Course Authors
Martin Carey, M.D.
Dr. Carey reports no commercial conflict of interest.
Estimated course time: 1 hour(s).
Albert Einstein College of Medicine – Montefiore Medical Center designates this enduring material activity for a maximum of 1.0 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
In support of improving patient care, this activity has been planned and implemented by Albert Einstein College of Medicine-Montefiore Medical Center and InterMDnet. Albert Einstein College of Medicine – Montefiore Medical Center is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.
Upon completion of this Cyberounds®, you should be able to:
Describe the basic anatomy of the urethra
List the complications of, and the contraindications to, the use of urinary catheters
Discuss techniques to manage the removal of a recalcitrant urinary catheter
Present the differential diagnosis of acute scrotal swelling in children.
In this Cyberounds®, we will discuss some typical male urological problems that present in the Emergency Department. A frequently seen situation involves the removal of a stubborn urinary catheter. Before one can pass a catheter, especially into the male urethra, it is important to recall the anatomy of the urethra.
Q. What do you recall of the anatomy of the male urethra? Where are the narrowest regions, and are there any sudden twists or turns one needs to be aware of?
A. The structure of the male urethra is rather complex. It consists of three parts -- the prostatic, membranous and spongy parts. It is about eight inches in total length. The prostatic urethra commences at the internal urinary meatus. It is embedded within the prostate gland. The urethra exits the prostate gland just anterior to the apex of the gland, and at this point it becomes the membranous urethra. The urethra is at its widest through the prostatic part. The ejaculatory ducts and the prostatic ducts open into the prostatic part of the urethra.
The shortest and least dilatable part of the urethra is the membranous part. The membranous part is about ¾ inch long, and passes through the deep peroneal pouch. The urogenital diaphragm is the muscle that fills the deep peroneal pouch. This muscle comprises the sphincter urethrae (also called the external urethral sphincter), and the deep transverse perineal muscles. The sphincter urethrae is a pear shaped muscle that encircles the urethra. The upper part of the 'pear' envelopes the lower part of the prostatic urethra, while the globular part is just above the perineal membrane.
The spongy urethra, also called the penile or anterior urethra, is about six inches long and contained within the corpus spongiosum of the penis. The spongy urethra can be divided into the bulbous and the pendulous parts. The bulbous part, continuous with the membranous urethra, passes through the perineal membrane and enters the bulb of the corpus spongiosum. It takes a right-angled curve forwards into the root of the penis. It then passes down the penis as the pendulous part. Just before the external urethral meatus there is a small, dilated part -- the navicular fossa.
The urethra is narrowest at the external urethral meatus, at the proximal part of the navicular fossa, in the membranous part and at the bladder neck. It is also important to be aware of the 90° turn at the base of the penis.
As many as 25% of patients who are admitted to hospital in the United States require a urinary catheter at some stage during their hospitalization. Urinary catheters are placed to relieve urinary retention, to enable accurate measurement of urinary output, to protect against skin breakdown, and for numerous other nursing and medical reasons. Many of these catheters are placed in the emergency department.
Urinary Catheters
In hospitalized patients, urinary catheters are a leading cause of nosocomial infections and of gram-negative bacteremia. Infections originating in the urinary tract represent as many as 40% of nosocomial infections. An estimated 800,000 patients annually are affected. The development of urinary infections in catheterized patients is directly related to the length of time that the catheter is in place. Bacteria can readily invade the urinary tract along the external surface of the catheter, or in the urine within the lumen of the catheter.
Because of the high risk of infection, all catheters should be inserted using a scrupulous sterile technique. Careful care of patients already catheterized is important. Infections are often found in clusters and are probably related to a lack of adequate sterile measures, including hand washing, when managing patients. The prophylactic use of antibiotics is not indicated, as it appears to simply encourage infection with resistant organisms. Recently, the use of a povidone-iodine cream on the meatus has been associated with a lower risk of infection, but this needs further study to confirm definite benefit.
Q. When is a urinary catheter contraindicated?
A. The major contraindication to the passage of a urethral catheter is the possibility of trauma to the urethra. Patients who have experienced significant trauma should have an examination of the perineum for bruising, the urethral meatus for evidence of bleeding and a digital examination of the prostate to ensure that it is not displaced prior to attempting the passage of a urinary catheter. If there is evidence of perineal bruising, bleeding at the meatus or a displaced or high riding prostate, urethral catheterization should be deferred until the continuity of the urethra can be confirmed.
An 88-year-old man appears in the emergency department with a urinary catheter in place. The nursing home reports that the catheter has been there for the past six weeks. The patient's primary care provider requested that it be removed, as it looked like the patient was getting an infection. Unfortunately, when the nurses attempted removal, they could not do so. They have sent the patient to you to remove his catheter.
Q. What techniques do you know that may help resolve this dilemma?
A. This scenario is not uncommon. Catheter removal can sometimes be difficult. Before we can decide what to do and which technique to try, we must determine the possible source of the problem. There are three possibilities:
- the valve where water is injected into the catheter may be blocked;
- external clamping or kinking may have damaged the tube; and
- crystallization of the fluid used to inflate the balloon may be preventing the balloon from deflating.
The first step is to cut the balloon port proximal to the inflation valve. If this does not result in a release of water, and ability to remove the catheter, then a wire is passed through the inflation channel. The wire from a central venous cannula set is appropriate for this task. The wire may be passed into the balloon and used to perforate it. However, sometimes a firmer structure is needed and, in this case, the venous catheter itself is used. It is passed over the guidewire into the balloon.
