Introduction
Acute lobar nephronia refers to a form of bacterial infection that affects the kidneys. It presents as a localized infection affecting the lobules of the kidneys, in which one or more lobules are affected. It is considered a disease between acute pyelonephritis (bacterial infection which causes inflammation of the kidneys) and renal abscess. It usually affects children, and it is a rare condition in adults.
What Is Acute Lobar Nephronia?
Acute lobar nephronia is also referred to as acute focal pyelonephritis or acute focal bacterial pyelonephritis. Acute lobar nephronia is a focal bacterial infection that affects one or more lobules of the kidneys. It presents as a non liquefactive infection. It is a renal disease that presents as a urinary tract infection.
Acute lobar nephronia is considered a benign inflammatory lesion of the kidney in which generalized pyelonephritis is present at one end, focal acute bacterial nephritis is present in the middle, and a renal abscess is present at the other end.
What Are the Causes of Acute Lobar Nephronia?
Acute lobar nephroniais caused by bacterial infections. The infection usually occurs through the urinary tract and, less commonly, through the bloodstream. Risk factors for this infection are prior urinary tract infections, sexual intercourse, diabetes, structural problems associated with the urinary tract, and the use of spermicides.
Acute lobar nephronia is usually caused by bowel organisms that enter the urinary tract. It is caused by Escherichia coli 70 to 80 percent and Enterococcus faecalis. Hospital-acquired infections are usually caused by coliform bacteria and enterococci or other organisms like Pseudomonas aeruginosa and other species of Klebsiella.
How Does Acute Lobar Nephronia Occur?
The focal infections may be due to the dissemination of bacterial emboli. Hematogenous spread causes the localization of infections that resemble the blood supply pattern of segmental arteries of the kidneys.
Acute lobar nephronia usually begins as urinary tract infections like cystitis and prostatitis. Escherichia coli bacteria enter the bladder by invading the superficial umbrella cells of the bladder. It then enters the renal parenchyma and affects one or more lobules of the kidneys. It then forms intracellular bacterial communities that mature into biofilms. The biofilms produced by these bacteria show resistance to antibiotic therapy and immune system responses, resulting in recurrent urinary tract infections.
The risk of infection is increased in the presence of abnormalities in the urinary tract, kidney stones, vesicoureteral reflux, urinary tract catheterization, ureteral stents, pregnancy, neurogenic bladder, prostate disease in men, diabetes mellitus, immunocompromised state, and family history with frequent urinary tract infections.
What Are the Signs and Symptoms Associated With Acute Lobar Nephronia?
Acute lobar nephronia causes nonspecific symptoms, which include the following:
Fever and flank pain are the prime indicators of acute lobar nephronia. Abdominal pain is usually associated with vomiting. It causes persistent abdominal pain, with signs of infections like malaise, unintentional weight loss, decreased appetite, blood in the urine, and lower urinary tract symptoms in chronic conditions.
What Are the Complications Associated With Acute Lobar Nephronia?
Acute lobar nephronia causes complications like renal scarring and recurrent renal scarring. It is a nonsuppurative infection but may progress to renal abscess with or without treatment. It may result in hypertension and renal failure in some cases.
How Is Acute Lobar Nephronia Diagnosed?
The diagnosis is based on history, examination, and radiographic imaging. Acute lobar nephronia is difficult to diagnose because the symptoms are similar to pyelonephritis. Acute lobar nephronia should be suspected if the symptoms last longer, even after antibiotic treatment.
Radiographic imaging is the major diagnostic tool for deciding the treatment of acute lobar nephronia. In radiographs, acute lobar nephronia usually appears as a hypodense lesion that is wedge-shaped and nonenhancing. It may appear as a mass-like hypodense lesion in severe conditions. The diagnosis of acute lobar nephronia is based on the following tests:
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Ultrasonography: It helps determine the hypoechoic lesions in the kidneys with or without liquefaction. Ultrasonography helps in diagnosing the nature of the lesion, consistency, perinephric extension, liquefaction, inflammation of the renal capsule, perinephric space collection, and hilum involvement.
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A Computed Tomography (CT) Scan: With an intravenous (IV) contrast medium helps in the delineation of the lesion that appears as a focal enlargement of the kidney. Edema is present with calyceal effacement. The lesion is less vascular due to the presence of edema and is poorly enhanced by IV contrast due to edema. A computed tomography (CT) scan is the major diagnostic criterion for acute lobar nephronia.
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Dimercaptosuccinic Acid (DMSA) Scan: It helps in the identification of the lesion. DMSA is a radioactive compound used as an intravenous contrast medium to image the kidneys. DMSA medium enters the kidneys and helps in determining the function of the kidneys. It shows the presence of focal photopenic areas during infection, which may progress to renal scarring.
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Blood Tests - Blood tests show the presence of elevated C-reactive proteins and neutrophilic leucocytosis.
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Urine Culture Tests - Urine culture tests are performed to identify the causative organism. Acute lobar nephronia shows the presence of Escherichia coli (E. coli) and Enterococcus.
How Is Acute Lobar Nephronia Treated?
Acute lobar nephronia requires antibiotic therapy. An intravenous administration of antibiotics for a period of two weeks and oral antibiotics for a period of one week is given. Studies showed that three-week antibiotic therapy is essential in managing acute lobar nephronia. Empiric therapy is given to target gram-negative organisms. Acute lobar nephronia shows a slow response to antibiotics. Usually, infection settles down with antibiotic therapy, but a poor response may be present due to the presence of E. coli. Surgical interventions are required if the lesion turns into an abscess. Surgical treatment is required to drain the pus.
Conclusion
Acute lobar nephronia is a rare condition affecting the lobules of the kidneys. It is being recognized and treated due to the availability of excellent imaging modalities. Early identification and timely intervention are essential to prevent the progression of the disease. This prevents the occurrence of serious complications like renal abscesses and scarring. Early diagnosis, the availability of antibiotics, imaging studies, and appropriate treatment is useful in preventing the incidence of scars in individuals affected with acute lobar nephronia.
