Two4 55B Infections of Urinary Tract - bladder, kidney infections

• Dysuria, frequency, urgency
• Occasionally suprapubic pain
• Hematuria 
• Foul-smelling urine

Acute cystitis is a superficial infection of the bladder mucosa, so fever, chills, and other signs of dissemination are not present. 


When urinary obstruction is associated with fever and chills, it should be regarded as a urologic emergency.

Vaginitis - vaginal irritation, discharge, multiple sexual partners 

Urethritis - dysuria, discharge, secondary to urethral injury after sexual intercourse

• Diagnose uncomplicated cystitis in women who have no other risk factors for complicated urinary tract infections based on: Strong EAU 2020
• • a focused history of lower urinary tract symptoms (dysuria, frequency and urgency);
• • the absence of vaginal discharge or irritation. 

Urinalysis - microscopic pyuria, bacteriuria and occasionally hematuria 

Urine culture remains the definitive test; and in symptomatic patients, the presence of 10² cfu/mL or more of urine usually indicates infection.

In women with recent onset of symptoms and signs suggesting acute cystitis and in whom factors associated with upper tract or complicated infection are absent, a urinalysis that is positive for pyuria, bacteriuria, or hematuria, or a combination should provide sufficient documentation of UTI, and a urine culture may be omitted.

• Urine cultures should be done in the following situations: Strong EAU 2020
• • suspected acute pyelonephritis;
• • symptoms that do not resolve or recur within four weeks after the completion of treatment;
• • women who present with atypical symptoms;
• • pregnant women.

Nitrofurantoin - 

• TMP-SMX - 
• - least expensive 
• - recommended in areas where the prevalence of resistance to these drugs among E. coli strains causing cystitis is less than 20%

• Fosfomycin 
• - minimal resistance 

Fluoroquinolones -  They have a high propensity for collateral damage (i.e., ecological adverse effects, such as drug resistance) and should be reserved as antimicrobials of last resort for acute cystitis; indeed this is in agreement with the FDA warning mentioned in an earlier section 

• Duration
• - 3 days for women
• - 7 days for men

• EAU 2020 - 
• Prescribe fosfomycin trometamol, pivmecillinam or nitrofurantoin as first-line treatment for uncomplicated cystitis in women. Strong
• Do not use aminopenicillins or fluoroquinolones to treat uncomplicated cystitis. Strong

Its the complicated UTI or infection with resistant pathogens. 

• Mild to moderate illness, no nausea or vomitiing - treat on OPD basis with oral fluoroquinolones, if the susceptibility pattern of the pathogen is known, TMP-SMX may be effective
• Severe illness or possible urosepsis - IV antimicrobials should be administered based on the susceptibility patterns of the known uropathogens at that institution. 
• Correct any underlying urinary tract abnormalities and treat host factors that exacerbate the infection.
• Therapy is usually continued for 10 to 14 days and switched from parenteral to oral therapy when the patient is afebrile and clinically stable.
• Repeat urine cultures should be performed if the patient fails to respond to therapy.

• Abrupt onset of chills, fever (100.3° F or greater)
• Unilateral or bilateral flank or costovertebral angle pain and/or tenderness.
• These so-called upper tract signs are often accompanied by dysuria, increased urinary frequency, and urgency

Acute pyelonephritis may also simulate gastrointestinal tract abnormalities with abdominal pain, nausea, vomiting, and diarrhea.

• Leukocytosis with a predominance of neutrophils.
• Urinalysis usually reveals numerous WBCs, often in clumps, and bacterial rods or chains of cocci.
• Leukocytes exhibiting brownian motion in the cytoplasm (glitter cells) may be present if the urine is hypotonic, but they are not in themselves diagnostic of pyelonephritis.
• Granular or leukocyte casts in the urinary sediment - suggestive of acute pyelonephritis.

Urine cultures are positive, but about 20% of patients have urine cultures with fewer than 10⁵ cfu/mL and therefore negative results on Gram staining of the urine.

Blood culture only if the patient have systemic toxicity. Blood culture do not influence decision regarding therapy in uncomplicated peylonephritis.

• Renal enlargement, hypoechoic parenchyma, and compressed central collecting complex. 
• When parenchymal destruction becomes pronounced, a more disorganized parenchyma and abscess formation associated with complicated renal and perirenal infections may be identified.

First determine which group the patient falls

• - Uncomplicated infection that does not warrant hospitalization - no nausea, vomiting 
• - Uncomplicated infection in patients with normal urinary tracts who are ill enough to warrant hospitalization for parenteral therapy (high grade fever, high WBC count, vomiting, dehydration, evidence of sepsisi)
• - complicated infection associated with hospitalization, catheterization, urologic surgery, or urinary tract abnormalities

Relieve obstruction 

Ambulatory patients - Fluoroquinolones for 7 days 

Complicated pyelonephritis and positive blood cultures - parenterel therapy until clinically stable, then continue the dose for 10-14 days 

In patients with fever lasting longer than 72 hours, CT is most helpful for ruling out obstruction and identifying renal and perirenal infections.

