Case In Point: Perilymphatic Fistula

A 4-year-old girl was brought to a local emergency department (ED) after an episode of dizziness, vomiting, and horizontal nystagmus. Her parents reported that she was following them when they entered their garage to get a ball. When the girl did not appear in the garage, her parents went to look for her and found her lying next to a tree. When they attempted to get her to stand up, she complained of dizziness and then vomited. Her parents noted that her eyes were moving back and forth rapidly. She was continent, alert, and interactive during the entire episode. All extremities moved equally and there were no signs of trauma, abrasions, or bleeding. The child remembered that she felt better lying down than sitting or standing. She recalled her parents coming for her but could not remember how she fell. In the ED, the patient's vital signs were normal. However, the ED staff noted horizontal nystagmus and also dried blood in the child's left ear canal. CT scans of the head were reported as normal. Serum electrolyte levels and results of a complete blood cell count were within normal limits. The patient was referred to Children's Hospital of Michigan because of continued nausea and nystagmus. In our ED, the patient was alert, oriented, and interactive. We also noticed horizontal nystagmus and the blood in the left ear canal. There were no other abnormal physical findings. An otolaryngology consult was obtained: the blood in the ear canal was thought to be secondary to external trauma. An audiogram was performed; results showed moderate to severe conductive hearing loss on the left. Tympanography findings were within normal limits. Hearing in the right ear was normal. CT scans of the temporal bone showed a left perilymphatic leak and displacement of the stapes bone from the oval window into the vestibule. The patient was taken to the operating room. Surgeons found that the tympanic membrane had sealed over a twig that protruded from the middle ear into the oval window. The twig had dislocated the stapes, which could not be found. A patch was placed over the oval window. The patient was treated with intravenous ampicillin/sulbactam (Unasyn). Her nystagmus and nausea diminished after 2 days and she was discharged home on oral therapy with amoxicillin/clavulanate (Augmentin).Discussion We initially considered temporal bone fracture (because of the child's fall), seizures, CNS tumor or infection, and labyrinthitis. Seizure was unlikely, however, because the patient had no history of seizure-like activity. A mass lesion was a concern because of the nystagmus and nausea, but was ruled out after CT scans of the head proved to be normal. Infection was excluded after the child remained afebrile and had a normal white blood cell count. Labyrinthitis was unlikely because the patient had no recent history of viral illness. Trauma was highest on our differential list because of the blood in the child's left ear canal. Vertigo and nausea after trauma may be caused by temporal bone fracture, damage to the inner ear, or perilymphatic fistula. Temporal bone fractures may be transverse or longitudinal. Transverse fractures are less common and usually manifest with vertigo, severe sensorineural hearing loss, and hemotympanum. Longitudinal fractures present with conductive hearing loss, bloody otorrhea, and loss of consciousness. A temporal bone CT is the recommended test for evaluating the inner ear. In our patient, the CT scans showed both an inner ear problem and a perilymphatic fistula, but not the foreign body. A perilymphatic fistula may result from any congenital or traumatic disruption of the labyrinth that allows perilymph to leak into the middle ear (Table).1,2 House and colleagues3 estimated the incidence at less than 1 per 1000 outpatient otolaryngology visits. However, the literature contains mostly case reports and case series conducted over long periods--often involving patients with perilymphatic fistulas misdiagnosed as Ménière disease or idiopathic sudden hearing loss.3