It is helpful to categorize the mechanism as prerenal (eg, resulting from decreased or abnormal renal perfusion), renal (eg, resulting from intrinsic renal disease), or postrenal (eg, disease of the urinary collecting system distal to the renal parenchyma). Prerenal and postrenal causes are often suggested by the history and physical examination. Additionally, it is be helpful to determine the presence and extent of acute kidney injury (AKI) that frequently accompanies oliguria and anuria.
Prerenal causes include hypovolemia, sepsis, and heart failure.
Renal causes include tubular, glomerular, vascular, or interstitial disease.
Supravesical obstruction rarely causes oliguria or anuria, because bilateral disease is required to reduce decreased urine flow. There are two types of supravesical obstruction: (1) ureteral obstruction (usually tumor) and (2) ureteropelvic or ureterovesical obstruction.
Intravesical or Infravesical Obstruction
Intravesical or infravesical obstruction is more common than supravesical obstruction and may be from many causes (Table 39–1).
Table 39–1. Diagnostic Clues to the Cause of Bladder Outlet Obstruction. ||Download (.pdf)
Table 39–1. Diagnostic Clues to the Cause of Bladder Outlet Obstruction.
|Cause||Frequency of Occurrence||Results of History and Physical Examination||Laboratory Tests and Other Studies|
|Prostatic hypertrophy||Common||Gradually increasing difficulty in voiding, often with abrupt worsening. Enlarged prostate on rectal examination is common||Urethral catheterization may be difficult.|
|Urethral strictures or valves||Uncommon||Often previous attacks of urethritis or urethral trauma. Onset may be gradual or abrupt||Urethral catheterization often difficult. Urethrogram or urethroscopy is diagnostic|
|Bladder stones or tumor||Uncommon||Hematuria is common. Obstruction may be intermittent||Urethral catheter is passed without difficulty. Cystogram or cystoscopy is diagnostic|
|Neuropathic bladder||Very common||Onset may be gradual and painless or abrupt and painful. Look for associated neurologic abnormalities (sacral dermatomal hypesthesia, poor rectal sphincter tone, neuralgic pain)||Urethral catheter passed without difficulty. Cystometrogram is diagnostic|
|Traumatic urethral injury||Uncommon||Male; history of trauma, prostatic dislocation, urethral bleeding||Do not pass catheter. Retrograde urethrogram and percutaneous cystogram are diagnostic|
Differentiate between reduced urine output (with normal or nearly normal voiding patterns) and oliguria associated with difficult in voiding, feeling of incomplete voiding, and diminished urinary stream. The latter findings suggest obstruction.
Associated Medical Conditions
Ask about coexisting cardiac, pulmonary, renal, or other underlying disease that might contribute to renal or prerenal oliguria.
The patient's medications might cause problems with urination or be nephrotoxic. Anticholinergics and sympathomimetics are most often the culprits of urinary retention.
Obtain a complete set of vital signs. Correct volume depletion, if present (Chapter 11).
Focus on signs of cardiac, pulmonary, renal, or hepatic disease that might contribute to oliguria of a prerenal or renal origin. Look for signs of volume depletion, such as dry mucous membranes or poor skin turgor.
Palpate the lower abdomen to determine whether a suprapubic mass, consistent with a distended bladder, is present. A distended bladder is manifested as a firm (but not hard) mass that is adjacent to the symphysis pubica and is dull to percussion.
Examine the prostate for masses, prostatic hypertrophy, prostatic tenderness, or prostatic dislocation (associated with trauma).
Detection of Bladder Outlet Obstruction
Bladder outlet obstruction (complete or partial) is strongly suggested by a palpable bladder in a patient who is unable to void or who has a weak urinary stream or a feeling of incomplete voiding. Severe lower abdominal pain is more likely to be present with acute obstruction and rapid bladder distention than gradually progressive obstruction.
The diagnosis may be confirmed by calculating postvoid residual using either catheter drainage, ultrasonography, or CT scanning immediately after the patient's attempt to completely empty their bladder. Diagnostic features of some of the common causes of bladder outlet obstruction are set forth in Table 39–1.
