Neuro I - First Aid Flashcards
The image below depicts the neural tube at about 21 days. Where would you expect most sensory fibers and motor fibers to develop?
During neural development, the alar plate (dorsal) will mostly develop into sensory fibers and the basal plate (ventral) will mostly develop into motor fibers.
What is the role of the notochord during early fetal development? What does this structure actually develop into itself?
Fetal development: induce overlying ectoderm to become neuroectoderm and form the neural plate. Final structure: nucleus pulposus in intervertebral discs.
What will the three primary brain vesicles shown below develop into as pregnancy progresses?
Cerebral hemispheres (telencephalon), thalamus & hypothalamus (diencephalon), midbrain (mesencephalon), pons & cerebellum (metencephalon) and the medulla (myelencephalon)
A mother comes to her OB for her first check up since she had a positive pregnancy test. Routine blood work of maternal serum reveals an elevated alpha-fetoprotein (AFP). What would be the next test you would run?
Test for AFP and AChE in amniotic fluid. Elevated AFP is a marker for neural tube defects. Since there is persistent connection between the amniotic fluid and spinal canal, amniotic AChE levels will be elevated due to leakage from fetal CSF into the amniotic fluid.
A mother comes to her OB for her first check up since she had a positive pregnancy test. Routine blood work of maternal serum reveals an elevated alpha-fetoprotein (AFP). What nutrient might this patient be deficient in?
Folic acid.
Two new babies are born in the labor and deliver department. Physical examination of their skin is shown below. What are possible diagnoses for these conditions?
The top one has spina bifida occulta. The bottom one has a meningocele or a meningomyelocele, further analysis to see if spinal cord is present is necessary to differentiate between the two.
An expecting mother goes to see her OB at 20 weeks. Routine blood work reveals elevated AFP in maternal serum. Ultrasound images are shown below. The doctor tells the expecting mother that in future pregnancies she will need folate supplementation. What condition may be revealed on further examination of her past medical history?
Type I Diabetes. Maternal type I diabetes is associated with anencephaly (failure of the forebrain and superior calavarium to develop)
A 23 year old pregnant woman goes to the ED because of profuse bleeding during the night. She is 22 weeks along and has a confirmed miscarriage. Delivery of the fetus reveals a baby with cleft palate and cyclopia (only one orbit). What forebrain anomaly is associated with these findings?
Holoprosencephaly. During weeks 5-6 the cerebral hemispheres fail to separate. This may be associated with the sonic hedgehog signaling pathway.
While doing rounds in the NICU, the pediatrician checks up on a baby with quadriplegia and a thoracic myelomeningocele. He checks the chart and the diagnosis is Arnold-Chiari II malformation. What anatomic characteristics would he find on examination of this child’s brain MRI?
Cerebellar tonsillar and vermian herniation through foramen magnum, aqueductal stenosis and hydrocephalus.
A mother brings her 8 month old boy to the pediatrician because she noticed his motor skills are not developing and he is way behind the other kids in his play group. Physical examination reveals spina bifida occulta. The boy’s brain CT is shown below. What is your diagnosis?
Dandy-Walker Malformation. This is characterized by a genesis of the cerebellar vermin with an enlarged 4th ventricle. Note that this condition is also associated with spina bifida.
A 22 year old man comes to the primary care clinic complaining of headaches and recent loss of pain and temperature sensation in his back, the back of his arms and hands. Physical exam reveals intact touch and vibratory sensation in these regions. What congenital malformation would you want to check for on this patient’s MRI?
Chiari I malformation. This condition is associated with syringomelia (cystic enlargement of central canal of spinal cord that damages the spinothalamic tract but leaves posterior column in tact)
In what location do you most often find a syrinx in a patient with syringomyelia?
C8-T1
What cells develop from the neuroectoderm?
CNS neurons, ependymal cells, oligodendrocytes & astrocytes. Microglia do not originate from the neuroectoderm, they are derived from the mesoderm.
What cells develop from the neural crest cells?
PNS neurons and Schwann cells
A mother gives birth to a child that is completely paralyzed below the neck. After running blood and imaging studies, there is still no apparent diagnosis. The doctor decides to do a biopsy and stain for neurons. What stain would he use?
Nissl substance. This stains RER, and thus will only stain cell bodies and dendrites because there is not any RER present in the axons.
You are out trimming your lawn. A piece of plastic gets shot toward your elbow and cuts you pretty bad. You lose sensation to your pinky and ring fingers. What histological changes would you see on analysis of the area where the ulnar nerve was cut?
Proximal axonal retraction and distal Wallerian degeneration of the axon.
A 47 year old man presents to the neurologist with recurring headaches and blindness in one eye. MRI reveals a brain tumor. Tumor biopsy reveals cells that are positive for GFAP. What are 6 normal functions carried out by the cells that form this tumor?
