Neuro Flashcards
1
Q
What is the difference between an evolving and a completed stroke?
A
- an evolving stroke is one that is worsening
- a completed stroke is one in which the maximal deficit has occurred
2
Q
What is a TIA?
A
- a type of ischemic stroke in which the neurologic deficit lasts less than 24 hours
- it resolves because the ischemia is resolved by dissolution of an embolus or collateral circulation before permanent infarction occurs
3
Q
TIA
A
- an ischemic stroke in which the neurologic deficit lasts no more than 24 hours
- they are usually embolic but can occur in the presence of severe carotid stenosis
- the deficit resolves because the embolus dissolves or collateral circulation reperfuses the tissue before permanent infarction can occur
- these patients then have a high risk of stroke in subsequent months
4
Q
What are the potential causes and most commonly associated locations for ischemic stroke?
A
emboli are the most common cause, specifically those that originated as a mural thrombus in patients with fib
- emboli may also originate from endocarditis
- most likely to lodge within and affect the MCA
thrombi most often occur at the bifurcation of the common carotid artery or within the MCA
5
Q
What are the most important risk factors for ischemic stroke in older and younger patients?
A
- in older patients: age and hypertension
- in younger patients: oral contraceptive use, hypercoagulable states, vasoconstrictive drugs like cocaine, polycythemia vera, and sickle cell disease
6
Q
What are thrombotic strokes most likely to originate?
A
most commonly seen at the bifurcation of the common carotid or in the MCA
7
Q
Embolic strokes most often affect what cerebral vessel?
A
the MCA
8
Q
Lacunar Stroke
A
- an ischemic stroke most commonly affecting the lenticulostriate vessels arising from the MCA, which serve the deep structures of the brain
- it is a complication of benign hypertension and occurs secondary to hyaline arteriolosclerosis, which thickens the vessel wall and narrows the arterial lumen
- after these areas of infarction heal, the result is a small cystic area known as a lacuna
9
Q
Subclavian Steal Syndrome
A
- an ischemic stroke caused by stenosis of the subclavian artery proximal to the origin of the vertebral artery
- exercise of the left arm causes reversal of blood flow down the ipsilateral vertebral artery to fill the subclavian artery distal to the stenosis
- the result is symptoms of vertebrobasilar arterial insufficiency (dizziness, double vision, vertigo, dysphagia, numbness of the ipsilateral face and contralateral limbs)
- the BP in the left arm will be less than in the right and there is upper extremity claudication
- the treatment is surgical bypass
10
Q
Explain the pathogenesis of subclavian steal syndrome.
A
- there is a stenosis of the left subclavian proximal to the origin of the vertebral artery
- when the left arm is exercised, it demands greater blood flow than the subclavian can therefore provide
- instead, blood flow reverses down the ipsilateral vertebral artery to fill the subclavian distal to the stenosis
- this results in cerebral ischemia and symptoms of vertebrobasilar arterial insufficiency
11
Q
What are the typical features of an MCA stroke?
A
- contralateral hemiparesis and hemisensory loss
- aphasia if it affects the dominant hemisphere
- apraxia, contralateral neglect, and confusion if it affects the non-dominant hemisphere
12
Q
What are the three classic presentations for a lacunar stroke?
A
- a pure motor stroke if it involves the internal capsule
- a pure sensory stroke if it involves the thalamus
- clumsy hand dysarthria if the pons is affected
13
Q
What is the typical presentation for a vertebral/basilar stroke?
A
- ipsilateral ataxis, diplopia, dysphagia, dysarthria, and vertigo
- contralateral homonymous hemianopsia with basilar
14
Q
Which patients should be screened with a carotid duplex ultrasound? Why?
A
- those with a carotid bruit, peripheral vascular disease, or CAD should all be screened
- the test estimates the degree of carotid stenosis and assess the patients risk of stroke
15
Q
What are two possible causes of a carotid bruit?
A
it could be a murmur referred form the heart or it could represent turbulence in the internal carotid artery due to atherosclerotic disease
16
Q
What is the first imaging study that should be obtained in patients suffering a stroke? Why?
