The Lake Louise Consensus Criteria for<unk> 
The presence of a change in mental status OR ataxia in a person with AMS
OR the presence of BOTH a change in mental status and ataxia in a person without AMS
The presence of a change in mental status OR ataxia in a person with AMS
OR the presence of BOTH a change in mental status and ataxia in a person without AMS
Lumbar puncture is not required, but if performed, will generally show elevated opening pressures (>44 mmH2O) and normal fluid analysis
CT or MRI may be confirmatory, but not necessary. Most beneficial to rule out alternative etiologies. If performed, may show signs of vasogenic edema. MRI will show white matter edema (increased T2 signal), particularly in the corpus callosum
High altitude cerebral edema
Acute mountain sickness
High altitude peripheral edema
Chronic mountain sickness
High altitude pulmonary edema
Decompression sickness
High altitude retinopathy
Sepsis 