GFAP is the astrocyte marker. Normally astrocytes 1) Provide physical support 2) Repair 3) K+ metabolism 4) Remove excess neurotransmitter 5) BBB 6) Reactive gliosis after injury
A 44 year old man comes to the ED with rapidly progressive dementia and encephalopathy. A few days later he dies. History reveals that he had AIDS. What glial cell abnormality would you expect to find in this patient?
Multinucleate giant cells from fused microglia. Microglia do this when they are infected by HIV.
What type of cells look like fried eggs on H&E in patients with multiple sclerosis?
Oligodendrocytes. Multiple sclerosis is a demyelinating disorder and affects these cells that myelinate CNS axons. Note that these will be the most abundant glial cell found in white matter because of abundance of myelinated axons (normal shown below)
A 50 year old man goes to the neurology clinic complaining of rapid-onset ascending paralysis. He is diagnosed with Guillain-Barre syndrome. Why might this patient have greater difficulty healing from a transected nerve during surgery?
Guillain-Barre syndrome attacks the Schwann cells that myelinate PNS axons. These cells are the ones responsible for axonal regeneration after transection.
On histological analysis of a peripheral nerve, how many axons will you likely see around each Schwann cell? What if you were in the CNS.
- Each Schwann cell myelinates only 1 PNS axon. In the CNS, each oligodendrocyte can myelinate up to 50 CNS axons.
What sensory nerve fibers are responsible for sensing pain and temperature?
C-fibers and A-delta fibers
Increased synthesis of what neurotransmitter in what region of the pons will increase anxiety and decrease depression?
NE. Synthesized in the locus ceruleus of the pons. Note that the locus ceruleus is the stress and panic center of the brain.
Increased synthesis of what neurotransmitter in what region of the midbrain will decrease Parkinson’s and decrease depression but increase schizophrenia?
Dopamine. Synthesized in the ventral tegmentum and substantia nigra of the midbrain.
Increased synthesis of what neurotransmitter in what region of the pons will cause decreased anxiety and decreased depression?
5-HT. Synthesized in the raphe nucleus of the pons.
Increased synthesis of what neurotransmitter in what region of the brain will decrease Alzheimer’s, decrease Huntington’s and increase REM sleep?
ACh. Synthesized in the basal nucleus.
Increased synthesis of what neurotransmitter in what region of the basal ganglia will decrease anxiety and decrease Huntington’s?
GABA. Synthesized in the nucleus accumbens. Note that the nucleus accumbens and septal nucleus are the center in the brain for reward, pleasure, addiction and fear.
What structures form the blood-brain barrier?
Nonfenestrated endothelium + Continuous basement membrane + Astrocyte foot processes
What molecules can diffuse freely across the blood-brain barrier? What molecules have transporters?
Free diffusion: small lipophilic molecules. Transported: Glucose + Amino Acids
What regions of the brain are most affected by the molecules in the blood?
Those without a blood-brain barrier: area postremia (causes vomiting after chemo), OVLT (osmotic sensor) and neurohypophysis (posterior pituitary)
Why do advanced astrocytomas commonly present with vasogenic edema?
They destroy the endothelial cell tight junctions of the BBB
Where is the major thalamic input for pain, temperature, pressure, touch, vibration and proprioception located? Where are these inputs sent off to?
VPL. This is where the thalamus receives input from the spinothalamic tract and dorsal column/medial lemniscus. Inputs to the VPL are sent to the primary somatosensory cortex.
A 66 year old woman presents with a resting tremor, rigidity, expressionless face and postural instability. A few years later the patient passes away. Autopsy of her brain is shown below. What pathology caused the symptoms she originally presented with?
One pathology associated with Parkinson’s is loss of dopaminergic neurons in the substantia nigra pars compacta. Loss of DA -> decrease stimulus of striatum D1 receptors -> decreased GABA release -> Globus pallidus internus inhibition of thalamus -> decreased cortical stimulation. Also: Loss of DA -> decreased stimulus of striatum D2 receptors -> decreased globus pallidus externus stimulation -> inhibited subthalamic nucleus activity -> globus apllidus internus inhibition of thalamus -> decreased cortical stimulation.
A 66 year old woman presents with a resting tremor, rigidity, expressionless face and postural instability. A few years later the patient passes away. Autopsy of her brain is shown below. What would you expect to see on histological analysis of this tissue?
Note the depigmented substantia nigra characteristic of Parkinson’s. You would find Lewy bodies composed of alpha-synuclein
A 44 year old man comes to the neurology clinic complaining of depression, aggression, dementia, slow writhing movements of the fingers (athetosis) and uncontrollable jerky movements (chorea). His father had a similar condition and died at the age of 51. What is causing the symptoms seen in this patient?
Anticipated CAG repeats caused Huntington’s disease to present earlier in this patient than in his father. The repeats cause NMDA receptor binding, glutamate toxicity and atrophy of the striatum (caudate + putamen). Atrophy of the striatum results in loss of ACh and GABA neurotransmitters and patients will present with chorea, depression, aggression and dementia.