A
- a CT without contrast
- although it may take a long time for an infarct to be visible on CT, it is immediately useful in excluding an intracerebral hemorrhage
17
Q
What is the benefit of an MRI over a CT in stoke patients?
A
it is more sensitive than a CT and will identify infarctions much earlier than a CT once intracerebral hemorrhage has been excluded by CT
18
Q
What are the complications associated with ischemic stroke?
A
- there is the obvious risk of progression of the neurologic insult
- cerebral edema occurs 1-2 after and can cause mass effects for up to 10 days with increased ICP
- hemorrhage into the infarct is rare
- seizures may occur
19
Q
How should ischemic stroke be treated?
A
- first rule out hemorrhage with a CT
- administer tPA if within three hours of symptom onset; if between 3-24 hours has passed, give aspirin or clopidogrel
- use antihypertensives only if the patient’s BP is more than 220/120 or if the patient has received tPA as hypertension increases the risk of hemorrhage conversion in these patients
20
Q
What is the timeline for tPA administration in patients with ischemic stroke and why is this?
A
- tPA must be given within three hours of onset
- otherwise, it increases the risk for hemorrhagic transformation
21
Q
What are the indications for a carotid artery endarterectomy?
A
it reduces stroke risk in symptomatic patients with carotid artery stenosis greater than 70%
22
Q
What are the recommendations regarding stroke prophylaxis?
A
- asymptomatic patients should undergo risk reduction for atherosclerotic disease and take a daily aspirin
- symptomatic patients with carotid stenosis greater than 70% should undergo carotid endarterectomy
23
Q
Intracerebral Hemorrhage
A
- a bleed into the brain parenchyma
- hypertension is the most common cause as this can lead to Charcot-Bouchard microaneurysms which then rupture
- other causes include hemorrhagic conversion of an ischemic stroke, amyloid antipathy, brain tumors, and AV malformations
- the basal ganglia is the most common site as this is where Charcot-Bouchard micro aneurysms tend to arise
- presents with the abrupt onset of focal neurologic deficits, headache, vomiting, and altered levels of consciousness
- a CT scan is highly sensitive for diagnosis
- complications include increased ICP, seizures, rebreeding, vasospasm, hydrocephalus, and SIADH
- treatment begins with securing the ABCs, gradual blood pressure reduction with nitroprusside, and control of ICP with mannitol if necessary
24
Q
What is the leading cause of intracerebral hemorrhage?
A
hypertension which causes the formation and then rupture of Charcot-Bouchard micro aneurysms in the basal ganglia
25
What is the treatment for intracerebral hemorrhage?
- secure the ABCs
- gradually reduce the blood pressure using nitroprusside; this reduces the risk of further bleeding but must be gradual to avoid hypotension and hypoperfusion
- use mannitol to control ICP as needed
- surgery is rarely helpful unless there is a cerebellar hematoma
26
Subarachnoid Hemorrhage
- a bleed into the subarachnoid space
- most frequently due to rupture of a berry aneurysm but it can also be the result of an AV malformation or anti-coagulated state
- presents as a sudden headache, classically described as the worst headache of the patients life, plus vomiting, nuchal rigidity, and photophobia
- CT scan is able to diagnose the majority but an LP with xanthochromia is the gold standard for diagnosis
- may be followed several days later by vasospasm and ischemic infarct, so provide nimodipine for prevention
- other complications include rerupture, communicating hydrocephalus, seizures, or SIADH
- usually treated by clipping the aneurysm, providing stool softeners to avoid straining, acetaminophen for headache, IVF, and nifedipine to prevent vasospasm
27
What is a berry aneurysm? Where are they most often located? What other disease are they associated with?
- it is an aneurysm lacking a media layer
- most frequently located in the anterior circle of Willis at branch points of the anterior communicating artery; secondarily at the posterior communicating artery or MCA
- associated with Marfan syndrome, Ehlers-Danlos syndrome, and ADPKD
- other risk factors include advanced age, hypertension, smoking, and African American race
28
Why is xanthochromia more specific for subarachnoid hemorrhage than blood in the CSF?
