Dear Cecil: I have a habit of containing my sneezes by quickly holding my nose and shutting my mouth. It makes sneezing in class, in church, during intimate conversations, and so on much less traumatic. I've got my sneezes down to such a low profile that they're barely noticeable. But at work the other day, Miss Atomic Sneezer Know-It-All in the next cubicle warned me in all earnestness that containing a sneeze is a sure way to spark a brain aneurysm. Well, I'm as big a fan as the next girl of a long and brain aneurysm-less life. So what's the straight dope? Katie, Tampa

Cecil replies:

Straight dope coming up:

(1) This obsession with suppressing your natural bodily functions seems a bit dainty, Kate. I mean, it’d be one thing if, during some intimate conversation, you threw up on my shoes. But I wouldn’t take you home early because you sneezed.

(2) Be that as it may, the chances of your getting a brain aneurysm from a sneeze, stifled or otherwise, are pretty slim.

(3) But it could happen.

The peril isn’t strictly from containing a sneeze, although this does present some danger. Judging from the case file, you’re equally or more at risk from giving your sneezes full vent. Some cautionary tales:

A 64-year-old man repeatedly experienced severe headaches after sneezing heavily, followed by slurred speech and weakness on his right side. On examination he was found to have two cerebral arterial aneurysms — that is to say, two weakened, enlarged blood vessels in his brain — both as yet unruptured, luckily for him.

“After a violent sneeze, a previously healthy 35-year-old man had severe left-side neck pain lasting ten minutes,” we read. He developed partial paralysis and sensory loss on his left side, plus other symptoms. After tests the doctors decided he had “unilateral upper cervical posterior spinal artery syndrome,” a seven-word noun phrase that’s about as close as you can get to German and still be speaking English. To put it in simpler terms, an aneurysm in the neck following the sneeze probably led to a loss of blood flow to part of the spinal cord, causing nerve problems.

It’s not just sneezing that’ll do you in, either. Check out this one:

A 48-year-old woman was hospitalized with blurred vision and partial right-side paralysis. For a time she had been unable to speak. Upon operating, surgeons found and repaired a three-centimeter-wide aneurysm on her carotid artery. What had she done to trigger the episode? She’d blown her nose, forcefully and repeatedly.

You’re thinking: cheezit, if I so much as cough my brain is going to explode like a water balloon. Relax — only a handful of sneeze-related aneurysms have been reported in the medical literature. Moreover, it appears that sneezing per se won’t cause an aneurysm in someone who previously didn’t have one. But the sharp head and neck movements accompanying a violent sneeze may cause the inner and outer walls of a blood vessel to tear loose from one another, an event known as a “dissecting aneurysm.” Or a sneeze may stir up trouble with a preexisting aneurysm — either it ruptures (although I know of no cases in which this resulted directly from a sneeze) or debris within the aneurysm can block the flow of blood to the brain or other vital organ.

Is suppressing a sneeze bad? Could be, due to something called the Valsalva maneuver, better known as a way of relieving pain in the ears caused by a rapid change in elevation. While pinching your nostrils shut, you blow into your nose hard. This opens the Eustachian tubes connecting your inner ear with your throat and equalizes the pressure on either side of your eardrums. But because the Valsalva maneuver increases pressure in the chest, it also briefly blocks the blood flow entering the heart, causing a sharp fluctuation in blood pressure. Conceivably this could cause an aneurysm to rupture. You’re performing the Valsalva maneuver when you contain a sneeze, but the same pressure spike can occur during an especially violent sneeze, nose blowing, etc. So while your efforts to be ladylike could be harmful, Miss Atomic Sneezer may not be doing herself any favors either. We won’t know till one of you tries it and winds up in the ER.

Still, no sense fixating on sneezing. The specialists tell me you can pop an aneurysm by doing anything that significantly increases your blood pressure, including (a) straining at stool or (b) having sex. One neurosurgeon I spoke to said he could recall three or four cases of the latter — typically a guy brought in by his mistress. I can think of worse ways to go.

Clarification

Reader Timothy S. Errera points out that I was a little casual in my discussion of the Valsalva maneuver. Although blowing against shut nostrils is commonly called the Valsalva maneuver, the classic maneuver, as described by Italian anatomist Antonio Valsalva (1666-1723), involves blowing against your shut glottis (windpipe). See item 8 on www.abracadabra.saipan.com/36Misinfor.htm (link now defunct) for more detail. Both procedures increase pressure in the chest and can cause a fluctuation in blood pressure, conceivably leading to a popped aneurysm. Still, one wants to be aware of the distinction, and now you are.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.