An unexpected, agonizing pain in the ass in the middle of the night could be a sign, according to Yukan Fuji (1/30) that you need to let off a bit of steam. Or at least just let off.

"There's more of this sort of thing going around," Mitsukuni Azuma, head of the Azuma Proctology Clinic, tells Yukan Fuji.

Azuma tells the lowbrow tabloid that discomfort in the derriere is probably a condition known as dissipative anal pain. Its symptoms are sudden development of excruciating pain in the anus during sleep or in the early hours of the morning that feels somewhat akin to the sphincter muscles being violently pinched. The pain is usually sufficient to wake the sufferer, but usually dissipates within 10 to 15 minutes of breaking out.

Azuma says most of the patients he treats for the affliction experience it for the first time the night before they see him and rush off for a diagnosis the following morning.

"One of its features is that you wake feeling a strong need to defecate, and having a poop or simply just farting is often enough to ease the pain. Warming the buttocks is also an effective way to soothe the pain," the proctologist says.

Azuma says dissipative anal pain is nothing more than a spasm in the sphincter and even a specialized examination of the area will not turn up anything untoward that causes it. The doctor says the main cause of the butt-wrenching bane is excess stress.

"What stands out among those who suffer it is that nearly all of them are either fastidious and fussy or really nervous types," Azuma tells Yukan Fuji. "It tends to easily affect those who are over-worked, too." (By Ryann Connell)