Oliguria and anuria are frequently accompanied by AKI. A standardized definition as well as objective grading system for AKI has been developed to help predict outcomes and aid in treatment (Table 39–2). It is important to note that laboratory markers of AKI such as serum creatinine usually lag behind oliguria or anuria.
Table 39–2. Acute Kidney Injury Network Staging Criteria for Acute Kidney Injury. ||Download (.pdf)
Table 39–2. Acute Kidney Injury Network Staging Criteria for Acute Kidney Injury.
|AKIN Stage||Serum Creatinine||Urine Output|
|1||Increased by 1.5–2 times baseline or by ≥0.3 mg/dL||<0.5 mL/kg/hr for 6 hrs|
|2||Increased between 2 and 3 times baseline||<0.5 mL/kg/hr for 24 hrs|
|3||Increased by >3 times baseline or to ≥4mg/dL with an acute rise of ≥0.5 mg/dL||<0.3 mL/kg/hr for 24 hrs|
Serious Underlying Disease
If the patient appears to be acutely ill, in shock, septic, in decompensated heart failure or has other serious coexisting conditions that might cause prerenal oliguria, these disorders must be evaluated and treated before those of the urinary tract.
Distended Bladder (Presumed Bladder Outlet Obstruction)
Draw blood for complete blood count (CBC), electrolyte determination, and blood urea nitrogen and serum creatinine measurements.
Try to pass an indwelling urethral (Foley) catheter. If this maneuver is successful, drain the bladder, record the volume of urine obtained, and send a specimen for urinalysis and culture. Monitor the patient for postobstructive diuresis. Gradual bladder draining is not a proven method of decreasing bladder atony or mucosal hemorrhage. If bladder outlet obstruction is relieved by passage of a Foley catheter and is apparently due to a transient cause (eg, drugs), the catheter may be removed and the patient observed for ability to void after the effects of any drugs are presumed to have dissipated. In patients with fixed bladder outlet obstruction (eg, benign prostatic hypertrophy), leave the catheter in place, and obtain urologic consultation within 1 week. If a standard Foley catheter cannot be passed secondary to prostatic hypertrophy, reattempt passage using a coudé catheter (which has a curved tip that usually allows passage beyond the enlarged prostate). Inability to pass the catheter beyond the proximal urethra is suggestive for urethral stricture.
If the coudé catheter is unsuccessful and a urologist is not available, insert a suprapubic catheter for temporary drainage (Chapter 7). A large (16-gauge) needle-clad catheter (eg, Intracath) will provide satisfactory emergency bladder drainage.
Treat Cystitis and Prostatitis, If Present
See Dysuria section, below.
Hospitalize Patients As Needed
Hospitalize patients who have systemic symptoms (fever, rigors, intractable emesis) and those who need additional diagnosis and treatment (eg, for management of postobstructive diuresis, azotemia, sepsis, or electrolyte abnormalities).
Bladder Not Palpable; Patient Able to Void
If the patient can void on command but continues to have subjective or objective evidence of a weak urinary stream or if the patient experiences a feeling of incomplete voiding, partial bladder outlet obstruction is likely.
Draw blood for CBC, electrolyte, blood urea nitrogen, and serum creatinine measurements. Send a urine specimen for urinalysis and culture. Treat cystitis or prostatitis, if present. If blood chemistry results and urinalysis are normal, refer the patient to a urologist. The presence of azotemia or electrolyte abnormalities indicates severe or long-standing obstructive uropathy, and the patient likely requires hospitalization.
Bladder Not Palpable; Patient Unable to Void
Consider the following in the differential diagnosis (1) intrinsic renal disease, (2) occult prerenal disease (unlikely, because most causes would be obvious on brief physical examination), (3) occult bladder outlet obstruction, or (4) supravesical obstructive uropathy (rare).
Draw blood for CBC; serum glucose, electrolyte, calcium, and phosphorus; and tests of renal and hepatic function. Obtain chest and abdominal X-rays to help evaluate the size of the kidneys and bladder. Ultrasonography is the best noninvasive test for evaluating kidney and bladder size.
Ensure adequate hydration. In an adult without obvious volume overload (eg, pulmonary or peripheral edema), give 1–2 L of fluid orally or intravenously, and observe the patient for 1–2 hours. In an individual with normal kidneys, this amount should produce a brisk flow of urine.
