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Renal abscesses: Classification and review of 40 cases
RENAL ABSCESSES: REVIEW
CLASSIFICATION
OF 40 CASES
KARL
A. ANDERSON,
M.D.
JACK
W. McANINCH,
M.D.
From the Department of Urology, School of Medicine, San Francisco,
--,----
AND
University California
of California
__-__
__-
ABSTRACT - Renal abscesses are misdiagnosed often and, consequently, mistreated or treated too late. Forty cases of renal abscesses divided into anatomic categories - perinephric, renal cortical, and corticomedullay - are reviewed. Various conditions seem to predispose to renal abscesses: urinary tract infections, vesicoureteral reflux, calculi, or other medical problems. This retrospective study discloses that a high correlation exists between organisms found in the patients’ urine cultures and those organisms cultured from all 3 categories of abscesses. Accurate and complete urine bacteriologic study is therefore an essential tool for diagnosis.
Renal abscesses are rare, their symptomatology varies, and their course is insidious. For these reasons their diagnosis is often elusive. We reviewed the cases of renal abscesses seen at San Francisco General Hospital from 1963 to 1978, and classified them according to their 3 anatomic locations: perinephric (occurring between the renal capsule and Gerota fascia), renal cortical (confined to the renal cortex), and corticomedullary (confluent in the cortex and medulla of the kidney). We then analyzed each group for various factors to aid in the future diagnosis, management, and treatment. Material
greater than 1 cm. in diameter. When these latter abscesses had ruptured through the renal parenchyma, thus forming the perinephric abscesses, they were included in the perinephric group. We analyzed each case, when possible, for age, gender, ethnicity, diagnosis at admission, hospital service of first admission, number of days to correct diagnosis, laterality of kidney involvement, location of abscess, presenting physical signs, laboratory data, radiologic procedures, treatment, and associated medical problems. Complete information for all areas analyzed was not available in each case.
and Methods Observations
We documented 40 cases of renal abscess representing 0.01 per cent of all admissions to the hospital during a fifteen-year period. We reviewed the discharge diagnoses, the radiology files, and all abscess specimens in the surgical and autopsy pathology files. We intentionally excluded all cases of pyonephrosis, psoas and retroperitoneal abscesses, and infected renal cysts. Renal cortical and corticomedullary abscesses were included only if they were
We found 23 cases of perinephric, abscesses (including one bilateral), I2 cases of renal cortical abscesses, and 5 cases of corticomedullary abscesses (including one bilateral, Fig. 1). Eighty per cent (32) of all patients were white, 15 per cent were black (6), and 5 per cent were Orientals (2). Over-all admission to the hosptial during the same period was 64 per cent white, 26 per cent black, and 3 per cent Orientals. Gender was of no significance. Male and female were equally divided. Distribution according to age showed that 42 per cent of the cases
-Presented at Annul Meeting Arizona, March 18, 1979.
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occurred between ages forty and sixty and 30 per cent between sixty and eighty years. The youngest patient was eighteen years old and the oldest eighty-two. The abscess occurred in the right side in 24 cases (60 per cent), and in the left side in 14 cases (35 per cent). Two cases had bilateral involvement. That diagnosis of renal abscess can be elusive is reflected in the fact that 16 cases (43 per cent) were initially admitted to the medical service and 12 cases (32 per cent) directly to the urology’ department. The general surgery service admitted 8 cases (22 per cent), and 1 case was admitted to the orthopedic service. Misdiagnosis
The difficulty of detecting a renal abscess is indicated by the great variety of diagnoses made. Only 18 cases were admitted with primary renal infection as diagnosis; 8 cases were designated as renal abscess and 10 as pyelonephritis. Incorrect diagnoses at admission included appendicitis, bowel obstruction, cholecystitis, perforated viscus, retroperitoneal tumor, and other medical problems. Time to correct diagnosis. The correct diagnosis was made within five days in 17 of 22 patients with perinephric abscesses, 5 of 11 with renal cortical abscesses, and 4 of 5 with corticomedullary abscesses. The renal cortical abscesses were the most elusive, with 5 of 11 taking longer than ten days to be diagnosed correctly. The diagnosis of a renal abscess was made preoperatively in 21 cases (50 per cent). Nine cases (25 per cent) were found at surgery and 10 cases (25 per cent) at autopsy. For the 9 cases found at surgery, the preoperative diagnoses were as follows: renal mass, probable tumor, 3; renal calculi, 2; retroperitoneal abscess, 1; retroperitoneal neoplasm, 1; bowel obstruction, 1; and perforated diverticulum, 1. Of the 10 cases found at autopsy, 8 directly contributed to the patient’s death. Perinephric Abscesses Of 23 cases, 16 occurred on the right and 6 on the left; 1 was bilateral. Symptoms
on admission
All patients in this group had some clinical sign or symptom. Temperature elevation was not diagnostic of a perinephric abscess: 12 cases had temperatures under 101” F. and 11 above 101” F. Weight loss greater than 10 pounds over
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FIGURE 1. KVB film of fifty-one-year-old man with perinephric abscess of right kidney showing collection of gas within Gerota fascia and throughout renal parenchyma.
