Urinary Tract Infections

Fig. 8.1

Abdominal skin of a woman in uroseptic shock showing areas of bleeding and ceased microcirculation as a sign of physiological chaos with counteracting host reactions (Courtesy of F. Wagenlehner)

Table 8.1

Clinical presentation of cystitis (CY), pyelonephritis (PN), and urosepsis (US) and grading of severity

Clinical diagnosis	Acronym	Clinical symptoms	Grade of severity
Cystitis	CY–1	Dysuria, frequency, urgency, suprapubic pain; sometimes unspecific symptoms (see Table 8.1)	1
Mild and moderate pyelonephritis	PN–2	Fever, flank pain, CV tenderness; sometimes unspecific symptoms (see Table 8.1) with or without symptoms of CY	2
Severe pyelonephritis	PN–3	As PN-2, but in addition nausea and vomiting with or without symptoms of CY	3
Urosepsis (simple)	US–4	Temperature >38 °C or <36 °C Heart rate >90 beats min Respiratory rate >20 breaths/min or PaCO₂ <32 mmHg (<4.3 kPa) WBC > 12,000 cells/mm³ or <4000 cells/mm³ or ≥10 % immature (band) forms With or without symptoms of CY or PN	4
Severe urosepsis	US–5	As US-4, but in addition associated with organ dysfunction, hypoperfusion, or hypotension Hypoperfusion and perfusion abnormalities may include but are not limited to lactic acidosis, oliguria, or an acute alteration of mental status	5
Uroseptic shock	US–6	AS US-4 or US-5, but in addition with hypotension despite adequate fluid resuscitation along with the presence of perfusion abnormalities that may include, but are not limited to lactic acidosis, oliguria, or an acute alteration in mental status. Patients who are on inotropic or vasopressor agents may not be hypotensive at the time that perfusion abnormalities are measured	6

Diagnostics

Patient evaluation is based on a careful history, physical examination, and urine analysis.

The diagnosis of a urinary tract infection is based on clinical signs and the demonstration of microorganisms considered to be causing the infection. In most cases, the diagnosis is easy like in acute cystitis in a young woman, but in spinal cord injured patients with urinary catheters, the symptoms are totally different and urine findings are difficult to interpret.

Patient assessment always starts with an evaluation of severity. The clinical presentation forms correspond to grades of severity ranging from cystitis to urosepsis (Table 8.1). Severity is modified by risk factors, which can be described by means of phenotyping in a system called ORENUC (Table 8.2). Each letter in the word ORENUC refers to special patient features such as R – recurrent UTI without other known risk factor, E – extraurogenital risk factors like pregnancy, and C – presence of a catheter. According to a new classification presented by European Section for Infection in Urology (ESIU), a full section of the European Association of Urology (EAU), severity grades, and phenotyping is intended to replace the old classification into uncomplicated and complicated UTI.

Table 8.2

Host risk factors in urinary tract infections categorized according to the ORENUC system

Category of risk factor	Examples of risk factors	Phenotype
NO known risk factor	Otherwise healthy premenopausal women	O
Risk factors for Recurrent UTI, but no risk of more severe outcome	Sexual behavior (frequency, spermicide) Hormonal deficiency in postmenopause Secretor type of certain blood groups Well-controlled diabetes mellitus	R
Extra-urogenital risk factors with risk of more severe outcome	Prematurity, newborn Pregnancy Male gender Badly controlled diabetes mellitus Relevant immunosuppression (not well defined)	E
Nephropathic diseases with risk of more severe outcome	Relevant renal insufficiency (not well defined) Polycystic nephropathy Interstitial nephritis, e.g., due to analgesics	N
Urological risk factors with risk of more severe outcome, which can be resolved during therapy	Ureteral obstruction due to a ureteral stone Well-controlled neurogenic bladder disturbances Transient short-term external urinary catheter Asymptomatic bacteriuria	U
Permanent urinary Catheter and nonresolvable urological risk factors with risk of more severe outcome	Long-term external urinary catheter Nonresolvable urinary obstruction Badly controlled neurogenic bladder disturbances	C

Symptoms

Urinary tract infections (UTIs) often affect young people and are an important cause of reduced quality of life due to disabling symptoms. In most cases, UTIs are accompanied by typical signs and symptoms, but asymptomatic infections also occur. For male genital infections, the clinical symptoms are not related to the severity of the infection. Asymptomatic chronic bacterial prostatitis due to Chlamydia trachomatis infection may cause severe complications such as decreased fertility. Generally, the symptoms of UTI depend on which part of the urinary tract that is affected. Doctors should learn the symptom language of each infection site.

Kidneys (i.e., acute pyelonephritis): upper back and flank pain; fever (not always); shaking and chills, nausea and/or vomiting (not always).
Bladder and prostate (i.e., cystitis and prostatitis): lower abdominal discomfort; a strong, persistent urge to urinate; a burning sensation when urinating; pelvic pressure; blood in urine (cystitis); rectal or perineal pain (prostatitis); sexual dysfunction (erectile dysfunction/premature ejaculation in case of prostatitis); in women symptoms of UTI occur without vaginal discharge or irritation.
Urethra (urethritis): Burning with urination and/or urethral discharge.

