Emphysematous pyelonephritis
Emphysematous pyelonephritis is a severe, life-threatening complication of acute pyelonephritis caused by gas-producing bacteria within the renal parenchyma and collecting system, occurring almost exclusively in patients with diabetes or immunocompromise. It requires emergency broad-spectrum antibiotics, aggressive resuscitation, and source control with percutaneous drainage or nephrectomy for extensive or refractory disease.
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What this article covers
- Overview
Emphysematous pyelonephritis (EPN) is a severe, necrotizing form of acute pyelonephritis caused by gas-producing bacteria, producing gas within the renal parenchyma and, often, the collecting system.
- Epidemiology
A rare but recognized complication of acute pyelonephritis, occurring specifically in the subset of patients with diabetes or immunocompromise who develop a complicated infection.
- Risk factors
Diabetes mellitus, the classic and dominant predisposing condition for emphysematous pyelonephritis, analogous to the diabetes/immunocompromise association described for emphysematous cholecystitis…
- Pathophysiology
Gas-producing bacteria infect the renal parenchyma and collecting system, generating gas that accumulates within the kidney, the defining structural abnormality of the disease.
- Clinical features
Fever, chills, and flank pain, with or without costovertebral angle tenderness, the same presentation as acute pyelonephritis, since EPN is a complication along that same clinical spectrum rather than a distinct presenting syndrome.
- Differential diagnosis
Uncomplicated acute pyelonephritis: responds to standard empiric antibiotics within 72 hours without imaging findings of gas, abscess, or obstruction, unlike EPN, which is defined by the CT finding of parenchymal or collecting-system gas.
- Diagnosis
The diagnosis is confirmed by demonstrating gas within the renal parenchyma and/or the collecting system, in a patient with clinical pyelonephritis whose fever persists beyond 72 hours of antibiotics…
- Management
First, resuscitate as for any severe complicated pyelonephritis or sepsis: IV isotonic fluids and hemodynamic support for any evidence of instability, escalating to critical care if septic shock is present.
- Complications
Progression to overwhelming sepsis and septic shock, given the necrotizing, bacteremia-prone nature of the infection.
- Prognosis
Outcome depends heavily on how quickly source control (drainage or nephrectomy) is added to antibiotics, since antibiotics alone are inadequate for necrotizing, gas-forming renal infection.
- Prevention
Treat uncomplicated pyelonephritis promptly with an appropriate empiric regimen (ciprofloxacin 500 mg PO twice daily for 7 days, or an initial dose of ceftriaxone 1 g IV/IM followed by a…
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- Nephrolithiasis
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