ICS-Dizziness Flashcards
What are the most common causes of vertigo?
BPPV (Benign Paraoxysmal Positional Vertigo) > Meniere’s > Vestibular Neuritis
A 60 year old female complains of dizziness when rolling out of bed to her left this morning. It lasted about 20 seconds. She says that it feels like the room spins towards her left ear. Physical exam reveals dizziness on any movement of the head, nausea and left nystagmus.
This patient has BPPV. Bouts are triggered by looking up and turning over in bed from cupula disturbance. When a patient says the room spins toward the left ear, she is indicating the slow phase of nystagmus, which means the eyes are moving to the right during the slow phase. Since the fast nystagmus is towards the left, she probably has something going on with the left semicircular canal.
What semicircular canal is most often affected in patients with BPPV?
Posterior semicircular canal. It has a dependent opening to the utricle, which houses all the otoconia that can dislodge, move to the cupula and trigger excitation of the ampullary nerve, causing a burst of vertigo.
What is the difference between vestibular neuritis and vestibular labrynthitis?
Hearing loss. Vestibular neuritis only involves the vestibular nerve. The labyrinth includes the cochlea & semicircular canals and will cause hearing loss in addition to vertigo.
How do the eyes move when the posterior semicircular canal has a otolith lodged in it?
Eye stimulation is down and in from stimulation of the eye muscles below. The nystagmus will be up and out.
How do you test for BPPV from posterior semicircular canal in the ED?
Dix Hallpike test: Pt seated on exam table w/head 45 degrees to right -> Rapidly move patient supine w/ head 30 degrees below horizontal -> Look for up and out rotary nystagmus for 1 min -> Rapidly lift upright -> look for opposite nystagmus (down and in) for 1 minute
How do you treat BPPV from the posterior SCC in the ED?
Epley Canalith Repositioning Maneuver. Pt seated on exam table w/head tucked @ 45 degrees toward affected ear -> Rapid to supine w/head extended @ 30 degrees and rotated 45 degrees toward affected ear -> hold 60s -> roll patient onto unaffected side w/head tucked 45 degrees to floor -> Sit pt up w/head rotated 45 degrees toward unaffected side w/chin tucked
A 38 year old male presents complaining of dizziness in the shower after waking up. At work he felt constantly dizzy and falls toward the right if he is not holding on to something. Lying still helps, but does not eliminate the spinning sensation. How do you treat this patient?
Note that the patient’s symptoms were PERSISTENT even when lying down. He has vestibular neuritis (neurotropic virus infection of the vestibular nerve). If he had accompanied hearing loss you would think of viral labyrinthitis or Meniere’s.
When a patient presents with vestibular neuritis and the room spins towards his left ear, which ear is damaged?
Right ear. Damage to the right side will cause the eyes to deviate right. This will cause the room to “spin” towards the left ear.
Physical exam techniques for vestibular neuritis?
Covered fundus exam (fixation on an object will suppress nystagmus in patients who have latent VN), Head thrust exam (rotate pt’s head from forward position while patient is fixated on your nose. If eyes fall from nose in left rotation, left ear is damaged), Fukuda step test (close eyes, march in place, if patient rotates right, right ear is damaged
A patient presents with a right beating nystagmus in the fundus. Which way is the actual nystagmus?
Left. The fundus is in the back of the eye, so the front of the eye will be reversed.
Alexander’s law
Nystagmus after vestibular neuritis will be towards the healthy ear. The nystagmus will be greatest when gaze is directed towards the healthy ear and may be absent when gaze is directed towards the unhealthy ear.
How do you treat vestibular neuritis?
You can use benzos to suppress vestibular nuclei. You can do Daroff exercises to help the CNS compensate (sit on the edge of the bed and lay down, alternating sides for about 10 minutes)
How do you determine of vertigo is centrally or peripherally mediated?
Peripheral = latency, nystagmus, bouts < 1 min, overcomes nystagmus w/fixation, unidirectional postural instability. Central = severe postural instability w/other neurological symptoms.
How can you use the vestibulocular reflex to test cortical function in a comatose patient?
Caloric reflex test. Put cold water in one ear. The eyes should deviate towards that ear with a rapid nystagmus away from it. Put warm water in one ear. The eyes should deviate away from that ear with a rapid nystagmus towards it. The cortex is responsible for the nystagmus you see.
