A 50 year-old woman with past medical history of diabetes mellitus presented complaining of a “spider bite” and abdominal pain. She later admitted to heroin abuse via “skin popping”. Significant vital signs on presentation included a HR of 115, RR of 34 with a normal temperature and blood pressure. She had abdominal pain without CVA tenderness and a soft tissue abscess on her left upper extremity. Significant labs included a WBC count of 19.7, glucose of 679, creatinine of 1.8, albumin of 1.9 and an anion gap of 14. She was diagnosed with sepsis, acute kidney injury and diabetic ketoacidosis. Vancomycin, an insulin drip, and aggressive fluid resuscitation were initiated. Her anion gap closed; however on hospital day two blood cultures from admission became positive for gram negative rods. Piperacillin-tazobactam was added. Due to continued abdominal pain, a CT of the abdomen and pelvis was obtained that revealed findings consistent with emphysematous pyelonephritis. Placement of a percutaneous nephrostomy tube was unsuccessful; as a result, the patient underwent open nephrectomy. Blood cultures and surgical specimens grew pan-sensitive Escherichia coli. Antibiotics were tailored to ciprofloxacin and the patient recovered well from the operation.
It is important for the hospitalist to recognize emphysematous urinary tract infections (UTIs), as early antibiotics and surgical intervention are needed to prevent morbidity and mortality. Emphysematous pyelonephritis is a severe necrotizing infection that is caused by gas forming bacteria (Escherichia coli, Klebsiella pneumoniae) that affects the renal parenchyma, particularly in diabetics. The elevated levels of tissue glucose in diabetics is thought to provide a favorable environment for gas forming bacteria. Similar to other types of urinary tract infection, emphysematous pyelonephritis is more common among women and in patients with urinary tract obstructions.
CT scan of the abdomen provides the most useful information for diagnosis. Furthermore, a classification system to predict prognosis and guide treatment has been delineated that relies on CT scan findings. Class 1 and 2 are the least severe with involvement limited to the renal parenchyma. Class 3a and 3b have extension to the perinephric and perirenal space respectively, while class 4 has bilateral renal involvement. Risk factors that increase mortality include thrombocytopenia, acute renal failure, shock and altered mental status.
Treatment is focused on aggressive empiric antibiotic therapy and, traditionally, early nephrectomy. However, more recent studies have shown improved outcomes when antibiotics are paired with percutaneous drainage versus open nephrectomy, including an overall mortality of 14 versus 25%. This approach is preferred to avoid a major operation and allow the opportunity for the kidney to regain functionality7. However, treatment should be guided by CT scan classification and presence of risk factors. Most patients with class 1 or 2 findings, plus those in class 3 without risk factors, can be treated with antibiotics and percutaneous drainage. Patients in class 3 with multiple risk factors should undergo early nephrectomy. Nephrectomy should be a last resort in patients with class 4 disease.
Hospitalists frequently encounter urinary complications. Emphysematous pyelonephritis should be recognized early as aggressive antibiotics and surgical intervention are needed for appropriate source control.
To cite this abstract:Wilkinson, B; Mauldin, BJ . SKIN POPPING LEADS TO KIDNEY POPPING. Abstract published at Hospital Medicine 2017, May 1-4, 2017; Las Vegas, Nev. Abstract 791. Journal of Hospital Medicine. 2017; 12 (suppl 2). https://www.shmabstracts.com/abstract/skin-popping-leads-to-kidney-popping/. Accessed September 23, 2019.