A 71 year old woman presents with an inability to string more than two words together in a sentence. She comprehends well. Where is the most likely location of a brain lesion in this patient?
Broca’s area (LEFT inferior frontal gyrus of frontal lobe: pars opercularis + pars triangularis)
A 71 year old woman presents with an inability to understand what anyone is saying and can only speak gibberish. Where is the most likely location of a lesion in the brain of this patient?
Wernicke’s area (LEFT superior temporal gyrus: supramarginal gyrus)
A 71 year old woman presents with an inability to repeat the phrase, “No, ifs, ands, or buts.” She comprehends speech well. Where is the most likely location of a lesion in the brain of this patient?
Arcuate fasciculus. This connects Wernicke’s area in the temporal lobe to Broca’s area in the frontal lobe and plays a role in short term memory, lesions create a conduction aphasia.
A 61 year old man comes to the ED complaining of a rapid onset of upper leg & arm weakness and double vision 2 hours ago. History reveals a surgery 2 days ago. Assuming that the patient had an embolus to a cerebral artery, what regions of the brain are at highest risk for ischemia?
Watershed areas: regions at the very end of their respective cerebral artery (area between the anterior cerebral & middle cerebral, area between the middle cerebral & posterior cerebral).
A 16 year old boy falls down the half pipe at the skate park and cracks his head on the concrete. He says he feels okay, but 2 hours later begins feeling serious neurological symptoms. What breathing technique should the paramedics employ as they take him to the hospital?
Hyperventilation. The decrease in PCO2 will decrease blood flow to the brain and help keep intracranial pressure lower.
A patient presents to the hospital with symptoms of stroke. MR angiogram is shown below. What symptoms will this patient most likely present with?
The occluded artery in the image is the middle cerebral artery. Occlusion of this artery will hit the motor cortex (contralateral paralysis of upper limb & face), sensory cortex (contralateral loss of sensation in upper limb & face), temporal lobe (Wernicke’s area) and frontal lobe (Broca’s area). The patient will present with aphasia if the occlusion is in the dominant hemisphere and hemineglect if it is on the non dominant side.
A patient presents to the hospital with symptoms of stroke. MRI is shown below. What symptoms will this patient most likely present with?
The area occluded is the anterior cerebral artery. Occlusion of this artery hits the lower limb motor cortex (contralateral LE paralysis) and the lower limb sensory cortex (contralateral LE loss of sensation).
A 71 year old man comes to the ED with symptoms of stroke. Imaging studies reveal occlusion of the anterior spinal artery. What symptoms will this patient most likely present with?
Occlusion of the ASA will cause infarction of the lateral corticospinal tract (causing contralateral hemiparesis in LE), the medial lemniscus (causing decreased contralateral proprioception) and the caudal medulla (hypoglossal dysfunction = ipsilateral tongue deviation). Note that this is commonly referred to as medial medullary syndrome because of medullary pyramid infarction from occlusion.
A 71 year old man comes to the ED with symptoms of stroke. Imaging studies reveal occlusion of the leniculostriate vessels and lacunar infarcts. What symptoms will this patient most likely present with? What are you likely to find in his past medical history?
Occlusion of the lateral striate artery will cause infarction of the striatum and internal capsule (causing contralateral hemiparesis and hemiplegia). PMH will likely reveal a history of unmanaged HTN.
A 71 year old man comes to the ED with symptoms of stroke. His CT is shown below. What symptoms will this patient most likely present with?
Note the infarct of the posterior cerebellum, this patient will present with ataxia & dysmetria. This occurs with occlusion of the posterior inferior cerebellar artery (PICA). Occlusion of this artery also causes infarction of the lateral medulla which includes the vestibular nuclei (vomiting, vertigo & nystagmus), lateral spinothalamic tract (contralateral decreased pain and temperature sensation to limbs), spinal trigeminal nucleus (ipsilateral loss of pain and temperature sensation to face), nucleus ambiguus (dysphagia, hoarseness & decreased gag reflex), sympathetic fibers (ipsilateral Horner’s syndrome)
What clinical symptoms are very specific for lateral medullary (Wallenberg’s) syndrome?
Nucleus ambiguus: dysphagia, hoarseness and gag reflex
A 71 year old man comes to the ED with symptoms of stroke. His angiogram is shown below. What symptoms will this patient most likely present with?
This patient has a basilar artery occlusion largely affecting the anterior inferior cerebellar artery (AICA). This can cause infarction of the lateral pons’ cranial nerve nuclei, vestibular nuclei (vomiting, vertigo & nystagmus), facial nucleus (facial paralysis, decreased taste, decreased lacrimation, salivation, decreased corneal reflex), spinal trigeminal nucleus (decreased pain and temperature sensation to ipsilateral side of face), cochlear nuclei (ipsilateral hearing loss), sympathetic fibers (ipsilateral Horner’s syndrome) and the cerebellum (ataxia, dysmetria).
