A 50-year-old woman comes to the emergency department due to increasing right flank pain, nausea, and hematuria. The flank pain started 3 days ago and is constant, dull, and nonradiating. She reports no dysuria. The patient was diagnosed with pancreatic cancer a month ago and received the first cycle of chemotherapy 2 weeks ago. She has smoked a pack of cigarettes daily for 30 years but does not use alcohol. Temperature is 37 C (98.6 F), blood pressure is 130/90 mm Hg, pulse is 88/min, and respirations are 16/min. Examination shows right flank and costovertebral angle tenderness. Bowel sounds are present. Peripheral pulses are normal and there is no edema. Laboratory results are as follows: Abdominal ultrasound shows an enlarged right kidney and normal left kidney; there is no evidence of hydronephrosis. The pancreatic mass is unchanged from prior scans. Which of the following is the most likely diagnosis?

Question

A 50-year-old woman comes to the emergency department due to increasing right flank pain, nausea, and hematuria.  The flank pain started 3 days ago and is constant, dull, and nonradiating.  She reports no dysuria.  The patient was diagnosed with pancreatic cancer a month ago and received the first cycle of chemotherapy 2 weeks ago.  She has smoked a pack of cigarettes daily for 30 years but does not use alcohol.  Temperature is 37 C (98.6 F), blood pressure is 130/90 mm Hg, pulse is 88/min, and respirations are 16/min.  Examination shows right flank and costovertebral angle tenderness.  Bowel sounds are present.  Peripheral pulses are normal and there is no edema.  Laboratory results are as follows:  Abdominal ultrasound shows an enlarged right kidney and normal left kidney; there is no evidence of hydronephrosis.  The pancreatic mass is unchanged from prior scans.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec25c8_d890_38f5_bc81_f9ee59fa2ff6_MD0003_00 This patient likely has acute renal vein thrombosis (RVT). RVT results in markedly increased glomerular pressure, leading to renovascular congestion, capsular stretch (manifesting as flank pain), and hematuria. RVTs most commonly occur in the setting of nephrotic syndrome (due to urinary loss of anticoagulant proteins and alteration of hemostatic balance) but can also occur with acquired hypercoagulability associated with malignancy (as in this patient) or trauma. Laboratory analysis typically demonstrates hematuria (with an otherwise bland urinalysis) and elevated lactate dehydrogenase levels (possibly related to necrosis in the setting of thrombosis); acute kidney injury (AKI) may occur but is more typical in the setting of bilateral RVTs. Renal ultrasound with Doppler and abdominal CT scan have a low sensitivity and may demonstrate only an enlarged kidney, although a Doppler ultrasound may show a reversal of diastolic flow. The diagnosis is confirmed by CT or MR angiography or renal venography. Management depends on the presence of AKI, which, if present, requires urgent clot removal (eg, thrombolysis, thrombectomy); otherwise, anticoagulation alone is appropriate. (Choice A) In adults, membranous nephropathy, a common cause of nephrotic syndrome, is also an important risk factor for acute RVT. However, this patient does not have proteinuria, making nephrotic syndrome unlikely. In addition, membranous nephropathy alone would not explain the patient's enlarged right kidney or gross hematuria (microscopic hematuria can be seen). (Choice B) Nephrolithiasis can cause flank pain and hematuria; however, it would not explain the enlarged right kidney without hydronephrosis, and the pain of nephrolithiasis is often paroxysmal rather than dull and constant. (Choice C) Pyelonephritis presents with dysuria, fevers, hematuria, and flank pain. The absence of fevers, irritative urinary tract symptoms (eg, dysuria), and urinary leukocytes or nitrites make this diagnosis less likely. (Choice D) There is significant overlap in the presentation of renal infarction and acute RVT; however, renal infarction most commonly occurs due to cardioembolic disease (eg, atrial fibrillation), resulting in incomplete infarction and a wedge-shaped area of ischemia on imaging. In addition, patients frequently report abdominal pain in addition to flank pain. An acute increase in blood pressure due to renin release is also common. Educational objective: Acute renal vein thrombosis presents with hematuria, renovascular congestion, and flank pain. The most common causes are nephrotic syndrome, malignancy, and trauma. Diagnosis can be confirmed by CT or MR angiography or renal venography. References: The forgotten urinalysis: an integral part of unmasking thrombophilia. (http://www.ncbi.nlm.nih.gov/pubmed/30788075) Adult idiopathic renal vein thrombosis mimicking acute pyelonephritis. (http://www.ncbi.nlm.nih.gov/pubmed/27790518)

A 50-Year-Old Woman Comes to the Emergency Department Due to Increasing