the previous month occurred in 5 cases, and dysuria was a complaint representative of urinary tract infection in 5 cases (21 per cent). Abdominal pain was present in 6 cases (25 per cent), unilateral flank pain occurred in 15 cases (65 per cent). However, 55 per cent of the renal cortical abscesses also presented with unilateral flank pain. The admitting physical examination revealed 6 palpable masses, 5 flank and 1 abdominal, occurring in 25 per cent of the cases. Unilateral flank tenderness was seen in 14 cases and abdominal tenderness in 7. The leukocyte count was not helpful: 6 patients had counts below 12,000/mm.3 and 9 above 20,000/mm.3 Urinalysis was normal in 7 cases (30 per cent); in half the cases, bacteriuria was found, with the same organism cultured from the urine and the abscesses. Pyuria occurred in 16 cases and hematuria in 13. Proteinuria was not found to be of diagnostic significance. Renal calculi were most common in this group (7 cases, or 30 per cent). There were 2 cases of infectious (staghorn) calculi, of which 1 was bilateral. Two more patients with bladder calculi brought the incidence of urinary tract calculi associated with perinephric abscesses to 9 of 23 cases (39 per cent). Diagnosis
Diagnosis of perinephric abscess was made in 17 of 22 cases (77 per cent), in the first five days after hospitalization. Four cases took five to ten days to diagnose, and 1 case took seventeen days. The correct admitting diagnosis of perinephric abscess was made in 6 cases (25 per cent). Other diagnoses of infection included acute pyelonephritis (3), chronic pyelonephritis
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FIGURE 3. Excretory pyelogram of fifty-nine-yearold woman with perinephric abscess of right kidney with upper pole gas formation and calculus in middle pole of left kidney.
FIGURE 2. Excretory urogram of twenty-fve-yearold woman with nonfunctioning right upper pole kidney mass which is perinephric abscess.
(1). Associ(4), renal calculi (Z), and septicemia ated medical problems included diabetes mellitus (4), alcoholism (Z), multiple sclerosis (2), hypertension (2), and quadraplegia or paraplegia (2). Associated infectious problems included pyelonephritis in (7), previously documented urinary tract infection (4), and known vesicoureteral reflux (2). These cases are additional evidence that causation of renal abscesses may be due to an ascending infection. One case was associated with intravenous drug abuse and 7 with renal calculi. The organism cultured from the perinephric abscess cases included Escherichia coli in 9 cases (39 per cent), Proteus mirabilis in 2 cases (9 per cent), Pseudomonas aeruginosa in 3 cases (10 per cent), and Staphylococcus aureus in 2 cases (9 per cent). Both the Proteus cases were associated with renal stones; 1 was a staghorn calculus. Nine cases yielded more than 1 organism from culture of urine or abscess. These were in chronically ill patients with multiple sclerosis, paraplegics under indwelling Foley catheterization, and patients with vesicoureteral reflux.
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pyelograms Radiologic diagnosis. Intravenous (IVP) showed perirenal gas (Fig. l), a renal mass with displacement of calyces (Fig. 2), renal calculi (Fig. 3), displacement of the kidney from its normal position, and nonvisualization of the affected kidney (9 cases). For the remaining 5 cases, no IVP was obtained. There were no false negative or positive results on IVPs. The admitting screening KUB film showed false negative findings in 2 cases in which the urogram was later positive. Renal arteriography was performed in 1 case and showed an avascular mass protruding beyond the renal parenchyma. Retrograde pyelograms were obtained in 6 cases because of nonvisualization on the urogram. Renal scan was performed in 6 cases, 4 gave positive and 2 false positive results. Ultrasonography was done in 3 cases, 2 gave positive findings (Table I). Treatment Treatment of 18 of the 23 patients was administration of preoperative antibiotics. Nine patients had incision and drainage, 10 required nephrectomy, and 4 underwent no surgical procedure because they either died before surgery was possible or because the diagnosis was made only at autopsy. Mortality There were no operative deaths in 26 of the 36 patients whose type of therapy was known. However, 1 patient in septic shock died 1 day postoperatively. Three other elderly patients
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died in the first few days after hospital admission, before diagnosis could be made or surgery performed - bringing the mortality rate to 17 per cent. In the renal cortical group, 4 of 12 patients died, 1 of cerebral vascular accident, 2 of cardiac arrest, and 1 of septic shock fourteen days postoperatively. Renal
Cortical
Abscesses