A 71 year old man presents to the ED with symptoms of stroke. His CT is shown below. What symptoms will this patient most likely present with?
This patient has an infarct in the occipital lobe and probably had a posterior cerebral artery occlusion. This would present with contralateral hemianopia.
What clinical symptoms are very specific for lateral pontine syndrome?
Facial droop
A 71 year old man presents with rapidly deteriorating neurological symptoms. CT angiogram is shown below. What are most likely his symptoms?
This patient has a saccular aneurism of the anterior communicating cerebral artery. This vessel lies on top of the optic chiasm. Consequently, aneurism most often results in visual field defects.
A 71 year old man presents with rapidly deteriorating neurological symptoms. His angiogram is shown below. What are most likely his symptoms?
He has an aneurism of the posterior communicating artery. This most often causes cranial nerve palsy at CN III. Clinically the patient will present with ptosis, pupil dilation and the ey pointed down and outward.
A 42 year old woman presents with a rapid onset headache she states is the worst one she’s ever had in her life. Physical exam reveals bitemporal hemianopia. Her angiogram is shown below. What things put her at high risk for this condition?
This patient history of possible subarachnoid headache, hemianopia and angiogram indicate a berry aneurism. Patients at higher risk are those with: Marfan’s, Ehler’s Danlos, ADPKD, elderly, HTN, smoking and African-American.
A 71 year old man comes to the ED with symptoms of stroke. History only reveals uncontrolled hypertension. His autopsy is shown below. What other conditions are associated with the cause of this patient’s death?
This patient had Charcot-Bouchard microaneurisms, often due to uncontrolled hypertension. Amyloid angiopathy, tumors and vasculitis can all cause weakening of the lenticulostriate blood vessels which put patients at risk for these types of aneurisms, most commonly in the basal ganglia and internal capsule.
A 14 year old boy falls off his unicycle at the school fair and hits his head. He is fine for a couple of hours, then he starts to have serious neurological symptoms. His CT scan is shown below. What symptoms is he most likely to present with?
He has an epidural hematoma. Note the fractured temporal bone that likely ruptured the middle meningeal artery. Expansion of the epidural hematoma can cause transtentorial (CNIII compression, compression of posterior cerebral artery and infarction) and subfalcine herniations (compression of anterior cerebral artery and tissue infarction).
A 95 year old man bumps his head on his motorized wheel chair while jousting with his other friend in a wheel chair. Three weeks later he starts to have a headache and progressive neurological symptoms. CT of his brain is shown below. What likely happened when he bumped his head?
He ruptured a bridging vein and got a subdural hematoma.
A 48 year old woman presents in the ED with the worst headache she has ever had in her whole life. History reveals ADPKD and a fall down the stairs two days ago. You decide to do a spinal tap while waiting for her CT to come back. What are you looking for on her spinal tap?
This patient has ADPKD, which is commonly associated with berry aneurisms (so is Marfan’s, Ehler’s Danlos and AVM). A ruptured berry aneurism would produce a subarachnoid hemorrhage and the worst head of her whole life. Spinal tap would reveal xanthochromic or bloody CSF. Note on her CT how the supra cellar cistern is filled with blood.
An 82 year old woman presents to the ED with rapid onset weakness and loss of sensation in her right arm, face and trunk. Why would you use the two imaging modalities seen below?
This patient is having symptoms of stroke. The top image is a non contrast CT, which won’t show signs of stroke until several hours after the event. However, it will show if the stroke is hemorrhagic (bright) or ischemic (dark), which tells you whether tPa is contraindicated or not. The bottom image is a DW MRI. This will show signs of stroke in 3-30 minutes of its occurrence and remain bright for 10 days.
An 82 year old woman presents to the ED with rapid onset weakness and loss of sensation in her right arm, face and trunk. Imaging reveals an ischemic stroke. How will the histology of the area of occlusion change over the next 2 weeks?
After 5 minutes: irreversible damage begins in the hippocampus, neocortex, cerebellum & watershed areas (most vulnerable). 12-48 hours: red neurons. 24-72 hours: necrosis & neutrophils. 3-5 days: macrophages. 1-2 weeks: reactive gliosis & angiogenesis. 2+ weeks: glial scar.
What is the time window for administering tPa to a patient presenting with symptoms of stroke?
If the stroke is not hemorrhagic, you can administer tPa within 4.5 hours as long as symptoms presents within 3 hours of symptom onset.
Angina is to MI as ________ is to stroke.
Transient ischemic attack. These are price episodes of focal neurological dysfunction typically lasting < 1 hour with a negative MRI.
How does the CSF released by the arachnoid granulations eventually make it out into the internal jugular vein?
Arachnoid granulations in superior sagittal sinus -> confluence of sinuses -> transverse sinus -> sigmoid sinus -> internal jugular vein.
What other sinuses, aside from the superior sagittal sinus, drain into the confluence of sinuses? What drains into the transverse sinus?
