- Anatomy
- The urinary bladder has a more or less
spherical shape and is located, at the end of both ureters, down in the
abdomen, right behind the pubic bone. The bladder can contain about 400
cc. of urine; while empty it is no larger than a tennis ball. Both ureters
enter the bladder from the sides. They actually go diagonally through the
bladder wall, so they are being squeezed somewhat when the bladder fills;
in this way a valve is formed that provides for a one-way flow,
prohibiting reflux of urine from the bladder to the kidneys. The openings
of the ureters is located near the bladder outlet. A triangle is thus
formed between the two ureteral openings and the bladder outlet, which is
the beginning of the urethra.
Although the bladder is located
in the lower abdomen, it is essentially not a part of it: it has nothing
to do with the bowels, while it is possible to open the bladder surgically
without opening the abdomen. In the male, the anal canal is right behind
the bladder and the prostate is located right under the bladder, around
the urethra. In the female the uterus and vagina lie in between the
bladder and the anal canal. The female urethra is, by the way, relatively
short (since she doesn't have a penis): only an inch or so.
A couple of blood vessels are
connected to the bladder from the sides, ensuring a wealthy blood supply,
so that even a few blood vessels can be missed - for instance after an
accident - without the bladder getting into trouble. The nerve supply is
also abundant; a virtual network of nerve-bundles are connected to the
bladder, while even quite a few nerve cells are present to be able to do
some on-the-spot regulating of the function of the bladder.
- Functions
- The urinary bladder is a rather simple
organ. The urine, produced by the kidneys, is transported by the ureters
towards the bladder to be stored there. Therefore the bladder is needed
for storage of urine, so that we humans do not lose urine all day long.
Apparently, this was a feature in the human design needed to carry us
through evolution; possibly we would have been easy prey for carnivores
had it not been for our bladder to prevent the spreading of vast amounts
of human scent.
A second important feature of
the bladder is the voiding of stored urine once a suitable spot has been
found to do that, i.e. a toilet. In order to get this done as quickly as
possible, the bladder wall is equipped with muscle fibers, so that the
bladder can shrink itself into the size of a tennis ball. Emptying the
bladder seems a simple feat, but isn't. Contrary to what many people
think, it is not the action of the abdominal wall muscles that empties the
bladder. Straining, i.e. using the muscles of the abdomen, is a rather
inefficient way to void urine. Straining will enhance the pressure on the
bladder contents and thus causes a more powerful flow of urine, but will
also squeeze the bladder outlet and enhance the outflow resistance. That
is the reason why nature gave the bladder its own muscle. At the same
moment, however, the sphincter around the urethra, that normally closes
the outlet to prevent leaking, has to relax: if you don't open the tap,
nothing will come out of it.
Fortunately, we do not have to
think about those things while passing urine; everything is controlled by
nerve cells in the spine and around the bladder. The sensitive spot in the
bladder consists of the triangular area between the openings of the ureter
and the bladder outlet, the trigone. Once this area gets stretched at a
certain degree of bladder filling, your brain gets a signal that the
bladder is going to need emptying. The signals will get stronger while the
bladder gets fuller; if you keep resisting (or, after a party will lots of
alcohol, don't wake up) the control center in the spine will take over and
will start the voiding procedure re: the bladder will empty itself
completely. Babies always pass urine this way; it will take a couple of
years before the child will have mastered to control the passing of urine.
What are the signs and
symptoms of the condition?
Diseases of the bladder can be
subdivided into a few categories:
Bladder
Cancer - In
bladder cancer the tumor arises on the inside of the bladder wall.
These tumors are often formed like a mushroom (with a small stem). Benign
tumors also exist in the bladder, but they occur only in young adults.
Bladder cancer normally shows itself because the fragile tissue often
bleeds a bit, causing a redness of the urine. Although this should be an
alarming sign, a lot of people do not visit their doctor when the observe
a red discoloration of the urine; unfortunately the bleeding often stops
by itself and the urine might not show anything wrong for several weeks or
months - the tumor will however not stop growing.
