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UTI Evaluation

Presenting symptoms

• Common: frequency, urgency, dysuria, suprapubic pain, fever
• Hematuria: can occur with UTI, check UA
• Pneumaturia/fecaluria: high suspicion for fistula
• Differential: bladder pain syndrome, STI, VUR, vaginitis/urethritis

Collecting the Sample

• Obtain clean catch (0 squamous cells is best sample)
• If tube (foley/PCN) present, consider exchanging (if possible) prior to collecting sample
• If ostomy, catheterize stoma for collection
• Do not collect from bag

Lab Findings

• Leukocyte esterase: sensitive but not specific for UTI
• Nitrites: produced by Enterobacteriaceae, also seen with pyridium
• Cloudy urine: pyuria or precipitated phosphate crystals in alkaline/concentrated urine

Defining Asymptomatic Bacteruria

• Bacteria in urine in the absence of any symptoms
• 1-5% healthy young women, 20% women older than 80
• 23-89% patients using CIC vs 100% patients with longterm catheter usage
• DO NOT TREAT even if diabetic, SCI, foreign body in GU tract
• Do not screen and do not treat prior to non-urologic surgery
• Only treat if pregnant or undergoing GU instrumentation

Oral Antibiotics for Outpatient UTIs

Antibiotic	Normal Dosing	Side Effects	Tips
Nitrofurantoin (Macrobid)	100mg BID	GI effects Peripheral neuropathy Hemolysis if G6PD Pulmonary hypersensitivity reaction (rare)	Only works well for GU infections (not tissue) Don't give if GFR < 50 (inadequte excretion) Caution in elderly patients Do not take with quinolones, Mg, or probenecid
Trimethoprim-Sulfamethoxazole (Bactrim)	Double-Strength (800/160mg) BID	Rashes GI effects Hyperkalemia Stevens Johnson syndrome (rare)	Avoid in pregnancy Can exacerbate effects of warfarin
Fosfomycin	3g sachet x1	Headache GI effects Vaginitis	Not used frequently in US due to cost ($70-90)
Ciprofloxacin (Cipro) Levofloxacin (Levaquin)	500mg BID 250mg BID or 750mg daily	GI effects, dizziness, photosensitivity CNS effects Tendon rupture	Avoid in children or pregnancy Decreased oral absorption with iron, zinc, or antacid (separate by 2hrs) Can lower seizure threshold
Cefuroxime Cefoxitin			Do not use if patient has prior immediate hypersensitivity to penicillins Use with caution if delayed hypersensitivity to penicillins
Ampicillin (w/ Sulbactam)	875/125mg BID	Hypersensitivity rash Diarrhea	Rash more likely when viral disease present

Cystitis

Tips for diagnosis/management

• Dysuria is most specific symptom, but differentiate from vaginitis
• If only symptoms are foul-smelling or cloudy urine, encourage hydration and reassess
• Dysuria + frequency + no vaginal irritation - UTI probability > 90%
• Repeat UCx is not necessary if symptoms resolve with treatment

Factors indicating complicated cystitis

• Anatomic: cystocele, fistula, diverticulum
• Obstruction: BOO, UPJO, stricture
• Iatrogenic: hospital-acquired infection, recent GU surgery, indwelling catheter
• Functional: NGB, PFD, VUR, elevated PVR, incontinence
• Other factors: pregnancy, stones, DM, immunosuppresion

Emphysematous cystitis

• Seen in patients w/ complicating factors: DM, age, BOO, NGB
• CT (required for diagnosis) shows air within bladder wall (submucosal)
• Treatment: abx, catheterization, and DM management

Renal Infections

Acute Pyelonephritis

• Acute pyelo is a clinical diagnosis: fever + flank pain, lower urinary symptoms may (not) be present
• DO NOT diagnose acute pyelo based on CT findings
• Obtain BCx if male, or female with systemic symptoms or with risk factors
• Imaging is not required, but can obtain renal US to assess for stones/hydro
• CT imaging warranted in patient with systemic symptoms or presumed complicated pyelo
• Uncomplicated patient can be treated outpatient with PO antibiotics
• Patients with persistent fever and symptoms > 72hrs despite abx, assess with CT imaging

Emphysematous Pyelonephritis

• Gas-forming infection usually seen with DM + obstruction
• Mortality rate 19-43%
• Most present with fever + vomiting + flank pain
• Diagnosis made by demonstrating air in renal parenchyma
• Treat w/ PCN placement - nephrectomy if extensive gas w/ renal destruction

Acute Focal/Multifocal Bacterial Nephritis

• Presents similar to pyelonephritis but with more severe symptoms
• Diagnosed via CT with contrast, area of decreased enhancement
• Treat with IV abx for 7+ days, then 7 days PO abx

Renal Abscess

• Can present with variety of symptoms - fever, chills, abd/flank pain, weight loss, cystitis
• If < 3-5cm (depending on reference), treat with abx and observe
• If > 3-5cm, clinically unstable, or immunocompromised, drain percutaneously

Infected Hydronephrosis +/- Pyonephrosis

• Bacterial infection in a hydronephrotic kidney +/- parenchymal destruction
• Imaging shows hydronephrosis with abnormal fluid, possible fat stranding
• Treat with either stent or PCN

Perinephric abscess

• Abscess extending through renal capsule but contained within Gerota's
• Caused by abscess rupture, extravasation of infected urine, or spread from another source
• Psoas abscess: limping, flexion + external rotation of hip
• Mortality rate 12-50%
• If < 3cm, treat with abx only, otherwise drain abscess
• Differentiate from pyelonephritis: usually have symptoms > 5 days, and repain febrile for longer than 4 days

Chronic pyelonephritis

• Rare cause of renal failure in patients without underlying abnormalities
• Blunted/dilated calyces and cortical scars seen on imaging

Xanthogranulomatous pyelonephritis (XGP kidney)

• Specific pathology due to accumulation of lipid-filled macrophages, requires pathology for diagnosis - may be mistaken for ccRCC
• Presents with flank pain, fever, persistent bacteruria
• CT triad: unilateral enlargement + little/no function + large stone in renal pelvis, present in 50-80% patients
• Usually treated with nephrectomy (may be difficult), although stones can be treated with PCNL

Genital infections

Fournier gangrene

• Gangrene of male genitalia, usually with underlying comorbidities/causes
• Spreads along tissue plans - Dartos fascia, Colles fascia, Scarpa fascia
• If suspected, perform immediate extensive debridement, SPT if urethral invovement, colostomy if colonic/rectal involvement
• Orchiectomy rarely required due to separate blood supply

Periurethral abscess

• Can spread through Buck fascia and cause extensive infection
• Treat with SPT drainage and debridement

Special considerations

Spinal Cord Injury Patients

• Do not screen or treat asymptomatic bacteruria in patients with SCI and indwelling catheters
• Antibiotic prophylaxis and irrigation have not been shown to decrease bacteruria

References

• Cooper, K. L., G. M. Badalato, and M. P. Rutman. "Infections of the urinary tract." Campbell-Walsh-Wein Urology. 12th ed. Elsevier (2020): 1129-1201.