The occipital sinus and inferior sagittal sinus via the straight sinus drain into the confluence of sinuses. The cavernous sinus drains into the transverse sinus via petrosal sinuses.
A 33 year old man presents to the neurology clinic with chronic headaches. Imaging reveals hydrocephalus in the fourth ventricle. Blockade of what part in the ventricular system would cause 4th ventricle hydrocephalus?
CSF is made in the choroid plexus and flows from the lateral ventricle -> interventricular foramen (Munro) -> III ventricle -> cerebral aqueduct (Sylvius) -> 4th ventricle -> SAS via the lateral foramina of Luschka or the medial foramen of Magendie OR it goes out the central canal. It was likely blockade of Luschka, Magendie or the central canal that caused 4th ventricle hydrocephalus.
A 72 year old man presents with urinary incontinence, ataxia and cognitive dysfunction. His spinal tap showed normal opening CSF pressure. His MRI is shown below. What is causing him to present with these symptoms?
Note the increase in arachnoid space volume w/o increased CSF pressure. This patient has normal pressure hydrocephalus from decreased reabsorption of CSF by arachnoid granulations. Compression of the fibers of the corona radiata causes the triad: incontinence, ataxia and cognitive dysfunction (wet, wobbly and wacky).
What is the difference between a communicating hydrocephalus and a noncommunicating hydrocephalus?
Communicating: decreased CSF reabsorption by arachnoid granulations. Noncommunicating: structural blockage of CSF circulation within the ventricular system.
An 83 year old man is brought to the clinic by his wife. She says that he has been forgetting things lately and has had recent changes in his personality. His MRI is shown below. What is causing the hydrocephalus in this patient?
This patient is presenting with frontotemporal atrophy and symptoms of Pick’s disease. Due to brain atrophy, he has hydrocephalus ex vacuo.
What spinal tracts are located in the regions indicated below?
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A 35 year old woman with metastatic breast cancer comes to the clinic complaining of loss of motor function in her legs and loss of sensation in her sacrum. Imaging reveals an invasive tumor in the spinal cord. Is this lesion most likely moving outside in or inside out of the spinal cord?
Outside in. In the lateral corticospinal tract (motor) the legs are located most lateral and arms most medial and she first lost motor function in her legs. In the anterior spinothalamic tract the sacrum in located most lateral and the cervical region most medial.
A patient comes to the neurology clinic complaining of decreased sensation in his right leg. He also says that leg seems more clumsy than usual. Physical exam reveals loss of 2-point discrimination in the right leg, but he maintains pain sensation. Where are the different locations that the affected spinal tract synapses?
This patient is having dorsal column symptoms. The primary sensory neuron passes through the DRG and ascends in the spinal cord where it synapses in the ipsilateral nucleus gracilis (fibers from below T6) or nucleus cuneatus (fibers from T6 and above) in the medulla. The secondary neuron decussates to the medial lemniscus, travels up and synapses in the VPL of the thalamus. The tertiary neuron synapses in the primary somatosensory cortex.
A patient comes to the neurology clinic complaining of decreased sensation in his right leg. Physical exam reveals loss of pain sensation and preservation of discriminative touch. Where are the different locations that the affected spinal tract synapses?
This patient is having spinothalamic tract symptoms. The primary neuron (C or A-delta fibers) passes through the zone of Lissauer and synapses in the ipsilateral gray matter. The secondary neuron decussates the anterior white commissure and ascends contralaterally all the way up to the VPL in thalamus where it synapses. The tertiary neuron synapses in the primary somatosensory cortex.
A patient comes to the neurology clinic complaining weakness in his right leg. Physical exam reveals increased DTRs and muscle tone. He had a positive Babinski sign and spastic paralysis was noted. Where are the different locations that the affected spinal tract synapses?
This patient is having lateral corticospinal tract symptoms. In this tract the primary neuron starts in the motor cortex, travels down through the internal capsule, decussates at the medulla’s pyramidal decussation and synapses on the contralateral alpha-motor neuron cell body in the anterior horn. The alpha-motor neuron leaves through the ventral horn and synapses at the neuromuscular junction.
How do lower motor neuron symptoms differ from that of upper motor neuron symptoms?
LMN: Atrophy, Fasciculations, Decreased tone, Decreased DTRs, Flaccid paralysis, Weakness. UMN: Increased DTRs, Increased tone, Babinski, Spastic paralysis, Clasp knife spasticity, Weakness.
What diseases destroy alpha-motor neurons in the anterior horn of the spinal cord and cause flaccid paralysis?
Poliomyelitis and Werndig-Hoffman disease.
A 38 year old woman presents with scanning speech, intention tremor and nystagmus. MRI reveals destruction of cervical and cerebral white matter. What is your diagnosis?
Multiple sclerosis. This is a demyelinating disease that causes random and asymmetric lesions.