- blood in the CSF could be from a traumatic tap
- xanthochromia results from RBC lysis and implies that blood has been in the CSF for several hours and is not due to a traumatic tap
29
Why must one always look for papilledema before performing an LP?
because if it is present, you can cause herniation with an LP
30
Parkinson Disease
- the degenerative loss of dopaminergic neurons in the substantia nigra of the basal ganglia, which is partly responsible for initiating movement
- presents with TRAP: tremor (pill rolling), rigidity (cog wheel), akinesia (or bradykinesia), and postural instability with shuffling gait; other features include masked facies, micrographic, and autonomic dysfunction
- dementia is a feature of late disease
- histology reveal the loss of the neuromelanin-pigmented neurons as well as Lewy bodies (eosinophilic inclusions of a-synuclein) but it is a clinical diagnosis
- carbidopa-levodopa is the most effective treatment but is associated with development of dyskinesias and an "on-off" phenomenon with long-term use
- dopamine agonists (bromocriptine and pramipexole) can be used early to delay the need for levodopa; selegiline is an MAOB inhibitor which increases dopamine availability
- trihexyphenidyl and benzotropine are anticholinergics that are particularly helpful for patients with tremor
31
Describe the tremor associated with Parkinson disease.
it is a pill-rolling tremor which occurs at rest, is worsened by emotional stress, and disappears when performing routine tasks
32
What is Shy-Drager syndrome?
parkinsonism symptoms plus autonomic insufficiency
33
Describe the treatment options available for those with Parkinson disease.
- carbidopa-levodopa is the most effective treatment but long-term use is associated with an on-off phenomenon and with the development of dyskinesias
- dopamine agonists bromocriptine and pramipexole can be used early in the course to delay the need for levodopa
- selegiline is an MAO-B inhibitor that can be used as an adjunct in order to increase the availability of dopamine
- anticholinergics, specifically trihexyphenidyl and benzotropine, are helpful in controlling those with tremor
- deep brain stimulation is reserved for refractory disease
34
How can Lewy body dementia and Parkinson disease be differentiated?
dementia is a late feature of Parkinson disease whereas Lewy body has parkinsonian features with early onset dementia and hallucinations
35
Lewy Body Dementia
- a degenerative disorder most similar to Parkinson disease
- presents with early-onset dementia (which distinguishes it from Parkinson disease), Parkinsonian features, and hallucinations
- histology reveals cortical Lewy bodies
36
Huntington Chorea
- a degeneration of GABAergic neurons in the caudate nucleus of the basal ganglia
- due to an autosomal dominant trinucleotide expansion of CAG in the huntingtin gene on chromosome 4
- this repeat demonstrates anticipation, specifically in spermatogenesis
- presents around age 40 with chorea, including athetosis, and can progress to include altered behavior, progressive dementia, and depression (suicide is a common cause of death)
- MRI shows atrophy of the caudate and putamen with hydrocephalus ex vacuo and DNA testing confirms the diagnosis
- treatment is symptomatic with dopamine antagonists to help with the psychosis and improve chorea
37
What mutation is associated with Huntington disease?
a CAG trinucleotide repeat in the huntingtin gene on chromosome 4, which demonstrates anticipation in spermatogenesis
38
What is an intention tremor? Where does it suggest there is a lesion?
- it is a slow, coarse, zigzag motion that arises when pointing or extending toward a target
- associated with ataxia, nystagmus, and dysarthria
- signifies cerebellar dysfunction
39
Essential Tremor
- a fine tremor that occurs with sustained posture and is worsened with movement or when anxious
- often autosomal dominant
- often self-medicated with alcohol
- treat with a nonselective beta-blocker or primidone (a barbiturate)
40
Friedreich Ataxia
- a degenerative disorder of the cerebellum and multiple tracts within the spinal cord
- due to an autosomal recessive, unstable trinucleotide repeat of GAA in the frataxin gene on chromosome 9, which is essential for mitochondrial iron regulation
- loss of this gene results in free radical damage
- presents in early childhood with ataxia, loss of vibratory sense and proprioception, muscle weakness in the lower extremities, and loss of deep tendon reflexes
- additional features include staggering gait, frequent falling, nystagmus, dysarthria, pes cavus, hammer toes, diabetes, and hypertrophic cardiomyopathy
- patients become wheelchair bound within a few years
41
Tourette Syndrome
- a disorder of sudden, rapid, recurrent, nonrhythmic, stereotyped motor and vocal tics that persist longer than one year with an onset before age 18
- associated with OCD and ADHD
- treatment is psychoeducation and behavioral therapy
- for intractable and distressing tics, clonidine, haloperidol, tetrabenazine, and guanfacine can be used
42
What are some potentially reversible causes of dementia?
