Predisposing Factors:
Immunocompromised state, diabetes,
elderly, female (short urethra), stagnant
urine (anatomical variant, obstruction,
neurogenic bladder, urinary reflux)
Bacterial entry (Less Common):
Indwelling catheter, surgical inoculation,
hematogenousspread, trauma
(Staphylococcus, Enterococcus, Candida)
Fecal bacteria access urethra
(E. coli, Proteus, Klebsiella)
Impairment of body’s natural defense
systems, or stagnant urine, allow for
bacterial accumulation
Portal of entry bypasses body’s physical
defenses (gravity and repetitive outward
urine flow)
Bacterial fimbriae and pili allow
them to ascend urethra and
adhere to epithelium
Lower Urinary Tract Infection (LUTI): Pathogenesis and clinical findings
Suprapubic
Tenderness
Bacterial colony irritates
urinary epithelium
Urgency:
Sensation of need to urinate
quickly or impending
incontinence
Stimulation of
inflammatory
response
Stimulation of urinary reflex
Pathogens use
enzymes to reduce
nitrate to nitrite
Delirium in Elderly
Frequency:
Repetitive need to
urinate
Unique response of altered fluid
status, electrolytes and mental
status, likely as a result of
increased inflammatory cytokines
Lower Urinary Tract Infection (“Cystitis”):
Infection of bladder or distal tract by capable bacteria
colonizing epithelium and causing symptoms
Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published March 16, 2014 on www.thecalgaryguide.com
Author:
Brett Edwards
Reviewers:
Riley Hartmann
Jan Rudzinski
Haotian Wang
Steve Vaughan*
* MD at time of publication
Usual Pathogens (“KEEPS”):
K – Klebsiella
E – E. coli (90%)
E – Enterococcus, Enterobacteriaceae
P – Proteus, Pseudomonas
S – Staph. saprophyticus, Serratia
Urine Findings:
↑ Colony Count (>107 CFU/L)
↑ WBC (>10 WBC/μL)
(+) Bacterial culture
(+) Nitrites, Leukocyte Esterase
(+) Foul, turbid urine
+/- Hematuria (rare)