Authors
Jessica Rodriguez, MS, PA-C
Physician Assistant
Community Regional Medical Center
Fresno, California
Disclosure: Jessica Rodriguez, MS, PA-C, has disclosed no relevant financial relationships.
Stacy Sawtelle, MD
Clinical Instructor of Emergency Medicine
UCSF Fresno
Fresno, California
Disclosure: Stacy Sawtelle, MD, has disclosed no relevant financial relationships.
Editor
Lars Grimm, MD, MHS
House Staff
Department of Diagnostic Radiology
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewers
Richard S. Krause, MD
Senior Clinical Faculty/Clinical Assistant Professor
Department of Emergency Medicine
University of Buffalo
State University of New York School of Medicine and Biomedical Sciences
Buffalo, New York
Disclosure: Richard S. Krause, MD, has disclosed no relevant financial relationships.
Bradley Fields Schwartz, DO, FACS
Professor of Urology
Director, Center for Laparoscopy and Endourology
Department of Surgery
Southern Illinois University School of Medicine
Springfield, Illinois
Disclosure: Bradley Fields Schwartz, DO, FACS, has disclosed no relevant financial relationships.
A 70-year-old woman presents to the emergency department with low back and abdominal pain, as well as nausea and vomiting. The pain came on suddenly 24 hours ago; it is dull, achy, and steadily worsening. The patient rated it as 8 out of 10. She denies hematuria, dysuria, fever, and rectal bleeding. She has uncontrolled diabetes, aortic stenosis, and coronary artery disease. She has had an aortic valve replacement and coronary artery bypass grafting. Her medications include warfarin (she missed the last 2 doses), clopidogrel, metformin, insulin, and aspirin. She denies using intravenous drugs, alcohol, or tobacco. An abdominal radiograph is performed from the waiting room (shown).
The patient’s abdominal radiograph (shown) is unremarkable. Blood pressure is 161/90 mmHg, pulse is 90 bpm, respirations are 16 breaths/min, oral temp is 37°C, and oxygen saturation is 100% on room air. On examination, the patient has a nontender, soft abdomen with normal bowel sounds and no costovertebral angle tenderness. Rectal examination revealed heme-negative stool. The patient’s heart had a regular rate and rhythm with a mechanical click. The neurological examination showed no deficits and skin examination revealed no rashes.
Selected laboratory results are shown. Electrocardiogram showed signs of left ventricular hypertrophy and lateral T-wave inversion with a regular rhythm and a rate of 74. The initial troponin test was negative.
What aspect of the patient’s presentation is concerning for mesenteric ischemia?
A. Pain out of proportion to examination
B. History of aortic valve replacement
C. Missed doses of warfarin
D. All of the above
Answer: D. All of the above
The differential diagnosis of abdominal/flank pain in the elderly is broad (shown). Based on the patient’s past medical history, clinical presentation, and urinalysis results, what is the best imaging study to order?
A. Abdominal ultrasound
B. Computed tomography (CT) of the abdomen and pelvis without contrast
C. CT angiography of the abdomen and pelvis with intravenous contrast
D. Magnetic resonance imaging of the abdomen
Answer: C. CT angiography of the abdomen and pelvis with intravenous contrast
Due to patient’s history of aortic valve replacement and subtherapeutic anticoagulation and lack of hematuria, CT angiography (shown) was ordered to look for signs of mesenteric ischemia. What abnormality is seen on this representative image?
A. Abdominal aortic aneurysm
B. Free intraperitoneal fluid
C. Mesenteric ischemia
D. Portal venous gas
E. Renal infarct
Answer: E. Renal infarct
A coronal reformatted image is shown. The hypodense areas in the left kidney correspond to multiple acute infarcts (arrow). There is no evidence of renal artery occlusion. The abdominal aorta, celiac axis, and mesenteric arteries show normal opacification. There is no dilation or bowel wall thickening involving the large or small bowel to suggest ischemia. There are no abnormal fluid collections or gas present.
A CT image showing thrombus in the renal vein (arrow) is shown. Renal infarction is a rare condition, often missed because it mimics renal colic and pyelonephritis. Infarct results from embolic or thrombotic occlusion of the renal arteries or veins, trauma, dehydration, or hypercoagulable states. Patients typically present with acute onset flank pain, abdominal pain, nausea, and vomiting. Microscopic or gross hematuria may be present. Hypertension may occur secondary to pain and an increase in renin released from the ischemic renal parenchyma. Image courtesy of Radiopaedia.org.
Laboratory findings commonly found in conjunction with renal infarct (shown) include leukocytosis, elevated aspartate aminotransferase, lactate dehydrogenase (LDH), and alkaline phosphatase. Coagulation studies are indicated for patients on anticoagulation to evaluate for subtherapeutic levels. An elevated serum LDH has a high sensitivity but low specificity; urinary LDH is more specific because this level should be normal in extrarenal disorders. Image courtesy of Bemanian et al.[1]
In elderly patients or those with diabetes, what study may be preferred over CT with contrast?
