Ch 3: Clinical Correlates pg 76-89 Flashcards
a lesion of the descending hypothalamic axons between the hypothalamus and the preganglionic sympathetic neurons in T1 spinal segment may result in… and to what side?
Horner’s syndrome and orthostatic hypotension
ipsilateral
lesion in axons of pontine UMNs and neurons in anterior hypothalamus above sacral S2-S4 levels may result in…
spastic bladder
*sacral parasym neurons that innervate bladder not inhibited effectively when bladder is stretched during filling so will involuntarily empty with minimum stretch
dorsal column/medial lemniscal system primary neuron synapse on what nuclei? and where do second neurons cross?
nucleus gracilis and nucleus cuneatus in caudal medulla
second neurons cross midline in vicinity of cell bodies–>form medial lemniscus
lesion of dorsal column results in…. and on what side?
loss of epicritic sensations- discriminative touch, joint position sensation, vibration/pressure sensations
ipsilateral and below lesion
dorsal column axons are sensitive to what types of diseases?
degenerative or demyelinating
*because use large-diameter, myelinated class Ia, Ib, II, and A-beta dorsal root fibers
neurosyphilis can result in what condition?
Tabes dorsalis= bilateral degeneration of the large-diameter dorsal root fibers, neuron cell bodies, and dorsal column axons (most commonly fasciculi gracilis)
what are the 3 “Ps” of Tabes dorsalis?
parethesias, pain, and polyuria
- parethesias: impaired vibration and position sense in lower limbs (carried by fasiculus gracilis)
- pain: hypersensitivity of small-diameter A-delta and class C pain and temp dorsal root fibers
- polyuria: loss of large-diameter sensory neurons that mediate bladder fullness–>frequent emptying; urine retention may also be present
**OTHER SYMP: muscle stretch reflex suppressed (degeneration of Ia dorsal root fibers) and Argyll Robertson pupils (accomodate but do not react to light)
how do you distinguish between dorsal column lesion (sensory ataxia) and lesion in midline of cerebellum (motor ataxia)?
ROMBERG TEST
- if positive (sways with eyes closed, but not when eyes open)–>sensory ataxia
- versus cerebellar lesion will sway even with eyes open and have balance problems
anterolateral system primary neurons synapse where? and where do second neurons cross?
collaterals ascend/descend 1-2 cord segments in dorsolateral tract of Lissauer before entering dorsal horn
second neurons cross in vicinity of cell bodies at all spinal cord levels–>spinothalamic tract
in the skin, tissue damage results in the release of what, which activates pain and temp sensitive free nerve endings?
prostaglandin and bradykinin
how do aspirin and nonsteroidal analgesics work as pain suppressants?
block enzyme used in synthesis of prostaglandins
unilateral lesion of axons in the spinothalamic tract in the spinal cord or brainstem results in… and where/on what side?
loss of pain and temp
contralateral
if in spinal cord: 1-2 segments below lesion
if in brainsteam: below lesion
if dorsal roots of anterolateral system are lesioned, this result in… and where/on what side?
loss of pain and temp
ipsilateral
limited to dermatomal distribution at the level of the lesion
syringomyelia is caused by…. and results in….
- cavitation/syrinx of the central canal of the spinal cord (commonly cervical segments)
- bilateral loss of pain and temp initially at or just below level of cavitation (*spinothalmic axons cross in ventral white commissure just below central canal)
- then as expands, LMN may be compressed–>flaccid paralysis of upper limb muscles
- unilateral or bilateral Horner’s may be late manifestation (compression of descending hypothalamic axons near ventral horns)
infants with Arnold-Chiani malformation can have…
synringomyelia
dorsal spinocerebellar tract carry what information, arise what nucleus and cross where?
proprioceptive input from muscle spindles/GTOs of lower limbs and trunk
Clarke’s nucleus (T1-L2)
DO NOT CROSS (ipsilateral)
cuneocerebellar tract carry what information, arise what nucleus and cross where?
proprioceptive input from muscle spindles/GTOs of upper limbs and trunk
external cuneate nucleus
DO NOT CROSS (ipslateral)
Friderich’s ataxia is caused by what? and results in what?
- degeneration of SPINOCEREBELLAR tracts, also dorsal columns and corticospinal tracts
- sensory ataxia (pos Romberg) initially, then hyporeflexia and altered vibratory sensations
- 2 ipsilateral long tract signs (UMN, dorsal column) and 1 contralateral long tract sign (spinothalamic)
- if at cervical spinal cord levels may have ipsilateral Horner’s
- if above S2, may have spastic bladder (likely will resolve because bilateral innervation)
- at level of lesion, incoming dorsal roots and outgoing ventral roots may be lesioned–>ipsilateral loss of all sensation (touch/pain/temp) and ipsilateral flaccid paralysis supplied by segments affected
what syndrome is this?
Brown-Sequard syndrome
spastic paresis ipsilateral to and below level of lesion of spinal cord
lesion of axons of UMN including corticospinal tract
loss of joint position sense, tactile discrimination and vibratory and pressure sensation ipsilateral to and below lesion of spinal cord
lesion to fasciculus gracilis or cuneatus
loss of pain and temp that is contralateral and 1-2 segments below the level of the lesion of spinal cord
lesion to spinothalamic tract
Brown-Sequard syndrome is caused by?
- lesion or compression of 1/2 of spinal cord caused by trauma, neoplasm or herniated disk
- if complete hemisection–>lesion in UMN, descending hypothalamic axons, 1 or both dorsal column, spinothalamic and dorsal spinocerebellar tracts
- at level of lesion incoming dorsal and outgoing ventral roots may be lesioned
patient with spinal cord hemisection or complete transection may undergo initial period of? and will be replaced by?
spinal shock
replaced by spastic weakness and UMN lesion signs
spinal shock is characterized by?
flaccid paralysis of muscles below transection, loss of all reflexes, and loss of all sensation below level of lesion
may also have transient atonic/flaccid bladder-fills to capacity then dribbles out bc failed detrusor contraction and weak urethral sphincter (to become spastic)
sudden occlusion of anterior spinal artery results in what?
bilateral spastic paresis and bilateral loss of pain and temp below level of lesion (perhaps following period of spinal shock)
**supplies ventrolateral parts of cord (corticospinal and spinothalamic)
vitamin B12 (cobalamin) deficiency causes what and can result in what condition?
swelling of myelin sheath in dorsal columns and corticospinal tracts in thoracic or cervical regions
peripheral myelin may also be involved
subacute combined degeneration
subacute combined degeneration is characterized by what symptoms?
bilateral spastic paresis and bilateral alteration of touch, vibration, and pressure sensations below the lesion sites
- if peripheral myelin involved, parethesias and impaired sensation in all 4 limbs
