Introduction:
Xanthogranulomatous pyelonephritis (XGP) is a rare, proliferative, chronic, granulomatous, inflammatory illness characterized by widespread renal parenchymal loss and replacement with isolated accumulations of xanthoma-like aggregates of lipid-laden epithelioid macrophages (foam cells).
What Is Xanthogranulomatous Pyelonephritis (XGP)?
Xanthogranulomatous pyelonephritis (XGP) is an uncommon and aggressive form of chronic pyelonephritis that results in a non-functioning kidney. It is most frequently associated with persistent blockage and stone formation in the presence of a persistent infection. It is sometimes referred to as a pseudotumor due to the appearance of an enlarged kidney mimicking a tumor.
What Are the Stages of Xanthogranulomatous Pyelonephritis?
Focal, segmental, and diffuse xanthogranulomatous pyelonephritis are the three basic types of the disease. The diffuse form is the most prevalent, and Malek and Elder have further classified it into three stages based on the level of involvement in the surrounding tissues. These include:
-
Stage One (Nephric): Disease that affects only the kidneys.
-
Stage Two (Perinephric): A disease affecting the renal pelvis or the perirenal fat within Gerota’s fascia.
-
Stage Three (Paranephric): The disease has spread to a larger area, affecting the neighboring organs and the retroperitoneum.
How Is Xanthogranulomatous Pyelonephritis Caused?
-
Although the specific cause of xanthogranulomatous pyelonephritis (XGP) is uncertain, it is widely agreed that the condition is caused by chronic renal obstruction and infection. Xanthogranulomatous pyelonephritis (XGP) is most frequently associated with Proteus or Escherichia coli infection but has also been related to Pseudomonas species. Although stones (often of staghorn dimensions) occur in around 80 percent of patients with XGP, they are not essential for diagnosis. Xanthogranulomatous pyelonephritis (XGP) is frequently observed in patients with diabetes, immunocompromised people, or combination. In patients with XGP, abnormal lipid metabolism has also been considered a causative factor.
-
Although stones (often of staghorn dimensions) occur in around 80 percent of patients with XGP, they are not essential for diagnosis. Xanthogranulomatous pyelonephritis is frequently observed in patients with diabetes, immunocompromised people, or combination. In patients with xanthogranulomatous pyelonephritis, abnormal lipid metabolism has also been considered to be a causative factor.
Who Is Most Commonly Affected With Xanthogranulomatous Pyelonephritis?
It is estimated that xanthogranulomatous pyelonephritis occurs in around one percent of all kidney infections. It affects both kidneys at the same time and with equal frequency. Women are affected more frequently than males, and it usually manifests itself in the fifth and sixth decades of life. Xanthogranulomatous pyelonephritis is uncommon in the pediatric population, yet it is discovered in roughly 16 percent of pediatric nephrectomy specimens, despite being rare. It is more frequent in boys than in girls, and it mainly affects children younger than eight years of age.
What Are the Symptoms Associated With Xanthogranulomatous Pyelonephritis?
1. Even though most patients are experiencing symptoms, their presentation is frequently non-specific, characterized by general malaise. Flanking or abdominal discomfort, lower urinary tract symptoms, fever, palpable painful mass, extensive haematuria, and weight loss are all commonly reported symptoms; nevertheless, urinary tract symptoms might be unexpectedly minor, leading to an initial misdiagnosis. Patients almost often report more than one symptom at a time.
2. Patients with XGP typically have a middle-aged female history of recurrent urinary tract infections, most commonly caused by Escherichia coli and Proteus mirabilis bacteria.
3. Fever, flank or stomach pain, and growth retardation are all possible symptoms in children who present with the condition.
4. Adult patients with XGP may present with the following signs and symptoms:
- The most common presenting problems in a patient with XGP are unilateral flank pain and fever, which are the most common presenting complaints in a patient with XGP.
- Dysuria, hematuria, and increased urine frequency are all common urinary symptoms.
- Anorexia, chills, and weight loss have been reported in a few instances.
What Are the Signs Seen on Physical Examination in Xanthogranulomatous Pyelonephritis?
These include:
-
The temperature is relatively high.
-
The anemia-induced pallor of the conjunctiva.
-
Palpation reveals a unilateral or bilateral renal mass.
-
Tenderness in the costovertebral angle when palpated.
-
Drainage of the fistula through the skin due to the creation of a nephrocutaneous fistula.
-
When there is an invasion of the liver, hepatomegaly (enlargement of the liver than its usual size) can occur in a few situations.
What Are the Diagnostic Tests for Xanthogranulomatous Pyelonephritis?