If anuria persists despite adequate hydration and if the bladder is not distended, the cause of the anuria is likely to be proximal to the bladder (prerenal, renal, or, rarely, bilateral ureteral obstruction). Bladder catheterization, with strict adherence to sterile technique, should be performed to confirm the lack of urine output. Hospitalize the patient for further evaluation.
Hospitalization is required for patients with persistent unexplained anuria or severe oliguria (<500 mL/d), those with systemic symptoms, and those with markedly abnormal electrolytes or renal function.
Patients with partial bladder outlet obstruction (ie, weak urinary stream, with or without palpable bladder) should be referred to a urologist if renal function is normal or nearly normal. Asymptomatic patients with an indwelling urethral catheter should be reexamined or referred to a urologist within 1 week.
Table 39–3. Diagnostic Clues to the Cause of Acute Scrotal Pain. ||Download (.pdf)
Table 39–3. Diagnostic Clues to the Cause of Acute Scrotal Pain.
|History||Physical Examination||Urinalysis Results||Other Laboratory Studies||Treatment and Disposition|
|Trauma||History of injury||Scrotal hematoma||Variable; may have hematuria||Sonogram||Obtain urologic consultation (Chapter 24)|
|Urolithiasis||Antecedent flank or back pain; occasionally abdominal pain||Testicle minimally tender or nontender||Hematuria||Stones on excretory urogram||Obtain urologic consultation|
|Viral (eg, mumps) orchitis||Gradual onset, coexisting mumps parotitis common||Tender testicles (unilateral or bilateral); epididymis rarely involved||Normal||Viral cultures (throat, stool) if available; characteristic fourfold rise in serum antibody titer.||Elevate and immobilize testicle (eg, athletic supporter), give analgesics, and discharge for follow-up care.|
|Incarcerated hernia||Gradual onset; crampy pain||Fluid rushes heard in scrotum (early); abdominal tenderness consistent with intestinal obstruction||Normal||Characteristically abnormal results on ultrasound studies; abdominal X-ray results often abnormal (intestinal obstruction)||Obtain general surgical consultation; hospitalize|
|Epididymitis||Gradual onset; history of urethritis or urinary tract infection common; older men (>age 25 yrs)||Tender epididymis (often unilateral) with normal testicle early in course; pain relieved by elevating scrotum.||Leukocytes; bacteriuria in some cases (coexisting urinary tract infection)||Normal results on Doppler and ultrasound studies; nuclide scan shows uptake in epididymis|
Prescribe bed rest and elevation of scrotum, with analgesics as needed.
Treat underlying urethritis or urinary tract infection with antimicrobials (Chapter 40)
Discharge all patients for follow-up care.
|Testicular torsion||Abrupt onset (minutes to hours); history of testicular pain in some; boys and young men (< age 25 yrs)||Tender testicle, often elevated and horizontally displaced; normal epididymis (if palpable)||Normal||Characteristically abnormal results on Doppler examination and radionudidescan||Obtain emergency urologic consultation; hospitalize for surgery. Attempt manual detorsion (see text)|
|Torsion of testicular appendage||Abrupt onset||Firm nodule with point tenderness on upper anterior pole of testis; testicle normal||Normal||Transillumination may reveal affected appendage as “blue dot,” normal results on Doppler ultrasound and radionuclide studies.|
Prescribed bed rest and elevation, with analgesics as needed
Surgery is often needed to relieve pain
Obtain urologic follow-up care
- Trauma is a common cause
- Infection accounts for orchitis and epididymitis
- Flank pain, hematuria, and scrotal pain usually indicates urolithiasis
- Incarcerated hernias cause scrotal pain
- Testicular torsion requires urgent diagnosis to salvage the testicle. A torsed testis may be high riding or horizontally lying; ultrasound will show diminished blood flow to the torsed testis
(See also Chapter 26) Trauma commonly causes testicular or scrotal pain. Careful questioning may be required to elicit the circumstances under which the trauma occurred.
Mumps virus and the enteroviruses may cause acute unilateral or bilateral orchitis. In orchitis due to mumps virus, associated parotitis is usually present.
