Diagnosis of Impotence /
Clinical Examination and
Medical History Taking:
1-Morning erection / nocturnal erection:
Normally, one experiences a rigid erection when he
wakes up every now and then. This is "Morning
erection" or "nocturnal erection".
Presence of normal morning erection is a sign that
impotence is psychogenic rather than
To explain this, during sleep, one is relieved of
psychological stress that prevents erection in day time, but is not
present to prevent erection that normally occurs at sleep. On the
contrary, if there is an organic cause to impotence, erection will
occur neither in day time nor at sleep.
Inquiring about morning erection may not always
meet an accurate answer. The method for objective evaluation of the
nocturnal erection: the rigiscan (see later).
2-Inquiring about causes and predisposing factors
Some data can help diagnosing the cause of
impotence such as the presence of psychological stress, symptoms
suggestive of hypertension (headache, bleeding nose, drowsiness),
symptoms suggestive of diabetes (frequent urination, frequent thirst
and hunger, family history of diabetes)..etc
Examination can point to signs of hormonal
imbalance, abnormal development of the genitalia and local diseases
of the penis such as fibrosis..etc.
In case there is high suspicion of organic
impotence or there
is failure of response to treatment, investigations are necessary:
Blood Sugar Analysis:
It is one of the most important lab analyses in
cases of impotence and is considered routine in many practices. It
points out to the presence of diabetes which is one of the most
common causes of impotence.
A blood sample is taken after 8 hours of
fasting (no eating or drinking sugary fluids), then another sample
is taken 2 hours after eating.
Glucose (sugar) concentration in tissues is
particularly important and should be normalized before surgery in
cases of severe impotence. It is again measured by a blood sample.
This is particularly important in older patients
where there is natural decline in testosterone levels, or in those
with signs of hormone imbalance such as lack of body hair (though
not a conclusive sign).
A blood sample is taken in day time, early morning
(9-11AM) to take the biological clock and the normal hormone level
fluctuations into consideration. Testosterone and prolactin
are measured. Testosterone is measured in terms of free testosterone
and total testosterone.
This is injection of chemicals that induce
erection directly into the penis. These chemicals are either
vasodilators or muscle relaxants.
In normal subjects, ICI should result in a
rigid erection that starts in 5 minutes time and lasts for at least
In subjects with organic impotence, erection may
not occur at all, or may be less than the minimum encountered in
Erection is graded on a scale from E0 to E5, where
E5 is the normal rigid erection that persists for 30 minutes.
If response to ICI is less than optimum, further
investigations are required to specify the diseased part: arteries?
veins?..etc. The next investigation is Penile Duplex.
It has to be noted that both normal subjects and
subjects with organic impotence due to nerve disease preventing
neuronal transmission may respond in an exaggerated pattern to ICI
with a rigid erection that lasts for hours.
/ Penile Ultrasonography:
Ultrasonography can inspect the interior of the
penis for fibrosis,
arterial occlusion or
venous leak. In order to evaluate
arteries and veins, erection is induced by intra-corporal injection
Normal arterial flow should be more than
25cm/second, while normal venous flow should be less than
5cm/second. Normally there should be no fibrosis or calcification in
the penis. If there is, penile duplex can determine their position,
extent, and relation to vital structures of the penis.
If duplex points to the possibility of venous
leak, this has to be confirmed by cavernometry, where erection is
induced by intra-corporal injection (see before), and the pressure
inside the penis is measured by a needle connected to a
If cavernosometry confirms the presence of venous
leak, the exact position and distribution of the leaking veins is
determined by cavernosography. A dye is injected in the penis after
induction of erection using intra-corporal injection (see before).
Normally, the dye should be trapped in the penis together with
blood. If there is a leak, the dye seeps out of the penis through
veins. These veins can be imaged and localized by roentgenograms.
Nocturnal Erection / Morning Erection: RIGISCAN:
As described before, the occurrence of normal
morning erection or nocturnal erection is indicative of the cause of
impotence being psychological. However, simple questioning about
morning erection may not always give accurate results.
Rigiscan is a device that can measure erection
that occurs at sleep, and can determine how many times it has
occurred, for how long, and how large was the diameter of the penis
at erection, and thereby the circumferential rigidity (side to side
Rigiscan is composed of a portable unit that is
attached to the thigh, from which emerge two wires, each attached to
a sensitive coil that is worn around a penis. The device is used by
the patient for 3 consecutive nights, to be worn at bed time. The
coils record changes in the penis and transmit them to the recording
unit around the thigh, from which data is downloaded and plotted as
a graph at the end of the examination.
Unfortunately, circumferential rigidity measured by
rigiscan is of minor importance in erection . Axial rigidity is the
most important. The latter is rigidity along the length of the penis
that prevents it from bucking if pressure is applied to the glans
towards the abdomen, just like normal intercourse.
Axial and circumferential