A thorough history and physical examination, and comprehensive laboratory testing are required for the diagnosis of xanthogranulomatous pyelonephritis.
1. Complete Blood Count: A complete blood count (CBC) with a differential is performed on a patient with XGP, which may reveal anemia and leukocytosis in the patient.
-
The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are frequently high in patients with chronic kidney disease.
-
Increased blood urea nitrogen and creatinine may be detected during renal function tests.
-
As a result of modest biliary retention, the liver function test is frequently abnormal.
2. Urinalysis: A urinalysis may reveal symptoms of a urinary tract infection (UTI), such as pyuria, bacteriuria, and hematuria, among other things.
-
Urine culture reveals the presence of organisms such as Escherichia coli, Proteus mirabilis, Pseudomonas, Enterococcus faecalis, Klebsiella, and other harmful bacteria in the body.
3. Radiographic Imaging: A plain X-ray of the abdomen, particularly the staghorn calculus, may reveal calculi.
-
It is possible to detect hydronephrosis and a lack of typical renal architecture using renal ultrasonography.
-
The computed tomography (CT) scan findings are the most helpful in diagnosing a case of XGP.
-
It is possible to see the replacement of normal renal tissue by several hypoechoic patches of the dilated collecting system that are surrounded by an enhanced rim of contrast medium, giving the appearance of a multiloculated look on a CT scan after contrast administration (known as the "bear paw" sign).
-
It is possible to do magnetic resonance imaging (MRI) on people allergic to contrast agents.
-
An intravenous urogram and a DTPA (diethylenetriamine pentaacetic acid) renal scan may be performed to determine if the kidney is not functioning properly.
4. Biopsy: The pathognomonic finding on biopsy is the presence of lipid-laden foamy macrophages, which can be difficult to distinguish from clear cell carcinoma of the kidney.
5. Immunohistochemical Staining: Patients with XGP have shown positive PAS (periodic acid Schiff) staining when discrimination between XGP and renal cell carcinoma is difficult to make.
How Is Xanthogranulomatous Pyelonephritis Treated?
The treatment depends on the type or stage of the xanthogranulomatous pyelonephritis.
-
Focal or Segmental Xanthogranulomatous Pyelonephritis: Antibiotics and percutaneous drainage were used to treat the infection. Partial or total nephrectomy can be performed if there is no improvement after a period of time.
-
Diffuse or Advanced Stage XGP: Nephrectomy is the procedure of choice in this situation. Antibiotic therapy is given before and after surgery to manage the local infection and prevent septic problems from developing. The goal of surgery is to completely remove all granulomatous tissue to avoid the creation of fistulas in the future. If sinuses or fistulas are discovered, they should be corrected as soon as possible.
-
Bilateral Xanthogranulomatous Pyelonephritis: Treatment for bilateral XGP should include bilateral nephrectomy and long-term dialysis.
-
Laparoscopic Nephrectomy: There has been some discussion about whether to do an open or laparoscopic nephrectomy. Given the inflammatory nature of the condition, laparoscopic nephrectomy is complex, and the conversion rate from laparoscopic to open nephrectomy is approximately 50 percent. An advanced laparoscopic nephrectomy can be performed in a restricted group of patients by a surgeon with extensive laparoscopic experience and skills. In individuals with XGP, laparoscopic nephrectomy is associated with less blood loss and a shorter hospital stay than open surgery.
What Are the Possible Complications of Xanthogranulomatous Pyelonephritis?
The following are some of the problems of xanthogranulomatous pyelonephritis that occur as a result of the involvement of surrounding organs:
-
Abscess of the psoas (collection of pus in the iliopsoas muscle compartment).
-
A perinephric abscess (an infection in the perinephric space and can occur due to rupture of renal abscess).
-
Nephrocutaneous fistula (can occur as a complication of renal surgery).
-
Secondary amyloidosis (abnormal protein build-up in the tissues) and nephrotic syndrome (damaged blood vessels in the kidneys that lead to excess protein excretion in urine).
-
Sepsis (life-threatening complication due to infection).
Conclusion:
Pyelonephritis xanthogranulomatous (XGP) is a rare and aggressive form of chronic kidney disease that is best addressed by a multidisciplinary team of medical and surgical specialists. Because of the similarities in signs and symptoms, it is frequently misdiagnosed with renal cell carcinoma and renal tuberculosis. Early detection and treatment of this disease can help avoid the complications that can arise. Because the condition can spread to multiple organs if left untreated, a multidisciplinary team consisting of an infectious disease specialist, an oncologist, a radiologist, a urologist, and a urological surgeon should carefully evaluate the disease and look for any complications before treatment is initiated.
