Lec 53 ANS Flashcards
What is a pancoast tumor? what is effect?
- tumor in apex of lung
- causes horners syndrome = ptosis, miosis, anhidrosis
What are 3 common causes of horner’s syndrome
canvernous sinus thrombosis
carotid dissection
pancoast tumor
What are features of CN 3 palsy?
- ptosis
- eye down and out
- mydriasis [ dilated]
What is afferent limb of BP control by autonomic?
- baroreceptors in heart and blood vessels sense pressure
- chemoreceptors in carotid body sense O2/CO2
- conveyed via CN 9 + 10 to nucleus of solitary tract
What is efferent limb of autonomic control of BP? ex. when you first go from lying down to sitting
- paraysmpathetic via CN 10 ti heart [decrease firing when you first stand up]
- sympathetic to heart [increase HR]
- sympathetic to peripheral arterioles [vasoconstriction]
What causes dysfunction of BP autonomic control? signs?
signs: orthostatic hypotension and syncope
CNS: parkinsons syndromes
PNS: autonomic neuropathy –> diabetes
Where is body temp regulated from?
- preoptic area
- anterior hypothalamus
Is sweating under sympathetic or parasympathetic control?
sympathetic
How do sudomotor sympathetics differ from other sympathetics?
postganglionic neurotransmitter is ACh
What causes anihidrosis [too littel sweating]?
- usually focal CNS lesion, neurodegenerative disorder, peripheral neuropathy
What is hyperhidrosis? two types?
primary focal = excess emotional sweating in hands/feet/axilla
generalized = al overdue to central dysregulation
What causes generalized hyperhidrosis?
central disorder of hypothalamic set point, medication induced, etc
What is the function of the insular cortex in the central autonomic network?
primary viscero-motor and sensory cortex
relays through hypothalamus
What is the function of the amygdala in the central autonomic network?
autonomic output related to emotional response
What is the function of the anterior cingulate in the central autonomic network?
autonomic response related to goal directed behavior
What is the function of the hypothalamus in the central autonomic network?
- location of homeostatic control
- connects to both ANS and endocrine and higher cortical structures
- sends autonomic output to brainstem, spinal cord via lateral and PVN
- integrates ANS and endocrine responses
What is the function of the nucleus of the solitary tract in the central autonomic network?
relay for visceral sensory info from CN VII, IX, X
medullary reflexes
What is function of ventrolateral medulla in central autonomic network?
contains:
nucleus ambiguus = CN IX, X, XI pharynx, larynx, esophagus
dorsal motor nuc of X = parasympathetic to viscera
What is the efferent sympathetic path from brain?
begins in hypothalamus –> reticulospinal tract –> intermediolateral cell column [T1-L3] –> exit CNS via ventral roots to para or pre-vertebral ganglia to join peripheral spinal nerves
What is the segmental organization of sympathetic intermediolateral column?
T1-T3 = head T2-T6 = upper limb and thoracic viscera T5-T11 = ab viscera T12-L3 = lower limb and pelvic
What is the parasympathetic efferent bath from brain?
beginins in hypothalamus but divides into cranial and sacral
cranial sources:
- edinger-westphal = control pupil constriction
- salivatory nuclei = tear + saliva
- nucleus ambiguus + dorsal motor nuc of X = supply vagus nerve that supplies all thoracic and ab viscera
sacral:
sacral parasympathetics exit spinal cord via ventral roots
What is horner’s syndrome?
disruption of sympathetics to face presents with:
ptosis, miosis, anhidrosis
What is the path of body sensing blood pooling in lower extremities?
- baroreceptors in heart and major vessels sense pressure
- chemoreceptors in carotid body sense O2 and CO2 levels
- info conveyed via CN IX and X to nucleus of solitary tract
- PNS efferents via vagus inhibited = increase HR
- SNS effects activated = increase HR AND increase BP via peripheral vasoconstriction
What is the 3-neuron path of sympathetic innervation of pupil?
