Step 1 - Neuro 3

denniskwinn's version from 2015-04-25 16:11


Question Answer
CN Xll lesion (LMN)tongue deviates toward side of lesion (lick your wounds). - - Decussates before medulla and synapse on contralateral hypoglossal nucleus.
CN V motor lesionjaw deviates toward side of lesion. Bilateral cortical input to lateral pterygoid muscle.
CN X lesionuvula deviates away from side of lesion. Weak side collapses and uvula points awav.
CN XI lesionweakness turning head lo contralateral side of lesion (SCM). Shoulder droop) on side of lesion (trapezius)
UMN facial lesion1. lesion of motor cortex or connection between cortex and facial nucleus. 2. Contralateral paralysis of lower face only, since upper face receives bilateral UMN innervation
LMN facial lesion Ipsilateral paralysis of upper and lower face
Bell’s palsy (1. Complete destructoin of the facial nucleus or its branchial efferent fibers (facial nerve proper) 2. Peripheral ipsilateral facial paralysis w/inability to close eye on involved side 3. Can occur idiopathically; gradual recovery in most cases 4. Seen as a complication in AIDS, lyme disease, herpes zoster, sarcoidosis, tumors, diabetes (ALexander graHam Bell with STD)
Kuh kuh kuhtests palate elevation (CNX - vagus)
La La La tests tongue (CNXII)
Mi Mi Mitests lips (CNVII)
Mastication musclesMasseter, Temporalis, Medial pterygoid - close jaw . . Lateral pterygoid open mouth. All are innervated by trigeminal nerve.
Innervation of glossus musclespalatoglossus innervated by vagus, all other innervated by hypoglossal
Muscles with palatall muscles with root palat in their names innervated by vagus nerve (except for tensor veli palatini - mandibular branch of CN V)
Inner ear (1. Series of tubes in temporal bone filled with perilymph - cochlea, vestibule, semicircular canals 2. Tubes within bony labyrinth filled with endolymph. 3. Hair cells are sensory elements in both vestibular and cochlea
PerilymphNa+ rich (similar to ECF)
EndolymphK+ rich (similar to ICF)
Utricle and sacculeHorizontal (U) and vertical (S) - detect linear acceleration
Semicircular canals containampullae - detect angular acceleration
Cochlear membranenarrow and stiff base (for high frequency), wide and flexible apex (for low frequency)
Sound path (1. Enters middle ear 2. Vibrates tympanic membrane and ossicle to the 3. Oval window to the 4. Vibration of basilar membrane bending of hair cell cilia against tectorial membrane to 5. Hair cell bending =hyper or de polarization of CN VIII
Hearing loss in the elderlyhigh frequency first to low frequency
Hearing loss (3) 1. Normal: air(AC) > bone conduction (BC) (Rinne) 2. If BC>AC: conduction deafness in that ear (Weber lateralizes to that ear) 3. If AC>BC (normal) but there is sensorineural loss, weber lateralizes to opposite ear)
RetinitisRetinal necrosis + edema —> atrophic scar.
IritisSystemic inflammation (e.g., Reiter's).
Near vision pathologyCiliary muscle contracts (zonular fibers relax —> lens relaxes —> more convex).
Distant vision pathologyCiliary muscle relaxes (lens flattens).
Pathology in Aging eye Sclerosis and ↓ elasticity cause lens shape to change.
Retinal artery occlusionAcute, painless monocular loss of vision; pale retina and cherry-red macula (has its own blood supply—choroid artery).
Aqueous humor pathwayDRAW PICTURE -
Glaucoma (1. Impaired flow of aqueous humor →↑ intraocular pressure→optic disk atrophy with cupping 2. Open/wide angle - obstructed outflow = painless/silent - Associated with myopia & ↑age, african american race 4. Closed/narrow angle - obstruction of flow b/w iris and cornea → pressure building = painful, ↓ vision, rock hard eye, frontal headache - do not give epinepherine
Cataract1. painless bilateral opacification of lens →↓ in vision
Cataract risk factorsage, smoking, EtOH, sunlight, classic galactosemia, galactokinase deficiency, diabetes (sorbitol), trauma, infection
Papilledema↑ in intracranial pressure → elevated optic disk with blurred margins, bigger blind spot (can be seen in hydrocephalus)
CN III damageeye looks clown and out: ptosis, pupillary dilation, loss of accommodation.
CN IV damagediplopia with a defective, downward gaze (adjust by tilling head toward lesion)
CN VI damagemedially directed eye
Strabismusmisalignments of eyes - many causes
Amblyopiareduction of vision from disuse in critical period. May be secondary to strabismus, deprivation, unequal refractive errors
Pupillary constrictionmiosis - pupillary sphincter muscle (aka circular muscle) - parasympathetic innervation - CNIII from Edinger-Westphal nucleus→ ciliary ganglion
Pupillary dilationmydriasis - radial muscle (dilator muscle) - sympathetic innervation -TI preganglionic sympathetic→ superior cervical ganglion→postganglionic sympathetic→long ciliary nerve
Pupillary light reflexlight in retina sends signal via CN II to pretectal nuclei in midbrain activating bilateral edinger-westphal nuclei = bilateral constriction
