Dizziness and Syncope Flashcards
dizziness - vertigo
*room spinning/pt feels that they are spinning around the room
*spinning
*vestibular system
*peripheral & central
dizziness - syncope/presyncope
*woozy, swimming, fainting
*“lightheadedness
*cardiovascular system
*heart, carotid, vessels
dizziness - dysequilibrium
*imbalance, off balance, unsteady
*dysequilibrium
*cerebellar circuitry
*cerebellar exam, MRI brain
dizziness - non-specific
*jitteriness/jittiness
*non-specific
*poorly localized
causes of non-specific dizziness
*hypo-/hyperglycemia
*panic attack, anxiety
*hyperventilation
*medications
approach to non-specific dizziness
*check blood sugar
*screen for anxiety and/or depression
*review meds
approach to dysequilibrium dizziness
*look for signs of cerebellar dysfunction (finger-to-nose and heel-to-shin testing)
*dysmetria
*ataxia
*necessitates imaging: MRI brain
syncope - definition
sudden onset of loss of consciousness
(pre-syncope: near loss of consciousness)
etiology of syncope
*reduced blood flow to the brain (reduced cerebral perfusion pressure)
*origin of reduced CPP can be cardiogenic, cardiovascular, or neurally-mediated
cardiogenic syncope
*cause = reduction in blood flow out of the heart (bradyarrhythmia, heart block, QTc abnormality)
*final result = cerebral hypoperfusion
*symptoms = presyncope / syncope
*evaluation: electrocardiogram (ECG), echo, etc
vascular-related syncope
*cause: problems in CV system after blood leaves the heart:
-aortic stenosis (blocked flow out of heart)
-proximal aortic lesion (coarctation)
-bilateral [NOT unilateral] carotid disease
*final result = cerebral hypoperfusion
*symptoms = presyncope/syncope
*evaluation: carotid artery ultrasound, vertebrobasilar imaging, echo
neurally-mediated syncope
*the development of arterial vasodilation in the setting of relative or absolute bradycardia
*disconnect between the sympathetic and parasympathetic nervous systems (too much parasympathetic and not enough sympathetic)
*aka vasovagal reaction, neurocardiogenic syncope, emotional fainting, or reflex syncope
neurally-mediated syncope: central stimulus
*strong emotional stimulus
*sudden scare, anxiety, panic
*direct activation of parasympathetic nervous system (increased vagal tone) and sympathetic withdrawal
neurally-mediated syncope: postural stimulus
*pooling of blood in the venous system
*reduced venous return to heart
*lack of reflexive tachycardia (e.g. relative bradycardia) resulting in inability to compensate
*orthostatic, dehydration, antihypertensives, autonomic neuropathy
**MOST COMMON CAUSE OF DIZZINESS
neurally-mediated syncope: situational stimulus
*micturition, defecation, post-tussive, valsalva
*specific stimulation of sensory or visceral afferents
*activation of strong parasympathetic tone without compensatory sympathetic counterbalance
*autonomic neuropathy
evaluation for neurally-mediated syncope
*blood pressure, heart rate
*orthostatic blood pressures
*tilt table testing
*neuropathy testing (for autonomic neuropathy)
treatment for postural neurally-mediated syncope
*lifestyle: slow to rise, compression stockings
*avoid: antihypertensives
*prescribe: fludrocortisone, midodrine
treatment for situational neurally-mediated syncope
*lifestyle: avoid situations that induce syncope
*avoid: beta blockers; reduce sympathetics
*prescribe: fludrocortisone, midodrine
vertigo
*the illusion of motion (whirling, tilting, moving, spinning)
chronic progressive vertigo
*think mass lesions (tumor in posterior fossa or vestibular schwannoma)
*can also be medication related
*can also be psychiatric
acute episodic (paroxysmal) vertigo
*occurs in episodes
*critical feature:
1) spontaneous (vestibular migraine, TIA, arrhythmia, PE/ACS, Meniere’s disease)
vs.
2) provoked/positional (BPPV, orthostatic hypotension, vertebrobasilar insufficiency)
benign paroxysmal positional vertigo (BPPV)
*example of positional acute episodic vertigo
*recurrent, severe vertigo provoked by head turn
*associated with torsional and upbeat nystagmus
*can be induced by bedside maneuvers such as Dix-Hallpike
*results from displacement of calcium crystals (otoliths) in the semicircular canals
vestibular migraine
*example of spontaneous acute episodic vertigo
*headache syndrome
*associated with dizziness and vertigo
*occurs in episodes
*may or may not be associated with actual head pain
acute vestibular syndrome
*acute onset of prolonged vertigo
*symptoms are persistent (often a day or more) and NOT in episodes
*dizziness/vertigo, often associated with nausea, vomiting gait instability, nystagmus, etc
*potential causes include:
1) peripheral (vestibular neuritis, labyrinthitis)
2) central (brainstem stroke)
peripheral acute vestibular syndrome (P-AVS)
*caused by irritation of vestibular apparatus or vestibular nerve
*vestibular neuritis (self-limited viral or post-viral syndrome)
*labyrinthitis, neurolabyrinthitis, etc
central acute vestibular syndrome (C-AVS)
*caused by brainstem stroke or cerebellar stroke
*other cause could be multiple sclerosis
how to determine if an acute vestibular syndrome is central or peripheral?
HINTS:
1. Head Impulse Test
2. Nystagmus
3. Test of Skew
head impulse test
*rapid and passive horizontal head rotation from center to lateral position with patient fixated at central target
*normal: eyes remain fixed to target
*abnormal: corrective saccade (head & eyes moves together, then eyes gradually look back to the examiner)
what does a normal head impulse test indicate in patients with acute vestibular syndrome
a CENTRAL cause of AVS (brainstem stroke or cerebellar stroke)
what does an abnormal head impulse test indicate in a patient with acute vestibular syndrome
a PERIPHERAL cause of AVS (vestibular neuritis, etc)
nystagmus
*repetitive, uncontrolled movements or shaking/jerking of the eyes
*unidirectional: eyes beat in the same way, regardless of which way the patient is looking
*direction changing: eyes beat in different ways depending on which way the patient is looking
what does unidirectional nystagmus indicate in patients with acute vestibular syndrome
*PERIPHERAL cause of AVS (vestibular neuritis, etc)
*note: unidirectional nystagmus is when eyes beat in the same way, regardless of which way the patient is looking
what does direction-changing nystagmus indicate in patients with acute vestibular syndrome
*a CENTRAL cause of AVS (brainstem stroke or cerebellar stroke)
*note: direction-changing nystagmus is when eyes beat in different ways depending on which way the patient is looking
test of skew
*skew deviation: vertical misalignment of the eyes
*subtle disconjugation of the eyes
*provoked by alternate cover test
*normal = no skew deviation
*abnormal = presence of skew deviation
what does an abnormal test of skew indicate in a patient with acute vestibular syndrome
*a CENTRAL cause of AVS (brainstem stroke or cerebellar stroke)
*note: abnormal test of skew = presence of skew deviation
signs of central acute vestibular syndrome
INFARCT:
*Impulse Negative
*Fast-phase Alternating (direction changing nystagmus)
*Refixation of cover test (skew deviation present)