Rarely, patients with urolithiasis present with pain localized mainly in the scrotum; however, in most cases, back or flank pain has preceded the scrotal pain, or a history of nephrolithiasis is present. In such cases, the testicle and epididymis are normal to palpation. Hematuria is an important diagnostic clue.
Inguinal hernias incarcerated in the scrotum may cause scrotal pain that may be confused with testicular pain. Bowel sounds are heard in the scrotum early in incarceration; if the hernia strangulates, bowel sounds are no longer audible. Intestinal hernia into the scrotum is almost always associated with clinical findings of intestinal obstruction (Chapter 15). Ultrasonography is diagnostic.
Testicular Torsion, Epididymitis, and Torsion of the Testicular Appendages
(See Table 39–3) Torsion of a testicular appendage, epididymitis, and testicular torsion are the three most common causes of acute scrotal pain and account for approximately 85–90% of cases. Because of the urgency to diagnose and treat testicular torsion within 6 hours to prevent loss of the testis, testicular torsion must be promptly ruled out in all patients with scrotal pain. It may be difficult to distinguish from epididymitis or torsion of testicular appendages as edema and inflammation progress to involve the entire scrotal sac and contents.
Testicular torsion tends to occur in young men and is rare in men older than 30 years; however, it can and does occur at all ages and a smaller peak also occurs in the first year of life. There is often a history of episodes of similar scrotal pain representing torsion with spontaneous repositioning of the testicle. The pain is abrupt in onset, severe, unilateral, and often associated with nausea and vomiting. Tenderness is initially noted only in the testicle; however, with persistent torsion and the resulting testicular hypoxia, pain and tenderness spread to involve contiguous intrascrotal structures.
Examination early in the illness shows an elevated testicle that is apt to have a horizontal lie (Bell clapper deformity). The epididymis may be felt in an abnormal position (eg, anteriorly) in the early stages. Later, the entire scrotal contents become swollen and tender, making the examination extremely difficult and less informative because the epididymis becomes indistinguishable from the testis on palpation.
Epididymitis tends to occur in sexually active men older than 20 years and is the most common misdiagnosis for testicular torsion. There may be a history of urinary tract infection or urethritis. Pain begins gradually and is less severe than in testicular torsion. The Prehn's sign is present if the pain is reduced when the scrotum is elevated. This finding is not specific to epididymitis nor is it a reliable discriminating clinical sign. Physical examination reveals a tender epididymis, often unilateral and often with erythema and edema of the scrotal skin. Early on, the testicle may be normal or minimally tender. However, as edema worsens, the epididymis becomes indistinguishable from the testicle on palpation, and a reactive hydrocele may develop, making it difficult to differentiate epididymitis from testicular torsion. Urinalysis frequently shows pyuria and possibly bacteriuria if a concomitant urethritis or urinary tract infection is present. Doppler ultrasound shows increased blood flow to the affected testis, in contrast to the decreased blood flow seen in testicular torsion.
Torsion of Testicular or Epididymal Appendages
Of the four appendages, the appendix testis, located on the anterosuperior pole of the testis, is the most frequently (92%) torsed appendage followed by the appendix epididymis (7%), located on the head of the epididymis. Pain is usually sudden in onset and can be severe, with nausea and vomiting. Physical examination occasionally (21%) reveals a small, tender, firm nodule (“blue dot” sign), representing the infarcted appendage in the anterosuperior pole of the testis. The scrotal skin and testicle are usually normal and minimally tender. In advanced cases, marked edema and appearance of a reactive hydrocele may obscure the diagnosis of testicular torsion.
Specialized Diagnostic Tests for Differentiating Torsion From Epididymitis
These tests should not delay emergency urologic consultation and surgical treatment of patients with high probability of testicular torsion (ie, patients younger than 18 years with acute unilateral testicular pain and no signs or recent history of urinary tract infection).