Marcus Gunn pupilafferent pupillary defect (optic nerve damage or retinal detachment) - ↓ bilateral pupillary constriction when light is shone in affected eye
CNIII cross section (2)1. peripheral is parasympathetic output (affected first by compression) - will effect pupillary light reflex 2. Center is output to ocular muscles - affected primarily by vascular disease - problems come from vascular disease
Retinal detachmentseparation of neurosensory layer of retina from pigment epithelium - leads to degeneration of photoreceptors and vision loss. Secondary to trauma or diabetes
ARMD (age-related macular degeneration)1. degeneration of macula (central area of retina) - loss of central vision (scotomas) 2. Dry is slow due to fat deposits (gradual ↓ in vision) 3. Wet is rapid - new vascularization
Visual field defectslook at the picture on 420
Meyer’s loopinferior retina; loops around inferior horn of lateral ventricle.
Dorsal optic radiationsuperior retina; takes shortest path via internal capsule
Internuclear ophthalmoplegia (MLF syndrome)1. Lesion in medial longitudinal fasciulus (MLF) lead to medial rectus palsy on attempted lateral gaze. 2. Nystagmus in abducting eye. 3. Common in MS 4. When looking left, the left nucleus of CNVI fires which contracts the left lateral rectus and stimulates the contralateral (R) nucleus of CNIII via via R MLF to contract the right medial rectus.
Cold water nystagmustoward lesion with quick phase to opposite side
Warm water nystagmusto opposite side with quick phase to same side
Dementiadecrease in cognitive ability, memory or function with intact consciousness
Alzheimer’s disease1. Most common dementia cause in elderly 2. Widespread cortical atrophy 3. ↓ACh 4. B-amyloid plaques, neurofibrillary tangles(insoluble cytoskeletal elements) 5. Genes (APP, presenlin -1 and 2 for early onset, , ApoE4 for late onset) 6. APOE2 is protective
Pick’s disease (frontotemporal dementia)1. Dementia, aphasia, parkonsonian aspects, change in personality 2. Spares parietal lobe and posterior 2/3 of superior temporal gyrus 3. Pick bodies (intracellular tau protein) 4. Frontotemporal atrophy
Lewy body dementia1. Parkinsonism w/dementia and hallucinations 2. Alpha-synuclein defect
Creutzfeldt-Jakob disease (CJD)1. Rapidly progressive (weeks to months) dementia with myoclonus 2. Spongiform cortex 3. Prions (alpha helix forms to beta sheet - which is resistant to proteases)
Other causes of dementia1. Multi-infarct (2nd most common in elderly) 2. Syphilis 3. HIV 4. Vitamin B12 deficiency, 5. Wilson’s disease
Multiple sclerosis 1. Autoimmune inflammation and demyelination of CNS 2. Can present with optic neuritis, MLF syndrome, hemiparesis, hemisensory sx, or incontinence. 3. Relapsing/remitting course
MS findings1. Increased protein (IgG) in CSF - oligoclonal bands are diagnostic 2. MRI gold standard - perventricular plaques (oligodendrocyte loss with preservation of axons)
MS classic triadScanning speech, Intention tremor, Incontinence, Internuclear ophthalmoplegia, Nystagmus
MS txBeta interferon or immunosuppressant therapy - symptomatic treatment for neurogenic bladder, spasticity, pain
Guillain-Barre syndrome (acute inflammatory demyelinating polyradiculopathy)1. Inflammation and demyelination of peripheral nerves and motor fibers of ventral roots (sensory effect less sever than motor), causing symmetric ascending muscle weakness beginning in distal lower extremities. 2. Facial paralysis in 50% of cases. 3. Autonomic function may be severely affected (cardiac irregularities, hypertension, hypotension) 4. Almost all patients survive; majority recover completely after weeks to months 5. Respiratory support is critical until recovery 6. Additional treatment: plasmapheresis, IV immune globulins
Guillain-Barre findings↑ CSF protein w/normal cell count (albuminocytologic dissociation). ↑ protein→ papilledema
Guillain-Barre infection association1. Campylobacter jejuni or herpesvirus infection 2. Autoimmune attack of peripheral myelin due to molecular mimicry
PML (progressive multifocal leukoencephalopathy1. demyelination of CNS due to destruction of oligodendrocytes. Associated with JC virus and seen in 2-4% of AIDS patients. 2. Rapidly progressive, usually fatal
Acute disseminated (postinfectious) encephalomyelitismultifocal perivenular inflammation and demyelination after infection (chickenpox, measles) or certain vaccinations (rabies, smallpox)
Metachromatic leukodystrophyautosomal-recessive lysosomal storage disease, most commonly due to arylsulfatase. A deficiency. Buildup of sulfatides leads to impaired production of myelin sheath
Charcot-marie-Tooth diseaseaka hereditary motor and sensory neuropathy (HMSN). Group of progressive hereditary nerve disorders related to the defective production of proteins involved in the structure and function of peripheral nerves or the myelin sheath


