Bove, in 'Diving Medicine', states
"Individuals with a history
of transient ischemic attack (TIA) must undergo evaluation for
cerebrovascular
or cardiac disease before being considered for sport diving. Often a
TIA
is an indication of carotid disease, intracardiac thrombus,
endocarditis,
or valvular heart disease. These must be ruled out before consideration
for diving".
Diver's
Alert Network has the following to say about "stroke" in an
article in the 'Alert Diver', May-June, 1999.
"Stroke, or loss of blood supply to the brain, causes damage to part of
the brain, or bleeding from a blood vessel in the brain, which results
in similar injury. Strokes come in all sizes and shapes, and the
resulting disability depends on size and location of the event.
Fitness & Diving:
- Most strokes occur in older people. The stroke itself identifies
the person as one who has advanced arterial disease, thus a higher
expectation of further stroke or heart attack.
- The extent of disability caused by the stroke (e.g., paralysis,
vision loss) may determine fitness to dive.
- Vigorous exercise, lifting heavy weights and using the
Valsalva method for ear-clearing when diving all increase arterial
pressure in the head and may increase the likelihood of a recurrent
hemorrhage.
- While diving in itself entails exposure to elevated
partial pressures and elevated hydrostatic pressure, it does not cause
stroke.
- There is certainly increased risk in diving for someone
who has experienced a stroke. Exceptional circumstances may exist, such
as cerebral hemorrhage in a young person in whom the faulty artery has
been repaired with little persisting damage. This type of recovery may
permit a return to diving, with small risk. Each instance, however,
requires a case-by-case decision, made with the advice of the treating
physician, family and diving partners. Consulting a neurologist
familiar with diving medicine is also advisable.
- There is a similar concern for significant residual symptoms, as
with post brain tumor surgery."