Friday, March 15, 2013

UTI: A brief review for medical practitioners

  Common and painful human illness
  Rapidly responsive to modern antibiotics..
  NFT in 1950 was 1st effective drug
  Most common presentation is acute cystitis (infection of the bladder)
  Asymptomatic Bacteuria(ABU)-Occurs in the absence of symptoms attributable to the bacteria in the urinary tract
  Cystitis - Symptomatic infection of bladder
  Pyelonephritis-symptomatic infection of kidneys
  Uncomplicated UTI- Acute cystitis or pyelonephritis in nonpregnant women without anatomic defect or instrumentation of urinary tract
Complicated UTI encompasses all other forms of UTI
       As many as 50–80% of women in the general population acquire at least 1 UTI during their lifetime.
  Approximately 7% of patients require hospitalization.
  20–30% of pregnant women with asymptomatic bacteriuria subsequently develop pyelonephritis.
  Between 1 year and ~50 years of age, UTI and recurrent UTI are predominantly diseases of females.
  During the neonatal period, the incidence of UTI is slightly higher among males than among females.
Male infants more commonly have congenital urinary tract anomalies.
  After 50 years of age, the incidence of UTI is almost as high among men as among women. The reason being obstruction from prostatic hypertrophy becomes common.
Risk factors:
  Recent use of diaphragm with spermicide
  Frequent sexual intercourse
  H/O  UTI
  Diabetes mellitus(compromised immune status)
  Urinary obstruction( Prostatic hypertrophy ,stone disease)
  Urinary incontinence(can lead to hygiene issues)
  Gram negative organisms
  E coli mc (75-90%)
  Staph saphrophyticus (5-15%)
  In majority of UTI bacteria ascend from urethra to bladder and kidneys
  Interplay of host, pathogen and environmental factors leads to symptomatic disease
  Presence of stone or catheter(presence of foreign body) provides an inert surface for colonization
  Hematogenous spread in only 2% cases; the  most common seen in candiduria
Clinical manifestations:
  ABU- No symptoms; incidental bacteriuria on routine screening
       Cystitis- frequency, urgency and dysuria, nocturia , hesitancy, suprapubic discomfort. Sometimes it may present as gross hematuria may be seen
       Pyelonephritis- High grade fever, nausea, vomiting, low back or loin pain
       Picket fence pattern of fever which resolves over 72    hrs of therapy
       It may lead to intraparenchymal abscess formation (if there is immunocomprsied patient, delay in diagnosis and treatment or wrong antibiotics).
It should be suspected in patient continued to be   febrile despite of antibiotic therapy
  Papillary necrosis- Analgesic nephropathy
                                      Sickle cell disease
                                      Diabetes and pyelonephritis
       Emphysematous pyelonephritis:Severe infection associated with production of gas in renal and perinephric tissues;commonly seen in diabetics
Xanthogranulomatous Pyelonephritis:
  Occurs due to chronic obstruction most commonly by staghorn calculi together with chronic infection
  Leads to suppurative destruction of kidneys
  Residual renal tissue is replaced by yellowish discolouration with lipid laden macrophages
Ø  Infectious or noninfectious
Ø  Acute or chronic prostatitis
Ø  Acute prostatis presents as fever with chills, dysuria,frequency and pelvic or perineal pain
Ø  Chronic prostatis presents as recurrent episodes of cystitis without classic manifestations of UTI; there can be dull pain in perineum or painful ejaulation
  History: use of diaphragm, recent sexual act(honeymoon cystitis)
  Presence of any one symptom of UTI gives the probability of cystitis to be 50%
  Along with complicating factors it rises to 90%
  Detailed evaluation of risk factors discussed earlier
Urine examination:
  Urine dipstick test
   Nitrite test- Positive test shown by members of   enterobacteriaceae family
  Leucocyte esterase test detects enzyme which converts nitrate to nitrite
  Either of test positive test can be used to make diagnosis
  Both test negative indicates consideration of other diseases
  Negative  test is not sufficient to rule out bacteriuria in pregnant women
Urine analysis and urine culture:
  Reveals  pyuria in almost all cases and hematuria in 30% cases
  Automated tests are not more reliable than patient clinical presentation
  Urine culture is gold standard
  Colony count of 10o/ml in women and 1000/ml in men is considered to be sensitive and specific

  USG abdomen and pelvis and CT scans are used in evaluation of complicated pyelonephritis
  Urological evaluation in cases of males with recurrent episodes of cystitis
  Each patient warrants a different approach to treatment based on particular clinical syndrome
  Other factors are:
1.   site of infection
2.   presence or absence of complications
 Antimicrobials are warranted for every symptomatic case
Uncomplicated UTI:
  TMP-SMX and NFT are first line agents recommended
  Fluoroquinolone and beta lactam agents are second line agents
  NFT does not reach significant levels in tissue and cannot be used to treat pyelonephritis( we see this drug commonly used in upper tract  infection and patient subsequently going into fulminant infection)
  Moxifloxacin cannot be used as it does not reach adequate urinary levels
Drug dosages:
  NFT 100 mg bid 5-7 days
  Tmp-smx 1 DS bid for 3 days
  Fluoroqinolone 3 days regimen
  Fluoroquinoles are first line therapy as much resistance is noted with septran
  Other options are aminoglycosides with or without ampicillin, an extended spectrum cephalosporin, or a carbapenam
  Combinations of beta lactam with beta lactamase inhibitor is used in patients with complicated histories previous episodes and recent instrumentations
UTI in pregnancy:
  In cases of pyelonephritis parenteral beta lactams with or without aminoglycosides.
UTI in men:
  7 to 14 day course of septran or fluoroquinolone in uncomplicated cases
  2-4 weeks antimicrobials in acute prostatitis based on cultures
  4-6 weeks for chronic bacterial prostatitis-Pruliflox 600 mg once a day for 1 month has been our drug of choice. Prostate massage or frequent ejaculation can be helpful in chronic prostatitis to flush out the bacteria.
Complicated UTI:
  Treatment must be based on cultures
  Need for urological interventions
  Xanthogranulomatous pyelonephritis is treated by nephrectomy
  Percutaneous drainage and elective nephrectomy in emphysematous pyelonephritis(the risk stratification is necessary and the final decision the surgeon has to take whether to treat medically with pigtail drainage with higher antibiotics or elective nephrectomy) 
  Surgical drainage in cases of abscesses
Asymptomatic Bactiuria:
  Does not require treatment
  Treatment is to be done in pregnant women and patients undergoing urological procedures
Treatment is guided by cultures
Catheter Associated UTI
  Change of catheter
  Urine and blood cultures
  Antibiotics for 7-14 days
       Candida albicans and non albicans
  Clinically varies from asymptomatic to pyelonephritis and to even sepsis
  Treatment is recommended only for patients with symptomatic cystitis or pyelonephritis and those who are at risk for disseminated disease
  Fluconazole 200-400mg/day for 14 days is first line.Amphotericin B and Caspofungin  
Renal Abscess:
  Renal abscesses >5 cm  managed with percutaneous drainage  with antimicrobial therapy
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  For abscesses that are not amenable to percutaneous drainage, surgical drainage and/or rescue nephrectomy may be required in severe cases for which medical treatment has failed.
  Nephrectomy may also be warranted  in a small, chronically pyelonephritic and poorly functioning kidney destroyed by previous episodes of infection.
  Drainage catheters should remain in place until drainage is minimal (usually up to seven days). Follow-up imaging should be performed.

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