Neurology, Neuroscience, Genetics Flashcards
Where does the basilar artery run? How would a basilar infarct present?
The basilar artery runs along the anterior median grove of the pons. A basilar infarct presents with locked in syndrome - characterized by quadriplegia with preserved reticular formation, intact vertical eye movement, and intact blinking.
How would an infarct involving the posterior inferior cerebellar artery (PICA) & vertebral artery present?
Lateral medullary syndrome. Ipsilateral manifestations - facial loss of pain/temp, ataxia, hoarseness, dysphagia, and Horner syndrome. Contralateral - pain/temp hemisensory loss. Additional signs will be N/V, nystagmus, vertigo. Pay attention to voice changes, swallowing difficulties, ataxia/nystagmus, and vertigo.
How would an infarct involving the anterior inferior cerebellar artery (AICA) present?
Lateral pontine syndrome. Ipsilateral manifestations - facial paralysis, loss of lacrimation, decreased salivation, loss of corneal reflex, loss of sensation to anterior 2/3 of tongue, Horner syndrome, sensorineural hearing loss, loss of facial pain/temp. Contralateral - pain/temp hemisensory loss. Pay attention to multiple signs of cranial nerve involvement.
Pathognomonic sign of a posterior cerebral infarct
Contralateral homonymous hemianopia with macular sparing. “partial loss of vision in the same half of both eyes with the center of the visual field preserved”
Pathognomonic sign of a posterior communicating artery infarct
Ipsilateral compression leading to CN III palsy (down and out eye, mydriasis)
For what disease is a pallidotomy indicated for?
Pallidotomy is carried out for advanced Parkinson’s disease by ligating the anterior choroidal artery. Anterior choroidal is a terminal branch of the internal carotid artery and supplies the globus pallidus and caudate nucleus. The infarction of the globus pallidus is considered the therapeutic mechanism behind pallidotomy. Pallidotomy is usually done unilaterally due to potential severe adverse effects of a bilateral pallidotomy.
Where is the locus coeruleus located? What does it contain? What psychological process is activation of this area involved in?
It is located in the located in the upper dorsolateral pontine tegmentum. It is the principal source of norepinephrine-containing neurons. It is involved in anxiety and panic –> activation of LC leads to increased NE release which in turn leads to activation of amygdala, neocortex, hypothalamus, hippocampus, cerebellum, and thalamus.
How does Juvenile Huntington’s disease present? How does this differ from adult onset? How is Juvenile Huntington’s disease inherited?
1&2) Dystonia and seizures (vs adult-onset with chorea)
3) Autosomal dominant from father (most commonly) due to anticipation (larger allelic expansion exclusively with paternal transmission)
How does radial nerve mononeuropathy present?
1) “Saturday Night Palsy”. Occurs when a person - typically in an alcohol-induced stupor - leans their upper arm against a chair for several hours, compressing the radial nerve.
2) Wrist drop, with paresis in supination of forearm and extension of all 5 MCP joints. Sensory loss along extensor surface of arm/forearm, back of hand, dorsum of fingers.
Which structure divides the hindbrain into the myelencephalon and metencephalon
Pontine flexure
Diagnostic criteria for fibromyalgia
1) Pain for at least 3 months
2) Pain involves 11 out of 18 points
Imaging findings in Progressive Multifocal Leukoencephalopathy (PML)?
Multifocal areas of demyelination more prominent in subcortical white mater. Random distribution.
Imaging findings in Multiple Sclerosis?
1) Lesions appear hyperintense on T2 and FLAIR with enhancement of acute lesions
2) Involves white matter, often ovoid
3) May have demyelinating periventricular plaques (Dawson’s fingers)
What type of brain tumor is a Glioblastoma Multiforme (GMB)? How does it appear on imaging?
1) Astrocytoma
2) Involves cerebral hemispheres. Mixed density mass. Can be unilateral OR can cross corpus callosum (butterfly glioma)
Pain and temperature sensation is carried by what spinal cord pathway?
Lateral spinothalamic tract
Coarse touch and pressure sensation is carried by what spinal cord pathway?
