A 65-year-old female diver surfaced from her second dive of the day; within 10 minutes she reported symptoms of extreme dizziness, vertigo and nausea/vomiting. A companion called the DAN emergency hotline, and the medic advised the ill diver to complete a field neurological exam. The assessment found she was unable to walk due to vertigo and twitching of her right eye.
Her dive profiles were as follows:
- First Dive: 95 fsw, 30 minutes, 35 percent EAN, surface interval 1:10
- Second Dive: 80 fsw, 45 minutes, 34 percent EAN
- All dives had appropriate safety stops, and she was wearing a 5 mm full wetsuit. The dives were from a boat in 2- to 4-foot seas.
She had no food or drink except for fresh water since the dizziness began. The caller said that the diver consistently has trouble equalizing and has a history of multiple cases of tympanic membrane ruptures, but there was no explicit report of difficulties on this particular dive during ascent or descent. There were no additional symptoms other than dizziness and nausea/vomiting.
The diver was transported to a nearby medical center, arriving roughly 90 minutes after symptoms began. She was treated by recompression and oxygen following a U.S. Navy Treatment Table 6. Symptoms had not resolved after five hours in the chamber.
Vertigo is a feeling that you or your surroundings are moving when there is no actual movement. You may feel as though you are spinning, whirling, falling or tilting. Persistent vertigo and vomiting after surfacing from a dive can be any number of things involving the brain or ear such as inner-ear decompression sickness (DCS), inner-ear barotrauma or stroke.
The time of symptom onset after the dive increases the probability that it was caused by the dive. The presence of nystagmus usually points to some type of vestibular dysfunction. The fact that it took about 10 minutes after surfacing to develop vertigo indicates DCS rather than barotrauma, although the latter should also be considered.
The vestibular organ of the inner ear is a part of the system that controls balance. When that organ does not function properly, incorrect signals are sent to the brain, causing vertigo. In a case of postdive vertigo, vestibular dysfunction could be caused by either inner-ear DCS or inner-ear barotrauma. Inner-ear DCS necessitates the need for hyperbaric oxygen therapy, while inner-ear barotrauma may actually worsen with treatment under pressure.
We tried to follow up with this diver, but we could not get her to reply to our messages and calls. We contacted the hospital where she was treated, but we obtained only limited information. It appears that the treating physician excluded the barotrauma and treated for DCS. The patient received one U.S. Navy Treatment Table 6 initially with no resolution of symptoms. She continued to receive two U.S. Navy Treatment Table 9 treatments per day for three additional days with some improvement.
Four days since the onset, symptoms improved but the patient still complained of dizziness. She was able to walk slowly unaided but unable to drive. At discharge, residual symptoms included one eye that was not completely straight and a reduction in hearing (she was using a hearing aid before the incident). According to her buddy, an otolaryngologist cleared the patient to dive 90 days after the incident, and she has completed 10-15 dives since then. Subjective residual symptoms include a change in her vision prescription and a reduction in hearing.
A long recovery indicates that there may be some permanent damage to the inner ear. Over time a patient will develop a compensation for the damaged organ that works in everyday life situations but may be compromised in diving. Thus, after an episode of inner-ear injury in diving, the diver must undergo a complete inner-ear evaluation before returning to diving.
Lana Sorrell, EMT, DMT