Neuro3 Flashcards
Attributes of lower motor neuron lesion
- -muscle weakness
- -hypotonia
- -loss of deep tendon reflexes
- -fasciculations
- -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?
Rabies
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
- -medulloblastoma
- -ependymoma
- -craniopharyngeoma
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
AIDP
With what infections is Guillan-Barre associated?
Campylobacter jejuni
CMV
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)
- -Trauma
- -Rupture of middle meningeal artery after skull fracture
- -lucid interval before loss of consciousness
What’s the likely diagnosis?
Epidural hematoma
