A 42–year–old man with no past medical history presented with right sided abdominal pain of 8 hours duration. He denied dysuria, frequency, or urinary urgency. He was afebrile and his blood pressure was 156/96 mmHg. His white blood cell count was elevated to 10.8 K per microliter. Serum creatinine was 1.0 mg/dL. Given concern for an acute appendicitis an abdominal CT scan was obtained and a wedge–shaped right renal infarct was found. Nephrology and Vascular Surgery were consulted. Transthoracic echocardiogram and emergent trans esophageal echocardiogram were done the afternoon of admission. No source of embolism was found. CT angiogram of the aorta was ordered to evaluate for atherosclerotic source of embolism; no obvious source of embolism was found. Detailed review of the CT imaging found a stable dissection of a segmental branch of the right renal artery with resulting ischemia or infarction of the upper pole, Figure 1. On day 3, a fever of 38.2 C with tachycardia triggered initiation of IV antibiotics. No source of infection was found and antibiotics were stopped. The patient was discharged on aspirin 325 mg daily and simvastatin 40 mg daily. At 1 month’s follow up the patient continued to do well with no symptoms and normal renal function, serum creatinine 0.8 mg/dL.
Spontaneous renal artery dissection, SRAD, is a rare entity, only 0.05% of arteriographic dissections. It was first described in 1944 by Bumpus. Typically it is associated with atherosclerosis, intimal fibrodysplasia, malignant hypertension, Ehlers–Danlos syndrome, and severe exertion. In a case series by Stawicki, 2 of the 3 cases had no identifiable risk factors. In cases with no identified risk factors, it is postulated that intramural hemorrhage from the vaso vasarum or penetration of blood through an intimal tear may initiate dissection. Treatment may be as simple as observation or may include anti–hypertensive and anti–platelet agents, endovascular techniques, extracorporeal renal artery bypass, and partial or total nephrectomy. It a case series by Lacombe, all patients presented with severe hypertension, headache, and ocular symptoms. Other case reports document abrupt onset of severe lumbar or flank pain as the chief complaint. SRAD most affects the right kidney and in newly hypertensive young and middle aged men.
Abdominal pain is the presenting symptom in 10% of emergency department visits. Like other uncommon diagnoses, it is easy to miss if it is not thought about. In this case, the diagnosis of SRAD was due to Radiology being suspicious for such a lesion and actively looking for a dissection. Correct diagnosis spared this patient 6 months of anticoagulation with warfarin.
Figure 1Stable dissection of a segmental branch of the right renal artery causing ischemia or infarct to the superior pole.