Two thirds of the 12 cases of renal cortical abscess (carbuncle) of our series occurred in forty to eighty-year-old women. The abscesses were evenly divided between the right and left kidney. This group took the longest to diagnose with 50 per cent of the cases identified after ten days of hospitalization. Cortical abscess as the admitting diagnosis was missed in every case, although 1 in 12 was admitted for a perinephric abscess. Four of the cortical abscess cases had associated renal calculi that certainly contributed to the infectious process. There were no significant signs or symptoms on admission that would help identify the cortical abscess group. One patient had a weight loss of more than 10 pounds during the preceding months. Even temperature, dysuria, and unilateral flank tenderness were not unique to this group. Temperatures at admission were below 101” F. in 50 per cent of patients and above 101” F. in the other half. Palpable masses included 1 in the flank and 1 in the abdomen later shown to be the spleen. Unilateral flank pain or abdominal
TABLE I. Radiologic procedures aiding in diagnosis __~-_--__-_____ __-__-Renal CorticoPerinephric Cortical medullary Procedures (23)-____-__ (12) (5) ---____ --___ __-IVP Normal 1 0 0 Abnormal 7 18 3 Not ordered 5 4 2 KUB only Normal 3 2 0 Abnormal 8 2 1 Renal arteriogram Normal 0 0 0 Abnormal 1 6 0 Not ordered 22 6 5 Retrograde pyelogram Normal 0 0 0 Abnormal 3 6 2 Not ordered 17 7 3 __---_-____ -----_--_-____
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pain, or both, occurred in 60 per cent of cases. Over one half of these cases had leukocyte counts below 15,000/mm.3 Seven of 10 cases had bacteriuria and 27 per cent dysuria on admission. Two cases had no recorded urinalysis. Later the urine cultures grew the same organism as that cultured from the abscess in 8 of the 10 cases. Thus preoperative antibiotic therapy can be directed at an exact organism causing the abscess. Associated medical problems included: alcoholism (6), renal calculi (4), and previous history of documented urinary tract infections (3). E. coli and P. mirabilis accounted for 4 cortical abscess cases each, with Ps. aeruginosa occurring twice, along with single occurrences of several other less common pathogens. Of note is the lack of gram-positive organisms associated with cortical abscesses. Radiography Seven of 8 cases showed abnormal findings on IVPs (Fig. 4A). Four patients never had urography, because they were either too unstable for the procedure, too ill to expect survival despite attempted treatment, or the diagnosis was not made until autopsy. There was 1 false negative urogram for which a renal arteriogram showed an avascular mass in the renal cortex. All renal arteriograms (6) delineated the cortical lesion (Fig. 4B), and a retrograde pyelogram was obtained in 3 cases to confirm the protrusion of the mass on the renal pelvis. A renal scan obtained for 2 cases showed a defect present in both. Ultrasonography done in 1 case of large lower pole cortical abscess was not of diagnostic value (Table I). Treatment Treatment of cortical abscesses consisted of preoperative administration of antibiotics in 10 of II cases. One case was thought to be a neoplasm, thus was not treated preoperatively. Three had incision and drainage, 4 required nephrectomy, and 3 were not treated surgically since the patients were either too ill to survive operation or the cortical abscess was not found until autopsy. None was treated with antibiotics alone and survived. Corticomedullary
Abscesses
The corticomedullary abscess group included 5 patients (4 men, 1 woman) in whom the gross abscess involved the renal medulla and cortex
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FIGURE 4. (A) Excretory pyelogram of eighteen-year-old woman showing mass in upper pole of left kidney with displacement of calyces by renal cortical abscess. (B) Selective left renal arteriogram showing displacement of-renal arterioles around cortical abscess. and had not ruptured through the renal parenchyma to form a perinephric abscess. One patient with severe Laennec cirrhosis (who subsequently died) had a bilateral abscess. Symptoms
at admission
Three of 4 patients had temperatures under 101” F. ; 1 complained of dysuria and 1 of lateral flank pain. Physical examination confirmed the unilateral flank tenderness. One of these patients had no clinical symptoms a seventyfour-year-old woman who had parotitis secondary to Staph. aureus. She had a history of E. coli urinary tract infections and had pyuria on admission, but with a sterile urine culture. (She eventually died of sepsis, and her corticomedullary abscess was discovered at autopsy with culture positive for E. coli.) The leukocyte counts for all 3 cases were greater than 25,000/mm.3 None of them had associated renal calculi, but 2 had hematuria, and 2 bacall had pyuria, teriuria. Diagnosis Diagnoses were chronic pyelonephritis, Laennec cirrhosis, and bladder tumor. The correct diagnosis was established in less than five days in 2 cases, 1 at seven days, and 1 at autopsy. One patient had associated diabetes mellitus. Urine and abscess cultures grew E. coli in 2 (with Ps. aeruginosa additionally in 1, Staph. aureus in 1, and Mycobacterium tuberculosis in 1). The fifth patient had sterile cultures.
