UTI: A brief review for medical practitioners

Introduction:

—  Common and painful human illness

—  Rapidly responsive to modern antibiotics..

—  NFT in 1950 was 1^st effective drug

—  Most common presentation is acute cystitis (infection of the bladder)

Definition:

—  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

Epidemiology:

•       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)

Aetiology:

—  Gram negative organisms

—  E coli mc (75-90%)

—  Staph saphrophyticus (5-15%)

—  Klebsiella

—  Enterococcus

—  Proteus

—  Citrobacter

Pathogenesis:

—  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:

•       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

Prostatitis:

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

Diagnosis:

—  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

Imaging:

—  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

Treatment:

—  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

Pyelonephritis:

—  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:

—  NFT

—  AMPICIILIN

—  CEPHALOSPORIN

—  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

Candiduria:

•       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.