated position
What are the “big 3” migraine triggers?
Hormones
Fasting
Alcohol
Where are oligodendrogliomas usually located?
Supratentorial
Frontal lobe
Usually white matter
A patient presents with sudden onset of:
- Left eye painless vision loss (aka amaurosis fugax)
Which artery is occluded?
Which areas of the brain are affected?
Left retinal aretery occluded
May be caused by plaque breaking off of the internal carotid
(ICA -> Ophthalmic artery -> central retinal artery)
- None of the brain is affected!
- Complete vision loss in one eye = retinal problem
Weakness, spasticity, clonus, and hyperreflexia are [UMN/LMN] signs of ALS
Weakness, spasticity, clonus, and hyperreflexia are UMN signs of ALS
Basal ganglia, indirect pathway
- Receptor:
- Signals to:
- Promotes or inhibits movement?
Basal ganglia, indirect pathway
- Receptor: D2 dopamine receptor
- Signals to: Globus pallidus external segment -> subthalamic nucleus -> GPi, SNr
- Promotes or inhibits movement: inhibits movement
What is dystonia?
Sustained but not fixed muscle contraction that can cause twisting or repetitive movements
- Caused by abnormal contraction of muscles
- May be generalized or focal
What are the symptoms of ciguatera fish poisoning?
Diarrhea, vomiting, numbness, itchiness, sensitivity to hot or cold, dizziness, weakness
Prevalence increasing with increased algal blooms associated with climate change :’(((((
Which area of the cerebellum is damaged?
- General balance problems
- Vestibulo-ocular reflexes
Flocculus, nodulus
What is chorea?
Excessive, spontaneous movements from a flow of muscle contractions
- Dance-like
- Irregularly timed (not rhythmic)
- Parkinsonism is rhythmic/predictable
- Randomly distributed/not predictable
List some of the characteristics of a cluster headache
- Unilateral, supraorbital and/or temporal
- VERY severe
- Occurs during sleep
- Wakes patients form sleep
- More common in males
- Weird facial stuff (at least one) on the side of the headache
- Conjunctival injection
- Facial sweating
- Lacrimation
- Miosis
- Nasal congestion
- Ptosis
- Rhinorrhea
- Eyelid edema
What is the go-to treatment for Parkinson’s Disease in older patients?
Levodopa + Carpidopa
- Levodopa = L-Dopa, converted to dopamine by endogenous L-dopa decarboxylase
- Carbidopa inhibits L-dopa decarboxylase peripherally, so more L-dopa can get into the CNS and be converted to dopamine there
Note: in younger patinets who may be more tolerant to side effects, give dopamine reuptake antagonist (amontidine) - prolonged (5+ year) levodopa can lead to dyskinesias
A migraine headache is caused by activation of a mechanism that results in the release of ____________ around the nerves and blood vesels of the head
A migraine headache is caused by activation of a mechanism that results in the release of pain-producing inflamatory substances around the nerves and blood vesels of the head
What exposures might precede Guillain Barre Syndrome?
- Illness
- Vaccination
- Dental procedure
- Surgery
-> Autoimmune response that leads to acute demyelination
Which kind of brain tumors are associated with Homer-Wright Rosettes?
Medulloblastoma (IV)
Weakness, atrophy, fasciculations, and cramps are [UMN/LMN] signs of ALS
Weakness, atrophy, fasciculations, and cramps are LMN signs of ALS
What are the two most common bacterial causes of encephalitis?
- Borrelia burgdorferi (lyme disease)
- Treponema pallidium (syphillis)
List some of the classic features of migraine
- Headache
- Unilateral
- Pulsatile
- Nausea
- Photosensitivity
- Aggravated by routine physical activity
- Lasts hours-days
- May be preceded by aura (usually visual)
IV tPA must be administered within ___ of the infarct
IV tPA must be administered within 4.5 hours of the infarct
-
ischemic penumbra = salvageable brain tissue that is supplied by the blocked artery and other arteries; damage is not immediate and may be reversible; it will infarct if not treated on time
- treatment to save the penumbra:
- IV tissue plasminogen activator (tPA), which is thrombolytic agent (up to 4 hrs from onset)
- intra-arterial catheter based methods for large vessel occlusions (up to 6 hrs from onset)
- Opening up a blocked artery has a decreasing effect as time increases ® core expands as penumbra is dying
- treatment to save the penumbra:
Describe the eye movements associated with benign positional paroxysmal vertigo (BPPV)
Ipsilateral beating and torsional nystagmus
A lesion in the right posterior canal will result in right beating and right torsional nystagmus
(drift to the left and snap back to the right)
Note: in BPPV, the snap back is toward the lesion side, whereas in vestibular neuritis the drift is toward the lesion side and the snap back is away
(idk if this is the right description)
[vestibular neuritis/benign paroxysmal vertigo] is caued by otoconia breaking off and lodging in the cristae ampullaris, resulting in overstimulation of the vestibular system
Benign paroxysmal vertigo is caued by otoconia breaking off and lodging in the cristae ampullaris, resulting in overstimulation of the vestibular system
Is Guillan Barre Syndrome axonal or demyelinating neuropathy?
Demyelinating
- Diffuse ascending weakness/paresis
- Vs. axonal, which is localized to a single dermatome or in a length-dependent glove and stocking pattern*
A patient presents with the “worst headache of their life (WHOL)”
This is _______ until proven otherwise
Subarachnoid hemorrhage
What are the major output nuclei of the basal ganglia?
- Substantia nigra pars compacta
- Internal segment of globus pallidus
Which area of the cerebellum is damaged?
- Overall decreased coordination
- Disorders of posture
- Disorders of eye/head movements
Vermis
What is the most severe, recurrent, primary headache?
Cluster headache
Glascow Coma Score for eye opening
(Which actions correspond with which scores?)
- 1 - No opening
- 2 - Opening to pain
- 3 - Opening to speech
- 4 - Spontaneous opening
Agents that cause [vasoconstriction/vasodilation] may be useful to treat migraine
Agents that cause vasoconstriction may be useful to treat migraine
Vasodilation and the release of inflammatory, pain-inducing substances are parts of the pathogenesis of migraine
What is the fundamental organizing principle of the central vestibular system?
The central vestibular system is built upon sensory integration of multiple inputs
- Somatic sensory
- Visual
- Vestibular
If one is damged, others will compensate
What is the most common modifiable risk factor for stroke?
Hypertension
Is there a direct output from the cerebellum to the spinal cord?
NO!
Output from the cerebellum loops back to the (ventral) thalamus, which is where it influences the motor tracts (corticospinal, rubrospinal, vestibulospinal, reticulospinal)