While the cancer remains
confined to the inside of the bladder wall, it can normally be removed
surgically and the patient can be cured. It has a tendency to recur,
however, so frequent controls are necessary for years. If it is not
treated in time, the cancer might start penetrating the bladder wall, and
might also spread to other parts of the body, like the lymph nodes. This
will make treatment more difficult.
The tissue on the inside of the
bladder closely resembles the tissues found in the ureters and renal
pelvis. X-rays of these organs will therefore also be part of the frequent
checkups once a bladder tumor has been found to make sure that no tumor
will be missed.
Cystitis. An infection of the bladder
is one of the more frequent sites of infections in humans. Bacteria can
easily slip up into the bladder, especially in the female (who has a very
short urethra). Normally, these bacteria are washed out of the bladder
during voiding, but in some cases (low on drinking, a lot of bacteria,
aggressive bacteria, low on resistance after an operation) an infection can
arise. The bacteria are mostly coming from ones own bowels, but 'strangers'
like gonorrhea can also cause cystitis. In the male, the cystitis is less
common, since the urethra is longer and the bladder further away from the
outside world. If a man does get an infection of the bladder, it often means
that there is something else going on too: bladder
stones,
enlargement of the prostate, etc. In the male, a cystitis can easily
lead to an infection of the prostate,
prostatitis or an epididymitis.
Bladder stones are usually not formed
by the bladder. They originate as kidney stones, pass through the ureter and
end up in the bladder. Compared to the bladder outlet and the urethra, these
stones are relatively small and they will normally be washed out quickly,
unless, for example, the
prostate is enlarged and blocking the exit, so the stone gets stuck in
the bladder and grows. Bladder stones are found more in men. A bladder stone
can be impregnated with bacteria, causing a persistent
infection of the bladder, that will only be
cured after removal of the stone.
Examinations
The bladder and its function can be
investigated in different ways. Not all possible investigations are, of
course, necessary. As a rule, the urologist will make a choice to be able to
eliminate or confirm possible causes of the patients problems. It is a
mistake to think that the latest invention in diagnostic tools will always
be the best available. In certain cases additional information can be
gathered from a 'new' test, but this is not always so; a CT-scan can be very
useful to get an impression of the extent of a kidney tumor, but it can be
very difficult to visualize a bladder tumor or a
stone, while these are easy to find at
cystoscopy.
- A few possible examinations will be
discussed here; there are more, but that would be impossible on this page.
Blood:
- Is there an infection in the body (for
example in the (kidneys,
bladder or
prostate)? To
find this out, the sedimentation rate can be measured and the number of
white blood cells (leukocytes).
- How about the matter that circulates in the
blood and which, in high concentrations could give cause to stone
formation? Like urate and calcium.
Urine:
- Is there an infection of the bladder
present? It is often impossible to find out where the infection is located
(kidneys,
bladder,
prostate).
However, sometimes an infection of the kidneys will give itself away
because of the enormous amount of white blood cells in the urine. An
infection of the bladder is generally less obvious in the urine.
- Are red blood cells present in the urine?
This could happen in cases of infection, but can also be a sign of cancer
of kidneys or bladder.
- Is there a lot of calcium or urate (or
another known stone-forming substance) in the urine, giving a higher
chance on bladder stones?
- How about the acidity of the urine? Urine
should be slightly acid, which serves as a barrier against infections.
X-rays. On a normal X-ray a
bladder stone is often visible. The bladder
itself is usually not visible.
- During a cystogram the bladder is filled
(through a catheter) with a liquid that will show on an ordinary X-ray.
Large bladder tumors will be visible in this way, while, after emptying
the bladder, it will show whether the bladder is really empty.
- Using ultrasound the bladder can be seen
very well by way of ultrasonic sound waves (so you cannot hear nor feel
them). Also other organs, like the uterus in females, can be seen. The
size of the bladder and the quality of emptying can be measured, while
bladder stones and large
tumors can be visualized.