Color-Flow Doppler Ultrasonography
Color-flow Doppler ultrasonography is the diagnostic study of choice in most institutions. It is widely available and has a sensitivity of 86–100% and a specificity of 100% as compared with a sensitivity of 80–100% and a specificity of 86–100% for radionucleotide imaging. The most frequent sonographic finding is absent or diminished blood flow to the affected testis, compared with the unaffected side. If the diagnosis is still unclear, then a nuclear study should be pursued. Ultrasound is more advantageous than nuclear scanning for elucidating other scrotal pathology including varicoceles, hydroceles, hernias, and masses.
In epididymitis, scanning of the scrotum after intravenous injection of technetium-99m sodium pertechnetate reveals increased scrotal uptake on the affected side, whereas torsion shows decreased uptake.
Treatment and Disposition
(See Table 39–3) If testicular torsion is present, obtain urgent urologic consultation, and prepare the patient for immediate surgery. Manual detorsion should be attempted if the urologist is not immediately available but definitive treatment should not be delayed. Detorsion of the testicle (either manual or surgical) must be accomplished within 6 hours to prevent testicular infarction. Torsion causes the patient's left testicle to rotate counterclockwise and the right to rotate clockwise (Figure 39–1); the affected testicle should be twisted in the opposite direction when detorsion is attempted. Because the testis affected by torsion is usually rotated a minimum of 360° (one turn), the physician should initially attempt to untwist the testicle by counter rotating it one turn. The testis will usually return to normal position on its own after this maneuver, even if it was originally twisted more than one complete revolution.
Torsion of the testicle. View of the testicles, epididymides, testicular appendages, and scrotum, showing direction of rotation of the testicles during torsion (as seen by the physician standing at the foot of the patient's bed and looking down at the patient). Manual detorsion should rotate the testicles in the opposite direction.
Regardless of the result of manual detorsion, emergency surgery is indicated to perform detorsion—if necessary—and to secure the testicle. Without surgery, torsion may occur again at any time.
In patients with suspected epididymitis or orchitis, urologic consultation should be sought if the diagnosis is in doubt. If epididymitis is present, see Chapter 42 for treatment. Torsion of the testicular appendage (after testicular torsion is excluded) is managed with bed rest, scrotal elevation, analgesics, and follow-up care within 1–2 days. Surgical excision is often needed for adequate pain control.
Painless Scrotal Mass Lesions
Table 39–4. Diagnostic Clues to the Cause of Common Painless Scrotal Masses. ||Download (.pdf)
Table 39–4. Diagnostic Clues to the Cause of Common Painless Scrotal Masses.
|History and Physical Examination||Other Diagnostic Studies|
|Varicocele||Usually asymptomatic mass; some patients have mild pain. Mass is separate from testis; feels like “bag of worms,” especially in upright position. Size increased by Valsalva maneuver. Right-sided varicocele should raise suspicion for inferior vena cava and intra-abdominal pathology. Sudden left-sided varicocele should raise suspicion for left renal vein obstruction||Not usually required, physical examination is diagnostic. Ultrasonography also helpful in diagnosis of enigmatic cases|
Gradually enlarging painless cystic mass that transilluminates.
Note: Hydrocele may complicate tumor
|Aspiration yields clear fluid. Ultrasonography helpful in diagnosis|
|Spermatocele||Asymptomatic mass separate from and superior to the testicle||Aspiration reveals white cloudy fluid with immotile sperm. Ultrasonography also helpful in diagnosis|
|Testicular tumor||Patient often a young adult. Asymptomatic enlargement of testis, rarely painful. Examination shows firm, nontender mass that does not transilluminate. Gynecomastia, virilization, or feminization rarely occur||Ultrasonography helpful in confirming mass lesion. Surgical exploration required for exact diagnosis of all testicular mass lesions|
- Malignancy is often painless
- A tense hydrocele or a firm spermatocele must be differentiated from a tumor. Ultrasound is the diagnostic study of choice
- Sudden onset of a varicocele in an older male may be a late sign of a renal tumor
Conditions causing painless (relatively painless) scrotal swelling are not true emergencies, although testicular tumors are life-threatening and require urgent evaluation (within a few days). Table 39–4 sets forth helpful diagnostic features of conditions associated with painless scrotal swelling. Patients with newly diagnosed testicular enlargement or mass lesions should be referred to a urologist.