- hypothyroidism
- neurosyphilis
- vitamin B12, folate, or thiamine deficiency
- medications
- normal pressure hydrocephalus
- depression
- subdural hematoma
43
What are the two major types of vascular dementia?
- multi-infarct dementia, which is a stepwise decline due to a series of cerebral infarctions, usually due to hypertension, atherosclerosis, or vasculitis
- Binswanger disease, which has an insidious onset and is the result of diffuse subcortical white pattern degeneration, usually due to long-standing hypertension and atherosclerosis
44
Normal Pressure Hydrocephalus
- an increase in CSF that results in dilated ventricles, which subsequently stretches the surrounding corona radiata
- presents in the elderly with triad of urinary incontinence, gait instability, and dementia ("wet, wobbly, and wacky")
- have a characteristic gait known as "magnetic gait" because their feet appear stuck to the floor
- characteristically, lumbar puncture improves symptoms and treatment is ventriculoperitoneal shunting
45
Pick Disease
- a degenerative disease of the frontal and temporal lobes
- presents primarily with behavioral and language symptoms in the early stages and then progresses to dementia
- characterized histologically by round aggregates of tau protein in neurons of the cortex
46
Creutzfeldt-Jakob disease
- the most common spongiform encephalopathy
- usually sporadic but can arise from exposure to prion-infected human tissue via human GH or corneal transplant
- presents as a very rapidly progressing dementia associated with ataxia and startle myoclonus
- death arises within one year
- "spike wave" complexes are seen on EEG
- variant CJD is a special form known as "mad cow" disease which arises from exposure to prion-infected bovine tissue
47
Progressive Multifocal Leukoencephalopathy
- a JC virus infection of oligodendrocytes
- arises from reactivation of latent virus in a newly immunosuppressed or immunocompromised patient
- presents with rapidly progressive neurologic signs and death
- there is an increased risk associated with use of natalizumab and rituximab
48
What is pseudodementia?
a decline in cognition, difficult to distinguish from Alzheimer's, which is in fact caused by depression and will respond to antidepressant therapy
49
Name five types of infections that can contribute to dementia?
- HIV infection (AIDS related dementia)
- cryptococcal
- neurosyphilis
- progressive multifocal leukoencephalopathy (JC infection of oligodendrocytes)
- Creutzfeldt-Jakob disease
50
Alzheimer Disease
- a degenerative disease of the cortex, causing dementia
- arises due to B-secretase degradation of the APP protein, which can't be processed like the A-secretase product and is deposited in the brain tissue instead
- risk factors are age, family history , and down syndrome; ApoE4, presenillin 1, and presenillin 2 are risk factors
- presents with slow-onset memory loss (beginning with short-term loss and then long-term), progressive disorientation, loss of learned motor skills and language, and changes in behavior or personality
- may be complicated by cerebral amyloid angiopathy
- gross examination of the brain reveals central atrophy, narrowing of the gyri, widening of the sulci, and dilation of the ventricles
- pathology includes collections of dilated, tortuous neuritic processes surrounding an amyloid core of amyloid beta protein as well as tau tangles, which are intracellular, hyperphosphorylated tau protein deposits
- treatment involves cholinesterase inhibitors like donepezil, rivastigmine, and galantamine; one study showed improvement with megadoses of vitamin E
51
What is the pathogenesis of Alzheimer's disease?
- normally a-secretase degrades the APP gene product to a structure that can be turned over by cells and properly handled
- in those with Alzheimer's B-secretase has degraded the APP protein to a different product that can't be properly handled and is instead deposited as AB-amyloid
52
What genetic risk factors exist for Alzheimer disease?
- the ApoE4 allele increases risk while the ApoE2 allele lowers it
- the presenilin 1 and 2 genes are associated with familial, early onset Alzheimer's
- most with Down syndrome have Alzheimer's by age 40
53
What is that pathology associated with Alzheimer disease?