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Radiography Excretory urography and retrograde pyelography were done in 3 cases; in the other 2 the abscesses were discovered only at autopsy. No renal arteriograms were necessary. Two thirds of the urograms showed unilateral hydronephrosis, compared with only 1 such finding in the group of perinephric abscesses and 3 in the group of renal cortical abscesses. A mass displacing the calyces was noted in 1 of 3 cases, as were an absent psoas shadow and nonvisualization of the affected kidney. There were no false positive or negative results on urograms in this group. A retrograde pyelogram was performed in 1 case and showed poor visualization of the renal pelvis. Neither renal scanning nor ultrasonography was done (Table I). Treatment Treatment was administration of antibiotics in 3 cases (including antituberculous medication in 1) and nephrostomy in the only operatively treated one. Four patients did not have operative procedures because they were so ill that they died preoperatively or because the diagnosis was made at autopsy. Comments This review elucidates several important points. Skin &u-uncles, pyelonephritis, diabetes mellitus, renal or bladder calculi, recurrent urinary tract infection, and possibly drug abuse
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were found to be associated with renal abscesses and thus may be diagnostic clues. In each case we found predisposing medical problems, renal calculi, or history of infection of the urinary tract. Symptoms at the time of admission, including fever, weight loss, dysuria, unilateral flank or abdominal pain were usually present. The corticomedullary abscess group tended to have temperatures less than 101” F. Dysuria, as a complaint, was present in 27 per cent of the patients with renal cortical abscesses and 20 per cent of those with perinephric abscesses. Seven of our 11 cases of renal cortical abscesses had bacteriuria, with positive urine and abscess cultures for the same gram-negative organisms. This is in contrast to other reports, including that of Moore and Gangai’ who found 4 of 5 negative urinalyses and cultures in patients with renal cortical abscesses. In addition, they found Staph. aureus to be the predominant organism. Evidence of hematologic causation of renal cortical abscesses was given by Moore and Gangai’ and Klein and Filpi’ with the skin, teeth, or respiratory system being the primary site of abscesses. We believe, however, that an ascending infectious process secondary to reflux, calculi, or other associated medical problems may allow for the high incidence of gramnegative organisms found in our renal cortical abscess group. While our series had a 33 per cent association of calculi with renal abscesses, it was less than in other series: Salvatierra, Buclew, and Morrow3 had 34 per cent, Truesdale, Rous, and Nelson4 62 per cent, and Thorley, Jones, and Sanford’ 22 per cent association of calculi with renal abscesses. Our perinephric abscess cases had 2 infec1 bilateral), 5 noninfectious calculi (staghorns, tious calculi (1 bilateral), and 2 bladder calculi. There was a concurrent Proteus infection in 1 case of each of the first 2 types of calculus and additionally I case of renal calculi in the renal cortical abscess group. The I noninfectious calculi case associated with Proteus
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had 8 stones in the kidney which probably should be considered an infectious type. This emphasizes that gram-negative urinary tract infections secondary to an ascending mechanism are associated with calculi, reflux, and pyelonephritis. Thus is demonstrated the necessity for accurate urinalysis since the urine cultures grew the same organisms as the abscesses in the majority of the cases. We also found E. coli to be the most common organism in perinephric and renal cortical abscesses, in contradistinction to other researchers3,4 who found Proteus and Staphylococcus to be the most common. The treatment was consistent with other series. When possible the abscess was incised and drained, and nephrectomy was resorted to only for diffisely damaged kidneys or cases of very old or septic patients who needed prompt intervention for survival. None of our cases was treated successfully with antibiotics alone. Such therapy was done because the patients were too ill for operation or because the diagnosis of abscess was missed. This contributed to the high mortality rate for this disease. In all, I3 of the 40 cases (33 per cent) of the renal abscesses died during the same hospital admission. Others reported mortality rates of 44 per cent5 and 46 per cent3 for perinephric abscesses. These statistics continue to show the severity of renal abscesses and the high mortality rate despite more effective antibiotics and newer diagnostic procedures. Department of Urology, M-553 San Francisco, California 94143 (DR. ANDERSON) References 1. Moore CA, and Gangai MP: Renal cortical abscess, J. Urol. 98: 303 (1967). 2. Klein DL, and Filpi RG: Acute renal carbuncle, ibid. 118: 912 (1977). 3. Salvatierra 0 Jr, Buclew WB, and Morrow JW: Perinephric abscess: a report of 71 cases, ibid. 98: 296 (1967). 4. Truesdale BH, Rous SN, and Nelson RP: Perinephric abscess: a review of 26 cases, ibid. 118: 910 (1977). 5. Thorley JD, Jones SR, and Sanford JP: Perinephric abscess, Medicine 53: 441 (1974).
