Page 970 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 75: Urinary Tract Infections 701

(ADPKD) in whom distinction of pyocyst from hemorrhage can be endophthalmitis, brain abscess, or prostatic abscess, with some devel-
difficult. Dependent debris in a renal cyst on ultrasound or CT sug- oping emphysematous prostatitis. To date, these K pneumoniae iso-
gests infection; however, absence of such a finding does not exclude lates have remained sensitive to first-generation cephalosporins and
pyocyst. Aspiration of cyst fluid for Gram stain and culture establishes fluoroquinolones. Transrectal biopsy of the prostate is associated with
80
the diagnosis, but is problematic in ADPKD. Pyocysts may arise from sepsis in approximately 2% of patients and rarely causes septic shock or
ascending infection or by hematogenous seeding. Infected cysts may metastatic infection. One day antimicrobial prophylaxis is protective,
70
manifest as persistent sepsis unresponsive to intravenous antimicrobial but failures have been associated with resistant organisms.
agents. Ultrasound and CT are both poor at diagnosing infected renal
or hepatic cysts in patients with ADPKD. Positron emission tomography URINARY TRACT INFECTION DUE TO CANDIDA
(PET) has emerged as the diagnostic modality of choice. Definitive
65
diagnosis by percutaneous aspiration of the particular cyst is possible in ■ PATHOGENESIS, EPIDEMIOLOGY, AND CLINICAL FEATURES
only a minority of cases. Lipophilic antimicrobial agents such as a fluo-
roquinolone or trimethoprim-sulfamethoxazole penetrate the cyst well Asymptomatic candiduria is the most common manifestation of candidi-
compared to β-lactams, and may be superior, provided the organism is asis in the urinary tract, due to the combination of urinary catheterization
sensitive. 66 and broad-spectrum antimicrobial use. Symptoms due to Candida cys-
Pyocystitis (pus in the urinary bladder) can present with sepsis, lower titis are rare in ICU, but may become manifest in the recovering patient
urinary tract signs, or pneumaturia due to gas-forming organisms. after transfer to the ward. In a very small minority, candiduria ascends
Patients with chronic anuria on dialysis or who have an ileal conduit are to the upper tract, causing pyelonephritis with or without dissemination.
predisposed. Antimicrobial therapy and bladder irrigations may be suf- A fungus ball in the renal pelvis occasionally arises, sometimes causing
ficient therapy, but necrosis of the bladder wall as demonstrated by gas obstruction. Disseminated invasive candidiasis usually originates from
in the muscular layers on CT will require surgical resection. 67,68 an infected central intravenous cannula but almost always involves the
kidneys through the bloodstream and may also cause candiduria. In gen-
Emphysematous Pyelonephritis: Emphysematous pyelonephritis is a eral, candidiasis originates from the patient’s own endogenous flora, but
rare fulminant disorder usually arising in patients with poorly con- occasionally a unique epidemic strain spreads within an ICU, from one
trolled diabetes, and historically associated with a mortality rate of catheterized patient to another due to a breakdown in Infection Control.
80%. The patient typically presents acutely with features of pyelo- A prospective observational study over 1 year in 24 adult French ICUs in
nephritis and severe sepsis with or without multiorgan failure. Gas 2006 showed that cross-transmission occurring in only one ICU involv-
formation occurs in the renal parenchyma and surrounding tissues ing seven patients. In this study, the incidence of candidemia and candi-
71
due to fermentation of glucose by Enterobacteriaceae, forming hydro- duria was 6.7 and 27.4 per 1000 admissions, respectively, with crude ICU
gen and carbon dioxide. Most patients have uncontrolled diabetes mortality of 61.8% for candidemic and 31.3% for candiduric patients.
