Ask the Doctor

From Andy:-
I had a vasectomy in April 1999 and had an epididymitis in Feb 2000. Also developed a thrush type rash on the glands of my penis. Nothing was found after ultrasound cystoscopy etc. Shortly after that I developed cognitive problems (can’t remember or spell words as I used to) along with a neuralgia type sensation to the right hand side of my face. This is very problematic and something I have lived with for seven years. I had an MRI brain scan in 2002 but all was apparently normal. I had a vasectomy reversal in 2006 to see if this would help with testicular pain but to no avail. To date I have ongoing penile rash, and the neuralgia and constant cognitive problems and don’t have any ideas where to go with this. Have you any ideas what mechanisms could be involved here.

Up until a very recent press report there has never been any implication of vasectomy with any type of neurologic disease or forms of dementia. A recent observational study with a very small group of patients has suggested a slightly higher risk of primary progressive aphasia (PPA), a type of dementia, in patients who have had a vasectomy. Unfortunately, the authors of the study could not really provide a good mechanistic explanation of how this relationship could exist and stated that further research should be conducted prior to saying that any such association exists between vasectomy and PPA. The media, however, has done a fantastic job at sensationalizing this small study because it catches the attention of many of the 600,000 men and their partners who undergo a vasectomy procedure annually and encourages people to buy their newspapers/journals/media. The fact that this study was published without the input from any urologist at the authors institution or elsewhere I think speaks volumes as to the intentions of this study to cause paranoia and not truly understand what relationship, if any, exists between vasectomy and PPA.

PPA occurs at an average age of 62 and all of the men in the above mentioned study were between the ages of 55 and 80. Obviously, many men without vasectomy develop this condition and there was only a slightly higher incidence in men who had a vasectomy. The average age of men undergoing a vasectomy is somewhere in their mid-thirties. Why and, more importantly, how can something like a vasectomy performed 20 to 50 years earlier cause PPA is unknown to me. I think we have to be careful in attributing every neurologic symptoms that a patient might have after a vasectomy to PPA, especially so shortly after the procedure, as in the case in question here.

As a physician who closely follows the medical literature, I have to say that there are hundreds of these types of observational studies published annually in our medical literature. Some of these studies turn out to have credible data. Many of these studies are refuted by better studies that control for variables that confound the results. Unfortunately, in my experience, I have never seen the media print a retraction or follow-up story when newer information disputing the previous information is reported. I think the best example of this is the recent scare we had with Viagra causing men to go blind. Subsequent, better controlled studies, showed that the risk of that particular form of blindness attributed to Viagra was no greater in men taking Viagra as compared to their counterparts who were not taking the medicine. I’m sure most people never heard the follow-up studies printed in our media.

Penile rashes are not related to vasectomy. A rash on the penis that persists for several years likely represents some type of dermatitis, lesion or infectious disease. These have never been reported in association with a vasectomy. You can only diagnosis these skin conditions by visual examination and possible biopsy if the rash/lesion looks suspicious. Otherwise, it is difficult to say what might be causing the problem.

Comment from RA:-
With dementia rampant in my maternal side and my Mother suffering from FTD, this discussion caught my attention. I have read the abstract posted in Cognitive and Behavioral Neurology. Could you explain this phrase, “Potential mechanisms mediating risk include vasectomy-induced immune response to sper, which shares antigenic epitopes with brain. Antisperm antibodies can also develop in women and become risk factors for PPA. I had a vasectomy 5 years ago.

The authors of the article dealing with primary progressive aphasia (PPA), a rare type of dementia, and vasectomy were probably asked by the editors of the journal Cognitive and Behavioral Neurology to postulate a mechanism for this association. This association was not anything they evaluated in their study, but something they simply guessed could cause this association.

There are certain epitopes in the brain that are very similar to those found on sperm and if you place sperm antibodies directly on these brain cells that there will be some binding. However, you have to remember the human body is just not that simple. The causal relationship SUGGESTED in the PPA article assumes many critical points that have not been well-proven. First, there is a blood-brain barrier which excludes most large molecules such as certain antibodies from crossing into the brain, even if they are found circulating in the blood. Nobody has ever shown that these antibodies exist in the fluid around the brain, only that there is cross reactivity if the antibodies are placed directly on the brain, such as in an experiment in rats.

The second big assumption that is made by their hypothesis is that even if the antibodies are able to cross the blood-brain barrier, does this cause any reaction by the man’s immune system to destroy healthy brain cells? The process by which antibodies cause auto-immune diseases, such as PPA, is by targeted destruction by your own immune system. This also has never been shown to be true.

Finally, if the body’s immune system targets the brain after binding of anti-sperm antibodies (ASA), why don’t we see a higher rate of other neurologic diseases such Parkinson’s Disease, Multiple Sclerosis or Cerebral Palsy, to name a few?

Furthermore, the authors suggest that ASA can also cause PPA to occur in women when they are exposed to sperm in the vagina. Since we as human beings have been having sexual intercourse for thousands of years and billions of women have had sexual intercourse, whereas only a small fraction of their partners have had vasectomies, shouldn’t we see a much higher rate of PPA in women? This has never been shown to be true either. Maybe we should recommend stopping all sexual intercourse since it can increase the risk of PPA in women? The likely outcome of that would be human extinction within a generation.

Unfortunately, heredity plays a big role in our own health. People who have a strong family history of dementia have a higher risk of developing dementia themselves. However, this is not an absolute and people shouldn’t go through life paranoid of this eventuality. People should also remember that this article only SUGGESTS that there is an increased risk of developing a certain rare type of dementia, PPA, and not your garden-variety dementia. I am excited to see what subsequent studies will be published on this subject and if the media ever publishes the results of any credible study that reads: “Vasectomy does not cause dementia, as previously reported.” That type of headline does not sell newspapers or advertising.