Symptom Finder - Pyuria
PYURIA
Pyuria is included here although it is not a symptom or a definitive finding on physical examination. Examination of the urine, however, is so frequently a part of every physical examination that the causes of pyuria should be available for immediate recall for all primary care physicians.
As in other cases of purulent discharge, inflammation is the cause of pyuria in most cases; thus an etiologic mnemonic would seem unnecessary. However, the mnemonic MINT must be considered at the outset so that one recalls the malformations, neoplasms, and traumatic foreign bodies that may cause an obstruction or provide a fruitful soil for bacterial growth. Unlike a nonbloody discharge elsewhere, pyuria is rarely associated with inflammation of a noninfectious nature; more than that, it is almost invariably due to bacteria. What is more, the bacteria are usually gram-negative bacilli, particularly Escherichia coli, Enterobacter, Proteus, or Pseudomonas organisms.
With this in mind, let us visualize the anatomy of the genitourinary tree and develop a system for ready recall of the diagnostic possibilities. The urethra brings to mind all the various causes of urethritis.
The prostate reminds one of prostatitis and prostatic abscess. The bladder suggests cystitis, stricture, Hunner ulcers, calculi, and papillomas that may initiate infection. Some urologists may recall finding a vesicovaginal fistula or rectovesical fistula in patients who have had previous abdominal surgery; a fistula may also form in regional ileitis. The ureters suggest the numerous congenital anomalies (e.g., stricture, congenital band, and
aberrant vessel) that may cause obstruction and infection.
The renal pelvis and kidney recall pyelitis and pyelonephritis, as well as renal carcinoma, calculi, and congenital anomalies, all of which may contribute to infection. The rare causes of pyuria must be considered. Tuberculosis of the kidney should be mentioned, because when routine cultures are negative, this is one of the conditions to look for. Even actinomycosis can cause pyuria, thus a culture on Sabouraud media may be warranted. Although Bilharzia haematobium parasites usually cause hematuria, pyuria is occasionally the initial finding.
An interstitial nephritis of toxic or autoimmune origin may occasionally cause a “shower” of eosinophils into the urine. Finally, there is probably not a surgeon alive who has not been fooled by the pyuria of an acute appendicitis, salpingitis, or diverticulitis.
Approach to the Diagnosis
How does one track down the cause of pyuria? First, it must be determined that the cloudy urine is really pyuria. Amorphous phosphates and other inert material will disappear on treating the urine with dilute acetic acid.
Then, just as for other nonbloody discharges, one must do a smear and culture for the offending organism; an examination of the urine, especially the unspun specimen, is axiomatic. If one finds clumps of leukocytes, renal gitter cells, or WBC casts, the infection almost certainly comes from the kidney. Motile bacteria in an unspun specimen examined under highpower microscopy and a colony count of over 100,000 per mL signify infection.
A three-glass test may be helpful in localizing the site of origin of the pyuria. Anaerobic cultures and cultures for Chlamydia may be needed. Look for eosinophils on a Wright stain of the urine if toxic nephritis is suspected.
Vaginal examination and culture may disclose a source for the infection. In the male, one episode of pyuria should be sufficient indication for an IVP; a female should have one after her second episode, especially if no cause can be found on physical examination. Cystoscopy and a voiding cystogram are often indicated at this time.
Other Useful Tests
1. CBC (pyelonephritis)
2. Sedimentation rate (pyelonephritis)
3. Chemistry panel (diabetes mellitus, nephritis)
4. ANA analysis (collagen disease)
5. Retrograde pyelography (tumor, malformation, obstructive
uropathy)
6. Urine for acid-fast bacillus smear and culture and guinea pig
inoculation (tuberculosis)
7. Sonogram (diverticulum, pelvic mass, cyst, abscess)
8. CT scan of abdomen and pelvis (tumor, malformation, obstructive
uropathy, extrinsic mass)
9. Tuberculin test or chest x-ray (tuberculosis)
Pyuria is included here although it is not a symptom or a definitive finding on physical examination. Examination of the urine, however, is so frequently a part of every physical examination that the causes of pyuria should be available for immediate recall for all primary care physicians.