- nerve starts in hypothalamus and descends in brainstem to synapse in intermediolateral colum
- preganglionic sympathetics from IML column T1/T2 ascend and synapse in superior cervical ganglion
- postganglionic sympathetics innervate pupil dilator muscle
What is sinus arrhythmia?
normal variablity in HR caused by dee breathing
inhalation –> increase HR
exhalation –> decrease HR
What is effect of parkinsonian disorders on ANS?
causes central ANS dysfunction
What is most common cause of peripheral autonomic neuropathy?
diabetes mellitus
What central autonomic structure regulates body temp?
preoptic area and anterior hypohtalamus
Is sweating under SNS or PNS control?
SNS
What is path of sweating mech?
- sudomotor fibers travel with peripheral somatic nerves to sweat glands, release ACh
What is effect of botulinum toxin on sweating?
prevents ACh release into synapse = inhibits sweating
Coordination of what 4 systems required for normal bowel, bladder, sex function?
- visceral and somatic afferents entering spinal cord via sacral DRG
- parasympathetic innervation from sacral cord via pelvic splanchnic
- somatic innervation from sacral cord via pudendal
- sympathetic innervation from thoracic cord via hypogastric
local inhibitory synapse on PNS efferents relaxes detrusor allowing for accumulation urine
What is function of visceral and somatic afferents in pelvic innervation?
signal bladder distension via stretch receptors
What is function of parasympathetic innervation in pelvic innervation?
relax internal sphincter + bladder contraction
–> urination
What is function of somatic innervation in pelvic innervation?
relaxation external sphincter = voluntary urination
What is function of sympathetic innervation in pelvic innervation?
contract internal urethral sphincter + bladder relaxation = urine retention
What is overflow incontinence?
lower motor neuron problem = flaccid bladder paralysis
- inability to sense when bladder is full; stress/overflow incontinence when bladder fills beyond capacity
- effects: urgency, nosturia, UTIs, renal impairment
What is pathophysiology of overflow incontinence? causes?
loss of bladder reflex circuit at S2-S4 due to loss of sensory afferents or loss of pudendal inhibition
due to:
- S2-S4 anterior horn lesion
- cauda equiona, conus medullaris lesion
- mononeuropathy of pelvic nerves, pudendal
- autonomic sensory small fiber neuropathies [DM]
- outflow obstruction = enlarged prostate
What is detrusor hyperreflexia?
UMN lesion, automatic/spastic bladder
bladder contracts when it shouldn’t and does not coordinate its action with sphincters
effects: urge incontinence [spasm at low urine volume], frequency, nocturia
What is pathophys/etiologies of detrusor hyperreflexia?
- disruption sympathetic innervation to bladder –> unopposed parasympathetic action; somatic reflex at S2-S4 still intact
due to:
- spinal cord injury > S2
- CNS lesion [MS, stroke]
- detrusor instability
What is difference in time frame of autonomic symptoms parkinsons disease vs parkinsons like disease?
parkinsons disease = late ANS dysfunction
parkinsons-like [shy-drager] = early ANS dysfunction
What is QSART test?
quantititaive sudomotor axon reflex test
release ACh onto skin, measure sweat response
How do you tell syncope vs seizure?
syncope = almost always positional (shortly after standing up or prolonged standing)
seizure = metabolic trigger, prodrome = stereotyped, visual or olfactory auras, convulsions, incontinence, postictal confusion
What are common causes of syncope?
need to rule out cardiac cause
neurodegenerative: parkinsons [PD] and associated or autonomic neuropathy
benign: neurocardiogenic [vasovagal]
syndromic: postural orthostatic tachycardia syndrome (POTS)
What is orthostatic hypotension? cause?
- due to neruodegenerative disorder, hypovolemia, autonomic neuropathy
- positional hypotension with compensatory tachycardia
- other tests of autonomic dysfunction are also abnormal
What is vasovagal syncope? cause?
the common faint
due to sudden increase in vagal tone
- have bradycardia and hypotension
What is POTS [postural orthostatic tachycardia syndrome]?
- dizziness, fainting upon standing and tachycardia WITHOUT change in BP
- more common in young women, post-viral, migraine associated, fibromyalgia
- all other tests normal
What are 3 central causes of ANS dysfunction?
multiple system atrophy [Shy-Drager] = early dysfunction
parkinsons disease = late dysfunction
neuro-degeneration of pure autonomic only
