Urinary tract infection (UTI) - B. Pharma 2nd Semester Pathophysiology notes pdf

Urinary tract infection (UTI)


       Urinary tract infection





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 be accounted 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




Upper tract infection

       Pyelonephritis involving the kidneys

According to Degree


       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


      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 tract infection

       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



       Flank pain

       Costovertebral tenderness

       Urinary frequency, dysuria


       UTI is defined as the presence of microorganisms in the urinary tract

       Escherichia coli, which accounts for 85% of community-acquired infections 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

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