A. CT without contrast
B. Magnetic resonance angiography
C. Digital subtraction angiogram
D. Ultrasound of the abdomen
Answer: B. Magnetic resonance angiography (MRA)
Ultrasound can sometimes detect a thrombus in the vasculature (the arrow shows a clot in the right renal vein), but it is operator dependent and limited for evaluating the degree of infarction. Angiograms can diagnose and potentially treat vascular occlusion but are invasive. CT angiography is generally the study of choice because it is fast, noninvasive, and evaluates renal parenchyma and vasculature. Although it may be preferred in the elderly or patients with diabetes, MRA is contraindicated for patients with severe renal insufficiency due to the risk of nephrogenic sclerosing fibrosis. Image courtesy of Radiopaedia.org.
Acute pyelonephritis can mimic segmental infarctions on CT; both may have a wedge-shaped appearance. However, pyelonephritis will typically be “striated” with multiple areas of low attenuation (arrows). Additionally, there may be perinephric stranding, loss of differentiation of the cortex and medulla, or renal swelling. Ultimately, the differentiation often comes down to clinical presentation and laboratory analysis. Pyelonephritis is almost always associated with significant pyuria and bacteriuria; patients are often febrile and leukocytosis is frequent. Image courtesy of Radiopaedia.org.
Coronal CT angiography shows a branching renal artery (arrows). Although normal renal vascular anatomy consists of a single renal artery and vein, it is not uncommon to have multiple accessory vessels. The vessels may be codominant or may supply a small portion of the kidney. Alternate vascular anatomy may help explain patterns of infarction and are important to identify prior to any potential invasive treatment planning. Additionally, renal arteries and veins may have aberrant courses that must be identified because they can affect surgical or procedural planning. Image courtesy of Radiopaedia.org.
Treatment modalities for renovascular occlusion include anticoagulation, endovascular interventions such as thrombolysis or stenting, or open surgical repair. Endovascular intervention allows for local thrombolysis as well as treatment for any underlying predisposing conditions, such as fibromuscular dysplasia (shown). Anticoagulation is typically achieved initially with intravenous heparin followed by oral warfarin. Surgical revascularization is best reserved for patients with bilateral renal artery occlusion or occlusion of a solitary kidney. Open surgical repair is the preferred treatment only for traumatic renal artery thrombosis; it is typically only successful if performed immediately.
While awaiting the CT results, the patient received intravenous fluids, intravenous opiate analgesics, and an antiemetic. Once the diagnosis was confirmed, she was admitted and anticoagulation was initiated with a heparin infusion. Blood cultures were drawn to evaluate for endocarditis. An echocardiogram was ordered to assess cardiac and aortic valve function and to evaluate for thrombus, which was normal (shown). Image courtesy of Wikimedia Commons.
Blood cultures came back negative and the patient remained afebrile. During her 4-day hospital stay, her symptoms resolved and her renal function remained stable. The patient was instructed to get her international normalized ratio and renal function checked 2 days after discharge. She will follow-up with her primary physician. The importance of medication and laboratory compliance was emphasized to the patient in an effort to assure therapeutic anticoagulation. Long-term prognosis related to renal infarct is unknown. Most patients have other medical problems that affect their morbidity and mortality, such as atrial fibrillation or atherosclerosis. Possible sequelae include loss of renal function and hypertension.[5] In one case series, 8% of patients required dialysis, but many patients go on to have normal kidney function.[6] Hypertension is often seen acutely and may resolve spontaneously or may be persistent. Image courtesy of Wikipedia Commons.
Authors
Jessica Rodriguez, MS, PA-C
Physician Assistant
Community Regional Medical Center
Fresno, California
Disclosure: Jessica Rodriguez, MS, PA-C, has disclosed no relevant financial relationships.
Stacy Sawtelle, MD
Clinical Instructor of Emergency Medicine
UCSF Fresno
Fresno, California
Disclosure: Stacy Sawtelle, MD, has disclosed no relevant financial relationships.
Editor
Lars Grimm, MD, MHS
House Staff
Department of Diagnostic Radiology
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewers
Richard S. Krause, MD
Senior Clinical Faculty/Clinical Assistant Professor
Department of Emergency Medicine
University of Buffalo
State University of New York School of Medicine and Biomedical Sciences
Buffalo, New York
Disclosure: Richard S. Krause, MD, has disclosed no relevant financial relationships.
Bradley Fields Schwartz, DO, FACS
Professor of Urology
Director, Center for Laparoscopy and Endourology
Department of Surgery
Southern Illinois University School of Medicine
Springfield, Illinois
Disclosure: Bradley Fields Schwartz, DO, FACS, has disclosed no relevant financial relationships.
Abdominal Cramps and Bloody Diarrhea
Persistent Productive Cough and Fever
Gross Hematuria and Abdominal Pain
Vague Symptoms Belying a Possibly Severe Condition
Worsening Pain in the Upper Extremity