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VOLUME XVI, NUMBER 4
CLASSIFICATION
OF 40 CASES
KARL
A. ANDERSON,
M.D.
JACK
W. McANINCH,
M.D.
From the Department of Urology, School of Medicine, San Francisco,
--,----
AND
University California
of California
__-__
__-
ABSTRACT - Renal abscesses are misdiagnosed often and, consequently, mistreated or treated too late. Forty cases of renal abscesses divided into anatomic categories - perinephric, renal cortical, and corticomedullay - are reviewed. Various conditions seem to predispose to renal abscesses: urinary tract infections, vesicoureteral reflux, calculi, or other medical problems. This retrospective study discloses that a high correlation exists between organisms found in the patients’ urine cultures and those organisms cultured from all 3 categories of abscesses. Accurate and complete urine bacteriologic study is therefore an essential tool for diagnosis.
Renal abscesses are rare, their symptomatology varies, and their course is insidious. For these reasons their diagnosis is often elusive. We reviewed the cases of renal abscesses seen at San Francisco General Hospital from 1963 to 1978, and classified them according to their 3 anatomic locations: perinephric (occurring between the renal capsule and Gerota fascia), renal cortical (confined to the renal cortex), and corticomedullary (confluent in the cortex and medulla of the kidney). We then analyzed each group for various factors to aid in the future diagnosis, management, and treatment. Material
greater than 1 cm. in diameter. When these latter abscesses had ruptured through the renal parenchyma, thus forming the perinephric abscesses, they were included in the perinephric group. We analyzed each case, when possible, for age, gender, ethnicity, diagnosis at admission, hospital service of first admission, number of days to correct diagnosis, laterality of kidney involvement, location of abscess, presenting physical signs, laboratory data, radiologic procedures, treatment, and associated medical problems. Complete information for all areas analyzed was not available in each case.
and Methods Observations
We documented 40 cases of renal abscess representing 0.01 per cent of all admissions to the hospital during a fifteen-year period. We reviewed the discharge diagnoses, the radiology files, and all abscess specimens in the surgical and autopsy pathology files. We intentionally excluded all cases of pyonephrosis, psoas and retroperitoneal abscesses, and infected renal cysts. Renal cortical and corticomedullary abscesses were included only if they were
We found 23 cases of perinephric, abscesses (including one bilateral), I2 cases of renal cortical abscesses, and 5 cases of corticomedullary abscesses (including one bilateral, Fig. 1). Eighty per cent (32) of all patients were white, 15 per cent were black (6), and 5 per cent were Orientals (2). Over-all admission to the hosptial during the same period was 64 per cent white, 26 per cent black, and 3 per cent Orientals. Gender was of no significance. Male and female were equally divided. Distribution according to age showed that 42 per cent of the cases
-Presented at Annul Meeting Arizona, March 18, 1979.
UROLOGY
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OCTOBER
of Western
1980
/
Section
VOLUME
AUA, Tucson,
XVI, NUMBER
4
333
occurred between ages forty and sixty and 30 per cent between sixty and eighty years. The youngest patient was eighteen years old and the oldest eighty-two. The abscess occurred in the right side in 24 cases (60 per cent), and in the left side in 14 cases (35 per cent). Two cases had bilateral involvement. That diagnosis of renal abscess can be elusive is reflected in the fact that 16 cases (43 per cent) were initially admitted to the medical service and 12 cases (32 per cent) directly to the urology’ department. The general surgery service admitted 8 cases (22 per cent), and 1 case was admitted to the orthopedic service. Misdiagnosis
The difficulty of detecting a renal abscess is indicated by the great variety of diagnoses made. Only 18 cases were admitted with primary renal infection as diagnosis; 8 cases were designated as renal abscess and 10 as pyelonephritis. Incorrect diagnoses at admission included appendicitis, bowel obstruction, cholecystitis, perforated viscus, retroperitoneal tumor, and other medical problems. Time to correct diagnosis. The correct diagnosis was made within five days in 17 of 22 patients with perinephric abscesses, 5 of 11 with renal cortical abscesses, and 4 of 5 with corticomedullary abscesses. The renal cortical abscesses were the most elusive, with 5 of 11 taking longer than ten days to be diagnosed correctly. The diagnosis of a renal abscess was made preoperatively in 21 cases (50 per cent). Nine cases (25 per cent) were found at surgery and 10 cases (25 per cent) at autopsy. For the 9 cases found at surgery, the preoperative diagnoses were as follows: renal mass, probable tumor, 3; renal calculi, 2; retroperitoneal abscess, 1; retroperitoneal neoplasm, 1; bowel obstruction, 1; and perforated diverticulum, 1. Of the 10 cases found at autopsy, 8 directly contributed to the patient’s death. Perinephric Abscesses Of 23 cases, 16 occurred on the right and 6 on the left; 1 was bilateral. Symptoms
on admission
All patients in this group had some clinical sign or symptom. Temperature elevation was not diagnostic of a perinephric abscess: 12 cases had temperatures under 101” F. and 11 above 101” F. Weight loss greater than 10 pounds over
334
FIGURE 1. KVB film of fifty-one-year-old man with perinephric abscess of right kidney showing collection of gas within Gerota fascia and throughout renal parenchyma.
