Other Causes
Hiccups naturally should last only a few seconds or minutes, if they last for more than that, it can be an indication of a bigger problem. Listed above are common causes of hiccups amongst people. However, if you have continuous, constant hiccups that last into days or weeks, it may be a clear indication of one of the following:
Central nervous system disorder
If a person consistently experiences recurring hiccups that occur for as long as days or weeks, then it may be a sign of a nervous system disorder. Infection or tumor in your CNS may cause your body to lose control of its reflexes, causing you to have uncontrolled hiccups.