A really smart theoretical physicist comes to see you complaining of increasing weakness in both lower extremities over the past few months. Physical exam reveals fasciculations and atrophy in both legs. He had a positive Babinski sign and decreased DTRs. Cognitive & sensory function were all normal. What genetic defect could cause him to have these symptoms? What could you give him to slow disease progression?
This patient has UMN & LMN symptoms and normal cognitive & sensory function. This is characteristic of ALS. Mutations in superoxide dismutase I predispose people to ALS because ROS destroy myelin. Riluzole can decrease disease progression by decreasing presynaptic glutamate release.
A patient comes to the ED after a car accident. He has lost all pain sensation and motor function in his lower extremities. He maintains vibration and two-point discrimination in his lower extremities. Imaging studies reveal fractures at T12, L1 and L2. What is likely causing this patient’s symptoms?
Occlusion or rupture of an anterior spinal artery. A lesion of this sort will infarct the anterior 2/3 of the spinal cord, producing lesions in the ALSTT, AWC and LCST. Note that the patient had symptoms that are consistent with a spared posterior column.
Why is the upper thoracic region at higher risk for neurological deficits caused by anterior spinal artery occlusion?
Levels below T8 are supplied by the artery of Adamkiewicz, levels above that are watershed areas.
A 72 year old man comes to the free inner city clinic complaining of loss of sensation in his legs and clumsiness. Physical exam reveals absence of DTRs, a + Romberg test and Argyll Robertson pupils (reactive to accommodation but not to light). What is your diagnosis?
Tabes dorsalis. This patient is presenting with posterior column symptoms that result from demyelination secondary to syphilis.
A 9 year old girl presents with bilateral loss of pain and temperature sensation on the back of her arms, hands and in her back. Her MRI is shown below. What congenital malformation is her condition associated with?
She has syringomyelia, which is a fluid-filled syrinx that damaged the anterior white commissure and causes associated bilateral loss of pain and temperature sensation. Syrinx formation is associated with Chiari I malformation (cerebellar tonsil herniation)
A 27 year old woman comes to see you complaining of decreased lower extremity coordination and tingling in her feet. Physical exam reveals an ataxic gait, loss of 2-pt tactile discrimination, + Babinski sign and + Romberg sign. History reveals that she is vegan. What is the most likely cause of her condition?
Vitamin B12 or E deficiency. Deficiency in these vitamins causes subacute demyelination of dorsal columns, lateral corticospinal tracts and spinocerebellar tracts.
You are working on a humanitarian mission in India and see a young boy with lower leg weakness, atrophy, fasciculations and hypotonia. He says that symptoms began a few weeks ago when he had a headache, nausea and a fever. Lumbar puncture reveals an increased WBC count with no change in glucose. How did the boy get this condition?
He is showing signs of destruction of alpha-motor neurons and viral infection, i.e. poliovirus. This virus is spread via the fecal-oral route, replicates in the oropharynx, small intestine and gets to the CNS after the patient becomes viremic.
A mother gives birth to a child that has marked hypotonia and tongue fasciculations (floppy baby). 7 months later the child passes away due to an autosomal-recessive disorder. What is your diagnosis?
Werdnig-Hoffman disease. This is a congenital degeneration of the anterior horn of the spinal cord.
A mother brings her 4 year old girl in to the neurology clinic. She says her daughter falls often, has painful joints and has trouble walking straight. Physical exam reveals nystagmus, pes caves, hammer toes and a mid systolic ejection murmur. What genetic condition does this little girl have?
Friedreich’s ataxia. This is due to GAA trinucleotide repeats that normally encode for frataxin. Frataxin allows mitochondria to dispose of ROS, but when mutated it can’t and ROS wreak havoc on the CNS.
A patient gets in an automobile accident and presents with a myriad of neurological symptoms. Since the radiologist knows you’re not great at reading MRIs, he draws this cartoon below to show you the damage to the patient’s spinal cord at T6. What symptoms will this patient likely present with? What if the lesion were above T1?
This patient will present with Brown-Sequard syndrome. This includes ipsilateral UMN signs below T6 (LCST damage). Ipsilateral loss of tactile, vibration & proprioception below T6 (dorsal column damage). Contralateral loss of pain & temp sensation below T6 (ALSTT damage). Ipsilateral loss of all sensation at T6 level (AWC + dorsal horn) damage). Ipsilateral LMN signs at T6 level (anterior horn damage). If the lesion were above T1 the patient would also present with Horner’s syndrome.
How could a tumor in the hypothalamus cause Horner’s syndrome?
The hypothalamus is the beginning of the oculosympathetic pathway. The primary axon descends down the spinal cord where it synapses in the intermediolateral cell column. The secondary axon then travels to the superior cervical ganglion where it synapses for the second time. Finally, the superior cervical ganglion gives off branches to the sweat glands of the forehead and face, smooth muscles of the eyelid and the pupillary dilator muscles, causing your classic symptoms of ptosis, miosis and anhydrosis.