the previous month occurred in 5 cases, and dysuria was a complaint representative of urinary tract infection in 5 cases (21 per cent). Abdominal pain was present in 6 cases (25 per cent), unilateral flank pain occurred in 15 cases (65 per cent). However, 55 per cent of the renal cortical abscesses also presented with unilateral flank pain. The admitting physical examination revealed 6 palpable masses, 5 flank and 1 abdominal, occurring in 25 per cent of the cases. Unilateral flank tenderness was seen in 14 cases and abdominal tenderness in 7. The leukocyte count was not helpful: 6 patients had counts below 12,000/mm.3 and 9 above 20,000/mm.3 Urinalysis was normal in 7 cases (30 per cent); in half the cases, bacteriuria was found, with the same organism cultured from the urine and the abscesses. Pyuria occurred in 16 cases and hematuria in 13. Proteinuria was not found to be of diagnostic significance. Renal calculi were most common in this group (7 cases, or 30 per cent). There were 2 cases of infectious (staghorn) calculi, of which 1 was bilateral. Two more patients with bladder calculi brought the incidence of urinary tract calculi associated with perinephric abscesses to 9 of 23 cases (39 per cent). Diagnosis
Diagnosis of perinephric abscess was made in 17 of 22 cases (77 per cent), in the first five days after hospitalization. Four cases took five to ten days to diagnose, and 1 case took seventeen days. The correct admitting diagnosis of perinephric abscess was made in 6 cases (25 per cent). Other diagnoses of infection included acute pyelonephritis (3), chronic pyelonephritis
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FIGURE 3. Excretory pyelogram of fifty-nine-yearold woman with perinephric abscess of right kidney with upper pole gas formation and calculus in middle pole of left kidney.
FIGURE 2. Excretory urogram of twenty-fve-yearold woman with nonfunctioning right upper pole kidney mass which is perinephric abscess.
(1). Associ(4), renal calculi (Z), and septicemia ated medical problems included diabetes mellitus (4), alcoholism (Z), multiple sclerosis (2), hypertension (2), and quadraplegia or paraplegia (2). Associated infectious problems included pyelonephritis in (7), previously documented urinary tract infection (4), and known vesicoureteral reflux (2). These cases are additional evidence that causation of renal abscesses may be due to an ascending infection. One case was associated with intravenous drug abuse and 7 with renal calculi. The organism cultured from the perinephric abscess cases included Escherichia coli in 9 cases (39 per cent), Proteus mirabilis in 2 cases (9 per cent), Pseudomonas aeruginosa in 3 cases (10 per cent), and Staphylococcus aureus in 2 cases (9 per cent). Both the Proteus cases were associated with renal stones; 1 was a staghorn calculus. Nine cases yielded more than 1 organism from culture of urine or abscess. These were in chronically ill patients with multiple sclerosis, paraplegics under indwelling Foley catheterization, and patients with vesicoureteral reflux.
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pyelograms Radiologic diagnosis. Intravenous (IVP) showed perirenal gas (Fig. l), a renal mass with displacement of calyces (Fig. 2), renal calculi (Fig. 3), displacement of the kidney from its normal position, and nonvisualization of the affected kidney (9 cases). For the remaining 5 cases, no IVP was obtained. There were no false negative or positive results on IVPs. The admitting screening KUB film showed false negative findings in 2 cases in which the urogram was later positive. Renal arteriography was performed in 1 case and showed an avascular mass protruding beyond the renal parenchyma. Retrograde pyelograms were obtained in 6 cases because of nonvisualization on the urogram. Renal scan was performed in 6 cases, 4 gave positive and 2 false positive results. Ultrasonography was done in 3 cases, 2 gave positive findings (Table I). Treatment Treatment of 18 of the 23 patients was administration of preoperative antibiotics. Nine patients had incision and drainage, 10 required nephrectomy, and 4 underwent no surgical procedure because they either died before surgery was possible or because the diagnosis was made only at autopsy. Mortality There were no operative deaths in 26 of the 36 patients whose type of therapy was known. However, 1 patient in septic shock died 1 day postoperatively. Three other elderly patients
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died in the first few days after hospital admission, before diagnosis could be made or surgery performed - bringing the mortality rate to 17 per cent. In the renal cortical group, 4 of 12 patients died, 1 of cerebral vascular accident, 2 of cardiac arrest, and 1 of septic shock fourteen days postoperatively. Renal
Cortical
Abscesses