• Uncomplicated pyelonephritis management - EAU 2020
• Treat patients with uncomplicated pyelonephritis not requiring hospitalisation with short course fluoroquinolones as firstline treatment. Strong
• Treat patients with uncomplicated pyelonephritis requiring hospitalisation with an intravenous antimicrobial regimen initially. Strong
• Switch patients initially treated with parenteral therapy, who improve clinically and can tolerate oral fluids, to oral antimicrobial therapy. Strong
• Do not use nitrofurantoin, oral fosfomycin, and pivmecillinam to treat uncomplicated pyelonephritis. Strong

• Repeat urine cultures should be performed on the fifth to the seventh day of therapy and 10 to 14 days after discontinuing antimicrobial therapy to ensure that the urinary tract remains free of infections.
• Patients who relapse usually are cured by a second 14-day course of therapy, but occasionally a 6-week course is  necessary. 
• Depending on the clinical presentation and response and initial urologic evaluation, some patients may require additional evaluation (e.g., voiding cystourethrogram, cystoscopy, bacterial localization studies) and correction of an underlying abnormality of the urinary tract.

Focal or multifocal bacterial nephritis - acute focal bacterial nephritis (AFBN) represents a midpoint on the spectrum between pyelonephritis and renal abscess. Wedge shaped area of decreased enhancement is seen. Failure to respond to antimicrobial therapy is an indication for appropriate studies to rule out obstructive uropathy, renal or perirenal abscess, renal carcinoma, or acute renal vein thrombosis. 

Infected hydronephrosis - is bacterial infection in a hydronephrotic kidney.

Pyonephrosis - infected hydronephrosis associated with suppurative destruction of the parenchyma of the kidney, in which there is total or nearly total loss of renal function. Where infected hydronephrosis ends and  pyonephrosis begins is difficult to determine clinically. 

Note - In focal ischemia, rim sign is seen, since the cortex is supplied by cortical vessels.

• Emphysematous pyelonephritis is a urologic emergency characterized by an acute necrotizing parenchymal and perirenal infection caused by gas-forming uropathogens.
• Because the condition usually occurs in diabetic patients, it has been postulated that the high tissue glucose levels provide the substrate for microorganisms such as E. coli, which are able to produce carbon dioxide by the fermentation of sugar.

In addition to diabetes, many patients have urinary tract obstruction associated with urinary calculi or papillary necrosis and significant renal functional impairment.

• Tissue gas that is distributed in the parenchyma may appear on abdominal radiographs as mottled gas shadows over the involved kidney.  This finding is often mistaken for bowel gas.
• As the infection progresses, gas extendsto the perinephric space and retroperitoneum. 
• USG - strong focal echoes suggesting the presence of intraparenchymal gas. 
• CT - imaging procedure of choice in defining the extent of the emphysematous process and guiding management. 
• - Absence of fluid in CT images or the presence of streaky or mottled gas with or without bubbly and loculated gas appears to be associated with rapid destruction of renal parenchyma and a 50% to 60% mortality rate.
• - Presence of renal or perirenal fluid, the presence of bubbly or loculated gas or gas in the collecting system, and the absence of streaky or mottled gas patterns are associated with a less than 20% mortality rate

• Class 1: Gas confined to the collecting system
• Class 2: Gas confined to the renal parenchyma alone
• Class 3A: Perinephric extension of gas or abscess
• Class 3B: Extension of gas beyond the Gerota fascia
• Class 4: Bilateral EPN or EPN in a solitary kidney

• It is surgical emergency 
• Most patients are septic, and fluid resuscitation, glucose and electrolyte management, and broad-spectrum antimicrobial therapy are essential.
• Ureteral obstruction, if present, is alleviated by a percutaneous nephrostomy tube or a stent
• Nephrectomy for patients who do not improve after few days of therapy or if non functioning kidney

This distribution of gas should not be confused with cases of emphysematous pyelitis in which air is in the collecting system of the kidney. Emphysematouspyelitis is secondary to a gas-forming bacterial UTI, often occurs in nondiabetic patients, is less serious, and usually responds to antimicrobial therapy.

Renal abscess or carbuncle is a collection of purulent material confined to the renal parenchyma.

