Term
| what might be the effect of cerebrovascular disease in the PCA territory to the occipital + inferior temporal lobes? |
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Definition
| visual field deficits or possibly wernicke's receptive aphasia |
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Term
| what is the blood supply to the postero-inferior medulla? |
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Definition
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Term
| what is the blood supply to the upper medulla, lower cerebellum, and inferior brain stem? |
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Definition
| posterior inferior cerebellar artery |
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Term
| what is the blood supply to the middle cerebellum and inferior pons? |
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Definition
| the anterior inferior cerebellar artery |
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Term
| what is the blood supply to the central pons? |
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Definition
| the deep penetrating long circumferential arteries |
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Term
| what is the blood supply to the upper cerebellum, superior pons and inferior midbrain? |
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Definition
| the superior cerebellar artery |
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Term
| what is the blood supply to the middle/upper midbrain and occipital lobes? |
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Definition
| the posterior cerebral artery |
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Term
| what is the landmark which separates the posterior cerebral artery and the superior cerebral artery? |
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Definition
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Term
| what are the manifestations of brainstem disease? |
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Definition
| dizziness (CN8), dysarthria/dysphagia (CN9, 10, 11, 12), and diplopia (CN3,4,6) - the 4 D's. bilateral involvement (close proximity). alteration in consciousness (may affect the RAS). |
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Term
| what are **crossed findings? |
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Definition
| if there is a lesion in the brainstem, the ipsilateral CN is involved but the contralateral corticospinal tract is involved (R facial involvement + L hemiparesis) |
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Term
| what characterizes the somatotrophic layout of the cerebellum? |
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Definition
| the arm is most lateral, the leg is intermediate and the trunk midline (all ipsilateral). for ex: R cerebellar lateral hemisphere tumor has finger-nose ataxia, but very little leg ataxia OR chronic alcoholic - midline cerebellar degeneration w/wide spread gait but some slurring of speech but little finger-nose ataxia |
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Term
| what is the function of the trigeminal nerve? |
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Definition
| facial sensation in three divisions (ophthalmic, maxillary and mandibular) and motor function of the muscles of mastication (temporalis, masseter, pterygoids) |
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Term
| what are the clinical manifestations of trigeminal neuralgia? |
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Definition
| sharp, shooting “lancinating” pain of excruciating intensity lasting seconds to min in distribution of CN5 (usually maxillary and mandibular) and almost always unilateral in nature. greatest incidence: 50-60. pain triggers: brushing teeth, combing hair, chewing, speaking. there is no involvement in the muscles of mastication and facial sensation is normal. |
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Term
| what is the etiology of trigeminal neuralgia? tx? |
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Definition
| MS, posterior fossa tumors, but the majority are "idiopathic" (associated w/compression of the CN5 entry zone by a vascular loop). tx: tegretol or sx (gangliolysis [glycerol] or posterior fossa craniotomy and decompression or nerve sectioning) |
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Term
| what characterizes the difference between UMN/LMN pathology in the facial nerve? |
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Definition
| nerve signals from the cortex travel to the contralateral pontine nucleus to the upper and lower muscles of facial expression. however, there is also a backup ipsilateral nerve path which runs just to the upper muscles of facial expression. thus, if there is an UMN lesion, only the contralateral lower muscles of facial expression will be affected. if there is a LMN lesion however, both the upper and lower muscles of facial expression will be affected. |
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Term
| what will be involved if the facial nucleus was damaged? |
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Definition
| facial muscles, taste, salivation, hearing, lacrimation and CN6 |
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Term
| what will be involved if the CN7 at the brainstem exit was damaged? |
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Definition
| the facial muscles, taste, salivation, hearing, lacrimation, and CN8 |
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Term
| what will be involved if the CN7 at the facial canal was damaged? |
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Definition
| facial muscles, taste, salivation and hearing (due to nerve to the stapedius which dampens vibrations, if not working = hyperacusis) |
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Term
| what will be involved if the CN7 at the stylomastoid foramen was damaged? |
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Definition
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Term
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Definition
| an inflammatory reaction of the nerve w/in the facial canal, likely related to herpes zoster. pts are more likely to have bell's palsy if they have DM, HTN, pregnancy, ramsey hunt syndrome and herpes zoster oticus. |
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Term
| what diseases can cause facial nerve paralysis (not palsy - cranial neuritis)? |
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Definition
| lyme disease and sarcoidosis |
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Term
| what are the symptoms of bell's palsy? tx? |
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Definition
| retroaural pain followed by sudden onset of facial weakness which peaks w/in 48 hrs (preceded by an ipsilateral headache the day before). if mild, pt recovers within 2-3 wks, but if severe, pt recovers within 6-8 mos and recovers incompletely (may lead to synkinesis: not the same somatotopic control - like food in mouth can lead to salivation+lacrimation). tx: protect eye, and prednisone [except severe DM pts] (antiviral agents are of doubtful benefit) |
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Term
| what is bulbar palsy? what can cause it? |
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Definition
| *LMN* palsy of any or all: CN9, 10, 11 or 12. this may manifest as dysphagia, decreased gag reflex [afferent] (CN 9) or dysphagia, decreased gag reflex [efferent], dysarthria, hoarseness, nasal quality to voice/nasal regurgitation of liquids (CN10, 11), or atropy+fasiculations of tongue/tongue deviates to side of lesion (CN12). etiologies: polio, motor neuron dz, and myasthenia gravis. |
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Term
| what is pseudobulbar palsy? what can cause it? |
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Definition
| *UMN* paralysis of the bulbar muscles - however, all have bilateral corticobulbar innervation (unilateral stroke will not produce bulbar paralysis). clinical manifestations: hyperactive gag reflex (dysphagia), spastic type dysarthria, reduced volitional activity w/relatively normal spontaneous and emotional activity and pathological laughter/crying (*pseudobulbar affect). etiology: bilateral strokes, ALS |
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Term
| what is cerebellopontine angle syndrome? |
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Definition
| acoustic neuroma/meningoma affects CN8 first (hearing loss, dizziness), then CN7 (facial weakness), then CN5 (facial numbness, masseter weakness), then cerebellum (ipsilateral ataxia). |
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Term
| what is vertebrobasilar insufficiency? |
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Definition
| brainstem ischemia due to disease of the vertebrobasilar system - most commonly occurs w/dizziness +/- other brainstem symptomatology (dizziness, dysphagia and dysarthria and diplopia). |
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Term
| what is wallenberg's syndrome? |
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Definition
| lateral medullary syndrome (**vertebral artery occlusion/PICA territory infarction) = lateral spinothalamic tract involvement(pain+temp)/nucleus ambiguus (pharynx+larynx)/CN5(facial pain+temp)/dorsal spinocerebellar involvement (ataxia) |
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Term
| what is the mneumonic for horner's syndrome? |
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Definition
| ptosis, anhidrosis, miosis, enophthalmos and loss of ciliospinal reflex (horny PAMELa). sympathetic pathology involving the reticulospinal tract. |
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