Urinary and kidney infections Notes

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Chronic pyelonephritis

Lower urinary tract infection

NOTES NOTES URINARY & KIDNEY INFECTIONS GENERALLY, WHAT ARE THEY? PATHOLOGY & CAUSES ▪ Infections involving kidneys, ureters, bladder, urethra (UTI) TYPES Upper UTIs (kidneys) ▪ Pyelonephritis SIGNS & SYMPTOMS Lower UTIs ▪ Dysuria (painful urination), frequent urination/urgency Upper UTIs ▪ Flank pain, fever, chills, nausea, vomiting, malaise, lower UTI symptoms Lower UTIs (bladder, urethra) ▪ Cystitis, urethritis CAUSES Bacterial infection (most common) ▪ Gram negative bacteria: Escherichia coli (E. coli), 80% of cases; Klebsiella; Proteus; Enterobacter; Citrobacter ▪ Gram positive bacteria: Enterococcus; Staphylococcus saprophyticus (S. saprophyticus), second most common, esp. in young individuals who are biologically female, sexually active Ascending infection ▪ Bacteria move from rectal area → urethra → bladder → kidney Descending infection ▪ Bacteria starts in blood/lymph → kidney → bladder, urethra COMPLICATIONS ▪ Urosepsis, septic shock DIAGNOSIS DIAGNOSTIC IMAGING Renal scintigraphy, dimercaptosuccinic acid (DMSA), radionuclide/DMSA scan ▪ Kidney scarring LAB RESULTS ▪ Pyuria (white blood cells in urine) ▪ > 105 colony-forming units/mL ▪ Leukocyte esterase (enzyme created by white blood cells) TREATMENT MEDICATIONS ▪ Antibiotic treatment (e.g. trimethoprimsulfamethoxazole, nitrofurantoin, penicillin) to dialysis ▪ Pain medications SURGERY ▪ Kidney transplantation OSMOSIS.ORG 853
PYELONEPHRITIS osms.it/pyelonephritis PATHOLOGY & CAUSES ▪ Inflamed kidney; result of bacterial infection; affects tubules, interstitium, renal pelvis ▪ Interstitial abscesses filled with pus ▪ Tubules damaged, contain neutrophil casts Chronic pyelonephritis ▪ Repeated episodes of acute pyelonephritis. ▪ Leads to fibrosis, renal interstitium scarring, renal tubules atrophy ▪ Localized in upper, lower poles of kidney ▪ Xanthogranulomatous pyelonephritis (XGP) ▫ Rare type of chronic pyelonephritis ▫ Infected kidney stone forms granulomatous tissue ▫ Can be mistaken for kidney tumors on imaging RISK FACTORS ▪ Urinary tract abnormalities, indwelling urinary catheter, diabetes, immunocompromised status, enlarged prostate SIGNS & SYMPTOMS ▪ ▪ ▪ ▪ May be asymptomatic Hematuria, polyuria/nocturia Flank pain Inflammatory response ▫ Leukocytosis; fever; chills; nausea, vomiting; gerontologic (e.g. altered mental status) Chronic pyelonephritis ▪ Same as acute pyelonephritis ▪ Hypertension DIAGNOSIS LAB RESULTS ▪ Urine culture, bacteria ▪ Pyuria, hematuria, bacteriuria, leukocyte casts ▪ Leukocyte esterase, nitrites, hematuria CAUSES Chronic pyelonephritis ▪ Vesicoureteral reflux (VUR) ▫ Most common cause ▫ VUR → predisposed to recurrent infections ▫ Failure of vesicourethral orifice → urine moves backward up urinary tract from bladder ▫ Increases risk of ascending upper UTI ▫ May result from primary congenital defect, bladder outlet obstruction Figure 120.1 A CT scan in the coronal plane demonstrating perinephric fat stranding and cortical rim loss seen in acute pyelonephritis. 854 OSMOSIS.ORG
Chapter 120 Urinary & Kidney Infections TREATMENT MEDICATIONS ▪ Antibiotics targeted to bacterial infection SURGERY Figure 120.2 The histological appearance of the kidney in a case of acute pyelonephritis. There are neutrophils present in the interstitium and within the tubular lumina. Chronic pyelonephritis ▪ Correct kidney obstruction/VUR ▪ Nephrectomy: removal of part/all of damaged kidneys ▪ Kidney transplant OTHER INTERVENTIONS ▪ Ensure individual well hydrated Chronic pyelonephritis ▪ Dialysis: machine works for kidneys too damaged to function Figure 120.3 A CT scan of the abdomen in the axial plane demonstrating a subcapsular abscess secondary to pyelonephritis of the right kidney. OSMOSIS.ORG 855
URINARY TRACT INFECTIONS osms.it/UTI PATHOLOGY & CAUSES ▪ UTI; bladder inflammation due to bacterial/ fungal infection, chemical irritants, foreign bodies, trauma ▪ AKA cystitis CAUSES ▪ Most common: bacterial infections (e.g. E. coli, S. saprophyticus) ▫ Ascending infection → bacteria move from rectal area → urethra → bladder ▫ Descending infection → bacteria starts in blood/lymph → kidney → bladder, urethra DIAGNOSIS DIAGNOSTIC IMAGING Renal ultrasound ▪ Children with kidney malformation Voiding cystourethrogram (VCUG) ▪ Individual given radiocontrast liquid, fluoroscopy (real-time X-rays); healthcare provider monitors urination ▪ Children with severe/recurrent UTIs, to detect vesicoureteral reflux (retrograde movement of urine from bladder back up into ureters, kidneys) LAB RESULTS RISK FACTORS ▪ Positive for nitrites ▫ Gram negative organisms (e.g. E. coli) convert nitrates to nitrites ▪ > 105 colony-forming units/mL from clean catch urine sample ▪ < 105 colony-forming units/mL, infection still possible ▪ Sterile pyuria (pyuria, urine culture without bacteria) → urethritis (urethra inflammation) ▫ Neisseria gonorrhoeae, Chlamydia trachomatis: most common causes, sexually transmitted infections (STIs) COMPLICATIONS Pyuria ▫ Cloudy urine ▫ > five white blood cells, high-powered field on microscopy, > 10 white blood cells/mL on hemocytometer ▫ Hematuria ▪ Young individuals who are biologically female (shorter urethra → shorter distance for ascending bacteria) ▪ Sexual intercourse; penile foreskin ▪ Postmenopause (decreased estrogen levels → decreased vaginal flora) ▪ Indwelling catheter ▪ Diabetes mellitus (hyperglycemia inhibits neutrophil diapedesis) ▪ Impaired bladder emptying/urinary stasis ▪ Pyelonephritis ▪ Urosepsis ▪ Septic shock SIGNS & SYMPTOMS ▪ Suprapubic pain, dysuria, frequent urination/urgency, urine voids small in volume ▪ Infants: fussy, fever, difficulties feeding ▪ Elderly individuals: fatigue, incontinence, altered mental status 856 OSMOSIS.ORG Dipstick test ▪ Leukocyte esterase
Chapter 120 Urinary & Kidney Infections TREATMENT MEDICATIONS ▪ Antibiotics: trimethoprim-sulfamethoxazole, ciprofloxacin, ceftriaxone, azithromycin, penicillin ▪ Pain medications OTHER INTERVENTIONS ▪ Increase fluid intake OSMOSIS.ORG 857

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