Abstract Introduction Retroperitoneal fibrosis (RPF) is a rare, immune-mediated fibroinflammatory disease thought to involve the adventitia of the abdominal aorta and iliac arteries, often extending to the surrounding peritoneum and may involve the thoracic aorta, pancreas, and mesentery. Clinical presentation is variable and may include nonspecific abdominal or back pain, lower extremity edema, or oliguria. We present a case of severe bilateral hydronephrosis suspected to be secondary to RPF complicated by acute renal failure. Description A 47-year-old female with polysubstance use disorder and limited engagement with the healthcare system presented with one week of progressive dyspnea, bilateral lower extremity swelling, and encephalopathy. She was initially hypertensive, tachycardic, and hypoxic. Physical examination revealed 2+ bilateral lower extremity pitting edema, diminished breath sounds bilaterally and left submandibular lymphadenopathy. Initial laboratory evaluation revealed potassium of 8.2 mmol/L, serum creatinine of 17.4 mg/dL, hemoglobin of 3.9 g/dL, lipase of 19 U/L, and positive urine drug screen for cocaine and opiates. Imaging demonstrated moderate to severe bilateral hydronephrosis, pancreatic enlargement with peripancreatic infiltration, ascending aortic ectasia measuring up to 4.8 cm, and moderate aortic atherosclerotic disease. Ultrasonography of the left neck showed submandibular and anterior cervical lymphadenopathy. She was admitted to the medical intensive care unit for CRRT. A foley was placed with gross hematuria noted. Bilateral hydronephrosis persisted, prompting bilateral percutaneous nephrostomy tube placement. Her renal function improved, and she did not require outpatient hemodialysis. She will be discharged to an inpatient rehabilitation facility for her substance use disorder with plans for further outpatient evaluation for her bilateral hydronephrosis. Discussion In this patient, the constellation of acute renal failure with bilateral hydronephrosis, evidence of pancreatic inflammation, aortic ectasia, and submandibular and cervical lymphadenopathy (raising concern for possible malignancy) was suggestive of IgG4-negative RPF. Alternative etiologies such as nephrolithiasis, infection, extrinsic tumor, or genitourinary structural abnormalities were excluded as well. RPF can be challenging to diagnose given nonspecific symptoms and variable clinical findings. There are no pathognomonic serologic or imaging findings, and biopsy may sometimes be warranted for diagnosis. Early recognition of idiopathic RPF is crucial given it may lead to renal failure, and outcomes are good if recognized. Conversely, secondary RPF in the setting of malignancy carries a poor prognosis, which may influence management decisions depending on goals of care. This abstract is funded by: None
Manktelow et al. (Fri,) studied this question.