Nose blowing-induced biphasic nystagmus of unknown origin

Nose blowing can increase middle ear and cerebrospinal fluid pressure. We report a case of biphasic nystagmus induced by nose blowing. The patient showed biphasic, right-beating, and left-beating nystagmus, and complained of spinning vertigo after blowing her nose. The nose-pinched and glottic Valsalva maneuver and the Toynbee maneuver suggested that biphasic nystagmus was induced by increased middle ear pressure. Diseases inducing biphasic nystagmus were ruled out. A left tympanotomy resolved the patient's vertigo and biphasic nystagmus, whereas right tympanotomy did not alleviate them. When middle ear pressure changes are thought to be the cause of vertigo and nystagmus, a right or left tympanotomy may be considered a possible option for diagnosis and treatment, even if the cause and the affected side of the disease are unknown.