CAUSES
β’ Physiological - mismatch of vestibular, visual and somatosensory systems triggered by an external stimulus, such as a stop after whirling turns, heights, motion sickness
β’ Pathological - imbalance in the vestibular system caused by a lesion within vestibular pathways (inner ear to cerebral cortex)
β’ Infections (especially viral, such as mumps)
β’ Tumors
β’ Vasculitis
β’ Infarction
β’ Ototoxic drugs, especially aminoglycosides
β’ Head injury
β’ Neuronitis
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DIFFERENTIAL DIAGNOSIS
β’ Acute viral labyrinthitis
β’ Benign paroxysmal positional vertigo (BPPV)
⒠Ménière syndrome
β’ Post-concussive syndrome
β’ Chronic bacterial otomastoiditis
β’ Drug-induced damage to vestibular labyrinth
β’ Vascular insufficiency
β’ Cerebellopontine-angle tumors, such as acoustic neuroma
β’ Multiple sclerosis
β’ Para-infectious encephalomyelitis
β’ Para-infectious cranial polyneuritis
β’ Ramsay Hunt syndrome
β’ Cerebral or systemic vasculitis
β’ Temporal lobe epilepsy
β’ HIV infection
β’ Perilymphatic fistula
SPECIAL TESTS
β’ Electronystagmography
β’ Caloric test
β’ Dollβs eye test
β’ Forced voluntary hyperventilation for 1 to 3 minutes to mimic symptoms if cause is physiologic or emotional
IMAGING CT or MRI for suspected lesions involving the eighth cranial nerve