Dehydration
AMS is not improved by fluid administration alone
Body hydration does not influence susceptibility to AMS
Exhaustion
Viral syndrome
Alcohol hangover
Substance abuse
Caffeine withdrawal
Hypothermia
CO poisoning
CNS infection: Meningitis, Encephalitis
Cerebral venous sinus thrombosis
Migraine
Whereas supplemental O2 helps headache due to AMS in 10-15min, O2 has no effect on migraines
TIA
Hypoglycemia
AMS is not improved by fluid administration alone
Body hydration does not influence susceptibility to AMS
Whereas supplemental O2 helps headache due to AMS in 10-15min, O2 has no effect on migraines<unk> 
Chronic<unk><unk> 
High altitude cerebral edema
High altitude pulmonary edema
High altitude peripheral edema
High altitude retinopathy
High altitude pharyngitis and bronchitis
Ultraviolet keratitis
Acute mountain sickness
Dehydration
Decompression sickness
AMS is not improved by fluid administration alone
Chronic mountain sickness
Body hydration does not influence susceptibility to AMS
High altitude cerebral edema
Exhaustion