- dilated, tortuous neuritic processes surrounding an amyloid core of amyloid beta protein
- tau tangles, which are intracellular deposits of hyperphosphorylated tau protein
54
What are Lewy bodies?
- cytoplasmic eosinophilic inclusions of a-synuclein that are visible on histology
- seen in those with Lewy body dementia (cortical) and Parkinson disease (substantia nigra)
- have a halo surrounding them
55
Consciousness relies on what two things?
- arousal, which is dependent on an intact brainstem, specifically the reticular activating system
- cognition, which is dependent on an intact cerebral cortex
56
What are possible causes of delirium?
use the acronym P. DIMM WIT
- Postoperative state
- Dehydration and malnutrition
- Infection
- Medications and drug intoxications
- Metals (heavy metal exposure)
- Withdrawal (from alcohol and benzos)
- Inflammation (fever)
- Trauma, burns
57
The glasgow coma scale rates what three things?
- eye opening
- motor response
- verbal response
58
Multiple Sclerosis
- autoimmune destruction of oligodendrocytes
- the major risk factors are women age 20-30
- the pyramidal, cerebellar, medical longitudinal fascicles, optic nerve, and posterior columns are commonly affected tracts
- deficits are transient and depend on the tract affected; fatigue, optic neuritis, internuclear ophthalmoplegia, ataxia, loss of bladder control, and autonomic dysfunction are common
- although a clinical diagnosis, MRI can be used to identify white matter lesions that vary in time and space, and an LP can be done looking for lymphocytes, an oligoclonal IgG expansion, and elevated myelin basic protein
- high dose steroids are used to treat and shorten an acute attack; interferon-B is used to slow progression of the disease
59
What is optic neuritis?
a visual disturbance common in patients with MS characterized by monocular visual loss, pain with eye movement, central scotoma, and decreased pupillary reaction to light
60
What is internuclear ophthalmoplegia?
ipsilateral medial rectus palsy on attempted adduction and horizontal nystagmus of the abducting eye contralateral to the lesion, which is of the medial longitudinal fasciculus
61
How is MS diagnosed
- it can be a clinical diagnosis
- MRI often reveals white matter lesions that vary across time and space
- spinal tap shows lymphocytes, an oligoclonal IgG expansion, and elevated levels of myelin basic protein
62
Guillain-Barre Syndrome
- an inflammatory demyelinating polyneuropathy affecting primarily the Schwann cells surrounding motor nerves
- it is usually preceded by a viral or mycoplasma infection, particularly campylobacter, hepatitis, CMV, etc.
- presents with abrupt onset of ascending weakness or paralysis in all four extremities, usually in a symmetric distribution
- diagnosed based on elevated protein but normal cell count in CSF and by decreased motor nerve conduction velocity
- treat by monitoring pulmonary function and providing IVIG or plasmapheresis for severe disease; do not give steroids as these often worsen the disease course
63
Myasthenia Gravis
- an autoimmune disorder caused by autoantibodies directed against the nicotinic ACh receptors of the neuromuscular junction, which leads to a post-synaptic response
- presents with skeletal muscle weakness that worsens by continued use and is improved by rest; sensation and reflexes are preserved
- this often manifests as ptosis, diplopia, blurred vision, dysarthria, and dysphagia
- EMG shows decremental response to repetitive stimulation, edrophonium test demonstrates a brief improvement in symptoms, or acetylcholine receptor antibody test
- should follow the diagnosis with a CT of the chest to rule out thymoma
- treat with AChE inhibitors like pyridostigmine, thymectomy even in the absence of a thymoma, corticosteroids and immunosuppressive drugs, and plasmapheresis in severe cases
64
What is the preferred treatment for myasthenia gravis?
pyridostigmine and a thymectomy
65
Duchenne Muscular Dystrophy
- a degenerative disorder characterized by muscle wasting and replacement of skeletal muscle by adipose
- due to an X-Linked recessive defect in the dystrophin gene, which encodes a protein important for anchoring the muscle cytoskeleton to the ECM
- mutations are often spontaneous and relatively common because the dystrophin gene is incredibly large; often a frameshift mutation that causes truncation of the protein product
- Duchenne presents with proximal muscle weakness at 1 year of age (begins in pelvic girdle and progresses superiorly), calf pseudo hypertrophy, and elevated creatinine kinase and aldolase
- Gower maneuver often seen, in which patients use upper extremities to help them stand, as is a waddling gait
- DNA testing has replaced muscle biopsy for diagnosis
- prednisone can provide some benefit and many require surgery to correct progressive scoliosis
- death due to cardiac (dilated cardiomyopathy) or respiratory failure secondary to replacement of the necessary muscles, including myocardium, with adipose
66
How does Becker muscular dystrophy differ from Duchenne's?