Two thirds of the 12 cases of renal cortical abscess (carbuncle) of our series occurred in forty to eighty-year-old women. The abscesses were evenly divided between the right and left kidney. This group took the longest to diagnose with 50 per cent of the cases identified after ten days of hospitalization. Cortical abscess as the admitting diagnosis was missed in every case, although 1 in 12 was admitted for a perinephric abscess. Four of the cortical abscess cases had associated renal calculi that certainly contributed to the infectious process. There were no significant signs or symptoms on admission that would help identify the cortical abscess group. One patient had a weight loss of more than 10 pounds during the preceding months. Even temperature, dysuria, and unilateral flank tenderness were not unique to this group. Temperatures at admission were below 101” F. in 50 per cent of patients and above 101” F. in the other half. Palpable masses included 1 in the flank and 1 in the abdomen later shown to be the spleen. Unilateral flank pain or abdominal
TABLE I. Radiologic procedures aiding in diagnosis __~-_--__-_____ __-__-Renal CorticoPerinephric Cortical medullary Procedures (23)-____-__ (12) (5) ---____ --___ __-IVP Normal 1 0 0 Abnormal 7 18 3 Not ordered 5 4 2 KUB only Normal 3 2 0 Abnormal 8 2 1 Renal arteriogram Normal 0 0 0 Abnormal 1 6 0 Not ordered 22 6 5 Retrograde pyelogram Normal 0 0 0 Abnormal 3 6 2 Not ordered 17 7 3 __---_-____ -----_--_-____
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pain, or both, occurred in 60 per cent of cases. Over one half of these cases had leukocyte counts below 15,000/mm.3 Seven of 10 cases had bacteriuria and 27 per cent dysuria on admission. Two cases had no recorded urinalysis. Later the urine cultures grew the same organism as that cultured from the abscess in 8 of the 10 cases. Thus preoperative antibiotic therapy can be directed at an exact organism causing the abscess. Associated medical problems included: alcoholism (6), renal calculi (4), and previous history of documented urinary tract infections (3). E. coli and P. mirabilis accounted for 4 cortical abscess cases each, with Ps. aeruginosa occurring twice, along with single occurrences of several other less common pathogens. Of note is the lack of gram-positive organisms associated with cortical abscesses. Radiography Seven of 8 cases showed abnormal findings on IVPs (Fig. 4A). Four patients never had urography, because they were either too unstable for the procedure, too ill to expect survival despite attempted treatment, or the diagnosis was not made until autopsy. There was 1 false negative urogram for which a renal arteriogram showed an avascular mass in the renal cortex. All renal arteriograms (6) delineated the cortical lesion (Fig. 4B), and a retrograde pyelogram was obtained in 3 cases to confirm the protrusion of the mass on the renal pelvis. A renal scan obtained for 2 cases showed a defect present in both. Ultrasonography done in 1 case of large lower pole cortical abscess was not of diagnostic value (Table I). Treatment Treatment of cortical abscesses consisted of preoperative administration of antibiotics in 10 of II cases. One case was thought to be a neoplasm, thus was not treated preoperatively. Three had incision and drainage, 4 required nephrectomy, and 3 were not treated surgically since the patients were either too ill to survive operation or the cortical abscess was not found until autopsy. None was treated with antibiotics alone and survived. Corticomedullary
Abscesses
The corticomedullary abscess group included 5 patients (4 men, 1 woman) in whom the gross abscess involved the renal medulla and cortex
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FIGURE 4. (A) Excretory pyelogram of eighteen-year-old woman showing mass in upper pole of left kidney with displacement of calyces by renal cortical abscess. (B) Selective left renal arteriogram showing displacement of-renal arterioles around cortical abscess. and had not ruptured through the renal parenchyma to form a perinephric abscess. One patient with severe Laennec cirrhosis (who subsequently died) had a bilateral abscess. Symptoms
at admission
Three of 4 patients had temperatures under 101” F. ; 1 complained of dysuria and 1 of lateral flank pain. Physical examination confirmed the unilateral flank tenderness. One of these patients had no clinical symptoms a seventyfour-year-old woman who had parotitis secondary to Staph. aureus. She had a history of E. coli urinary tract infections and had pyuria on admission, but with a sterile urine culture. (She eventually died of sepsis, and her corticomedullary abscess was discovered at autopsy with culture positive for E. coli.) The leukocyte counts for all 3 cases were greater than 25,000/mm.3 None of them had associated renal calculi, but 2 had hematuria, and 2 bacall had pyuria, teriuria. Diagnosis Diagnoses were chronic pyelonephritis, Laennec cirrhosis, and bladder tumor. The correct diagnosis was established in less than five days in 2 cases, 1 at seven days, and 1 at autopsy. One patient had associated diabetes mellitus. Urine and abscess cultures grew E. coli in 2 (with Ps. aeruginosa additionally in 1, Staph. aureus in 1, and Mycobacterium tuberculosis in 1). The fifth patient had sterile cultures.
