Neurological Disorders Flashcards
Label the following:
Optic nerve, Lens, Anterior chamber, Posterior chamber, Sclera, Vitreous body, Cornea, Ora serrata, Iris, Retina, Uvea
Label the following:
Bruch’s membrane, Sclera, Inner limiting membrane, Inner nuclear layer, Ganglion layer, Outer nuclear layer, Region of rods and cones, Choroid, Axon layer, Inner plexiform layer, Outer plexiform layer, Retinal pigmented epithelium, Outer limiting membrane
Explain the pathogenesis of glaucoma
- Increased intraocular pressure
- Blocks flow through intraocular vessels in the uvea
- Reduced blood flow deprives retina of nutrients
- Retinal atrophy
What causes increased intraocular pressure? (2)
- Increased production of vitreous humor
- Decreased drainage of vitreous humor
How does glaucoma present clinically?
- Retinal damage → blurred vision and impaired dark adaptation
- Corneal damage → halos around light
- Optic nerve atrophy
Label the following:
Facial nerve (CN VII), Tympanic membrane, Stapes, Malleus, Incus, Vestibulocochlear nerve (CNVIII), Round window, Vestibular branch of CN VIII, External acoustic meatus, Tympanic cavity, Cochlear branch of CN VIII, Oval window, Vestibule, Cochlea, Internal acoustic meatus
What is otosclerosis?
- Bony growth around the oval window
- Failure of resorption
- Immobilization of the stapes
What is transient tinnitus?
- Rining in the ears not associated with diseases
- Excessive stimulation of hair cells
What is persistent tinnitus?
- Ringing in the ears associated with hearing loss
- Associated with cochlear dysfunction or cranial nerve VIII dysfunction
Terminals of motor axons synapse with _____. Neurotransmitter is _____.
- Sarcolemma
- Acetylcholine
What is myasthenia gravis?
- Auto-antibodies against acetylcholine receptors
- Induce aggregation and degradation of receptors
- Antibodies can also interact with thymus
Explain the clinical presentation of myasthenia gravis
- Fluctuating weakness
- Diplopia (double vision) and ptosis (eyelid drooping)
- Decreased muscle responsiveness upon repeated stimulation
How can myasthenia gravis be treated? (3)
- Acetylcholinesterase inhibitors
- Immunosuppressive therapy or plasmapheresis
- Thymectomy for patients with thymoma
_____ is an autoimmune disease that targets components of the myelin sheath
Multiple sclerosis (MS)
True or false. In MS, lesions are usually softer than the surrounding tissue.
False. Firmer (hence sclerosis)
What are the common signs and symptoms of MS?
- Unilateral visual impairment
- Brainstem involvement
- Spinal cord lesions
What symptoms in MS are associated with damage to the brain stem? (4)
- Cranial nerve signs
- Ataxia
- Nystagmus
- Internuclear ophthalmoplegia
By what mechanisms can ethanol damage the CNS? (3)
- Hepatic encephalopathy
- Thiamine deficiency
- Ethanol toxicity
What is hepatic encephalopathy?
- Damaged liver (by EtOH) cannot remove toxins from blood
- elevated ammonia and pr-inflammatory cytokines
- Glial cells in CNS respond to toxins (cerebral cortex & basal ganglia)
- Astrocytes get enlarged nuclei and minimal reactive cytoplasm (Alzheimer Type II cells)
What is Wernicke encephalopathy?
- Acute thiamine deficiency associated with EtOH abuse
What are the symptoms of Wernicke’s encephalopathy? How is it treated?
- Psychotic symptoms
- Ophthalmoplegia
- Reversible with thiamine supplementation
What is Korsakoff syndrome? How is it treated?
- Chronic thiamine deficiency due to ethanol abuse
- Irreversible
What are the symptoms of Korsakoff syndrome? They are typically associated with a lesion to what area of the brain?
- Short term memory problems
- Confabulation
- Associated with lesion to thalamus
_____ dysfunction is seen in 1% of chronic alcoholics
Cerebellar
How does cerebellar damage present clinically in patients with chronic ethanol toxicity?
- Truncal ataxia
- Unsteady gate
- Nystagmus
Cerebral edema is caused by_____
- Accumulation of excess fluid within brain parenchyma
- Caused by excess fluid leakage from blood vessels or CNS cellular damage