28 CHAPTER 1 Preliminary investigation

Digital rectal examination (DRE)

The immediate anterior relationship of the rectum in the male is the prostate. The DRE is the mainstay of examination of the prostate.

Explain to the patient the need for the examination. Ensure that the examination is done in privacy. The exam is usually performed with the patient leaning over the exam table, but may be done in the left lateral position with the patient lying on their left side and with the hips and knees flexed to 90* or more. This positioning may make it possible to examine the base of a large prostate or examine a more obese patient.

Examine the anal region for fistulae and fissures. Apply plenty of lubricating gel to the gloved finger. If in the lateral position, lift the buttock upward with your other hand to expose the anus. Apply gentle pressure with the lubricated index finger and slowly insert your finger into the anal canal and then into the rectum. Note the presence of any rectal masses or hemorrhoids. Rectal tone should also be noted.

Palpate anteriorly toward the pubis with the pulp of your finger, and feel the surface of the prostate. Note the consistency (normal, boggy, firm, rock hard), its surface (smooth or irregular), and symmetry and estimate its size. Describe any focal areas of firmness or frank nodularity.

A normal adult prostate is about 20 g and 3–4 cm long and wide. Normal prostate consistency is similar to that of the contracted thenar eminence of the thumb and is often described as rubbery.

It can be helpful to relate its size to common objects such as fruit or nuts: normal prostate (walnut or chestnut), moderately enlarged (tangerine), and markedly enlarged (apple or orange). A +1 to +4 system also gives a very rough idea of the prostate size. Estimating the gram size based on DRE is very unreliable and is best done by imaging such as transrectal ultrasound.

The normal bilobed prostate has a groove (the median sulcus) between the two lobes and in prostate cancer this groove may be obscured. The lateral sulci should be distinct. Obliteration can be seen after radiation therapy to the prostate or rectum or with locally advanced prostate cancer. Normal seminal vesicles should never be palpated and, if felt, suggest a pathological process, most often infiltration by prostate cancer.

Many men find DRE uncomfortable or even painful, and the inexperienced doctor may equate this normal discomfort with prostatic tenderness. Prostatic tenderness is best elicited by gentle pressure on the prostate with the examining finger. If the prostate is really involved by some acute, inflammatory condition, it will be very tender. However, it is best to avoid DRE with the possibility of abscess or acute bacterial and prostatitis in the profoundly neutropenic patient (risk of septicemia).

Firmness or nodularity can be caused by BPH, prostate cancer or other malignancy such as urothelial carcinoma, lymphoma, sarcoma or other rare tumor, chronic prostatitis with calcifications, prior prostate surgery, ejaculatory duct cysts, and granulomatous prostatitis, among others.

DIGITAL RECTAL EXAMINATION (DRE) 29

Other features to elicit in the DRE

The integrity of the sacral nerves that innervate the bladder and of the sacral spinal cord can be established by eliciting the bulbocavernosus reflex (BCR) during a DRE. The sensory side of the reflex is elicited by squeezing the glans of the penis or the clitoris (or in catheterized patients, by gently pulling the balloon of the catheter onto the bladder neck).

The motor side of the reflex is tested by feeling for contraction of the anus during this sensory stimulus. Contraction of the anus represents a positive BCR and indicates that the afferent and efferent nerves of the sacral spinal cord (S2–S4) and the sacral cord are intact.

30 CHAPTER 1 Preliminary investigation

Lumps in the groin

Differential diagnosis

This includes inguinal hernia, femoral hernia, enlarged lymph nodes, saphena varix, hydrocele of the cord (or of the canal of Nück in women), vaginal hydrocele, undescended testis, lipoma of the cord, femoral aneurysm, and psoas abscess.

Determining the diagnosis

Hernia

A hernia (usually) has a cough impulse (i.e., it expands on coughing) and (usually) reduces with direct pressure or on lying down unless, uncommonly, it is incarcerated (i.e., the contents of the hernia are fixed in the hernia sac by their size and by adhesions). Movement of the lump is not the same as expansion. Many groin lumps have a transmitted impulse on coughing (i.e., they move) but do not expand on coughing.

Since inguinal and femoral hernias arise from within the abdomen and descend into the groin, it is not possible to get above them. For lumps that arise from within the scrotum, the superior edge can be palpated (i.e., it is possible to get above them).

Once a hernia has protruded through the abdominal wall, it can expand in any direction in the subcutaneous tissues. Therefore, the position of the unreduced hernia cannot be used to establish whether it is inguinal or femoral. The point of reduction of the hernia establishes whether it is an inguinal or femoral hernia.

•Inguinal: the hernia reduces through the abdominal wall at a point above and medial to the pubic tubercle. An indirect inguinal hernia often descends into the scrotum; a direct inguinal hernia rarely does.

•Femoral: the hernia reduces through the abdominal wall at a point below and lateral to the pubic tubercle.

Enlarged inguinal lymph nodes

These present as a firm, noncompressible, nodular lump in the groin. Look for pathology in the skin of the scrotum and penis, the perianal area and anus, and the skin and superficial tissues of the thigh and leg.

Penile cancer can spread to the inguinal nodes. Superficial infections of the leg and sexually transmitted disease (STD) such as chancroid, herpes, and lymphogranuloma venereum can cause tender inguinal lymphadenopathy.

Saphena varix

This is a dilatation of the proximal end of the saphenous vein. It can be confused with an inguinal or femoral hernia because it has an expansile cough impulse (i.e., expands on coughing) and disappears on lying down. It is easily compressible and has a fluid thrill when the distal saphenous vein is percussed.

LUMPS IN THE GROIN 31

Hydrocele of the cord (or of the canal of Nück in women)

A hydrocele is an abnormal quantity of peritoneal fluid between the parietal and visceral layers of the tunica vaginalis, the double layer of peritoneum surrounding the testis and which was the processus vaginalis in the fetus. Normally, the processus vaginalis becomes obliterated along its entire length, apart from where it surrounds the testis where a potential space remains between the parietal and visceral layers.

If the central part of the processus vaginalis remains patent, fluid secreted by the “trapped” peritoneum accumulates and forms a hydrocele of the cord (the equivalent in females is known as the canal of Nück). A hydrocele of the cord may therefore be present in the groin.

Undescended testis

The testis may be on the correct anatomical path, but may have failed to reach the scrotum (incompletely descended testis) or may have descended away from the normal anatomical path (ectopic testis). The “lump” is smooth, oval, tender to palpation, and noncompressible, and there is no testis in the scrotum.

Lipoma of the cord

A noncompressible lump is in the groin, with no cough impulse.

Femoral aneurysm

This usually occurs in the common femoral artery (rather than superficial or profunda femoris branches) and is therefore located just below the inguinal ligament. It is easily confused with a femoral hernia. Like all aneurysms, they are expansile (but unlike hernias they do not expand on coughing).

Psoas abscess

The scenario is one of a patient who is very ill with a fever, with a soft, fluctuant, compressible mass in the femoral triangle.