Patients definition of
dizziness may not match with that of the examiner, defining the patients thoughts
and feelings is important.
Dizziness: Any discomfort other than pain, related to
the head. The etiology could be visual, cerebral, vestibular or gastrointestinal.
Vertigo: Actual sensation of motion, often rotatory,
in which either the patient or the environment is moving.
Unsteadiness: is a loss of equilibrium in
relationship to ones environment. Often described as bumping into
things, or almost falling. The etiology could be cerebellar, cerebral,
posterior column or vestibular. A pure labyrinthine etiology rarely gives rise to
unsteadiness without vertigo.
Lightheadedness: is described by the patient as a
feeling of going to faint.
History
And Examination
Determine the duration, frequency, of each episode, and whether it
is constant, episodic, or related to position or other activity.
Past medical history of dizziness, fainting, collapse, fits, etc.
should be taken into consideration when arriving at a diagnosis.
General medical history of diabetes, cardiovascular disorders,
neurological dsiorders and drugs should always be obtained.
A complete ENT and neurological examination which includes
observation of nystagmus in three directions of gaze is a requisite.
Audiometric tests, radiology for posterior fossa and IAM, caloric
tests or ENG can be obtained if needed.
Positional testing is performed if the symptoms are induced when
the patient assumes a particular position.
Note:
Sudden change of position may aggravate the symptoms of any type of dizziness without
necessarily implying a disease of labyrinthine origin or positional vertigo.
Clinical
Features
Certain clinical
presentations, although they result from a diverse group of etiologies manifest the same
clinical picture, they are discussed here rather than individually.
Sudden Unilateral
Vestibular Loss
Causes:
Blunt or sharp trauma
Surgical ablation of labyrinth
Suppurative or viral labyrinthitis
The sudden loss of vestibular function with normal function in the
opposite labyrinth evoke certain symptoms. They are;
Severe whirling vertigo, with nausea, vomiting, pallor and
sweating.
Intensity is maximum at one hour, and remain at the same intensity
for 12 to 36 hours.
Vertigo gradually resolves, but reappears with sudden head
movements. There are problems with gait, picking objects from the floor, reading and
driving.
Patients develop adaptation by 2-3 months.
Gradual Unilateral
Vestibular Loss
Causes:
Space occupying lesions of the IAM or vestibular nerve.
The process takes place over months.
No vertigo is perceived. Symptoms are related to gait and station
instability, worsened by fatigue and darkness when compensatory mechanisms fail.
Gradual Symmetric
Vestibular Loss
Causes:
Vestibulotoxic drugs.
Symptoms are related to gait and station problems. Gait becomes
staggering and broad based.
Differential
Diagnosis
When evaluating a
patient with vertigo, one should try to differentiate between vertigo of peripheral and
that of central origin.
Peripheral
Central
1. A definite sensation of movement is
present.2. Severe and paroxysmal.
3. Attacks last from minutes to days, often accompanied by nystagmus and
autonomic symptoms.
4. Patient never loses consciousness.
1. The vertigo is mild and more like a
sensation of unsteadiness.2. Vague and with no specific onset or
termination.
3. The attacks lasts for weeks, often without nystagmus.
Vestibular neuronitis (Vestibular
paralysis)
Usually follows an upper respiratory infection.
Patient experiences sudden attack of vertigo with nausea,
vomiting, sensation of blacking out and unsteadiness. This is aggravated by sudden
movements.
Can last for days to weeks.
Cochlear symptoms (Deafness and tinnitus) are absent.
No neurologic deficit.
When seen initially there is spontaneous nystagmus towards the
contralateral side.
A caloric test shows marked hypofunction or no response..
Audiometry and radiology of IAM is normal.
After the subsidence of the acute attack, the patient may continue
to experience unsteadiness for or lightheadedness for several weeks.
Some patient experience a relapse in 3 to 6 months.
Etiology: Degenerative changes, otitis media, concussion, ear
surgery, and occlusion of anterior vestibular artery.
Histology has demonstrated otoconia on the cupula of the posterior
semicircular canal.
Patient presents with sudden attacks of vertigo precipitated by
certain head positions.
Vertigo is always of short duration.
Diagnosis is confirmed by positional testing.
There are no cochlear symptoms.
Vertigo Due to Whiplash Injury
Patients often complain of dizziness following whiplash I injury.
Onset of dizziness is usually after 7-10 days of injury
particularly on head movements to the side of injury.
Symptoms may last for months or years after the accident.
Otological examination is normal.
Vestibular examination can reveal spontaneous or positional
nystagmus with the head turned in the direction of whiplash.
Electronystagmography is essential in evaluating these patients.
Cervical Vertigo
It can caused by cervical spondylosis and other etiologies.
There are several theories about the causation of vertigo due to
cervical spondylosis;
Osteophytes cause irritation of the vertebral sympathetic plexus,
which is in close proximity to the vertebral artery. Spasm causes temporary ischemia
leading to vertigo.
Loss of proprioception in the neck causes vertigo.
Subclavian steal syndrome may also cause cervical vertigo.
S/S:
Headache,
vertigo, syncope, nausea and vomiting (Vagal),visual symptoms such as flashing lights due
to ischemia of the occipital lobe caused by involvement of the posterior cerebral artery,
a branch of the basilar artery.
All above symptoms occur when the head and neck
are in certain positions.
Treatment:
Avoidance of critical neck positions.
Neck exercises.
Cervical traction.
Cervical collar.
Migraine
Vertebro-basilar migraine is due to impairment of circulation to
brainstem.
Symptoms include vertigo, dysarthria, ataxia, paraesthesia,
diplopia, scintillating scotomas, and homonymous hemianopia.
The initial phase of vasoconstriction is followed by
vasodilatation leading to throbbing headache.