As in other cases of purulent discharge, inflammation is the cause of pyuria in most cases; thus an etiologic mnemonic would seem unnecessary. However, the mnemonic MINT must be considered at the outset so that one recalls the malformations, neoplasms, and traumatic foreign bodies that may cause an obstruction or provide a fruitful soil for bacterial growth. Unlike a nonbloody discharge elsewhere, pyuria is rarely associated with inflammation of a noninfectious nature; more than that, it is almost invariably due to bacteria. What is more, the bacteria are usually gram-negative bacilli, particularly Escherichia coli, Enterobacter, Proteus, or Pseudomonas organisms.
With this in mind, let us visualize the anatomy of the genitourinary tree and develop a system for ready recall of the diagnostic possibilities. The urethra brings to mind all the various causes of urethritis.
The prostate reminds one of prostatitis and prostatic abscess. The bladder suggests cystitis, stricture, Hunner ulcers, calculi, and papillomas that may initiate infection. Some urologists may recall finding a vesicovaginal fistula or rectovesical fistula in patients who have had previous abdominal surgery; a fistula may also form in regional ileitis. The ureters suggest the numerous congenital anomalies (e.g., stricture, congenital band, and
aberrant vessel) that may cause obstruction and infection.
The renal pelvis and kidney recall pyelitis and pyelonephritis, as well as renal carcinoma, calculi, and congenital anomalies, all of which may contribute to infection. The rare causes of pyuria must be considered. Tuberculosis of the kidney should be mentioned, because when routine cultures are negative, this is one of the conditions to look for. Even actinomycosis can cause pyuria, thus a culture on Sabouraud media may be warranted. Although Bilharzia haematobium parasites usually cause hematuria, pyuria is occasionally the initial finding.
An interstitial nephritis of toxic or autoimmune origin may occasionally cause a “shower” of eosinophils into the urine. Finally, there is probably not a surgeon alive who has not been fooled by the pyuria of an acute appendicitis, salpingitis, or diverticulitis.
Approach to the Diagnosis
How does one track down the cause of pyuria? First, it must be determined that the cloudy urine is really pyuria. Amorphous phosphates and other inert material will disappear on treating the urine with dilute acetic acid.
Then, just as for other nonbloody discharges, one must do a smear and culture for the offending organism; an examination of the urine, especially the unspun specimen, is axiomatic. If one finds clumps of leukocytes, renal gitter cells, or WBC casts, the infection almost certainly comes from the kidney. Motile bacteria in an unspun specimen examined under highpower microscopy and a colony count of over 100,000 per mL signify infection.
A three-glass test may be helpful in localizing the site of origin of the pyuria. Anaerobic cultures and cultures for Chlamydia may be needed. Look for eosinophils on a Wright stain of the urine if toxic nephritis is suspected.
Vaginal examination and culture may disclose a source for the infection. In the male, one episode of pyuria should be sufficient indication for an IVP; a female should have one after her second episode, especially if no cause can be found on physical examination. Cystoscopy and a voiding cystogram are often indicated at this time.
Other Useful Tests
1. CBC (pyelonephritis)
2. Sedimentation rate (pyelonephritis)
3. Chemistry panel (diabetes mellitus, nephritis)
4. ANA analysis (collagen disease)
5. Retrograde pyelography (tumor, malformation, obstructive
uropathy)
6. Urine for acid-fast bacillus smear and culture and guinea pig
inoculation (tuberculosis)
7. Sonogram (diverticulum, pelvic mass, cyst, abscess)
8. CT scan of abdomen and pelvis (tumor, malformation, obstructive
uropathy, extrinsic mass)
9. Tuberculin test or chest x-ray (tuberculosis)
