DIVING

2. Dive Injuries
Vertigo
Vertigo was reported in 70 cases. There are many possible causes of vertigo and the diagnosis is generally based on a
set of specific tests, as well as evolution of symptoms over time. Sometimes vertigo resolved before the diagnoses was
established. In divers, vertigo can occur during the depth change such as on descent and ascent or post-dive. It can be
the result of barotrauma (during ascent or descent) or possible decompression sickness (the final stages of decompression
or after surfacing). Subjective reports are difficult to evaluate because divers often confuse vertigo with dizziness.
Here are two typical cases reported to MSCC.
Case 2-05: Acute dizziness beginning at depth
The caller identified himself as a dive instructor. He had a 30 year old female dive student who had difficulty on her first
open water dive. The maximum depth reached was 30 fsw (9 msw) with a total bottom time of 20 minutes. Upon initial
descent the student gestured that she felt dizzy. They proceeded to perform skills but after 20 minutes the dizziness
became intolerable for the student. Instructor and student made a controlled safe ascent to the surface. Once back on
the boat the student began vomiting. She denied any difficulty with equalization on this dive or at any time during her
water training. The vomiting subsided on return to the resort. The diver slept for about 1 hour and felt no better. She was
experiencing nausea with head movements.
The caller was concerned that her symptoms could indicate a decompression injury including a possible AGE. It was
explained that since the symptoms started at depth any form of decompression illness was highly unlikely. There were
many potential causes for her symptoms and a prompt evaluation by a physician was the best course of action. The
physician’s evaluation revealed no significant findings. The final diagnosis was acute motion sickness/anxiety.
Case 2-06: Acute vertigo after a long and shallow dive
A physician who is an emergency department attending contacted DAN regarding a 44 year old male commercial diver.
He had made repeat dives within the hull of a docked ship to pump water out of the vessel. The maximum depth was
30 fsw (9 msw) for up to 4 hours. Similar dives had been made for the last 2 days without incident. Within 45 minutes of
surfacing from today’s dive he experienced sudden onset of acute vertigo, nausea and vomiting. He had difficulty walking
and needed to reduce head movements as this increased the symptoms. EMS transported him to the local emergency
department. On examination the diver also displayed nystagmus as well as all of the previously mentioned symptoms.
He denied any difficulty with equalization especially any forceful maneuvers. Otoscopic examination of the tympanic
membranes showed no evidence of any barotrauma. The caller was trying to determine if treatment in a chamber was
indicated.
The shallow depth of the exposure would not typically suggest the possibility of inner ear decompression sickness
(IEDCS). However, in the context of prolonged bottom times and physical exertion at depth, IEDCS could not be ruled
out. DAN‘s dive physician consulted with the attending physician. The conclusion was again that despite the shallow dive,
IEDCS could not be eliminated as a differential diagnosis and treatment in a chamber would be indicated. The patient
was transferred to an appropriate facility some 45 minutes away from the initial hospital.
The first treatment was a USN TT6 which did not result in any significant improvement. The next morning he was treated
with a second TT6 with measurable improvement. The patient still had some difficulty with walking but his vertigo was
greatly reduced and the nausea, vomiting and nystagmus were resolved. A USN TT9 was provided the next day with
marginal improvement. The patient was able to walk safely on his own and the opinion of the treating physician was that
he would continue to improve with time. He was discharged that afternoon and was to consult with an ENT specialist.
The diver did improve gradually over the next few weeks with ultimately complete resolution of all symptoms.
Annual Diving Report – 2012-2015 Edition
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