mellitus and some have obstruction of the urinary tract. Pathology Eight percent of candiduric patients had candidemia with the same spe-
69
demonstrates extensive necrotizing pyelonephritis with abscess for- cies. Attributable mortality of candidemia for adults is reported between
mation and papillary necrosis. Poor perfusion is present in most 14.5% and 50%, but that attributed to candiduria alone is virtually zero. 75
cases due to infarction, vascular thrombosis, arteriosclerosis, and/or By microscopic examination, Candida species are readily recognized
glomerulosclerosis. Plain radiographs may show diffuse mottling of as gram-positive, ovoid, unicellular forms or as pseudohyphae and grow
69
the parenchyma as an early sign. More advanced cases show extensive readily on routine culture. A report of ≥10 organisms/mL indicates
4
bubbles in the parenchyma and a gas crescent surrounding the kidney colonization or infection of the bladder, but procurement contamination
within the perinephric space. Ultrasound and CT are much more should be excluded by repeat culture. Persistent candiduria in most sta-
sensitive than plain films at detecting gas. Case reports prior to 1982 ble ICU patients is a benign condition that resolves with removal of the
57
associated surgical intervention within 48 hours and antimicrobial urinary catheter. Observation for any features of upper tract infection or
therapy with improved outcome. Although relief of obstruction was disseminated invasive candidiasis is all that is usually required. However,
sometimes sufficient, nephrectomy was frequently necessary. More transplant and neutropenic patients with candiduria should be treated,
recent reports have suggested that a combination of antimicrobial as should those undergoing invasive urologic procedures. On occasion
agents, ICU support, tight glucose control, and percutaneous drainage candiduria may be a valuable pointer to Candida pyelonephritis or
is successful in most cases, with nephrectomy reserved for a minority disseminated candidiasis as the true cause of enigmatic sepsis.
(18% mortality rate in a series of 46 cases). 69 In disseminated invasive candidiasis of nonurinary origin, postmor-
Acute Prostatitis and Prostatic Abscess: Acute bacterial prostatitis rarely tem examination of the kidneys typically reveals widespread micro-
causes sepsis requiring ICU admission. It presents with high fever and abscesses. Neutropenia, transplantation, immunosuppressive therapy
urgency, frequency, dysuria, difficulty voiding, or acute retention of including corticosteroids, mucositis due to chemotherapy, burns, diabe-
urine, with suprapubic or perineal pain. Rectal examination demon- tes mellitus, total parenteral nutrition, severe pancreatitis, central venous
strates a tender and swollen prostate. Gram-negative bacilli are the catheters, and upper gastrointestinal surgery all predispose to candi-
most frequent pathogens, and enterococci may also be responsible. demia and disseminated invasive candidiasis. Colonization of mucous
Most antimicrobial agents cross the prostatic epithelium effectively, membranes, often accompanied by candiduria, frequently precedes
72
because of the intense inflammatory response. An oral antimicrobial invasion and delay in antifungal therapy is associated with increased
73,74
agent to which the pathogen is susceptible and that penetrates the unin- mortality.
fluoroquinolone, or doxycycline, is preferred for a total of 6 weeks to ■ TREATMENT
flamed prostatic acini well, such as trimethoprim-sulfamethoxazole, a
minimize the risk of chronic prostatitis. Prostatic abscess, if present, With uncommon exceptions, fluconazole is the treatment of choice
can be confirmed by transrectal ultrasonography or CT. Transurethral for candidiasis confined to the kidneys or urinary tract. It is primarily
resection of the prostate or perineal aspiration of pus guided by tran- excreted in urine, is well tolerated, nontoxic, relatively inexpensive, well
srectal ultrasound usually provides adequate drainage. absorbed orally, and has less drug-drug interactions than other azoles.
Prostatitis and prostatic abscess generally arise by the ascending Urinary levels exceed 100 μg/mL, greatly exceeding MICs for fully
route; however, for the past two decades bacteremic prostatic abscess susceptible yeasts (≤8 μg/mL) but also for those with dose-dependent
due to mucoid strains of K pneumoniae has been increasingly described, susceptibility (MIC, 16-32 μg/mL) and sometimes even for resistant
usually in Asian men with poorly controlled diabetes mellitus or cir- strains (MIC, ≥64 μg/mL). Tissue concentrations in the kidney are
rhosis. Most cases have liver abscess; a minority also have meningitis, greater than three times that in the serum. All species other than
75

section05_c74-81.indd 701 1/23/2015 12:37:27 PM