Mary Thorndike Gillian Lieberman, MD

August 2001

Acute Renal Infections Mary Thorndike Harvard Medical School Year III Gillian Lieberman, MD

Mary Thorndike Gillian Lieberman, MD

• • • • •

Acute bacterial pyelonephritis Renal Abscess Emphysematous Pyelonephritis Pyohydronephrosis Xanthogranulomatous Pyelonephritis

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Mary Thorndike Gillian Lieberman, MD

Acute Bacterial Pyelonephritis • Infection of collecting system and parenchyma

• Ascending: Escherichia coli • Hematogenous: Staphylococcus aureus • Flank pain and fever

Usually a clinical diagnosis

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Mary Thorndike Gillian Lieberman, MD

Imaging of Acute Pyelonephritis: Indications • • • •

Diagnostic uncertainty Very ill patients Persistent symptoms despite treatment Recurrent renal infection

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Mary Thorndike Gillian Lieberman, MD

Imaging of Acute Pyelonephritis: Modalities • Intravenous Urography • Ultrasound • Computed Tomography (CT Scan) • Nuclear Scanning

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Mary Thorndike Gillian Lieberman, MD

Intravenous Urography • • • •

X-ray with IV contrast Historically method of choice Not very sensitive Normal in 75% of pyelonephritis cases

No longer used in most situations 6

Mary Thorndike Gillian Lieberman, MD

Ultrasonography • Lower sensitivity than CT or nuclear scans • Modality of choice in pregnant women Positive Findings: • Enlargement of entire kidney • Hypoechoic cortex: edema • Focal hyperechoic areas: early abcess 7

Mary Thorndike Gillian Lieberman, MD

Sonogram: Acute Pyelonephritis Hypoechoic kidney with perinephric extension

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Radiology Clinics of North America 34:5, p.968

Mary Thorndike Gillian Lieberman, MD

CT Scanning • Sensitive and accurate • Demonstrates Anatomic changes • Demonstrates Functional deficits

Modality of choice in most patients 9

Mary Thorndike Gillian Lieberman, MD

Non-Contrast CT Film Findings • Focal swelling • Irregularity of calyces • Perinephric fat stranding • Thickening of Gerota’s Fascia 10

Mary Thorndike Gillian Lieberman, MD

Non-Contrast CT: Pyelonephritis

Enlarged right kidney

BIDMC PACS System

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Mary Thorndike Gillian Lieberman, MD

CT with Contrast: Nephrogenic Phase Film Findings: Cortical perfusion defects: – – – –

Areas of decreased attenuation Often wedge-shaped May indicate early abcess formation Striated nephrogram 12

Mary Thorndike Gillian Lieberman, MD

Contrast CT: Pyelonephritis

Focal perfusion deficit

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BIDMC PACS System

Mary Thorndike Gillian Lieberman, MD

Contrast CT: Pyelonephritis

Focal perfusion deficits

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BIDMS PACS System

Mary Thorndike Gillian Lieberman, MD

Contrast CT: Pyelonephritis

Focal perfusion deficits

Courtesy of Michelle Swire, MD

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Mary Thorndike Gillian Lieberman, MD

Contrast CT: Pyelonephritis

Focal perfusion deficit Renal cyst

BIDMC PACS System

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Mary Thorndike Gillian Lieberman, MD

Contrast CT: Pyelonephritis

Focal perfusion deficit Fat stranding and fascial thickening 17

BIDMC PACS System

Mary Thorndike Gillian Lieberman, MD

Contrast CT: Pyelonephritis

Focal perfusion deficits

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BIDMC PACS System

Mary Thorndike Gillian Lieberman, MD

Coronal Reconstruction Focal perfusion deficit

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BIDMC PACS System

Mary Thorndike Gillian Lieberman, MD

Differential Diagnosis for Perfusion Deficits on CT • • • •

Acute pyelonephritis Infarct Emboli Lymphoma 20

Mary Thorndike Gillian Lieberman, MD

Differential Diagnosis for Striated Nephrogram • • • •

Acute pyelonephritis Acute obstruction Renal vein thrombosis Infantile polycystic disease • Medullary sponge kidney 21

Radiology Recall

Mary Thorndike Gillian Lieberman, MD

Radionuclide Imaging • Infection-seeking agents – Gallium citrate (GA-67) – Indium-111-labeled white blood cells (IN-111WBC)

• Concentrate within areas of inflammation which are “hot” spots • Can localize occult sites of infection • Alternative to CT

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Mary Thorndike Gillian Lieberman, MD

Radionuclide Imaging • Kidney-seeking agents – Technetium Tc-99m glucoheptonate (Tc-99m GH) – Technetium Tc-99m dimercaptosuccinic acid (Tc-99m DMSA)

• Concentrate in renal cortex, area of infection is therefore a “cold” spot • Children: most sensitive modality • Adults: functional studies post-infection

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Mary Thorndike Gillian Lieberman, MD

TC-99m-DMSA Scan (Kidney Seeking) Cortical Loss

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Radiologic Clinics of North America 34:5 p. 974

Mary Thorndike Gillian Lieberman, MD

Renal Abscess

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BIDMC Film Library

Mary Thorndike Gillian Lieberman, MD

Emphysematous Pyelonephritis

Gas in kidney

http://www.bbmcradiology.org/CasesoftheMonth/Casejan99/COM2dec98.home.html

Life-threatening Infection in Diabetic Patients

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Mary Thorndike Gillian Lieberman, MD

Pyohydronephrosis • Infection of obstructed kidney • CT with contrast is modality of choice • Radiologic presentation: – Pyelonephritis – Obstruction

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Mary Thorndike Gillian Lieberman, MD

Xanthogranulomatous Pyelonephritis

www.eurorad.org

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Mary Thorndike Gillian Lieberman, MD

Review of imaging recommendations for renal infection • Modality of Choice: CT with IV Contrast Findings: Focal Perfusion Deficits • Pregnant women: Ultrasound • Children: Radionuclide scans 29

Mary Thorndike Gillian Lieberman, MD

References Gay, Spencer, and Richard J. Woodcock, Jr. Radiology Recall (2000). Philadelphia: Lippincott Williams & Wilkins.

Langer, Jill E. “Computed Tomography and Ultasonography of Acute Renal Abnormalities”. Seminars in Roentgenology 36:2 (2001), pp.99-107.

Papanicolaou, Nicholas, and Richard C. Pfister. “Acute Renal Infections”. Radiologic Clinics of North America 34:5 (1996), 30 pp.965-995.

Mary Thorndike Gillian Lieberman, MD

Acknowledgements Daniel Saurborn, MD Michelle Nebres Swire, MD Aradhana Venkatesan, MD Gillian Lieberman, MD Pamela Lepkowski Larry Barberas and Cara Lyn D’amour 31