The most common clinical presentations of UTIs are outlined below.

Acute Uncomplicated Cystitis

The typical patient with acute (uncomplicated) cystitis is a female of reproductive age who presents with irritative urinary symptoms. The diagnosis can be made with a high probability based on a focused history of dysuria, frequency, and urgency in the absence of vaginal discharge or irritation. No risk factors for complicated urinary tract infections should be present.

The most common symptoms are dysuria, frequent voiding of small volumes, and urgency, sometimes hematuria and less often suprapubic discomfort or pain. In case of recurrent cystitis without other risk factors, the young patients may show psychological symptoms such as depression with a subsequent reduction in quality of life. Recently, a simple standardized self-reporting questionnaire for acute uncomplicated cystitis was presented. This is an 18-item self-reporting questionnaire, named Acute Cystitis Symptom Score (ACSS), including (a) six questions about “typical” symptoms of acute uncomplicated cystitis, (b) four questions regarding differential diagnoses, (c) three questions on quality of life, and (d) five questions on additional conditions which may affect therapy. The questionnaire has been validated and can be recommended for clinical studies and for initial diagnosis and monitoring of treatment of acute uncomplicated cystitis. Also, Clayson et al. developed a 14-item UTI Symptoms Assessment questionnaire (UTISA), to measure the severity and bothersomeness of the most frequently reported symptoms and signs of uncomplicated urinary tract infections [5]. This instrument comprises three four-item domains (urination regularity, problems with urination, and pain associated with UTI) with two additional items measuring hematuria. This questionnaire has demonstrated excellent psychometric properties and good accuracy in evaluation of severity and bothersomeness of UTI symptoms. The authors highlighted the importance of specific symptoms of UTIs that can decrease the patient’s quality of life: frequency and urgency, pain or burning on urination, feeling of incomplete emptying, pain/pressure in lower abdomen, and low back pain.

Key Message

The combination of newly onset frequency and dysuria, in the absence of vaginal discharge, is diagnostic for an acute uncomplicated cystitis.

Acute Uncomplicated Pyelonephritis

The presence of flank or back pain in an otherwise healthy patient with lower urinary tract symptoms (dysuria, frequency, urgency, hematuria, suprapubic pain) is highly indicative of acute uncomplicated pyelonephritis. Moreover, these patients can sometimes present with systemic symptoms, such as nausea, vomiting, fever, chills, and abdominal pain. The history of recurrent lower urinary tract infections or a recent episode of acute uncomplicated cystitis is a risk factor of acute pyelonephritis. Other risk factors like diabetes, ureteral reflux, and incontinence may support the diagnosis of acute pyelonephritis in the presence of typical symptoms.

Key Message

The combination of newly onset frequency and dysuria, with flank or back pain, with or without systemic symptoms, in an otherwise healthy patient, is highly indicative of an acute uncomplicated pyelonephritis.

Fig. 8.2

Pain at costovertebral angle

Risk Factors, Phenotyping, and Complicated UTIs

A urinary tract infection in a patient with a structural or functional abnormality of the genitourinary tract was used to be called a complicated urinary tract infection, and the clinical presentations varied across a wide spectrum, ranging from mild lower tract irritative symptoms, such as frequency and urgency, to severe systemic manifestations, such as bacteremia and sepsis. In particular, complete urinary obstruction or trauma to the genitourinary tract with hematuria is associated with more severe clinical presentation forms. This complex picture was a main argument for the introduction of severity grades and phenotyping of risk factors thus enabling a more differentiated description of the patient and the symptoms than just a “complicated” urinary tract infection.

An important feature of the new ESIU/EAU classification is the status of asymptomatic bacteriuria which is regarded as a risk factor, not a specific type of UTI. The prevalence of asymptomatic bacteriuria is very high (almost 100 %) in patients with chronic indwelling catheters and 30–40 % in patients with a neurogenic bladder managed by intermittent catheterization.

Key Messages

Patients with indwelling urological devices and systemic symptoms, such as fever should be suspected of having UTI even in the absence of local genitourinary signs and symptoms.
Bacteriuria in patients with indwelling urological devices should only be treated if clinical symptoms of UTI are present.

Acute and Chronic Bacterial Prostatitis

Even if bacterial prostatitis represents a small portion of UTIs (about 10–15 %) of all urological visits in outpatient clinical setting, the impact on patient’s quality of life is considerable. Patients with acute bacterial prostatitis present with typical signs and symptoms of an acute urinary tract infection including irritative and/or obstructive voiding complaints and often have additional symptoms of systemic infections like malaise, nausea, vomiting, chills, and fever and sometimes present with signs of urosepsis. They also complain of perineal and suprapubic pain, associated with pain or discomfort of the external genitalia. Chronic bacterial prostatitis represents the most frequent cause of recurrent urinary tract infections in young and middle-aged men. The initial clinical presentation of chronic prostatitis is similar to acute prostatitis, but chronic bacterial prostatitis can be a devastating disease, characterized by relapsing febrile episodes, if not treated adequately from the beginning.

