Urinary tract infection (UTI)
Contents
• Urinary tract infection
• Etiology
• Classification
• Pathogenesis
Objectives
At the end of this lecture, student will be able to
• Define UTI
• Classify
UTI
• Explain the etiology and pathogenesis of UTI
Urinary tract infections (UTIs)
• A wide variety of syndromes
• Including urethitis, cystitis, prostatitis, and pyelonephritis
• Presence of microorganisms in the urinary tract that cannot bebaccounted for by contamination
• Infection may be limited to the growth of bacteria in the urine
• Frequently may not produce symptoms
Classification of UTI
Lower tract infection
• Cystitis
• Urethritis
• Prostatitis
Upper tractbinfection
• Pyelonephritis involving the kidneys
According to Degree
Complicated
• Predisposing lesion of the UT
• Congenital abnormality or distortion of the UT
• A stone a catheter
• Prostatic hypertrophy, obstruction, or neurological deficit
• All can interfere with the normal flow of urine and urinary tract defenses.
Recurrent UTIs
• Multiple symptomatic infections with asymptomatic periods
• Re infection
– Caused by a different organism than originally isolated and account for the majority of recurrent UTIs
• Relapse
– Repeated infections with the same initial
organism and usually indicate a persistent infectious source
Etiology of UTI
The microorganism that cause UTIs usually originate from the bowel flora of the host
Uncomplicated UTI:
• E. coli accounts for 85%
• S. saprophyticus 5-15%
• K. pneumoniae, Pseudomonas, and Enterococcus 5-10%
• S. epidermidis if isolated should be considered a
contamination
Complicated UTIs
• Occurs because of anatomic, functional, or pharmacological factors
• Predisposes the patient to persistent
infection, recurrent infection, or treatment failure
Clinical presentations
Lower tract infection
• Include dysuria, urgency, frequency, nocturia,
suprapubic heaviness, and hematuria in women
• No systemic symptoms
Upper tractbinfection
• Flank pain, costovertebral tenderness,
abdominal pain, fever, nausea, vomiting and malaise.
Elderly patients
• Frequently do experience specific urinary
symptoms
• Altered mental status, change sin eating
habits, or GI symptoms
Patients with catheters
• Will have no lower tract symptoms
• Just flank pain and fever
Pathophysiology of UTI
• Infection spreads from renal pelvis to renal
cortex
• Kidney grossly edematous; localized abscesses
in cortex surface
• E. Coli responsible organism for 85% of acute pyelonephritis; also Proteus, Klebisella
Manifestations of UTI
• Rapid onset with chills and fever
• Malaise
• Vomiting
• Flank pain
• Costovertebral tenderness
• Urinary frequency, dysuria
Summary
• UTI is defined as the presence of microorganisms in the urinary tract
• Escherichia coli, which accounts for 85% of community-acquiredbinfections and is a frequently isolated pathogen , but it accounts for less than 50% of infections
• Between the ages of 1 and 5 years, UTIs occur more frequently in females
• UTI can be acquired through three routes ascending, hematogenous and lymphatic
• Natural host defence mechanism including free flow of urine, low pH, high osmolality, high ammonia are bacteriostatic in nature and changes in these defence mechanism will lead to urinary tract infection
Also, Visit: Pathophysiology Notes