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Radiography Excretory urography and retrograde pyelography were done in 3 cases; in the other 2 the abscesses were discovered only at autopsy. No renal arteriograms were necessary. Two thirds of the urograms showed unilateral hydronephrosis, compared with only 1 such finding in the group of perinephric abscesses and 3 in the group of renal cortical abscesses. A mass displacing the calyces was noted in 1 of 3 cases, as were an absent psoas shadow and nonvisualization of the affected kidney. There were no false positive or negative results on urograms in this group. A retrograde pyelogram was performed in 1 case and showed poor visualization of the renal pelvis. Neither renal scanning nor ultrasonography was done (Table I). Treatment Treatment was administration of antibiotics in 3 cases (including antituberculous medication in 1) and nephrostomy in the only operatively treated one. Four patients did not have operative procedures because they were so ill that they died preoperatively or because the diagnosis was made at autopsy. Comments This review elucidates several important points. Skin &u-uncles, pyelonephritis, diabetes mellitus, renal or bladder calculi, recurrent urinary tract infection, and possibly drug abuse
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were found to be associated with renal abscesses and thus may be diagnostic clues. In each case we found predisposing medical problems, renal calculi, or history of infection of the urinary tract. Symptoms at the time of admission, including fever, weight loss, dysuria, unilateral flank or abdominal pain were usually present. The corticomedullary abscess group tended to have temperatures less than 101” F. Dysuria, as a complaint, was present in 27 per cent of the patients with renal cortical abscesses and 20 per cent of those with perinephric abscesses. Seven of our 11 cases of renal cortical abscesses had bacteriuria, with positive urine and abscess cultures for the same gram-negative organisms. This is in contrast to other reports, including that of Moore and Gangai’ who found 4 of 5 negative urinalyses and cultures in patients with renal cortical abscesses. In addition, they found Staph. aureus to be the predominant organism. Evidence of hematologic causation of renal cortical abscesses was given by Moore and Gangai’ and Klein and Filpi’ with the skin, teeth, or respiratory system being the primary site of abscesses. We believe, however, that an ascending infectious process secondary to reflux, calculi, or other associated medical problems may allow for the high incidence of gramnegative organisms found in our renal cortical abscess group. While our series had a 33 per cent association of calculi with renal abscesses, it was less than in other series: Salvatierra, Buclew, and Morrow3 had 34 per cent, Truesdale, Rous, and Nelson4 62 per cent, and Thorley, Jones, and Sanford’ 22 per cent association of calculi with renal abscesses. Our perinephric abscess cases had 2 infec1 bilateral), 5 noninfectious calculi (staghorns, tious calculi (1 bilateral), and 2 bladder calculi. There was a concurrent Proteus infection in 1 case of each of the first 2 types of calculus and additionally I case of renal calculi in the renal cortical abscess group. The I noninfectious calculi case associated with Proteus
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had 8 stones in the kidney which probably should be considered an infectious type. This emphasizes that gram-negative urinary tract infections secondary to an ascending mechanism are associated with calculi, reflux, and pyelonephritis. Thus is demonstrated the necessity for accurate urinalysis since the urine cultures grew the same organisms as the abscesses in the majority of the cases. We also found E. coli to be the most common organism in perinephric and renal cortical abscesses, in contradistinction to other researchers3,4 who found Proteus and Staphylococcus to be the most common. The treatment was consistent with other series. When possible the abscess was incised and drained, and nephrectomy was resorted to only for diffisely damaged kidneys or cases of very old or septic patients who needed prompt intervention for survival. None of our cases was treated successfully with antibiotics alone. Such therapy was done because the patients were too ill for operation or because the diagnosis of abscess was missed. This contributed to the high mortality rate for this disease. In all, I3 of the 40 cases (33 per cent) of the renal abscesses died during the same hospital admission. Others reported mortality rates of 44 per cent5 and 46 per cent3 for perinephric abscesses. These statistics continue to show the severity of renal abscesses and the high mortality rate despite more effective antibiotics and newer diagnostic procedures. Department of Urology, M-553 San Francisco, California 94143 (DR. ANDERSON) References 1. Moore CA, and Gangai MP: Renal cortical abscess, J. Urol. 98: 303 (1967). 2. Klein DL, and Filpi RG: Acute renal carbuncle, ibid. 118: 912 (1977). 3. Salvatierra 0 Jr, Buclew WB, and Morrow JW: Perinephric abscess: a report of 71 cases, ibid. 98: 296 (1967). 4. Truesdale BH, Rous SN, and Nelson RP: Perinephric abscess: a review of 26 cases, ibid. 118: 910 (1977). 5. Thorley JD, Jones SR, and Sanford JP: Perinephric abscess, Medicine 53: 441 (1974).
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