Acute Pyelonephritis

Pyelonephritis refers to infection of the renal parenchyma with local and systemic effects.

Aetiology

Ascending (gram-negative bacilli) or hematogenous route (usually gram-positive cocci)

Causative organisms:

• Gram Positives: Enterococcus faecalis, S. aureus, S. saprophyticus
• Gram Negatives: E. coli, Klebsiella, Proteus, Pseudomonas, Enterobacter spp.

Risk Factors

• Nephrolithiasis
• Prostatic obstruction
• Vesicoureteric reflux
• Neurogenic bladder
• DM, SCD, Immunosuppression, Polycystic kidney disease
• Pregnancy
• Post renal transplant
• Instrumentation

Clinical Features

• Rapid onset. Usually, less than 24hrs
• Fever, chills, N&V, malaise
• Costovertebral angle tenderness and/or flank pain
• Lower urinary tract symptoms: frequency, urgency, hematuria. Dysuria only in concomitant cystitis.

Investigations

• Urinalysis, Urine M/C/S
• FHG- Elevated WBCs
• Imaging: Renal Ultrasound, contrast-enhanced CT Scan, DMSA.

Complications

• Pyonephrosis
• Perirenal abscess

Treatment

• Hemodynamically stable – Oral outpatient antibiotics (Admit if no improvement in 24hrs)
• First choice: Cephalexin 1g QID for 14 days; Ciprofloxacin 500mg BD for 7 days.
• Second choice: Cefuroxime 750-1500mg TDS for 14 days; Gentamycin- Dose adjusted according to renal function and serum levels.
• Severe or non-resolving – Admit, hydrate, IV antibiotics
• Emphysematous pyelonephritis – Nephrectomy after IV antibiotics started and patient stabilized.
• Renal obstruction – Stenting or percutaneous nephrostomy tubes.