A<unk>  is a loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive in<unk>  typically<unk> er than five meters (16 feet), when the swimmer does not necessarily experience an urgent need to breathe and has no other obvious medical condition that might have caused it.  Victims are often established practitioners of breath-hold diving, are fit, strong swimmers, and have not experienced problems before.
Many drowning and near drowning events occur among swimmers who<unk>  underwater while free-diving or doing breath-hold pool laps.  Blacking out, or browning out, near the end of a breath-hold dive is common. Although the mechanism is well understood, it is not common knowledge among breath-hold divers.<unk>  is related to, but differs from deep<unk><unk>  in its characteristics, mechanism and prevention; deep<unk><unk>  is precipitated by depressurization on ascent from depth.<unk>  may also be referred to as a syncope or fainting.
Shallow water blackout
Renal papillary necrosis
Shunt nephritis
Acute tubular necrosis
Transistasis
Interstitial nephritis
Renal colic
Renal cortical necrosis