Info
🌱 來自: Huppert’s Notes
Genitourinary (GU) Infections🚧 施工中
Genitourinary (GU) Infections
Asymptomatic bacteriuria
• Definition: Bacterial growth in a properly collected urine culture specimen from a patient without symptoms of inflammation of the GU system, such as urinary urgency, frequency, dysuria, or flank pain
• Management:
- Does not warrant treatment in most individuals because there is a low risk for progression to a UTI
- Three populations who warrant treatment of asymptomatic bacteriuria include:
• Pregnant individuals: Asymptomatic bacteriuria confers worse outcomes in pregnancy, including preterm birth, perinatal mortality, and low fetal birth weight
• Renal transplant recipients: Treatment of asymptomatic bacteriuria is indicated within one month of renal transplant, as these patients are at higher risk for symptomatic UTI and acute graft rejection
• Patients undergoing a urologic procedure expected to cause mucosal bleeding: Untreated bacteriuria prior to a urologic intervention is associated with increased rates of infectious complications
Simple cystitis
• Definition: An infection of the urinary tract without signs or symptoms that suggest extension beyond the bladder and lower urinary tract, such as:
- Temperature ≥100.0°F or 37.8°C
- Signs and symptoms of systemic illness, such as rigors, chills, or significant malaise
- Flank pain or costovertebral angle tenderness
- Perineal or pelvic pain in men (which can suggest prostatitis)
• Pathophysiology: Simple cystitis arises from ascent of bacteria (usually intestinal flora) that gain access to the urinary tract
• Pathogens: E. coli (80%), S. saprophyticus, Klebsiella spp., Enterococcus spp., Proteus spp., Pseudomonas aeruginosa, Enterobacter spp., Group B strep
• Clinical features: Symptoms of lower urinary tract inflammation, such as, urinary frequency or urgency, dysuria, suprapubic pain
• Diagnosis:
- Urinalysis (UA): A urinalysis that demonstrates pyuria is required, but not sufficient, for diagnosis of a urinary tract infection. Pyuria is also very common in asymptomatic bacteriuria, so pyuria is not equivalent to a UTI. The absence of pyuria strongly suggests against a UTI. The urinalysis may demonstrate:
• Leukocyte esterase, which reflects the presence of WBCs in the urine
• Nitrites, which reflect the presence of Gram-negative organisms of the Enterobacteriaceae family
• WBCs seen on microscopic analysis of urine (>10/hpf = pyuria)
- Urine culture: Assists with identifying the causative organism and tailored antibiotic therapy
• Treatment:
- First-line options include:
• Nitrofurantoin 100 mg BID for 5 days
• Trimethoprim-sulfamethoxazole 1 DS tablet BID for 3 days
- Alternative agents (e.g., because of intolerance or allergies):
• Amoxicillin-clavulanate 500 mg BID for 5–7 days
• Cefpodoxime 100 mg BID for 5–7 days
• Cephalexin 500 mg PO QID for 5–7 days
Pyelonephritis
• Pathophysiology: Arises when ascending infections extend beyond the bladder and enter the upper urinary tract (e.g., the ureters and kidneys)
• Microbiology:
- Gram-negative: E.coli, Klebsiella spp., Enterobacter spp., Pseudomonas aeruginosa
- Gram-positive: Enterococcus faecalis, S. aureus (suggests descending UTI from a bloodstream infection)
• Clinical features: Flank pain, costovertebral angle (CVA) tenderness, signs of systemic illness (fevers, chills, rigors)
• Diagnosis:
- Clinical features suggestive of pyelonephritis + pyuria and/or bacteriuria is sufficient to make the diagnosis of pyelonephritis
- Urinalysis and urine culture; false negative UA/UCx can occur with obstructing kidney stones
- Blood cultures: Pyelonephritis can lead to bloodstream infections. Obtain blood cultures in patients with severe sepsis, septic shock, or other symptoms of bacteremia (e.g., rigors)
- Imaging is not necessary in all patients with pyelonephritis, but consider ordering a renal ultrasound or CT abdomen/pelvis in the following situations:
• Severely ill patients (e.g., severe sepsis or septic shock)
• Persistent illness despite 48–72 hours of appropriate antibiotic therapy in order to rule out renal abscess, urinary tract obstruction, and prostatitis
• Suspected urinary tract obstruction (e.g., progressive oliguria, worsening renal function, known nephrolithiasis)
• Treatment:
- Outpatients: Oral antibiotic regimens such as PO ciprofloxacin, levofloxacin, trimethoprim-sulfamethoxazole, cefpodoxime, or cephalexin
- Inpatients:
• If low risk for multidrug-resistant organisms and not critically ill: ceftriaxone 1 g IV daily
• Review prior urine cultures to see if the patient has had prior UTIs with P. aeruginosa or ESBL-producing organisms; consider a prior antibiotic regimen if the patient has a history of multidrug- resistant organisms
• Also consider a broader empiric antibiotic regimen if the patient is critically ill
Catheter-associated UTI (CAUTI)
• Epidemiology: CAUTIs are the most common health care-acquired infection
• Microbiology: Similar to other UTIs with the addition of Candida spp.