Identify the nerve that supplies each dermatome indicated below:
Good landmarks to remember: C2-skull cap, C3-high turtle neck, C4-T-shirt collar, T4-“teat pore”, T10-belly butTEN, L1-inguinal ligament, L4-knee caps, S2,S3,S4-poo,pee and erection off the floor.
Why do you get that weird pain in your shoulder sometimes when you are running?
The liver is attached to the diaphragm, which bounces as you run. This pulls on the diaphragm and causes referred pain to the shoulder via the phrenic nerve.
What structures are indicated in the dorsal view of the brainstem seen below?
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Indicate whether the nerve below is sensory, motor or both:
S=sensory. M=motor. B=both: “Some(I) Say(II) Marry(III) Money(IV) But(V) My(VI) Brother(VII) Says(VIII) Big(IX) Brains(X) Matter(XI) Most(XII)”
What canal do the structures indicated below exit from?
A) CN II -> Optic canal w/opthalmic artery & central retinal vein B) III, IV, V1, VI -> Superior orbital fissue w/Opthalmic vein & sympathetic fibers C) VII & VIII -> Internal auditory meatus D) IX, X & XI -> Jugular foramen w/jugular vein E) XII -> Hypoglossal canal. Note that V2 goes through foramen rotundum and V3 through foramen ovale.
A patient comes to see you complaining of decreased pain, temperature and light touch sensation on his face and anterior 2/3 of his tongue. What motor function may he have trouble with?
Mastication. These are sensory symptoms of CN V. CN V also provides motor innervations for the muscles of mastication.
A patient comes to see you complaining of dry mouth and decreased taste sensation in the anterior 2/3 of his tongue. What motor function may have have trouble with?
Facial movement. These are sensory symptoms of CN VII. Note that CN VII innervates the submandibular and sublingual glands but NOT the parotid gland.
A patient comes to see you complaining of difficulty swallowing and dry mouth. Physical exam reveals complete absence of gag reflex. What is the sole muscle innervated by this cranial nerve? What other symptoms might he present with?
Stylopharyngeus. These are symptoms of CN IX. Note that that CN IX innervates the parotid gland via the otic ganglion. CN IX also provides GVA fibers from the carotid body, carotid sinus, chemo- and baroreceptors. Consequently he may present with an irregular blood pressure and heart rate.
A patient comes to see you complaining of difficulty swallowing and talking. Physical exam reveals deviation of the uvula to the right side. What other symptoms might this patient present with?
These are symptoms of a LEFT (contralateral to uvula deviation) CN X lesion. CN X also provides GVE fibers to the thoracoabdominal viscera, so he may present with constipation. It also provides GVA fibers from the chemo- and baroreceptors in the aortic arch so he may present with an irregular blood pressure and heart rate.
A patient comes to see you complaining of this. What cranial nerve has been affected?
This patient has a lesion of the LEFT (ipsilateral to side tongue deviates) CN XII. CN XII innervates all of the muscles of the tongue except for the palatoglossus.
A patient presents with difficulty performing the tests below. What cranial nerve has been affected?
CN XI. It provides motor innervation to the SCM and trapezius. When there is a lesion, you will see weakness turning the head to the contralateral side of the lesion and shoulder droop on the ipsilateral side of the lesion.
What cranial nerves have a close anatomical relationship to the midbrain? Pons? Medulla? Spinal Cord?
Midbrain = CN III & IV. Pons = CN V, VI, VII, VIII. Medulla = IX, X, XII. Spinal Cord = XI.
Why are the sensory nuclei located laterally and motor nuclei medially in the brainstem?
Embryologically the alar plate (sensory) starts posterior and the basal plate (motor) anterior. In the medulla, the CNS opens up to form the 4th ventricle from the back, bringing the alar plate more anterior, but lateral to the basal plate.
What nerves are you testing when you try to elicit the gag reflex?
CN IX (afferent) and CN X (efferent)
A woman presents to the clinic with acute onset of a “lazy eye”. She also has decreased maxillary sensation. She said this has never happened before. Imaging studies reveal an expanding pituitary mass that compressing cranial nerves. What structures are at risk for compression as this mass continues to expand?
The pituitary gland is right next to the cavernous sinus. Further expansion of the mass would compress structures in the sinus. These structures are CN III, IV, V1, V2, VI, postganglionic sympathetic fibers and the internal carotid artery.
A patient was in a motor vehicle accident and has decreased motor function in the lower muscles on the right side of his face. Why does he still have full function of his frontalis muscle?
The forehead is spared when a lower motor neuron is severed because there is bilateral upper motor neuron innervation to the upper division of the facial nucleus.
A 47 year old male presents to the ED after falling off his unicycle. He hit his head pretty hard and was okay at first, but now he is experiencing the worst headache of his life and blurred vision. His family has a history of kidney disease. Physical exam findings are shown below. What do you see through your fundascope? What does this mean?
