Diagnostics of the pyelonephritis

Diagnosis of pyelonephritis is based on the characteristic clinical manifestations and results of laboratory and instrumental studies:

• the definition of characteristic local symptoms (pain and muscle tension in the lumbar region, a positive symptom of effleurage);
• research of urine sediment by quantitative methods;
• bacteriological research of urine;
• Functional studies of the kidneys (decrease in the density of urine, possible azotemia);
• ultrasound examination of the kidneys;
• excretory urography;
• dynamic scintigraphy;
• CT and MRI. 

[1], [2], [3], [4], [5], [6], [7],

Examination and physical examination for pyelonephritis

When examining, usually draw attention to the signs of dehydration, dry lined tongue. Possible bloating, forced bending and bringing the leg to the body on the side of the lesion. Muscle tension in the lumbar region, soreness with simultaneous bilateral palpation of the kidney area, sharp soreness in the rib-vertebral corner of the corresponding side are noted. Determine the rapid pulse; hypotension is possible.

[8], [9], [10], [11]

Laboratory diagnostics of pyelonephritis

Characteristic laboratory features of pyelonephritis include:

• bacteriuria;
• leukocyturia (may be absent in case of ureter occlusion on the side of the lesion);
• microhematuria;
• proteinuria (usually does not exceed 1-2 g / day);
• cylinduria.

Macrogematuria is possible with renal colic caused by urolithiasis, as well as with papillate necrosis. Relative density of urine can decrease not only in chronic course of the disease, but also transiently in the acute stage of the disease. Leukocytosis with a shift of the leukocyte formula to the left is determined (especially a significant shift of the leukocyte formula is observed with a purulent infection), a moderate decrease in the level of hemoglobin, an increase in ESR. In the acute stage of the disease, when involved in the process of the second kidney, there may be an increased content of urea and creatinine in the serum.

As a rule, the diagnosis of acute forms of pyelonephritis does not cause much difficulty - it is much more difficult to diagnose in chronic forms, especially when latent (latent) flow.

Instrumental diagnosis of pyelonephritis

With acute pyelonephritis, ultrasound can determine:

• relative increase in kidney size;
• restriction of mobility of the kidneys during respiration due to swelling of paranephric fiber;
• thickening of the renal parenchyma due to interstitial edema, the appearance of focal changes in the parenchyma (hypoechoic areas) with purulent pyelonephritis (in particular, with kidney carbuncle);
• expansion of the cup-and-pelvis system in case of a violation of the outflow of urine.

In addition, ultrasound can detect concretions and abnormalities of kidney development. To later manifestations (with chronic pyelonephritis) include:

• deformation of the kidney contour;
• reduction of its linear dimensions and thickness of the parenchyma (change in the renal-cortical index);
• coarsening of the contour of the cups.

With the help of X-ray methods of investigation it is possible to reveal:

• expansion and deformation of pelvis;
• spasm or dilatation of the calyx necks, a change in their structure;
• pyeloectasia;
• asymmetry and uneven contours of one or both kidneys.

Radionuclide methods allow to identify the functioning parenchyma, delimiting scarring sites.

Computer tomography does not have much advantage over ultrasound and is used mainly for:

• differentiation of pyelonephritis with tumor processes;
• clarifying the features of the kidney parenchyma (with acute pyelonephritis allows to detail the destructive changes in the renal parenchyma), pelvis, vascular pedicle, lymph nodes, paranephric fiber.

Advantage of MRI is the possibility of its use with intolerance of contrast agents containing iodine, as well as chronic renal failure, when the administration of contrast agents is contraindicated.

A kidney biopsy for the diagnosis is of little importance due to the focal character of the lesion.

Diagnosis of chronic pyelonephritis should include anamnestic indications of previous episodes of acute pyelonephritis (including gestational in women), cystitis, and other infections of the urinary tract.

Differential diagnosis of pyelonephritis

With acute pyelonephritis it is necessary to exclude cholecystitis, pancreatitis, appendicitis, in women - adnexitis (and other gynecological pathology), in men - prostate diseases. In children, elderly and senile patients should be borne in mind the need for differential diagnosis of acute pyelonephritis with acute infections (influenza, pneumonia, some intestinal infections). Great difficulties arise in the differential diagnosis of apostematous nephritis. In these cases, the most diagnostic reliable computer tomography.

Diagnostic criteria of acute pyelonephritis:

• pain in the lumbar region, fever, chills, excessive sweating, dysuria;
• a positive symptom of Pasternatsky;
• positive results of the rapid test for bacteriuria and leukocyturia.

Women need to exclude gynecological pathology, in men - prostate diseases.

Chronic pyelonephritis of the latent flow in clinical picture is similar to chronic latent glomerulonephritis, chronic interstitial nephritis, hypertension, and tuberculosis of the kidneys, therefore, differential diagnosis of pyelonephritis is based on the detection of asymmetric nature of renal damage (scintigraphy, excretory urography, ultrasound), characteristic changes in urine sediment , anamnesis data.

[12], [13], [14], [15]