Diagnosis

Pyelonephritis

Etiology

Cause [e9w]

• Escherichia coli, klebsiella pneumoniae, Proteus, Pseudomonas, Enterococci, Staphylococci, enterobacteria, Candida spp

Pathophysiology [e9w]

1. Urinary tract infections occur more frequently in females due to their shorter urethras, hormonal changes, and proximity of the urethra to the anus

2. Urinary outflow obstruction --> incomplete bladder emptying --> urinary stasis --> bacteria multiplication without being flushed out

3. Pyelonephritis is a complication of UTI: Ascending urinary tract infection that spreads from the bladder and travels up the urether to the kidneys

4. Hematogenous spread is uncommon (immunocompromised, ureteral obstructions)

5. Chronic pyelonephritis:

   • Recurrent infections and long-term inflammatory changes --> pyogenic scarring

6. Complicated pyelonephritis:

   • Pregnant patients

   • Uncontrolled diabetes

   • Kidney transplants and immunocompromised patients

   • Urinary anatomical abnormalities

   • Acute or chronic kidney failure

   • Hospital-acquired bacterial infections

Risk factors -> postrenal obstruction/urinary stasis

• BPH

• Abdominal cancer

• Urolithiasis

• Vesicoureteric reflux

Complications [e9w]

• Acute renal failure

• Chronic pyelonephritis

• Emphysematous pyelonephritis - a necrotizing kidney infection

• Obstructive pyelonephritis

• Papillary necrosis

• Perinephric abscess

• Renal abscess

• Renal scarring and atrophy

• Renal vein thrombosis

• Sepsis and urosepsis

• Xanthogranulomatous pyelonephritis

Epidemiology

Incidence per 100.000 [e9w][hou][k7r][8ps][6gc][zco]

Approach

• Blood test: complete blood cell count, CRP, creatinine, BUN

• Urine stix

• Urine culture

• Blood culture

• CT abdomen

• UL abdomen

• MRI (pregnant patient)

Treatment

1. Antibiotics: [e9w][oun]

   • Uncomplicated pyelonephritis: outpatient

     • Amoxicillin-clavulanate 875 mg orally twice daily for 7 to 10 days

     • Cefixime 400mg x 1 for 10-14 days

     • Cephalexin 500mg x 2 for 10-14 days

     • Ciprofloxacin 500mg x 2 for 7 days

     • Sulfamethoxazole-trimethoprim 160/8000mg x 2 for 14 days

   • Inpatients with parenteral treatment: [oun]

     • Carbapenem (imipenem or meropenem) plus vancomycin

     • Ertapenem 1g x 1

     • Ceftriaxone 1g x 1

     • Aminoglycosides (Gentamicin 5mg x 1)

     • Piperacillin-tazobactam (Enterococcus or Pseudomonas)

     • Cefotaxime

     • Cefuroxime

     • Vancomycin or linezolid if a Gram-positive organism is suspected

2. Analgesics and antipyretics (NSAIDs)

Differential diagnoses

Acute pancreatitis, Appendicitis, Cervicitis, Cholecystitis, Costochondritis, Diverticulitis, Endometritis, Glomerulonephritis, Herpes zoster, Hydronephrosis, Ovarian abscess, Pelvic inflammatory disease, Perforated ulcer, Pneumonia, Prostatitis, Pyonephrosis, Renal hemorrhage, Renal thrombosis, Rib fracture, Ruptured ectopic pregnancy, Ruptured ovarian cyst, Urinary tract infection, Urolithiasis, Urosepsis