• Etiology 
• - Gram negative organism (more common, ascending route) - in complicated UTI associated with stasis, calculi - ascending infection - renal damage 
• - gram positive organisms (less common, hematogenous route) - multiple skin carbuncles and IV drug abuse introduces organisms in the blood stream, search for such history 1-8 weeks before onset of UTI

• Lab findings 
• - marked leukocytosis 
• - pyuria or bacteriuria may not be evident unless the abscess communicates with the collecting system

USG - An echo-free or low-echodensity space-occupying lesion with increased transmission is found on the ultrasound image. 

CT - Initially, CT shows renal enlargement and focal, rounded areas of decreased attenuation. After several days of the onset of the infection, a thick fibrotic wall begins to form around the abscess. An echo-free or slightly echogenic mass caused by the presence of necrotic debris is seen. CT of a chronic abscess shows obliteration of adjacent tissue planes, thickening of the Gerota fascia, a round or oval parenchymal mass of low attenuation, and a surrounding inflammatory wall of slightly higher attenuation that forms a ring when the scan is enhanced with contrast material. The ring sign is caused by the increased vascularity of the abscess wall.

• < 3cm - IV antibiotic therapy 
• 3-5 cm - manage conservatively if patient is stable 
• >5 cm - percutaneous drainage. Typically, abscesses of this size require multiple drains, multiple drain manipulations, or eventual surgical washout and potential nephrectomy. 

Abscesses of all sizes in immunocompromised hosts or those that do not respond to antimicrobial therapy should be drained percutaneously. 

• When hematogenous dissemination is suspected - organism is usually penicillin resistant Staphylococcus, and drug of choice is penicillinase-resistant penicillin, If a history of penicillin hypersensitivity - vancomycin.
• If ascending infection is suspected - organism is usually gram-negative pathogens, treated empirically with IV third- generation cephalosporins, antipseudomonal penicillins, or aminoglycosides

• Perinephric abscess usually results from rupture of an acute cortical abscess into the perinephric space or from  hematogenous seeding from sites of infection.
• Patients with  pyonephrosis particularly when a calculus is present in the kidney, are susceptible to perinephric abscess formation.
• Diabetes mellitus is present in approximately one third of  patients with perinephric abscess.
• In about one third of the cases, perinephric abscess is caused by hematogenous spread, usually from sites of skin infection.

• <3cm - antibiotic alone for immune competent patients 
• >3cm - drainage or nephrectomy if kidney is non functional (Unlike in renal abscesses, early drainage of abscesses greater than 3 cm in diameter is recommended.)

Patients with polycystic renal disease who undergo hemodialysis may be particularly susceptible to the progression from acute UTIs to perinephric abscess.

• Thorley’s study found that two factors differentiated perinephric abscess and acute pyelonephritis:
• (1) most patients with uncomplicated pyelonephritis were symptomatic for less than 5 days before hospitalization, whereas most with perinephric abscesses were symptomatic for longer than 5 days; and
• (2) no patient with acute pyelonephritis remained febrile for longer than 4 days once appropriate antimicrobial agents were started. All patients with perinephric abscesses had a fever for at least 5 days, with a median of 7 days.

There are no symptoms of chronic pyelonephritis until it produces renal insufficiency, and then the symptoms are similar to those of any other form of chronic renal failure.

Radiological features - asymmetry and irregularity of the kidney outlines, blunting and dilation of one or more calyces, and cortical scars at the corresponding site. Regardless of the etiology of chronic pyelonephritis, CT findings will be  consistent with atrophy, cortical/parenchymal thinning, calyceal clubbing, and possible hypertrophy of residual normal tissue and asymmetry.

• Pathology 
• - scarring is often polar with underlying calyceal blunting 
• - parenchyma thin, corticomedullary demarcation is lost 
• - Portions of the parenchyma may be replaced by fibrosis, and, although glomeruli may be preserved, periglomerular fibrosis is often seen.
• - In some affected areas, glomeruli may be completely fibrosed and tubules atrophied. Leukocyte and hyaline casts are sometimes present in the tubules; the latter may cause resemblance to the thyroid colloid, hence the description renal thyroidization.

Treating infection if present, preventing future infections, and monitoring and preserving renal function.

Achievement of acceptable bactericidal levels of a drug in the urine of a patient with chronic pyelonephritis may be difficult because the diminished concentrating ability of pyelonephritis may impair excretion and concentration of the antimicrobial agent. duration of antimicrobial therapy is often prolonged to maximize the chance of cure.

• A rare, severe, chronic renal infection typically resulting in diffuse renal destruction. 
• Most cases are unilateral and result in a nonfunctioning, enlarged kidney associated with obstructive uropathy secondary to nephrolithiasis.
•  It begins within the pelvis and calyces and subsequently extends into and destroys renal parenchymal and adjacent tissues.
• Imitate virtually every other inflammatory disease of the kidney, as well as renal cell carcinoma, on radiographic examination.

The primary factors involved in the pathogenesis of XGP are nephrolithiasis, obstruction, and infection.

