Материал: Oxford American Handbook of Urology ( PDFDrive )

32 CHAPTER 1 Preliminary investigation

Lumps in the scrotum

Differential diagnosis

•Testicle: Testicular malignancy (germ cell tumor such as seminoma, embryonal, choriocarcinoma, yolk sac tumor), lymphoma, benign testicular tumor (adenomatoid tumor, Leydig or Sertoli cell tumor), torsion of testicle or appendix, trauma with testicular rupture, benign cysts, granulomatous orchitis, syphilitic gumma

•Epididymis: epididymitis/epididmo-orchitis, epididymal cyst, cystadenoma, adenomatoid tumor

•Paratesticular masses: hydrocele, spermatocele, varicocele,

hematocele, hydrocele of the cord, cord lipoma, rhabdomyosarcoma of the cord

• Others: inguinal hernia, lesions of the scrotal wall (cysts, carcinoma)

Determining the diagnosis

Determination of the duration of the mass and whether it is painful can help establish the diagnosis. Painful masses include those from trauma, epididymitis, torsion, and hernia. Painless masses include tumors, hydrocele, spermatocele, varicocele, and epididymal masses.

Inguinal hernia

An indirect inguinal hernia often extends into the scrotum. It usually has a cough impulse (i.e., it expands on coughing) and usually reduces with direct pressure or on lying down. It is not possible to get above the lump.

Hydrocele

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. It is usually painless, unless the underlying testicular disease is painful.

A hydrocele has a smooth surface, and it is difficult or impossible to feel the testis, which is surrounded by the tense, fluid collection (unless, rarely, the hydrocele is very lax). The superior margin can be palpated (i.e., you can get above the lump). It is possible to transilluminate a hydrocele (i.e., the light from a flashlight applied on one side can be seen on the other side of the hydrocele). Ultrasound is most reliable to evaluate for underlying testicular pathology in this setting.

Hydroceles may be primary (idiopathic) or secondary. Primary hydroceles develop slowly (over the course of years, usually) and there is no precipitating event such as epididymo-orchitis or trauma, and the underlying testis appears normal on ultrasound (no testicular tumor). Secondary hydroceles (infection, tumor, trauma) represent an effusion between the layers of the tunica vaginalis (the visceral and parietal layers), analogous to a pleural or peritoneal effusion.

In filariasis (infection with the filarial worm Wuchereria bancrofti), obstruction of the lymphatics of the spermatic cord gives rise to the hydrocele.

LUMPS IN THE SCROTUM 33

Epididymal cyst

This is also known as a spermatocele if there are spermatozoa in the contained fluid. Cysts derive from the collecting tubules of the epididymis and contain clear fluid. They develop slowly over years, lie within the scrotum (you can get examining finders above them), and usually lie above and behind the testis. They are often multiple or multiloculated.

Orchitis

This occurs in the absence of involvement of the epididymitis and is due to a viral infection, e.g., mumps. Orchitis often occurs with enlargement of the salivary glands.

Epididymitis

This is often difficult to differentiate from testicular torsion. Typically, it is caused by an ascending infection. Common agents include coliform bacteria, Pseudomonas, Chlamydia, and gonorrhea.

Acute epididymitis can be accompanied by pain, frequency, and dysuria. Early the epididymis can be palpated and is very tender. Later the testicle can become involved secondarily.

Tuberculous epididymo-orchitis

Infection of the epididymis (principally) by tuberculosis (TB) spreads from the blood or urinary tract. The absence of pain and tenderness is noticeable. The epididymis is hard and has an irregular surface. The spermatic cord is thickened and the vas deferens also feels hard and irregular (a “string of beads”).

Testicular tumor (seminoma, embryonal cell, yolk sac tumor, teratoma)

This is a solid mass on the testicle which, and if very large, may extend up into the spermatic cord. The typical malignant tumor in the testicle is painless and discovered incidentally, often after a minor trauma that probable calls attention to the area. Very rarely it can present with pain and tenderness in the testis and with fever.

The lump is usually firm or hard and may have a smooth or irregular surface. Examine the contralateral testicle and for abdominal and supraclavicular lymph nodes.

Gumma of the testis

This condition is rare. Syphilis of the testis results in a round, hard, insensitive mass involving the testis (a so-called billiard ball). It is difficult to distinguish from a tumor.

Varicocele

A variocele is dilatation of the pampiniform plexus—the collection of veins surrounding the testis and extending up into the spermatic cord (essentially varicose veins of the testis and spermatic cord). Small, symptomless varicoceles occur in approximately 20% of normal men and are more common on the left side.

They may cause a dragging sensation or ache in the scrotum; they are said to feel like a “bag of worms.” The varicocele disappears when the patient lies down.

Urological investigations

Urine examination 36 Urine cytology 38

Prostatic specific antigen (PSA) 39 Radiological imaging of the urinary tract 40 Uses of plain abdominal radiography (KUB

X-ray—kidneys, ureters, bladder) 42 Intravenous pyelography (IVP) 44 Other urological contrast studies 48

Computed tomography (CT) and magnetic resonance imaging (MRI) 50

Radioisotope imaging 52 Uroflowmetry 54

Post-void residual urine volume measurement 58 Cystometry, pressure-flow studies, and

videocystometry 60

36 CHAPTER 2 Urological investigations

Urine examination

Dipstick testing

Analysis for pH, blood, protein, glucose, and white cells can be done with dipstick testing.

pH

Urinary pH varies between 4.5 and 8, averaging between 5.5 and 6.5.

Blood

Normal urine contains <3 RBCs per high-powered field (HPF) (~1000 erythrocytes/mL of urine; upper limit of 5000–8000 erythrocytes/mL). Positive dipstick for blood indicates the presence of hemoglobin in the urine.

Hemoglobin has a peroxidase-like activity and causes oxidation of a chromogen indicator, which changes color when oxidized. Sensitivity of urine dipsticks for identifying hematuria (>3 RBCs/HPF) is >90%; specificity is lower (i.e., a higher false-positive rate with the dipstick), due to contamination with menstrual blood or dehydration (concentrates what RBCs are normally present in urine).

Hematuria due to a urological cause does not elevate urinary protein. Hematuria of nephrological origin often occurs in association with casts, and there is almost always significant proteinuria.

Protein

Normal, healthy adults excrete about 80–150 mg of protein per day in their urine (normal protein concentration <20 mg/dL). Proteinuria suggests the presence of renal disease (glomerular, tubulointerstitial, renal vascular) or multiple myeloma, but it can occur following strenuous exercise. A dipstick test is based on a tetrabromophenol blue dye color change (green color develops in the presence of protein of >20 mg/dL).

White blood cells

Leukocyte esterase activity detects the presence of white blood cells (WBCS) in the urine. Leukocyte esterase is produced by neutrophils and causes a color change in a chromogen salt on the dipstick. Not all patients with bacteriuria have significant pyuria.

False negatives are due to concentrated urine, glycosuria, presence of urobilinogen, and consumption of large amounts of ascorbic acid. False positives are due to contamination.

Nitrite testing

Nitrites in the urine suggest the possibility of bacteriuria. They are not normally found in the urine. Many species of gram-negative bacteria can convert nitrates to nitrites, and these are detected in urine by a reaction with the reagents on the dipstick that form a red azo dye.

The specificity of the nitrite dipstick for detecting bacteriuria is >90% (false-positive nitrite testing is contamination). Sensitivity is 35–85% (i.e., lots of false negatives); it is less accurate in urine containing fewer than 105 organisms/mL.