Clinica Medica

temperature of 103°F after 3 days of therapy. The urine culture grows

Escherichia coli, which is sensitive to the antibiotics being used. On examina-

tion, he appears ill and has marked left flank tenderness. Ultrasound depicts an

abnormal collection of fluid around the left kidney.

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What is the most likely diagnosis?

What anatomical structure is involved?

172 CASE FILES: ANATOMY

ANSWERS TO CASE 25: PERINEPHRIC ABSCESS

Summary: A 55-year-old male continues with high fever and flank pain despite

3 days of broad-spectrum intravenous antibiotic therapy. The urine isolate of

E. coli demonstrates in vitro sensitivity to the antibiotics used. Renal ultra-

sound shows fluid around the left kidney.

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Most likely diagnosis: Perinephric abscess

Anatomical structure involved: Kidney and anatomically related

structures

CLINICAL CORRELATION

This 55-year-old male who is suspected of having pyelonephritis is not

improving despite appropriate antibiotic therapy. Pyelonephritis is an infection

of the kidney parenchyma usually caused by an ascending infection of bacte-

ria that advances from the urethra to bladder to ureters and then to the kidney.

Kidney infection usually manifests as fever, flank tenderness, white cells in the

urine, and serum leukocytosis. After 48 to 72 hours, one would expect

decreases in fever and flank tenderness. E. coli is isolated, which is the bac-

terium that most often causes urinary tract infection. The ultrasound examina-

tion is performed to rule out complications of pyelonephritis. The two most

common complications would be a nephrolithiasis or ureterolithiasis (kidney

stone) and perinephric abscess. Intervention is required before improvement is

seen. The abscess must be drained, usually by placement of a percutaneous

catheter under radiologic guidance.

APPROACH TO THE KIDNEYS

Objectives

1. Be able to describe the anatomy of the kidneys, their fascial coverings,

and blood supply.

2. Be aware of the structures next to the kidneys and their relations.

Definitions

Perinephric abscess: Collection of pus in the tissues surrounding the kidney.

Pyelonephritis: Usually a bacterial inflammation of the renal tissue, the

calyces, or renal pelvis.

Nephrolithiasis: Presence of renal calculi or stones.

CLINICAL CASES 173

DISCUSSION

The kidneys are paired retroperitoneal organs that are located in the par-

avertebral gutters. The left kidney lies slightly higher than the right, its

hilum is at the level of L1, and its superior and inferior poles are at the 11th

rib and L3, respectively. The hilum of the right kidney lies at the level of the

disc between L1 and L2, and its inferior pole is nearly 1 to 2 cm superior to

the iliac crest. Each kidney is an encapsulated solid organ, with an outer cor-

tex and an inner medulla, with the latter arranged in renal pyramids. The hilum

of each kidney leads to a space, the renal sinus, which contains fat, branches

of the renal vessels, and the urine-collecting structures (minor and major

calyces and renal pelvis). Within the sinus, the apex of the 6 to 12 renal pyra-

mids is cupped by a minor calyx, which collects the urine produced. Typically

two to three minor calyces unite to form a major calyx, and two to three major

calyces form the renal pelvis. The renal pelvis is continuous with the ureter at

the inferior margin of the hilum (see Case 32 for the anatomy of the ureter).

Four muscles are related to each kidney posteriorly: the diaphragm superi-

orly and the transverses abdominis, quadratus lumborum, and psoas muscles

inferiorly, from lateral to medial. The suprarenal glands and colon contact

both kidneys anteriorly. The duodenum and liver also contact the right

kidney anteriorly, and the

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