Anterior spinothalamic tract
What are the two fiber groups within the spinal cord that are responsible for carrying proprioceptive and fine touch sensations? How do they differ? What tract do they both run within?
1) Fasciculus gracilis and Fasciculus cuneatus
2) Fasciculus gracilis (trunk and lower extremities) / Fasciculus cuneatus (trunk and upper extremities)
3) Dorsal column of the spinal cord
What are the most common causes of sensory neuronopathy/dorsal root ganglionopathy (4)? What about causes from toxicity (2)? How does this present?
1) Paraneoplastic disease, Sjögren’s syndrome, HIV associated, and idiopathic sensory neuronopathy.
2) Cis-platinum toxicity, Vitamin B6 (pyridoxine) toxicity
3) DRAMATIC loss of proprioception (so more than just gait instability) with significant vibration loss. Pan-modality sensory loss in affected extremities. PRESERVED MOTOR STRENGTH!
Post-stroke depression is associated with a lesion in which brain region?
Left frontal lobe
What is the triad found in Lennox-Gastaut syndrome?
1) Multiple seizure types (usually including generalized tonic-clonic, atonic, and atypical absence seizures)
2) EEG showing spike and slow-wave discharges (< 2.5 Hz) 3) Impaired cognitive function in most but not all cases
EEG finding in Juvenile Myoclonic Epilepsy VERSUS Absence seizures
1) Juvenile Myoclonic Epilepsy –> 3-6 Hz generalized polyspike and wave discharge
2) 3 per second generalized spike AND slow wave discharge
Genetic cause of Adrenoleukodystrophy? What is the presentation?
1) Abnormality in the ABCD1 gene located on the X-chromosome (so predominantly affects males) –> leads to accumulation of very long chain fatty acids in peroxisomes
2) Diffuse brain demyelination, progressive cognitive impairment, spasticity, and weakness. Also may have concurrent adrenal insufficiency –> hyponatremia and hyperkalemia
What enzyme is found in low levels in plasma in patients with conduct disorder?
dopamine B-hydroxylase (converts dopamine to NE) –> leads to the decreased noradrenergic functioning implicated in conduct disorder
Genetic mutation commonly found in FTD? What chromosome is it linked to? What is the inheritance pattern?
1) Microtubule-associated protein tau (MAPT)
2) Chromosome 17 (FTDP-17)
3) Autosomal Dominant (50% of passing altered gene to progeny)
Lambert-Eaton syndrome, Malignant hyperthermia, hypokalemic periodic parlysis, and familial hemiplegic migraine are all caused by defects it what ion channels?
Calcium Channel Systems
Benign familial neonatal convulsions result from defects in what type of ion channels?
Potassium
The Papez circuit connects the ____ to the mamillary body via the ____ ; then from the mamillary body to the ___ , ____, _____, and back to the ______.
1) Hippocampus
2) Fornix
3) Thalamus
4) Hypothalamus
5) Cingulate gyrus/cortex
6) Hippocampus
While considered part of the limbic system, the Papez circuit does not include the ____. The primary function of the Papez circuit?
1) Amygdala
2) Cortical control of emotion and memory storage and contains centers that regulate aversion and gratification.
What is the defect and inheritance mechanism of phenylketonuria (PKU)? What are the characteristic features?
1) Deficiency in phenylalanine hydroxylase (chromosome 12)
2) Autosomal recessive
3) Intellectual disability, microcephaly, “mousy” odor, infantile spasms, and light hair/skin pigmentation.
Overstimulation of D2 receptors in the _____ leads to tics and extraneous motor movements. Blockade of these receptors lead to ____.
1) Caudate (caudate neurons regulate motor activity by determining which motor acts get carried out)
2) Bradykinesia (as in Parkinson’s disease)
Carotid endarterectomy is indicated for symptomatic ICA stenosis of greater than ____ %
70%
What is the inheritance pattern of Duchenne’s and Becker’s muscular dystrophy?