- Painful urination that represents acute inflammation of the urethra, bladder, or prostate
- Frequency and urgency may also be present
- Workup should be guided by other associated symptoms, ie, hematuria or discharge
- Urinalysis or sexually transmitted disease testing usually confirms the diagnosis
Common causes of dysuria and their associated clinical findings are given in Table 39–5. Urethral diverticula, urolithiasis, endocervical gonorrhea, balanitis, and urethral warts are uncommon causes of dysuria.
Table 39–5. Diagnostic Clues to Common Causes of Dysuria. ||Download (.pdf)
Table 39–5. Diagnostic Clues to Common Causes of Dysuria.
|Condition||Sex More Commonly Affected||History and Physical Examination||Diagnostic Studies|
|Urethritis||Men||Dysuria, usually severe. Clear or purulent urethral discharge||Leukocytes in urethral discharge or on urethral swab. Tests for gonococcal or chlamydial infection are often positive|
|Prostatitis||Men only||Pelvic pain and dysuria. Fever common. Tender, boggy prostate on examination||Prostatic massage produces leukocytes and bacteria in urethral discharge or urine (“3-glass test”)|
|Urethral stricture||Men||Dysuria, may have split or reduced urinary stream||Urethroscopy or urethrogram|
|Urethral caruncle||Women (usually postmenopausal)||Mild dysuria; examination may show lesion||Urethroscopy|
|Dysuria-frequency syndrome||Women only||Dysuria and urgency. May have urethral discharge||Pyuria; leukocytes in urethral discharge or on urethral swab|
|Vaginitis||Women only||External dysuria, vaginal discharge dyspareunia||Vaginal smear or culture shows Candida, Gardnerella vaginalis, or Trichomonas vaginalis|
|Genital herpes||Women||History of herpes (if recurrent); vesicles and ulcers on external genitalia||Positive results on tests for herpes simplex|
|Urinary tract infection||Mainly women||Dysuria, urgency, frequency; cloudy or foul-smelling urine. May have fever, flank, or suprapubic tenderness||Pyuria and bacteriuria, urine culture shows more than 103 bacteria/mL (often >105/mL)|
|Urethral trauma||Either (mainly children)||History or evidence of genital manipulation or trauma||Hematuria occasionally|
|Psychogenic||Either||No logical pattern to symptoms. Examination normal||Normal results on urinalysis. No leukocytes on urethral swab. Tests for gonococcal and chlamydial infection negative|
In males, urethritis is a much more common cause of dysuria than is urinary tract infection. Attempt to express urethral discharge by milking the urethra, and send the material for culture and smear. If no discharge can be obtained, sample the anterior 2–3 cm (¾–1 3/16 in) of the urethra with a calcium alginate, Dacron, or cotton swab, or wire loop and send the swab for PCR or culture for Neisseria gonorrhoeae and Chlamydia trachomatis. Do not use a wood-handled cotton swab, because wood is toxic to the Chlamydia organism. The presence of more than 5 leukocytes per × 400 field indicates urethritis; the presence of intracellular diplococci (gram-negative if a Gram stain was done)—especially without other bacteria—indicates gonococcal urethritis. See Chapter 42 for treatment of gonorrhea and nongonococcal urethritis.
Dysuria without evidence of urethral or urinary tract inflammation (<5 white blood cells per × 100 field, negative culture) is rare in men and may represent low-grade infection. Treatment for urethritis is usually indicated.
If no evidence of urethritis is found, obtain a midstream clean-voided urine specimen. Polymorphonuclear neutrophils in the urine in the absence of urethritis are diagnostic of urinary tract inflammation. Prostatitis (either alone or associated with urinary tract infection) may be excluded by rectal examination. For further information on treatment, see Chapter 42.
Leukocytes, usually with bacteria, are found on microscopic examination of a midstream urine specimen. Urine dip reagent strips that test for the presence of leukocyte esterase and nitrite are equivalent to the urine sediment analysis at detecting pyuria when both are positive. They are increasingly being used as a screening tool and often eliminate the need for microscopic examination. Culture usually shows bacteria of a single species (usually >105 colony-forming units per milliliter but occasionally only 102–104, especially with certain organisms [eg, Candida species or enterococci]). Note: Urinary tract infection is unusual in men younger than 60 years unless associated urinary tract abnormalities are present or the patient engages in anal intercourse.