Question Answer
Causes of seizure in children (5)1.genetic, 2. infection (febrile), 3. trauma, 4. congenital, 5. metabolic
Causes of seizures in adults (4)1.tumors 2. Trauma 3. Stroke 4. Infection
Causes of seizure in elderly (5)1. Stroke 2. Tumor 3. Trauma 4. Metabolic 5. Infection
Partial seizures1. Happen in one area of the brain - most commonly originates n mesial temporal lobe. 2. Often preceded by seizure aura - can secondarily generalize
Simple partial seizuresconscious intact - motor, sensory, autonomic, psychic
Complex partial seizureimpaired consciousness
Absence seizuresdiffuse (Petit mal, 3Hz, no postictal confusion) - blank stare
Myoclonic seizuresdiffuse - quick, repetitive jerks
Tonic-clonic seizurediffuse - (grand mal) - alternating stiffening and movement
Tonic seizurediffuse stiffening
Atonic seizurediffuse - “drop” seizures (falls to floor) - commonly mistaken for fainting


Question Answer
HeadachePain due to irritation of structures such as dura, cranial nerves or extracranial structures, not brain parenchyma itself
Migraine1. Unilateral 2. 4-72 hours of pulsating pain with nausea, photophobia or phonophobia +/- aura.due to irritation of CNV and release of substance P, CGRP, vasoactive peptides.
Auraneurologic symptoms before headache including: visual, sensory and speech disturbances
Migraine treatmentpropanolon, NSAIDS, sumatriptan for acute migraines
Tension headachebilateral > 30 minutes of steady pain - not aggravated by light or noise - no aura
Cluster headaches (4)1. unilateral; repetitive brief headaches characterized by periorbital pain 2. associated with ipsilateral lacrimation, rhinorrhea, Horner’s syndrome. 3. Much more common in males 4. Treat with sumatriptan
Other causes of headache (5)SAH (worst headache of life), meningitis, hydrocephalus, neoplasia, arteritis


Question Answer
VertigoIllusion of movement, not to be confused with dizziness or lightheadedness
Peripheral vertigo1. More common 2. Inner ear etiology (semicircular canal debris, vestibular nerve infection, Meniere’s disease) 3. Positional testing→ delayed horizontal nystagmus
Central vertigo1. Brain stem or cerebellar (vestibular nuclei, posterior fossa tumor) 2. Positional testing - immediate nystagmus in any direction; may change directions


Question Answer
Sturge-Weber syndrome1. Congenital disorders w/port wine stains (nevus flammeus). 2. Can cause glaucoma, seizures, hemiparesis and mental retardation 3. Occurs sporadically
Sturge-Weber seen in 1. Typically in V1 ophthalmic distribution 2.ipsilateral leptomeningeal angiomas 3. Pheo
Tuberous sclerosis1. Hamartomas in CNS, skin, organs; cardiac rhabdomyoma, renal angiomyolipoma, supependymal gian cell astrocytoma, mitral regurgitation, seizures, hypopigmented “ash lead spots”, sebaceous adenoma, shagreen patch. Autosomal dominant
Neurofibromatosis type I (von Recklinghausen’s disease)1. Cafe au lait spots 2. Lisch nodules (pigmented iris hamartomas) 3. Neurofibromas in skin, optic gliomas, pheo 4. Autosomal dominant mutated NF-1 gene on chromosome 17
Von Hippel-Lindau diseasecavernous hemangiomas in skin, mucosa, organs :bilateral renal cell carcinoma, hemangioblastoma in retina, brain stem, cerebellum: pheo. Autosomal dominant mutated tumor suppressor VHL on chromosome 3
Hamartomabenign, focal malformation that resembles a neoplasm in the tissue of its origin