• Clinical features: Symptoms are often non-specific; can cause dysuria and abdominal pain
• Diagnosis:
- Pyuria and bacteriuria (≥105 CFU/mL) or funguria in a patient with an indwelling urinary catheter AND
- Systemic findings suggestive of an infection (e.g., fever, leukocytosis) or findings that localize to the urinary tract (e.g., flank pain, suprapubic pain)
AND
- Exclusion of an alternative source of infection (e.g., skin and soft tissue infection, bacteremia, pneumonia)
• Treatment: Antibiotics, remove urinary catheter as soon as possible
Prostatitis
• Pathogens**:** Gram-negative rods: E.coli, Klebsiella spp., Proteus spp., Pseudomonas aeruginosa, Enterobacter spp.
Acute bacterial prostatitis:
• Pathophysiology: Pathogens gain entrance to the prostate via the urethra
• Clinical features: Patients are typically acutely ill with high fevers, chills, dysuria, urgency, frequency, as well as pelvic or perineal pain (most localizing feature to the prostate)
• Diagnosis: Digital rectal exam will reveal a boggy, exquisitely tender prostate. Urinalysis may show profound pyuria with sheets of WBCs on microscopy. Urine culture is almost always positive.
• Treatment:
- Mild illness: Outpatient management with empiric trimethoprim-sulfamethoxazole 1 DS tablet BID or ciprofloxacin 500 mg BID
- Severe illness: Admit to the hospital and treat with IV ciprofloxacin or ceftriaxone. Carbapenems (e.g., ertapenem 1 g IV daily) may be used in those with risk-factors for multidrug-resistant organisms or previously cultured ESBL-producing organisms
- Narrow antibiotics based on culture results
- Duration of antibiotics: 2–6 weeks depending on severity of illness
• Complications:
- Some patients will develop bacteremia or a prostatic abscess, or they will go on to develop chronic bacterial prostatitis
- In patients who fail to improve despite initial antibiotic therapy, obtain a CT of the abdomen/pelvis with IV contrast to evaluate for a prostatic abscess, which may require procedural drainage
Chronic bacterial prostatitis:
• Pathophysiology: Similar to acute prostatitis, with chronic bacterial prostatitis arising from incomplete treatment
• Clinical features: More common than acute bacterial prostatitis. Occurs in men age 40–70 yr. These patients are often asymptomatic or only mildly ill. Patients often have symptoms of recurrent urinary tract infections, and the same organism is frequently isolated from urine culture. Dull back, scrotal, perineal, or suprapubic pain may be present
• Diagnosis: More difficult to diagnose than acute bacterial prostatitis. Diagnostic standard is finding bacteria at a higher concentration in prostatic fluid compared to urinary tract specimens, but testing is insensitive, so the diagnosis can also be presumed and treatment can be empiric
• Treatment: Prolonged antibiotics (4 weeks). Fluoroquinolones or trimethoprim-sulfamethoxazole both achieve excellent concentrations in prostatic tissue