If the venous catheter does not rupture the balloon, leave the catheter in place and use it to introduce chemicals into the balloon. These chemicals will sufficiently degrade the balloon so that it ruptures but does not disintegrate. Chemicals such as ether, chloroform, acetone or mineral oil are used. Of these, mineral oil is recommended. Ten ml of mineral oil are drawn up into a syringe and introduced into the catheter balloon. After waiting for about 15 minutes, an attempt is made to remove the urinary catheter. If unsuccessful, an additional 10 ml is instilled.
If the balloon ruptures, inspect it carefully and ensure no bits have been left behind. They can act as a nidus for infection, or calculus formation, and can produce significant irritation when voiding.
Now let's discuss some other urological-type problems.
A 12-year-old boy presents to the emergency department with a history of lower abdominal pain. The pain had started acutely when he was straining to throw a ball from the outfield during a game of softball. He describes the pain as a constant dull ache in the lower part of the abdomen and the pain seems to go 'between my legs'. The pain is worse on the right than the left. He feels nauseated but has no other associated symptoms. He has no relevant past history. Examination reveals a well-developed 12-year-old, who appears to be in some discomfort. Observations are remarkable only for a resting pulse rate of 110 beats per minute. Abdominal examination reveals some mild lower abdominal tenderness. Bowel sounds are present and active.
Q. What should the examining physician be sure to do before putting this down to just a muscular sprain?
A. The examiner must be sure to examine the testes and scrotum. Unfortunately, there are numerous examples reported annually of missed diagnoses in this situation.
Q. So, what should be considered in the differential diagnosis in this case?
A. Although this could represent muscular sprain or strain, this should be a diagnosis of exclusion. Acute lower abdominal pain in children could be related to testicular torsion. Torsion is often described as starting in relation to exertion. Other possible diagnoses in this situation may include an inguinal hernia and trauma to the testes.
Q. The diagnosis of testicular torsion is confirmed in this case by Doppler scan. What could the emergency physician do to manage this problem in the ER?
A. The incidence of torsion of the testis is about 1 in 4000 males under 25 years of age. The majority of cases occurs in late childhood and early adolescence. As many as 50% of patients presenting with an acute torsion will have a history of recurrent, self-limited episodes of lower abdominal or scrotal pain.
Torsion can occur, though, at any age. It may be seen in the newborn (usually within the first ten days of life) and can even occur prenatally. Examination of the newborn will reveal edema of the scrotum with discoloration. A firm mass in the scrotum may be found. The differential diagnosis includes an acute hydrocele or an incarcerated hernia. If the torsion occurs in utero, the testis is not salvageable. If the torsion occurs after delivery, then the testis may be salvageable if the diagnosis is made promptly. There may be an autoimmune response if an infarcted testis is left in place and this can affect the normal testis. Thus, many physicians believe that the infarcted testis should always be removed.
In older children, torsion is due to an anatomical abnormality of the attachment of the testis within the scrotum. The tunica vaginalis inserts high on the spermatic cord instead of on the lower pole of the testis. This results in the testis lying abnormally and allows the testis to rotate freely within the tunica vaginalis. This is the so-called 'bell-clapper' deformity. It is important to remember that this abnormality is usually bilateral, which is why surgeons detort one testis and then surgically anchor the other testis (orchiopexy). With torsion, the testis will rise within the hemi-scrotum from spermatic cord shortening. Usually the cremasteric reflex (a movement of the scrotum with firm stroking of the inside of the thigh on the same side) is usually absent in cases of acute torsion. However, the presence of this reflex does not exclude the diagnosis.
Manual detorsion can be attempted, but may be very difficult, because of pain and scrotal edema. It is important to note that manual detorsion of the testis does not eliminate the need for exploration of the testis. A surgeon should be contacted urgently.
Q. There is much confusion between the terms 'phimosis' and 'paraphimosis'. What IS the difference?
A. Phimosis is the inability to retract a previously retractable foreskin or the inability to retract the foreskin of a male after puberty. In young males, the foreskin usually becomes retractable between the ages of three and five years. In older children or adolescents, the presence of a thickened margin between the glans penis and the foreskin when it is retracted as far as possible indicates the presence of infection and a true phimosis. In these cases, circumcision is usually required and the patient should be referred to a surgeon.
On the other hand, in paraphimosis, though the foreskin can be retracted, it remains proximal to the glans penis. As a result, significant swelling can ensue, and the viability of the foreskin and of the glans can be compromised because of the restriction of blood flow. Causes of paraphimosis include failure to retract the foreskin over the glans after catheterization, and failure to retract the foreskin after it has been retracted in patients with adhesions between the foreskin and the glans.
Q. If a patient presents with a paraphimosis, how can it be reduced?
A. Reduction of paraphimosis can be difficult. The most effective technique is to place the index and middle fingers of each hand behind the paraphimotic ring, with the shaft of the penis between the digits. The thumbs then exert firm, constant pressure on the glans penis, pushing it gently back through the paraphimotic ring, which is supported by the four fingers. The technique can be painful and a penile anesthetic block may be required. If reduction is not successful, then urgent referral for a dorsal slit through the foreskin may be required. A newer technique involves the use of a 20-gauge needle to make 15 to 20 holes in the edematous prepuce. The prepuce is then gently compressed and the edema fluid expressed. With this technique, reduction is described as being significantly easier.