Cystoscopy means looking into the
urethra and bladder using a small tube, which can be made of metal (rigid)
or plastics (flexible). This is perhaps the most important examination of
the bladder, since even very small bladder tumors
or stones can be found, while the urethra and
prostate can be inspected in one go. One does also get an impression of
the quality of the bladder muscles. 
A urodynamic examination is necessary to test
the function of the bladder. The bladder is first emptied through a
catheter. After another small catheter is inserted into the bladder, it is
filled, very gently, with water, while, at the same time the amount of
water flowing in an the bladder pressure is measured. In this way
information is gathered about the bladder capacity, the sensitivity and
the way the bladder is emptied again. The examination is important to get
information about the condition the bladder is in (which is important for
the prediction of the outcome of an operation of the prostate) and to find
the cause in cases of incontinence.
What are the
treatments?
- It is impossible to present all possible
therapeutic options for all diseases of the bladder. More frequent forms
of treatment will be mentioned.
- Cystitis -
Treatment depends on the nature, i.e. cause of the cystitis. If only a
cystitis is present, then treatment should be instituted using
antibiotics, if possible focused on the type of bacteria causing the
disease. In some cases there is more going on. A
bladder stone, impregnated with bacteria, could be present, in which
case the stone should also be treated. Or there might be an obstruction of
the bladder outlet, because of prostatic enlargement or a urethral
stricture. In these cases a residue of urine will often be left in the
bladder after voiding, enhancing the chance of recurring infection. In
cases of concurrent prostatitis an intermittent cystitis frequently
exists. Too low an acid content of the urine can also cause recurrent
infections.
A frequent cause of infection of the bladder is
insufficient urine production, for instance in hot weather. If this cleaning
mechanism of the bladder is interrupted, for example because of loss of
water in the form of sweat, the bacteria will not be flushed out of the
bladder often enough and will get time to multiply.
- Bladder Stone - If
the stone is not very large (an inch or so) it will generally be possible
to crush it by using the cystoscope and flush
out the debris. This is not a suitable method for very large stones, which
can better be removed during a 'conventional' operation. It should be
borne in mind that there might be a cause for the bladder stone, like
kidney stones or an enlarged prostate, which should then also be treated.
- Bladder Cancer -
The treatment of bladder cancer is very much depending on the size of the
tumor and whether it is still confined to the inside of the bladder wall
or not. The presence of tumor spread to other parts of the body also
influences the choice of therapy. If the tumor is confined to the inside
of the bladder wall, it can usually be removed by cystoscope through the
urethra (TURT: TransUrethral Resection of Tumor); afterwards only a small
scar will mark the spot. Frequent checkups by
cystoscopic examination will be necessary to be able to detect and to
remove recurrent tumor early in its development.
If the tumor has grown into the bladder wall,
it is generally impossible to remove it through the cystoscope. In those
cases, an operative procedure will be necessary to remove a part of the
bladder containing the tumor. Often the bladder as a whole will need to be
removed and the ureters will be connected to the skin (stoma) via a small
isolated part of the small bowel. This type of operation is quite demanding
on the general health of the patient and will only be done if he or she can
take it. If not, radiotherapy can be an alternative. In certain cases
additional therapy with chemical agents or a combination of surgery and
radiation may be the best choice.
If tumors recur frequently, frequent rinsing of
the bladder with certain chemical agents will often help, although it will
completely cure the tumor.
- Incontinence -
The treatment of incontinence also depends on the cause of the disease. If
caused by a highly sensitive bladder (there is a problem in postponing
urination and the voiding frequency is high), the probable solution will
be medical: some medicines will calm the bladder down. If caused by an
insufficient sphincter, the there is a choice. Either exercising the
sphincter, which will take time and effort of the patient, and will
frequently be done under the guidance of a physiotherapist. If it helps,
the effect will last a long time. Or a surgical approach, in which the
tissues surrounding the urethra will be stretched tight. The effect will
be instantaneous right after the operation, but it does not last forever
and will often need a re-do after 5-7 years or so. A lot of patients still
opt for a surgical approach, probably because it is easier and gives
quicker results.
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