Key Message

The new-onset irritative and/or obstructive voiding symptoms associated with perineal or testicular discomfort/pain are highly indicative of acute bacterial prostatitis. Moreover, all perineal discomfort/pain with or without typical signs and symptoms of urinary tract infection should be investigated in order to exclude a bacterial prostatitis due to possible future complications.

Physical Examination

The patient history and urinalysis are the most important tools for diagnosing UTIs. Even if there are no key diagnostic signs, a focused physical examination is still an important part of the diagnostic work-up. However, sometimes the physical examination is diagnostic as in cases of acute bacterial prostatitis and acute pyelonephritis.

Clinical condition	Local signs	Possible signs	Systemic signs
Acute uncomplicated cystitis	None	Suprapubic tenderness	Rarely
Acute uncomplicated pyelonephritis	Costovertebral angle tenderness	Discomfort during kidney palpation	Commonly (fever, tachycardia)
Acute bacterial prostatitis	Painful, swollen prostate	Perineal pain/discomfort Perineal pain and anal sphincter spasm	Usually (fever, nausea)
UTIs in patients with risk factors (complicated UTI)	Depending on risk factor	Not specific	Commonly (fever, tachycardia)
Prostatic abscess	Fluctuation during prostate palpation	Perineal pain/discomfort	Rarely
Chronic bacterial prostatitis	Painful prostate	Perineal pain/discomfort	Rarely

The aim of the physical examination is to assess the severity of the infection and to look for risk factors. In septic patients, one should always look for focal manifestations of circulatory failure (Fig. 8.3). In adults, the physical examination should be done in order to specifically evaluate:

Fig. 8.3

Necrotic fingers in a young woman in septic shock due to delayed diagnosis of pyonephrosis resulting from an obstructing ureteral stone

Abdomen
- Previous surgical scars
- Abdominal meteorism and signs of ileus
- Costovertebral tenderness (pain elicited by blunt striking of the back, flanks, and the angle formed by the 12th rib and lumbar spine – with a fist) (Fig. 8.4)
  
  Fig. 8.4
  
  Localization of the costovertebral angle
- Palpable renal mass
- Dullness to percussion in the lower abdomen (bladder distension)
In women, genitals should be evaluated for:
- Vaginal discharges
- Vaginal mucosa
- Urethral secretion
- Signs of infection of subcutaneous tissue (Fournier gangrene)
In men, the physical examination of genitals should evaluate:
- Urethral secretion (the penis should be examined by retracting the foreskin)
- Testicular tenderness
- Painful/swollen prostate
- Perineal pain and anal sphincter spasm
- Signs of infection of subcutaneous tissue (Fournier gangrene)
In children, one should also evaluate the external urethral orifice.

In case of risk factors, the physical examination should be focused on genitourinary signs and symptoms related to each risk factor. In case of patients with indwelling catheter, the physical examination should always include systemic signs such as fever, nausea, and tachycardia (systemic inflammatory response syndrome).

Lab and Culture

Even if the diagnosis of UTIs can be made with a high probability based on history and physical examination, the verification of causative microorganism is the definitive diagnostic measure in UTIs. The microbiological evaluation is mandatory in cases of recurrent UTIs, in the presence of risk factors, and in patients with unusual signs and symptoms. As a rule, a urine sample should always be taken for culture before initiation of empiric antibiotic treatment. A good microbiological evaluation of a patient with UTIs requires that the urine specimen is appropriately collected, that a uropathogen is isolated, and the number of organisms is counted.

Sampling Technique

There is general consensus about the importance of using a midstream, clean-caught urine specimen to diagnose UTIs, although some authors found no significant difference in numbers of contaminated or unreliable results between specimens collected with and without preparatory cleansing.

Dipstick

In most cases of UTIs without risk factors, the urine dipstick testing has the same sensitivity and specificity, convenience, and cost-effectiveness, as conventional urinalysis and urine microscopy. This is due to the fact that nitrites and leukocyte esterase are the most accurate indicators of UTIs in symptomatic patients. A diagnosis of UTI can be safely made in patients with typical symptoms who are found to have a positive urine dipstick test or urinalysis, without obtaining a urine culture.

It is important to know that nitrite tests may be negative if the UTI is caused by a non-nitrate-producing pathogen such as Enterococci, S. saprophyticus, and Acinetobacter and if the urine is too dilute. Pyuria is frequently present in patients with lower urinary tract infection and always in those with acute pyelonephritis. However, the absence of pyuria does not exclude a urinary tract infection in patients with typical symptoms. Nitrites and leukocyte esterase may be negative in urine of patients with bacterial prostatitis.

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