I am 63 and was told my prostate is normal for my age, slightly enlarged. I know that frequent p.m. urination can be affected by several things. But  the other symptoms, like weak urine stream and dribbling, will fluctuate...some times less than other times. What could account for this? Seems unlikely, but can someone's prostate fluctuate in size at different times of the day or from one day to the next?   Thanks

Lee, other than the gradual increase with aging, the prostate fluctuates in size only related to sexual excitation.  With arousal it fills up with fluid which it then releases with ejaculation (making up about 2/3 of the semen).  The quality of the stream can fluccuate usually related to the amount of urine in the bladder (assuming in this example for a given degree of obstruction from the prostate).  This is related to the amount of stretch on the muscular bladder wall based on the laws of LaPlace.  The minimally stretched or overstretched bladder muscle will contract less forcibly and thus the urine is passed through the urethra in a lesser stream.  With a moderate amount of urine in the bladder, the muscle is stretched "just right" and the propulsion force is maximal.  Dribbling after urination is generally most prominent in those conditions where the force of the stream is less.

Post voiding dribbling is a very common problem.  It is due to trapping of some urine in the urethra which then leaks out after one has finished urinating.  Minor leakage is common in most men.   It is usually due to an obstruction such as from a swollen prostate, a narrowing of the urethra (stricture) or a narrowing at the penile opening (meatus).  The most common causes are from a swollen prostate (either an inflammation, so called prostatitis or a benign enlargement of the prostate - BPH).  In my experience, another frequent cause is in those men who remove their penis through the unzippered fly, void and then put the penis back.  Often, the space is not adequate for total free flow as the lower (bottom) edge of the fly can actually push on the urethra causing urine to be trapped.  This phenomenon can be totally avoided by dropping the trousers and then urinating in the standing or sitting position.  If the dribbling persists but is mild, get in the habit of "stripping" or milking the urethra from just behind the scrotum forward a couple times after voiding and then pat dry.  If the problem persists or is more severe, one need to see a urologist in consultation. 

There are many causes for urinary frequency.  The common ones include urinary tract infections, excessive fluid consumption (especially coffee, tea and beer which produce an additive diuretic effect), prostate conditions in men (ie benign or cancerous enlargement, prostatitis, prostatic congestion which is most often due to infrequent ejaculation, etc.), diabetes, urinary stones, a variety of kidney disorders associated with inability to concentrate the urine properly, urinary stones, several types of urinary bladder diseases (ie neuropathic bladder, stones, interstitial cystitis, etc.), overactive bladder syndrome and anxiety.  Some individuals develop frequency induced by chemical residues from soaps and detergents in the bath water  that may wash up into the bladder and urethra causing inflammation. Therefore, if one is  a bath person, discontinue this practice immediately and take only showers.

I hope this clarifies some of the many factors invoked regarding fluctuation of the symptoms one may experience from BPH.  Good luck.


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Arthur Goldstein, M.D.


Problems or questions related to the field of urology; ie urinary stone disease, urinary cancers (kidney, bladder, prostate, testis, etc.), urinary infections, etc. I no longer answer questions related to erection problems or male sexual dysfunction.


I am retired from the active practice of urology. My 34 years was totally in the clinical field and involved the entire gamut of genitourinary problems, with special interest in endourology.

American Medical Association, American Urological Association, American College of Surgeons

College degree - BS Medical degree - MD Master of Science - MS

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