UTIs: Renal System Health & Disease (PDF)

Renal system in health and disease Urinary tract infections (UTIs) Dr Christian Cobbold Learning Objectives At the end of this session you should be able to… Discuss the causes and pathophysiology of urinary tract infections (UTIs) Acute cystitis Acute and chronic pyelonephritis Urinary tract infect...

Renal system in health and disease Urinary tract infections (UTIs) Dr Christian Cobbold Learning Objectives At the end of this session you should be able to… Discuss the causes and pathophysiology of urinary tract infections (UTIs) Acute cystitis Acute and chronic pyelonephritis Urinary tract infections (UTIs) UTIs cause inflammation of the urinary epithelium, usually by bacteria from gut flora Can be anywhere along urinary tract – Urethra, prostate, bladder, ureter, kidney What are the body’s natural defences against UTIs? Low pH and high osmolarity of urine Bactericidal secretions from urinary tract epithelium Prevention of urine reflux to ureters and kidneys (by constrictures during bladder contraction) Long urethra and prostate secretions (men) Urinary tract infections At risk groups: Sexually active and pregnant women Pre-pubertal children Women treated with antibiotics that disrupt vaginal flora Classification (by location): Bladder inflammation (cystitis) Inflammation at upper urinary tract (pyelonephritis) Urinary tract infections Acute cystitis More common in women due to shorter urethra and closeness of the urethra to the anus Approx 10% women have cystitis each yr Infecting organisms: E.coli (85%), staphylococcus (10%) Retrograde movement of bacteria into urethra and bladder Pathophysiology Infection Inflammatory response Bladder swelling Stretch receptors activated Symptom of bladder fullness Urination urgency & frequency Urinary tract infections Acute cystitis Bladder appearance Mild inflammation: red More advanced: haemorrhage and pus formation Prolonged infection: sloughing of bladder epithelium with ulceration Severe: necrosis and gangrene Evaluation Urine culture of specific microorganisms Treatment Increased fluid intake relieves symptoms Antibiotics Cranberry juice.... Urinary tract infections Acute pyelonephritis Inflammation of ureter, kidney tubules, interstitium & CDs Most cases start off as cystitis and make their way up the urinary tract from the bladder Infection causes inflammation and infiltration of WBCs Pus forms in tubules → damage and sloughing Symptoms Painful urination Systemic – fever, chills, groin pain Treatment Organism-specific antibiotics Urinary tract infections Chronic pyelonephritis Persistent or recurrent infection leading to scarring Signs of infection (fever, weight loss, malaise, blood in urine) Pathophysiology Chronic kidney disease Chronic upper UTI Antibiotic & immune system resistant Progressive inflammation What effects does tubular dysfunction have on plasma Na, K, H and water levels? Tubule destruction & scarring Impaired urineconcentrating ability