X-linked (locus Xp21 on the short arm of the X chromosome)
What is the rate limiting enzyme in dopamine synthesis?
Tyrosine hydroxylase (converts L-tyrosine to L-DOPA_
What is the most common myopathy over the age of 50? Which muscles are preferentially affected? How does it present?
1) Inclusion body myositis
2) Affects STRENGTH of distal muscles of arms and legs. Preference to wrist and finger flexors, and quadriceps.
3) WEAKNESS (no pain). Chronic, progressive weakness that is poorly responsive to steroids or immunosuppressive agents
Compression of what nerve results in meralgia paresthetica? How does this present?
Compression of the lateral femoral cutaneous nerve as it passes beneath the inguinal ligament. Pain and sensory loss (numbness) to the lateral thigh. No motor deficits. Seen in obesity, pregnancy, and too tight pants/heavy belt.
What is the most common cause of metastasis to the brain?
Lung cancer (accounts for 2/3 of all brain mets, particularly non-small cell)
What is the characteristic triad of Tabes dorsalis?
Sensory ataxia, lighting pains, urinary incontinence.
Tropical spastic paraparesis is a chronic progressive _____ associated with infection by ______. It is characterized by upper motor neuron weakness, bladder disturbance, and sensory loss.
1) Myelopathy
2) Human T-Lymphotropic virus type 1 (HTLV-1)
What is Todd’s paralysis?
Brief period of transient hemiparesis or hemiplegia after a seizure. Temporary, resolve within 48 hrs.
Four examples of neurodegenerative disorders associated with trinucleotide repeats? What are the anticipation patterns for each?
1) Fragile X syndrome (CGG repeat); Maternal anticipation
2) Myotonic dystrophy , type 1 (CTG repeat); Maternal anticipation
3) Friedrich’s ataxia (GAA repeat); paternal anticipation
4) Huntington’s disease (CGG repeats); paternal anticipation
What is the “battle sign”?
Hematoma overlying the mastoid that results from a basilar skull fracture.
Triphasic waves on EEF are characteristic of what?
Hepatic or metabolic encephalopathy
What is a common cause of Kluver-Bucy syndrome?
Pick’s disease (FTD)
What is the genetic abnormality in Klinefelter’s syndrome? What are the clinical features?
1) Extra X chromosome (XXY)
2) Small dysfunctional testes, intellectual disability, pear-shaped stature.
What is the genetic abnormality in Prader-Willi syndrome? How does it present?
1) Deletion on the paternal chromosome 15
2) Profound intellectual disability, hypogonadism, hypotonia, behavioral disinhibition, rapid and excessive weight gain, and facial dysmorphism.
What are the neurochemical findings associated with intermittent explosive disorder (3)?
Decreased cerebral serotonergic transmission, low CSF levels of 5-hydroxyindolacetic acid, and high CSF testosterone in men.
What is the primary (most important) mechanism in removing dopamine from the SYNAPTIC cleft?
Neuronal reuptake by DAT
What are common findings to look out for in subacute combined degeneration? What mineral deficiency can mimic it?
1) Signs of both central/peripheral neuropathy – so complaints of loss of sensation with mild weakness. On exam, increased reflexes, loss of proprioception/vibration senses, upgoing toes, ataxia.
2) Copper deficiency! (seen in patient’s post-gastric bypass or in patient’s taking excess zinc – as zinc and copper are absorbed via the same transporter
What is the prolactin level that warrants referral from brain MRI?
Levels over 118
Classic presentation of transverse myelitis?
RAPID onset of bilateral leg weakness that presents with a clear-cut sensory level below the level of the lesion (pain and temp usually affected). Urinary and/or bowel incontinence usually present.
Prosopagnosia is classically associated with what lesion? What other findings would occur with this lesion?
1) Bilateral occipital-temporal lesions
2) Agraphia and achromatopsia (inability to recognize colors and hues)
Anosognosia, or the denial of disease or hemiparesis, is seen with lesions where?
Lesions of the nondominant hemisphere
What is the most frequent viral pathogen associated with Bell’s palsy?
HSV
