BLOOD STREAM INFECTIONS OF THE KIDNEY*
Authors: CABOT HUGH 
Published: November 2008

In this communication only blood‐borne infections of the kidney are considered, and chiefly those produced by the pus‐producing cocci. For many years it has been known that various of these cocci may be found in otherwise normal urine of patients with peripheral infections, such as boils, carbuncles, septic wounds, and acute infections of the upper respiratory tract. In order to investigate this latter point more closely a series of 46 patients with acute inflammatory processes about the mouth, throat, and ear were studied. The group was selected from among patients who had a urine normal to ordinary tests, who had some fever, but no signs or symptoms suggesting an infection of the kidney. The urine was carefully obtained, always by catheter in the female. It was studied by smear and culture, the smear being made from urine centrifuged for a considerable period at high speed. Of these 46 cases 32 showed organisms in the smear, and 18 in the culture.

A group of 10 control cases, of people apparently normal, showed a negative smear in all. In 2 there was a positive culture showing streptococci.

Etiology.–It is important to note that the pus‐producing cocci appear in the urine early in the disease; they disappear as a rule in a few days, though occasionally persisting for several weeks in an otherwise normal urine.

Pathology.–The lesions are primarily cortical and medullary. They tend to coalesce with the production of massive abscess, very usually show early and marked perinephritis, and often go on to perinephritic abscess.

Diagnosis.–Besides the classical methods of diagnosis stress is laid upon the value of radiography in the diagnosis of these cases. Clouding or obliteration of the shadow of the psoas muscle is generally discoverable in perinephritic abscess by modern methods. Scoliosis is not rare, but is a rather late sign. Limitation of the motion of the diaphragm on the infected side as studied by the fluoroscope is more important than the literature would suggest. Particular emphasis is laid upon the value of pyelography both by the excretory and the retrograde method. This will give precise information as to the development of massive abscess by showing deformities of the calices. It will also be of much value in showing displacement of the kidney by perinephritic abscess, sometimes at an early period. Stress is laid upon the value of limitation of the normal mobility of the kidney due to the early development of perinephritis, often in the absence of perinephritic abscess. A series of observations is reported, showing diminished visualisation of the infected kidney as seen in the excretory urogram. Further study will be necessary to evaluate this sign, since it may be produced either by diminution of the function of the kidney or by the obscuring of the shadow of the renal pelvis by overlying inflammatory tissue.

Treatment.–For the purpose of treatment the cases are divided into four groups:‐(1) Operation is believed to be the only available method of treatment for the fulminating cases. (2) This is the group of acute cases characterised by chills, high fever, leukocytosis, and costomuscular tenderness in association with a urine normal except for the practically universal presence of cocci obtained by staining the sediment after prolonged centrifugalisation at high speed. For these cases operation has been generally regarded as almost invariably necessary. With this opinion the author disagrees, believing that in a majority recovery will take place under medical treatment. A position of “armed watchfulness” should always be maintained, carefully observing the reaction of the patient to the disease, particularly as regards the tendency of the pulse to become more rapid and anemia to develop. Coupled with this should be frequent observations of the conformation of the renal pelvis both by the excretory and by the retrograde pyelogram. This will enable massive abscess and perinephritic abscess to be discovered early. (3) The third group is that of the subacute cases in which the picture is less stormy, but in which there is clear evidence of a lesion of the kidney. For these, operation is not indicated except for those who develop perinephritic abscess. (4) The fourth group consists of borderline cases occurring not rarely as a complication of infections of the upper respiratory passages in which the diagnosis can only be made on the basis of slight costomuscular tenderness, fever not satisfactorily accounted for by the conditions in the throat, and by the finding of cocci in the urine as above described. For these cases operation is practically never necessary, since perinephritic abscess is very uncommon.

Indications for operation are: (1) the fulminating type of infection, (2) the widespread infection of the kidney in which the patient seems unable to control the disease, as shown by the development of anemia and failing general conditions, (3) massive abscess of the kidney as shown by the pyelogram, and (4) perinephritic abscess.

The types of operation indicated are: (1) nephrectomy for the fulminating cases, (2) nephrectomy for widespread infection, but without massive abscess when the patient is losing ground, (3) decapsulation and drainage for cases with massive abscess well localised, (4) exploration for perinephritic abscess, the precise operation being determined by the following factors: (a) if the pyelogram shows no evidence of massive abscess or evidence of deformity of the pelvis, simple drainage, (b) if there is perinephritic abscess and evidence of massive abscess, the perinephritic abscess must be drained and the kidney explored in the region indicated by the pyelogram, and (c) for perinephritic abscess of long standing, even with evidence of destruction of kidney tissue as shown by the pyelogram, drainage of the perinephritic abscess alone is indicated in the first instance. Many of these patients will then recover, since the massive destruction of the kidney has already drained into the perinephritic space. It is not wise to uncover the kidney widely in these cases, since extensive dissection will be necessary with the breaking down of well‐established barriers. If, the perinephritic abscess having been drained, the wound fails to heal, or after healing re‐opens, then further exploration can be safely undertaken.