Emphysematous Pyelonephritis Caused by Citrobacter freundii in a Patient with Type 2 Diabetes and Neurogenic Bladder
A 57-year-old woman presented at the emergency department with confused mentality, fever, myalgia, and general weakness. The patient had a medical history of type 2 diabetes, hypertension, neurogenic bladder, and bilateral renal abscesses with sepsis caused by extended spectrum beta-lactamase (ESBL) producing E. coli, 1 year ago. Meropenem (1 g/day) was administered for approximately 4 weeks with an indwelling urinary catheter for approximately 2 weeks at that time.\nInitial systemic examination revealed that the patient had a body temperature of 38.0℃, blood pressure of 138/64 mmHg, heart rate of 124 beats/min, respiratory rate of 34 breaths/min, tenderness in the left costovertebral angle, and peripheral pitting edema.\nFurther tests revealed that the patient had hypochromic normocytic anemia with hemoglobin levels of 9.3 g/dL, a white blood cell count of 13,700/mm3 (59% neutrophils and 26% band forms), and a platelet count of 194,000/mm3. Kidney function test revealed blood urea nitrogen (BUN) of 39.8 mg/dL and creatinine (Cr) of 3.9 mg/dL. Similar tests performed 1 year ago had revealed the BUN and Cr to be 31.9 mg/dL and 1.3 mg/dL, respectively. Furthermore, urinalysis revealed pyuria, glycosuria, and proteinuria without ketone bodies or nitrites. Arterial blood gas tests indicated that the pH of the patients' blood was 7.31, pCO2 were 35 mmHg, pO2 were 72 mmHg, SaO2 were 93%, and HCO3- were 17.6 mEq/L. Concentrations of C-reactive protein, sodium, potassium, and chloride were 11.12 mg/dL, 135 mEq/L, 6.7 mEq/L, and 102 mEq/L, respectively; tests for serum ketone body was negative. The initial blood glucose concentration was 411 mg/dL and glycosylated hemoglobin level was 9.8%. Concentrations of fibrin degradation product, fibrinogen, D-dimer, and anti-thrombin III were 26.8 µg/mL, 819 mg/dL, 1.5 µg/mL, and 82%, respectively. A chest radiograph showed bilateral pulmonary congestions.\nThe patient further displayed clinical features of sepsis with renal failure in the form of fever, tachycardia, tachypnea, leukocytosis, azotemia with hyperkalemia, and pulmonary congestion. Initially, a broad-spectrum intravenous antibiotic (meropenem, 1 g/d) was administered based on prior admission history. Contrast-enhanced abdominal computed tomography (CT) images of the kidneys showed hydroureteronephrosis and a collection of gas bubbles with heterogenous enhancement in the enlarged left kidney (12.5 × 6 cm). Further, perinephric infiltration with fluid collection and wall thickening of the calyces, renal pelvis, and ureter were also observed (). Prompt percutaneous nephrostomy (PCN) with a pig-tail tube was performed in the left kidney, resulting in 50 mL of pus being drained with air. Microbiological examination of both blood and pus obtained from the PCN revealed the presence of C. freundii. As a result, the antibiotic regimen was switched to a third generation cephalosporin based on the results of culture and sensitivity tests. The patient responded to the treatment and became afebrile and clinically stable. PCN was maintained for 2 weeks and the antibiotic was continued for 6 weeks. After treatment, an abdominal CT showed improved lesions of left kidney with no gas bubbles detected in the renal parenchyma, pelvis, and calyces. Despite the improvements in patient's condition following treatment, the patient developed permanent kidney failure, which required hemodialysis.