Inspect the penis and urethral meatus for balanitis and intrameatal pathologic structures (warts, herpetic ulcers) that are commonly associated with dysuria. Urethral strictures often cause dysuria, and patients may describe a split or intermittent urinary stream.
Obtain an uncontaminated urine specimen for microscopic analysis. Contamination of the specimen is usually indicated by the presence of squamous (vaginal) epithelial cells visible microscopically (eg, ≥5 cells per × 100 field); if these are seen, discard the specimen and obtain another uncontaminated specimen. Proper collection techniques for adults are as follows:
Midstream Clean-Voided Urine
This method of collection is satisfactory in most cases but requires a cooperative patient and some coordination.
A small, straight (9 F) catheter should be used for quick “in and out” catheterization, because it is more comfortable than the 14–19 F Foley-type catheter. Contamination may occur.
(See Chapter 7) Suprapubic aspiration is useful in special situations (eg, for infants) and is associated with a very low contamination rate.
Clinical Differentiation of Causes of Dysuria in Women
Dysuria-Frequency Syndrome (Urethral Syndrome) and Urinary Tract Infection
These conditions are characterized by dysuria without vaginal symptoms (eg, discharge) and by pyuria (<5 white cells per × 400 field). If bacteria are seen in the urinary sediment, urinary tract infection is a more likely diagnosis than urethral syndrome. Occasionally women with dysuria-frequency syndrome may have no pyuria.
If results on urinalysis are normal, if vaginal symptoms associated with dysuria are present, or if pain is felt outside the urinary tract (external dysuria), perform a pelvic examination to look for vaginitis, genital herpes, or a urethral caruncle. Urethral caruncle is found in postmenopausal woman and is a small, nontender red lesion resembling a strawberry on the dorsal aspect of the urethral meatus. In addition, it is helpful to culture endocervical mucus for gonococci, because gonococcal infection in women may be associated with dysuria.
Dysuria Associated with Hematuria in Either Sex
The presence of large numbers of erythrocytes in the urine in either sex should suggest hemorrhagic cystitis, concomitant urolithiasis, or urethral manipulation (see Hematuria section, below).
Treatment and Disposition
Treat the various causes of dysuria as follows:
For treatment of cystitis, pyelonephritis, and urethral syndrome, see Chapter 42.
Patients with other conditions (eg, urethral stricture or diverticulum) should be referred to a urologist or gynecologist for evaluation.
- Hematuria is often an early sign of genitourinary cancer
- Hematuria with associated flank or groin pain is suggestive of urolithiasis
- Dysuria and frequency may accompany hematuria of an infectious cause
Common causes of hematuria (microscopic defined as >3 red blood cells per high-power field) and their associated clinical findings are set forth in Table 39–6. See Chapter 26 for management of hematuria associated with trauma or genitourinary manipulation. In all cases of atraumatic hematuria, nonglomerular diseases including infection account for 25% of cases, stones account for 20% of cases, cancer accounts for 12% of cases, and 10% of cases have an unknown cause.
Table 39–6. Diagnostic Clues to Common Causes of Hematuria. ||Download (.pdf)
Table 39–6. Diagnostic Clues to Common Causes of Hematuria.