- Becker is due to some mutation (usually a non-frameshift insertion) that leaves a partially functional gene product rather than a truncated one as in Duchenne's
- Becker presents as a milder form with later onset in adolescence or early adulthood
67
Describe the anatomy of the spinothalamic tract, what information it carries and at what level it decussates.
- it carries pain and temperature sensation
- the first order neuron is located in the dorsal root ganglion and synapses on a second-order neuron in the posterior horn
- this second-order neuron then decussates via the anterior white commissure near at the level where it enters
- the second-order neuron then ascends via the spinothalamic tract to the thalamus where it synapses on the third-order neuron
- this third-order neuron projects to the cortex
68
Describe the anatomy of the corticospinal tract, what information it carries and at what level it decussates.
- upper motor neurons descend and decussate in the medullary pyramids
- they continue to descend and synapse on lower motor neurons in the anterior horn
- these lower motor neurons then project to the NMJ
69
Describe the anatomy of the dorsal column-medial lemniscus tract, what information it carries and at what level it decussates.
- first order neurons enter via the dorsal root and ascend within the ipsilateral dorsal column and project to second order neurons located in the medulla
- second order neurons then decussate and ascend via the medial lemniscus to the thalamus where third order neurons are located
- third order neurons finish carry pressure, touch, vibration, and proprioception information to the cortex
70
Describe the anatomy of the hypothalamospinal tract, what information it carries and at what level it decussates.
- first order neurons located in the hypothalamus synapse on the T1 lateral horn
- from there, second-order neurons synapse on the superior cervical ganglion (sympathetic chain ganglion)
- this third-order neuron then projects to the eyelids, pupil, and skin on the face carrying sympathetic input
71
Describe a lumbosacral plexus injury?
- most often caused by a post-surgical hematoma in the pelvis
- results in motor and sensory deficits in the L5-S3 distribution
72
Lambert-Eaton Syndrome
- autoantibodies directed against presynaptic calcium channels prevent presynaptic release of neurotransmitter at the neuromuscular junction
- presents with proximal muscle weakness and hyporeflexia with symptoms improving with related muscle stimulation
- associated with small cell lung cancer
73
Neurofibromatosis Type I
- an autosomal dominant neurocutaneous disorder
- caused by a mutation of the NF1 tumor suppressor gene on chromosome 17, which encodes a negative regulator of RAS called neurofibromin
- presents with cafe-au-lait spots, Lisch nodules (pigmented iris hamartomas), cutaneous neurofibromas, optic gliomas, and pheochromocytomas
- the neurofibromas are derived from neural crest cells
74
Neurofibromatosis Type II
- an autosomal dominant neurocutaneous disorder
- caused by a mutation of the NF2 gene on chromosome 22
- presents with bilateral acoustic Schwannomas, juvenile cataracts, meningiomas, cafe au last spots, and neurofibromas
75
Tuberous Sclerosis
- an autosomal dominant neurocutaneous disorder
- features follow the HAMARTOMASS acronym: Hamartomas in CNS/skin, Angiofibromas, Mitral regurgitation, Ash-leaf spots, cardiac Rhabdomyoma, (Tuberous sclerosis), autosomal dOminant, Mental retardation, renal Angiomyolipoma, Seizures, and Shagreen patches
- also have an increased incidence of subependymal astrocytomas and ungal fibromas
76
Sturge-Weber Syndrome
- a somatic mosaicism for an activating mutation of GNAQ causes congenital, non-inherited neural crest anomalies
- affects small blood vessels to cause a port-wine stain of the face in a CN V1/V2 distribution
- also presents with ipsilateral leptomeningeal angioma (capillary angiomas of the pia matter) causing seizures and epilepsy, intellectual disability, and episcleral hemangioma causing increased IOP and early onset glaucoma
- STURGE: Sporadic, port-wine Stain, Tram track calcifications (opposing gyri), Unilateral, Retardation, Glaucoma, GNAQ gene, Epilepsy
77
Von-Hippel-Lindau Disease
- a syndrome of tumors due to a deletion of VHL on chromosome 3, which normally ubiquitinates hypoxia-inducible factor 1a
- syndrome includes HARP: Hemangioblastomas of the retina, brain stem, cerebellum, and spine; Angiomatosis; bilateral Renal cell carcinomas; and Pheochromocytomas
78
Syringomyelia
- a cystic degeneration of the spinal cord
- arises with trauma or in association with a type I Chiari
- usually occurs at C8-T1 and involves the anterior white commissure
- presents as a loss of pain and temperature sensation in the upper extremities bilaterally in a "cape-like" distribution
- may expand to involve and damage the anterior horn (lower muscle signs) or lateral horn (Horner syndrome)
- diagnosed by MRI
79
What is the deficit produced by a spinal cord hemisection?
