DEFINITIONPyelonephritis is an infection, usually bacterial in origin, of the upper urinary tract (Fig. 213–1).PHYSICAL FINDINGS AND CLINICAL PRESENTATION● Fever● Rigors● Chills● Flank pain● Dysuria● Polyuria● Hematuria● Toxic feeling and appearance● Nausea and vomiting● Headache● Diarrhea● Physical examination notable:

1. Costovertebral angle tenderness2. Exquisite fl ank pain

CAUSE● Gram-negative bacilli such as Escherichia coli and Klebsiella

spp. in more than 95% of cases● Other, more unusual gram-negative organisms, especially

with instrumentation of the urinary system● Resistant gram-negative organisms or even fungi in hospital-

ized patients with indwelling catheters● Gram-positive organisms such as enterococci● Staphylococcus aureus: presence in urine indicates hematoge-

nous origin● Viruses: rare, but usually limited to the lower tract● Candida albicans (Emphysematous pyelonephritis, see Fig.

213–4)

DIFFERENTIAL DIAGNOSIS● Nephrolithiasis (see Fig. 216–3)● Appendicitis● Ovarian cyst torsion or rupture● Acute glomerulonephritis● Pelvic infl ammatory disease (PID)● Endometritis● Other causes of acute abdomen● Perinephric abscess● Hydronephrosis (see Fig. 214–3)LABORATORY TESTS● CBC with differential● Renal panel● Blood cultures● Urine cultures● Urinalysis● Gram stain of urineDIAGNOSTIC IMAGING● Urgent renal sonography (Fig. 213–2) if obstruction or

closed space infection suspected● CT scanning (Fig. 213–3) may better defi ne the extent of

collections of pus.TREATMENT● Antibiotic therapy should be initiated after cultures are ob-

tained and guided by the results of culture and sensitivity testing.

● Prompt drainage with nephrostomy tube placement for obstruction

● Surgical drainage of large collections of pus to control infection

● Diabetic patients, as well as those with indwelling catheters, are especially prone to complicated infections and abscess formation (Fig. 213–4).

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Chapter 213: Pyelonephritis 213

Chapter 213 Pyelonephritis

Fig 213–1Acute pyelonephritis. Renal tissue shows a dilated tubule with neutro-phils enmeshed in proteinaceous debris (pus casts; arrowhead) with adjacent interstitial infl ammation.(Courtesy of C. Alpers.)

Fig 213–2Acute pyelonephritis. Ultrasound demonstrates an enlarged echogenic kidney; bipolar length of kidney � 12.9 cm.(From Johnson RJ, Feehally J: Comprehensive Clinical Nephrology, 3rd ed. St. Louis, Mosby, 2007.)

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Fig 213–3Acute pyelonephritis. CT scan obtained 24 hours after image shown in Figure 213-2 demonstrates multiple nonenhancing abscesses (arrow-heads).(From Johnson RJ, Feehally J: Comprehensive Clinical Nephrology, 3rd ed. St. Louis, Mosby, 2007.)

Fig 213–4Emphysematous pyelonephritis. Shown are cortical necrosis (solid ar-row), diffuse cortical hemorrhage (open arrow), and dilation of the col-lecting system (arrowheads) in a nephrectomy specimen from a dia-betic patient who received combined medical-surgical therapy and survived emphysematous pyelonephritis caused by an unusual patho-gen, Candida albicans(From Cohen J, Powderly WG: Infectious Diseases, 2nd ed. St. Louis, Mosby, 2004.)

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213 Section 8: Kidneys

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