XGP should be suspected in patients with UTIs and a unilateral enlarged nonfunctioning or poorly functioning kidney with a stone or a mass lesion indistinguishable from a malignant tumor.

Diabetes - the risk of developing the disease

Proteus is the most common organism involved in XGP.

• Gross
• - kidney massively enlarged and has a normal contour.
• - In the diffuse form of the disease, the entire kidney is involved, whereas in segmental XGP, only the parenchyma surrounding one or more calyces or one pole of a duplicated collecting system is involved.
• - The calyces are dilated and filled with purulent material, but fibrosis surrounding the pelvis usually prevents dilation.
• - The papillae are often destroyed by papillary necrosis
• - In advanced stages of the disease, multiple parenchymal abscesses are filled with viscous pus and lined by yellowish tissue
• - The capsule is often thickened, and extension of the inflammatory process into the perinephric or paranephric space is common

• Microscopic examination
• - dark sheets of lipid-laden macrophages (foamy histiocytes with small, dark nuclei and clear cytoplasm) intermixed with lymphocytes, giant cells, and plasma cells
• - Xanthogranulomatous cells are not specific to XGP but may be present anywhere inflammation or obstruction coexists.
• - Microscopic appearance of XGP has been confused with clear cell adenocarcinoma of the kidney on frozen section and has led to radical nephrectomy.

Triad of unilateral renal enlargement, non functioning kidney and large calculus in the renal pelvis - 50-80% of cases

Large, reniform mass with the renal pelvis tightly surrounding a central calcification but without pelvic dilatation. 

Renal parenchyma is replaced by multiple water-density masses representing dilated calyces and abscess cavities filled with varied amounts of pus and debris.

In classic bear paw sign, there is no calyx seen, and its the destroyed parenchyma. Fluid like content is not bear paw sign, architectural derangement of the parenchyma is bear paw sign. (ref?)

The primary obstacle to the correct treatment of XGP is incorrect diagnosis. Radiologic studies, although distinctive, often cannot be used to differentiate between XGP and renal cell carcinoma.

Antimicrobial therapy may be necessary to stabilize the patient preoperatively, and, occasionally, long-term antimicrobial therapy will eradicate the infection and restore renal function.

• XGP has been associated with renal cell carcinoma, papillary transitional cell carcinoma of the pelvis or bladder, and infiltrating squamous cell carcinoma of the pelvis; thus, if malignant renal tumor cannot be excluded, nephrectomy should be performed.
• When diffuse and extensive disease into the retroperitoneum exists, removal of the kidney and perinephric fat may be needed. Under these circumstances, the surgery may be difficult and may involve dissection of granulomatous tissue from the diaphragm, great vessels, and bowel.

Potentially life-threatening form of necrotizing fasciitis involving the male genitalia. 


Predisposing factors include diabetes mellitus, local trauma, paraphimosis, periurethral extravasation or urine, perirectal or perianal infections, and surgery such as circumcision or herniorrhaphy.

History of perineal trauma, instrumentation, urethral stricture associated with sexually transmitted disease. 

• Immediate debridement 
• Orchiectomy is almost never required. 
• Suprapubic diversion in which urethral trauma or extravasation is suspected. 
• Colostomy if there is a colonic injury or rectal perforation.

Catheter-associated UTI refers to UTIs occurring in a person whose urinary tract is currently catheterised or has been catheterised within the past 48 hours.

• Do not carry out routine urine culture in asymptomatic catheterised patients. Strong
• Do not use pyuria as sole indicator for catheter-associated (CA-UTI). Strong
• Do not use the presence or absence of odorous or cloudy urine alone to differentiate catheter-associated asymptomatic bacteriuria from CA-UTI. Strong

• Treat symptomatic CA-UTI according to the recommendations for complicated UTI. Strong
• Take a urine culture prior to initiating antimicrobial therapy in catheterised patients in whom the catheter has been removed. Strong
• Do not treat catheter-associated asymptomatic bacteriuria in general. Strong
• Treat catheter-associated asymptomatic bacteriuria prior to traumatic urinary tract interventions (e.g. transurethral resection of the prostate). Strong
• Replace or remove the indwelling catheter before starting antimicrobial therapy. Strong
• Do not apply topical antiseptics or antimicrobials to the catheter, urethra or meatus. Strong
• Do not use prophylactic antimicrobials to prevent catheter-associated UTIs. Strong
• The duration of catheterisation should be minimal. Strong

• Do not routinely use antibiotic prophylaxis to prevent clinical UTI after urethral catheter removal.
• Weak

Catheters should be placed only as necessity, rather than convenience, consideration of use of alternatives to indwelling catheters when considered appropriate (Condom catheter, CISC) - HICPAC