- ipsilateral UMN signs below the lesion
- ipsilateral LMN signs at the level of the lesion
- ipsilateral loss of tactile, vibration, and proprioception below the lesion
- contralateral loss of pain and temperature sensation below the lesion
- potential for ipsilateral Horner syndrome if the lesion occurs above T1
80
What are the causes and features of Horner syndrome?
- causes include pan coast tumor, internal carotid dissection, brainstem stroke, or neck trauma
- manifests as ipsilateral ptosis, miosis, and anhidrosis
81
What are miosis and mydriasis?
- miosis is pinpoint pupils
| - mydrasis is widely dilated pupils
82
Poliomyelitis
- damage incurred by lower motor neurons in the anterior horn due to poliovirus infection
- polio is transmitted via the fecal-oral route and infects the oropharynx and small bowel, replicates in the Peyer's patches, and eventually spreads to the CNS
- initially, it presents with fever, sore throat, n/v, and abdominal pain; later it presents with asymmetric lower motor neuron signs
83
What is the difference between central and peripheral vertigo and how can the two be differentiated clinically?
- peripheral vertigo is that which arises from an inner ear deficit
- central is that which arrises due to a CNS lesion
- the two can be differentiated clinically because central vertigo is accompanied by a bidirectional or vertical nystagmus which doesn't occur in peripheral cases
- additionally, only peripheral vertigo will be accompanied by hearing loss or tinnitus
84
Describe the etiologies and presentation of central vertigo.
- a feeling of spinning caused by a CNS lesion
- etiologies include multiple sclerosis, vertebrobasilar insufficiency, or migraine-associated vertigo
- typically has a gradual onset with additional brainstem findings; the accompanying nystagmus can be bidirectional or horizontal
85
Describe the presentation of benign positional vertigo and its treatment?
- it is a peripheral vertigo experienced only in specific positions or during change in position
- it has an abrupt onset and lasts for only a few moments
- treated with meclizine and recovery is usually complete
86
Describe the presentation and treatment of meniere disease.
- it is a triad of peripheral vertigo, tinnitus, and hearing loss
- attacks may last for hours to days and hearing loss eventually becomes permanent
- treated with sodium restriction and diuretics
87
What are five different causes of peripheral vertigo?
- benign positional vertigo
- meniere disease
- acute labyrinthitis (viral infection)
- ototoxic drugs (ahminoglycosides and some loop diuretics)
- acoustic neuroma
88
Compare and contrast central and peripheral vertigo.
- central tends to have a more gradual onset and the intensity of the vertigo, associated n/v, and nystagmus are more mild
- central has no refractoriness meaning a tilt test will show the same result every time; not the case for peripheral
- central has nystagmus that can be bidirectional or vertical
89
Amyotrophic Lateral Sclerosis
- a degenerative disorder of the upper and lower motor neurons of the corticospinal tract
- presents with asymmetric upper and lower motor neuron signs; atrophy and weakness of the hands is usually the first indicator
- bowel and bladder control, sensation, cognitive function, extra ocular muscles, and sexual function are never affected
- cases are sporadic and arise in adults 50-70 years old
- diagnose with EMG and nerve conduction studies
- treat with riluzole, a glutamate-blocking agent
90
Describe Broca's aphasia.