|History and Physical Findings||Diagnostic Studies|
|Trauma||History or evidence of local genital, abdominal (renal), or pelvic trauma or recent genitourinary instrumentation||See Chapter 24|
|Tumor||Often long-standing painless hematuria||Intravenous pyelogram reveals upper urinary tract tumors; cystogram or cystoscopy shows bladder tumor|
|Urolithiasis||Intermittent hematuria usually associated with pain. Bladder stones may be painless but may be associated with intermittent urinary obstruction||Intravenous pyelogram reveals ureteral stone, obstruction, or postobstructive hydroureter; cystoscopy or cystography shows bladder stones|
|Infection||Dysuria common||Pyuria often present. Urine culture shows bacteria (usually ≥105 colonies/ml)|
|Glomerulonephritis||May follow streptococcal infection; often associated with autoimmune diseases (eg, systemic lupus erythematosus). Gradual onset. Hypertension common||Urinalysis shows leukocytes, red cell casts, and frequently proteinuria; blood urea nitrogen and serum creatinine elevated|
|Prostatitis||Dysuria often present. Abnormal (large or tender) prostate||Pyuria often present|
|Urethral stricture, foreign body, or manipulation||Often painful. Local abnormality may be obvious on examination||Urethroscopy reveals stricture or foreign body|
|Sickle cell or sickle cell trait||Intermittent hematuria that may be painless (trait) or painful (disease)||Urinalysis shows red blood cells and isosthenuria. Hemoglobin electrophoresis abnormal|
|Bleeding diathesis||Painless hematuria. History of coagulation defect. Evidence of bleeding elsewhere (eg, purpura). Anticoagulant use||Coagulation tests show thrombocytopenia, prolonged prothrombin time, etc. (Chapter 39)|
Renal vein thrombosis, renal arterial embolization, drug-induced (cyclophosphamide, penicillins) interstitial cystitis, glomerular diseases, abdominal aortic aneurysm, and malignancy are less common causes of hematuria. In the elderly, painless gross hematuria is malignancy until proven otherwise.
Hematuria associated with abdominal or flank pain and tenderness suggests urolithiasis or, less commonly, reno-vascular disease. Diagnostic clues may come from timing of the hematuria. Initial, terminal, or total stream hematuria suggests bleeding from the following respective areas: anterior urethral, posterior urethra to trigone, or bladder sources or beyond.
Hematuria associated with dysuria and urinary urgency and frequency suggests hemorrhagic cystitis (drug-induced, infectious, or idiopathic). Systemic conditions associated with hematuria include thrombotic thrombocytopenic purpura, Henoch-Schönlein purpura, sickling hemoglobinopathies, excessive anticoagulation therapy, or coagulopathies.
Bleeding from other perineal areas, especially menstrual flow, may be mistaken for hematuria.
Examine the external genitalia for local causes of hematuria (eg, intraurethral trauma). Examine the abdomen, back, and pelvis for tenderness and evidence of trauma.
In males, perform a rectal examination for evaluation of the prostate after a urine specimen has been obtained, because prostatic manipulation can induce pyuria.
Perform urinalysis to confirm the diagnosis of hematuria. Carefully performed microscopic examination of a freshly voided midstream urine specimen is essential to the evaluation of hematuria; look especially for erythrocyte casts, which suggest glomerulonephritis. In men, fractionate urinalysis (initial, midstream, and terminal specimens) is also helpful in localizing the source of hematuria.
Further laboratory testing (except possibly urine culture) is not usually needed for bacterial hemorrhagic cystitis. Patients with urolithiasis may require baseline serum electrolyte determinations and renal function tests. Patients in whom a bleeding disorder is suspected or the cause of hematuria is unknown should have the following laboratory examinations: CBC with differential; prothrombin time, partial thromboplastin time, and international normalization ratio; serum electrolytes; and renal function.
A CT scan may be necessary for the evaluation of urolithiasis, trauma, tumors, and other causes. Compared with ultrasound, CT scanning is a better diagnostic study for evaluation of intra-abdominal pathology and tumors, especially those that are less than 3 cm in size. In pregnant females, ultrasound is the test of choice for evaluating hematuria.
Cystoscopy is essential for evaluation of bladder or urethral hematuria due to tumors and other causes. It may also be helpful for localizing hematuria of the upper genitourinary tract to one side or the other. The need for cytoscopy should be determined by the consulting urologist.
Other studies such as radionuclide scans or angiograms may be needed in special situations, but urologic consultation should be obtained before these studies are requested.
Treatment and Disposition
Treat the various causes of hematuria as follows:
Refer the patient to a urologist for evaluation. Consider hospitalization in order to expedite diagnostic procedures.
Hospitalize the patient, and obtain consultation with a nephrologist.
Urethral Strictures and Foreign Bodies
Refer the patient to a urologist.
Patients with hematuria of an unknown cause need urgent urologic consultation.
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1This chapter is a revision of the chapter by Charles F. McCuskey, MD, from the 6th edition.