Related Subjects:
|Pyelonephritis and Urosepsis (UTI)
|Pyonephrosis
|Perinephric abscess
|Acute Kidney Injury (AKI) / Acute Renal Failure
|Renal/Kidney Physiology
|Chronic Kidney Disease (CKD)
Pyonephrosis = pus in the renal collecting system due to infection + obstruction, leading to rapid loss of renal function ⚠️ Essentially an infected hydronephrosis → can progress quickly to sepsis and multi-organ failure. Always a urological emergency.
🔬 Aetiology
- Thick pus blocks the urinary tract → back pressure → acute kidney injury (AKI).
- Any age group can be affected (from neonates 👶 to elderly 👴).
- Untreated → high risk of Gram-negative septicaemia.
🦠 Microbiology
- E. coli (most common) 🧫
- Klebsiella
- Proteus (urease producer, stone-forming)
- Pseudomonas
- Enterococcus
- Staphylococcus
- Fungal pathogens (e.g., Candida → fungal balls)
⚡ Risk Factors
- Immunocompromised states: HIV, diabetes, chemotherapy, corticosteroids.
- Kidney stones (esp. staghorn calculi 🪨).
- Renal tumours or external compression (colon/testicular cancer).
- Pregnancy 🤰, renal papillary necrosis, TB.
- Congenital anomalies: duplex kidneys, vesicoureteral reflux, neurogenic bladder.
🩺 Clinical Features
- Fever + flank pain + renal angle tenderness = classic triad.
- Sepsis: hypotension, rigors, septic shock 🚨.
- Lower urinary symptoms: dysuria, foul-smelling urine.
🧪 Investigations
- Bloods: FBC (↑WCC), U&E (renal impairment), CRP (infection marker), LFTs.
- Urinalysis & culture: Usually requires catheter/suprapubic sample for accuracy.
- USS (first-line): Detects hydronephrosis, stones, tumours.
- CT KUB: Gold standard for localisation of obstruction & complications.
🛠️ Management
- Immediate resuscitation: ABC, IV fluids 💧, broad-spectrum IV antibiotics.
- Urgent decompression:
- Percutaneous nephrostomy tube (preferred in unstable patients).
- Antegrade ureteric stenting (where feasible).
- Definitive treatment: Treat the cause (stone removal, tumour resection, antifungal therapy).
- Nephrectomy: If kidney is non-functional or abscessed despite drainage.
📚 References