- intact comprehension
- expressive but non-fluent speech and impaired repetition (patient uses short non-grammatical sentences that do convey meaning)
91
Describe Wernicke's aphasia.
- impaired comprehension and impaired repetition
- fluent speech
- speech is grammatically correct and fluid but doesn't make much sense because they cannot understand their own words or the context in which they are speaking
92
Describe conduction aphasia.
- caused by damaged to the arcuate fasciculus
- speech comprehension is intact and the individual will have fluent speech
- the only thing impaired is repetition
93
Describe a global aphasia.
- results from damage to the arcuate fasciculus, Broca's area, and Wernicke's area
- presents with non-fluent speech, impaired comprehension, and impaired repetition
94
Bell Palsy
- a hemifacial weakness or paralysis of the muscles innervated by CN VII
- can be caused by herpes simplex infection, Lyme disease, and other unknown things
- presents with an acute onset affecting both the upper and lower parts of the face
- usually resolves on its own after several weeks but prednisone and acyclovir can be used
- prednisone should never be used if Lyme disease is the suspected etiology
95
Trigeminal Neuralgia
- brief but frequent attacks of severe, lancinating facial pain without any motor or sensory deficits
- usually idiopathic in origin
- the diagnosis is clinical but an MRI should be performed to rule out cerebellopontine angle tumor
- treat with carbamazepine; baclopfen and phenytoin are second line options
96
What are the typical characteristics and possible etiologies for a cardiac syncopal episode?
- they are usually sudden and without prodromal symptoms
- causes include arrhythmias, obstruction of blood flow as in aortic stenosis or hypertrophic cardiomyopathy, and massive MI
97
Vasovagal Syncope
- the most common cause of syncope
- typically elicited by emotional stress and preceded by pallor, diaphoresis, lightheadedness, nausea, etc.
- there is normally an increase in sympathetic tone during periods of stress or changes in cardiac output but in those with vasovagal syncope, this response is interrupted and parasympathetic activity predominates leading to inappropriate bradycardia, vasodilation, and hypotension with inadequate cerebral perfusion
- a tilt table can reproduce these symptoms and is used for diagnosis
- usually limited to just one episode but therapy can include beta-blockers or disopyramide
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What are the risk factors for orthostatic hypotension?
- age
- diabetes and resulting autonomic neuropathy
- patients taking ganglion-blocking agents
- vasodilators
- diuretics
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How is orthostatic hypotension treated?
increase sodium and fluid intake; use fludrocortisone as needed
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What is a tilt-table test used for?
to diagnose neurocardiogenic syncope as in orthostatic hypotension or vasovagal syncope
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What is the most important test to run following an episode of syncope?
an ECG
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What are possible causes of seizures?
the four M's and four I's
- metabolic and electrolyte disturbances
- mass lesions
- missing drugs (noncompliance of anticonvulsants or withdrawal)
- miscellaneous (pseudo seizures, eclampsia, hypertensive encephalopathy)
- intoxications
- infections
- ischemia
- increased ICP
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What are partial seizures?
those that begin in one part of the brain, most often the temporal lobe
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What is the difference between a simple and a complex partial seizure?
- during a simple partial seizure, consciousness remains intact
- during a complex partial seizure, consciousness is impaired
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What are the drugs of choice when treating partial seizures?
phenytoin or carbamazepine
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Describe an absence seizure?
- typically involves a school-age child
- they seem disengaged and as if staring into space, which is often confused with daydreaming
- these episodes are brief, involve no loss of postural tone or incontinence, and there is no postictal confusion following
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What is the treatment for status epileptics?
- IV diazepam
- IV phenytoin
- 50 mg dextrose
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What are indications for starting anti epileptic drugs?
- they are not used to treat patients with a single seizure
| - they are indicated for patients in status epilepticus, those with an abnormal EEG, those with an abnormal MRI
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What are the drugs of choice for treating absence seizures?
ethosuximide or valproate
