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Flashcards in Neuro3 Deck (47):

Attributes of lower motor neuron lesion

--muscle weakness
--loss of deep tendon reflexes
--fibrillation potentials seen on EEG
--loss of voluntary movement


Lesion of the pyramidal decussation would clinically manifest as what?

Bilateral upper motor neuron symptoms, as this is where the corticospinal (upper motor) neurons cross


What does the locus ceruleus synthesize; what is its function?

This nucleus synthesizes norepinephrine, and is involved in the control of cortical activation (arousal).


What structure is contained in the floor of the third ventricle?

The hypothalamus


What structure is located in the floor of the fourth ventricle?

The area postrema, which is part of the medulla?


What is the area postrema?

The area postrema contains the chemoreceptor trigger zone, and is the area of the brain that controls vomiting


Noise-induced hearing loss is mediated by damage to what structure?

damage to hair cells in the organ of corti

These cells can be damaged by trauma from very loud noises, or by ototoxic drugs


What is presbycusis?

Age-related hearing loss.

results of loss of hair cells at the base of the cochlea, leading to high frequency hearing loss.


How can a sudden, extremely loud noise produce hearing loss?

By rupturing the tympanic membrane


Anatomy and function of the middle ear

Air-filled space with three bones called the ossicles: malleus, incus, stapes.

The ossicles conduct and amplify sound from the eardrum to the inner ear.


What would posterolateral herniation of an intervertebral disc cause injury to?

(1) Spinal cord
(2) Spinal root
(3) Anterior ramus
(4) Posterior ramus

The spinal root

This herniation results in the nucleus pulposus occupying the space of the intervertebral foramen, which contains the spinal nerve root.

The anterior (ventral) and posterior (dorsal) rami are found *lateral* to the intervertebral foramen.

The spinal cord is located within the vertebral canal. A *posterior* herniation of the nucleus pulposus would compress the spinal cord


What nerve innervates the cricothyroid muscle?

The external branch of the superior laryngeal nerve


What are negri bodies pathognomonic for?



What are the most frequent neoplasms that would present with blocking of the fourth ventricle, and a non-communicating hydrocephalus?

Medulloblastoma and ependymoma


What are the childhood primary brain tumors?

--pilocytic (low-grade) astrocytoma


18 year old comes to the physician because of difficulty walking. Two days ago he experienced weakness in both of his legs, and now he is unable to walk. Physical exam shows symmetric hyporelfexia of the lower extremities. Two weeks prior, he had an upper respiratory tract infection that was treated with azithromycin. What is the likely diagnosis?

Guillan-Barre syndrome


How does Guillan-Barre syndrom classically present?

With symmetric, ascending, bilateral (motor) weakness and hyporeflexia that starts in the lower extremities following an infection.

Sensory symptoms can occur, but motor symptoms predominate


What is Guillan-Barre also known as?

Acute Inflammatory Demyelinating Polyradiculopathy



With what infections is Guillan-Barre associated?

Campylobacter jejuni


What is thought to be the pathophysiologic mechanism of GBS (Guillan-Barre Syndrome)?

Autoimmune attack of peripheral myelin due to molecular mimicry, inoculation (infection), and stress.


What is the feared complication of GBS?

GBS can progress to complete paralysis and respiratory failure. Respiratory support is critical until recovery


Patient presents with "worst headache of my life"; MRI shows a berry aneurysm. What is the likely diagnosis?

Subarachnoid hemorrahage


What genetic disorders are associated with development of a berry aneurysm?

Connective tissue disorders:
--Ehlers-Danlos syndrome
--Marfan syndrome

Also associated with:
Adult Polycystic Kidney Disease (ADPKD)


--Rupture of middle meningeal artery after skull fracture
--lucid interval before loss of consciousness

What's the likely diagnosis?

Epidural hematoma


--Rupture of bridging veins

What's the likely diagnosis?

Subdural hematoma


How would you treat GBS?

--plasmapheresis (remove autoantibodies)
--IVIG (attach to/inhibit autoantibodies)


Why are connective tissue disorders associated with the development of berry aneuryms?

Because these disorders can cause weakening of the blood vessel wall


What are the 5 types of generalized seizures?

(1) Absence
(2) Myotonic
(3) Tonic
(4) Tonic-Clonic
(5) Atonic


What is the general definition of general seizures?

Diffuse; initially involve both hemispheres


What is the general definition of partial (focal) seizures?

They affect 1 area of the brain


--A brief loss and return of consciousness
--EEG shows generalized spike and slow-wave changes
--no postictal state
--no loss of muscle tone
--blank stare

Seizure type?

Absence seizure (petit mal)

*absence seizures are characterized by blank stares and absence of any change in position


--Transiently increased muscle tone: quick, repetitive jerks.

Seizure type?

Myoclonic seizure


Alternating stiffening and movement (relaxation)

Seizure type?

Tonic-clonic (grand mal) seizure.


In addition to stiffening and relaxation, what other symptoms are tonic-clonic seizures associated with?

--loss of consciousness
--loss of bladder/bowel function
--an extended postictal phase, during which the patient slowly recovers


Stiffening in a child

Seizure type?

Tonic seizure


Patient suddenly loses consciousness and falls to the floor with a loss of consciousness. Bystanders wonder if the patient has fainted.

Seizure type?

Atonic seizure

commonly mistaken for fainting


What is the postictal state?

The altered state of consciousness after a seizure

usually lasts between 5 and 30 minutes


What is epilepsy?

A disorder of recurrent seizures

*note: febrile seizures are not epilepsy


What is status epilepticus?

continuous seizure for >30 minutes or recurrent seizures without gaining consciousness between seizures for >30 minutes.

This is a medical emergency


What is the most common site/origin of focal seizures?

medial temporal lobe


What often precedes a focal seizure?

a seizure aura


What is the difference between a simple partial and complex partial seizure

In a simple partial seizure, consciousness is intact; in a complex partial seizure, consciousness is impaired


What is the blood supply for Wernicke's area?

(inferior division of) the middle cerebral artery


Where, specifically, is Wernicke's area located in the cerebral cortex?

In the posterior part of the superior temporal gyrus (of the language-dominant hemisphere--typically the left)


What is a common associated feature (comorbidity) of Wernicke's aphasia (temporal lobe damage)

contralateral upper right quadrantanopia

This is because Meyer's Loop, is located in the temporal lobe.


What would result from a lesion to the arcuate fasciculus?

The arcuate fasciculus connects Wernicke's and Broca's areas. A lesion to this area would result in a conduction aphasia, which is characterized by a striking inability to repeat, while language comprehension and output are largely preserved.


What would result from a lesion to the crus cerebri?

Contralateral UMN signs