Bilateral papilledema. This is optic disc swelling due to increased intracranial pressure. This patient is having increased ICP due to a subarachnoid hemorrhage from possible berry aneurism rupture.
A 27 year old singer comes to see you complaining of anxiety, seizures and anesthesia. Let’s pretend that it is 1970. What drugs could you prescribe him and why did we have to go back in time for this concept?
Barbiturates (phenobarbital, pentobarbital, secobarbital, thiopental). These drugs facilitate GABAa by increasing the duration the Cl- channel is open, hyperpolarizing nerve terminals. These drugs have the capacity to open GABAa receptors on their own when taken in high doses and can cause fatal cardiorespiratory and CNS depression. Additionally, patients develop tolerance to the sedative effects, but not to the physiological depressing effects, making it even more dangerous.
Fill in the blank:
Season affective disorder. Depressive symptoms go away when the person is exposed to full-spectrum bright light.
A patient presents to your clinic complaining of 3 previous panic attacks. She says that whenever she goes to the grocery store she has palpitations, paresthesia, nausea, chest pain, shortness of breath and sweating. What drugs are used to treat patients with this condition?
She has a panic disorder associated with agoraphobia. This is treated with CBT, SSRIs, venlafaxine and benzos. Of special note, panic disorders have a strong genetic component.
A mom brings her 14 year old to see the doctor because he won’t speak when he is supposed to during English class. How do you treat this boy?
This is social phobia. First you try to treat it with systematic desensitization to the trigger of his unreasonable and excessive fear. If that doesn’t work you can use SSRIs.
A patient comes to see the doctor in clinic who closes the door three times each time he enters and leaves a room. How do you treat this patient?
This patient probably has OCD (commonly associated with Tourette’s). OCD is characterized by obsessions, compulsions and ego dystonic behavior (behavior inconsistent with one’s beliefs and attitudes). CBT, SSRIs and clomipramine can be used to treat patients.
An air force cadet comes to the clinic complaining of a tummy ache. It just so happens that their PT test is that afternoon, but you give him a sick pass because you have to believe him. You give him some medicine, but he doesn’t even take it. The next day he is completely fine. What is this called?
Malingering. This is different from factitious disorder because the “show” ends once the patient gets what he wants. In factitious disorder, the patient maintains
A 17 year old girl comes to the clinic because she wants surgery on her nose. Her nose looks perfectly fine to you, but she says it’s crooked and nobody likes her because of it. She refused to go out on the weekends because of it. What is her diagnosis?
Body dysmorphic disorder
A patient comes to see you who has trouble trusting others. What type of personality disorder might she have and what are the diagnostic criteria?
Cluster A: paranoid personality disorder: suspicious about everything and thinks that everyone is out to get them. These are often associated with schizophrenia.
What antidepressants act at different regions of the nerve terminals shown below?
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You are working at the university health clinic during an outbreak of bacterial meningitis at the dorms. What lab characteristics of the offending bacteria would you expect to see in these patients?
In teens and young adults, the most common cause of bacterial meningitis is Neisseria meningitidis. It is a gram-negative cocci in pairs, oxidase positive.
What food-borne pathogen can cause meningitis and is especially bad for a pregnant woman to get? What does it look like in the lab?
Listeria. It can cause miscarriage in pregnant women and severe disease in immunocompromised patients. In the lab it is gram + rod, catalase positive, beta hemolytic.
A 37 year old male with HIV presents with a sudden onset fever, headache and stiff neck. Physical exam reveals + Kernig and Brudzinski signs. You decide to do a lumbar puncture to see what the offending agent is. What are the common causes of meningitis in patients with HIV and how would you differentiate between them based on the CSF?
Cryptococcus, toxoplasmosis, CMV, JC virus in addition to the other common causes in people without HIV. Bacterial, fungal and viral meningitis all have different CSF values seen below.
A 60 year old man presents with progressive paralysis of his lower limbs, vision loss, impaired speech and cognitive deterioration. History reveals recent kidney transplant and he is take immunosuppressants. His MRI is shown below. What is likely causing his symptoms?
This patient is immunocompromised and at risk for JC virus reactivation. Reactivation of JC virus can cause progressive multifocal leukencephalopathy (PML), which basically destroys the white matter of the brain as seen in the MRI.
A patient comes to see you with a fever and headache that started yesterday. His throat hurts really bad and he is delirious. History reveals being bitten by a raccoon 19 years ago. Peripheral nerve biopsy is shown below. How will this virus progress through his nervous system if it goes untreated?
This patient has rabies, note the Negri cytoplasmic inclusion body. Rabies is taken up by peripheral nerves at the site of infection. It is transported via retrograde axoplasmic flow to the CNS if left untreated.
What physical exam finding will you see in measles just prior to skin manifestations?
Koplik’s spots on the inside of the cheeks. Note that the skin is the last organ hit by measles, so patients are at risk for encephalitis far before this.
