Sources of Effusions

The overwhelming majority of perirenal abscesses are secondary to a renal infection. The underlying condition is most often pyelonephritis, tuberculosis, or carbuncle. Perforation of the renal capsule then leads to contamination of the perirenal space.

Perirenal Space

Fig. 8-117. Coronal anatomic section.

The cone of renal fascia (arrows) envelops the adrenal gland, kidney (K), and perirenal fat. Medially it blends with the fascia of the psoas muscle (PM). The perirenal fat is particularly abundant in relationship to the lower pole of the kidney. The hepatic angle abuts on pararenal and perirenal fat. L = liver; Sp = spleen.

(Courtesy of Manuel Viamonte, Jr., M.D., Mt. Sinai Hospital, Miami Beach, FL.)

Fig. 8-117. Coronal anatomic section.

The cone of renal fascia (arrows) envelops the adrenal gland, kidney (K), and perirenal fat. Medially it blends with the fascia of the psoas muscle (PM). The perirenal fat is particularly abundant in relationship to the lower pole of the kidney. The hepatic angle abuts on pararenal and perirenal fat. L = liver; Sp = spleen.

(Courtesy of Manuel Viamonte, Jr., M.D., Mt. Sinai Hospital, Miami Beach, FL.)

Lateroconal Fascia

Fig. 8—118. The edge of the cone and lateroconal fascia (arrows) seen by magnetic resonance imaging on coronal plane.

Renal Fascia Radiology

Fig. 8—119. The lower cone of renal fascia.

CT shows the narrowed cone of renal fascia on the left near its inferior apex (arrows) just above the level of the iliac crests in two different patients. Thickening and adjacent changes render it visible secondary to (a) a leaking abdominal aortic aneurysm and (b) pancreatitis.

Fig. 8—120. Postmortem injection into the perirenal space.

After the introduction of 450 mL of contrast medium, the distended cone of renal fascia is vertical and presents an inferiorly convex border overlying the iliac crest (arrows). This contour is highly characteristic of acute fluid distention of the perirenal space. (Reproduced from Meyers et al.12)

Perirenal Space

Fig. 8-121. Opacification of the perirenal space, occurring as a complication of attempted selective renal venography.

The distended cone extends to the level of the iliac crest. At this level, pressure from the overlying hepatic flexure disrupts the typical inferiorly convex border (arrows).

Perirenal Effusion Imaging

Fig. 8—122. Opacification of the perirenal space.

Gross extravasation during high-dose urography in a case of traumatic fracture of the kidney opacifies the distended perirenal space, demonstrating its convex lower contour

Perirenal Space

Fig. 8—122. Opacification of the perirenal space.

Gross extravasation during high-dose urography in a case of traumatic fracture of the kidney opacifies the distended perirenal space, demonstrating its convex lower contour

Two predominant forms are encountered. An acute gas-producing infection can diffusely involve the perirenal compartment. It is secondary to Escherichia coli, Aerobacter aerogenes, or, rarely, Clostridium and develops especially in diabetics. Or, the infection may localize within the perirenal fat as a coalescent abscess. The offending organism is usually E. coli, B. proteus, or a streptococcus. Bilateral involvement is rare and is secondary to bilateral renal infections. In children, hematogenous spread occasionally occurs to the perirenal fat from remote sites of infection, such as furunculosis, wound infection, or upper respiratory disease.160

Chronic extravasation of urine into the perirenal compartment is a result of perforation of the collecting system. The collection develops as a uriniferous peri-renal pseudocyst (urinoma).

Hematomas within the perirenal space as well as within the subcapsular zone, are secondary to trauma or to lesions of the kidneys and their blood vessels, ranging from neoplasms to periarteritis nodosa.161

Fig. 8—123. The distended perirenal space.

Direct coronal CT section reveals fluid collections in both perirenal spaces (2). The distended cone of renal fascia on the left extends more inferiorly to the level of the iliac crest. RK = right kidney. (Reproduced from Feldberg.17)

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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