From the Guidelines
Extensive perinephric fat stranding on a CT scan is a significant finding that indicates inflammation or infection around the kidney, which can be associated with conditions such as acute pyelonephritis, renal abscess, or renal infarction, and may require prompt medical attention. This finding can also be seen with traumatic injury to the kidney, urinary obstruction, or recent kidney surgery. Perinephric fat stranding appears as linear areas of increased density in the fat surrounding the kidney on CT imaging, and the severity and extent of the stranding often correlates with the degree of inflammation present.
Some possible causes of extensive perinephric fat stranding include:
- Acute pyelonephritis, as discussed in the study by Soulen et al 1
- Renal abscess or emphysematous pyelonephritis, which can be diagnosed using CT scans, as mentioned in the study by Taniguchi et al, although not directly related to the question, the study 1 provides context for the use of CT in diagnosing kidney infections
- Erdheim-Chester disease, a rare condition that can cause perinephric infiltrates and renal insufficiency, as described in the study 1
- Traumatic injury to the kidney, urinary obstruction, or recent kidney surgery, which can also cause perinephric fat stranding
When this finding is extensive, it suggests a more significant inflammatory process that may require prompt medical attention. Treatment depends on the underlying cause but often includes antibiotics for infection, pain management, and addressing any obstruction if present. Additional CT findings such as kidney enlargement, focal lesions, or fluid collections can help narrow the diagnosis. Patients with extensive perinephric fat stranding may require hospitalization, especially if they have systemic symptoms like fever, severe pain, or signs of sepsis. The study by Soulen et al 1 highlights the importance of using CT scans to diagnose and manage kidney infections, and the study by 1 provides context for the diagnosis and treatment of Erdheim-Chester disease, which can cause perinephric fat stranding.
From the Research
Extensive Perinephric Fat Stranding on CT Scan
Extensive perinephric fat stranding on a computed tomography (CT) scan can indicate several conditions, including:
- Acute pyelonephritis, as suggested by studies 2, 3
- Bladder outlet obstruction, which may be associated with perirenal fat stranding 4
- Renal cell carcinoma, where perinephric fat features can have prognostic value 5
Possible Conditions Associated with Perinephric Fat Stranding
Some possible conditions associated with perinephric fat stranding include:
- Infection or inflammation of the kidney, such as acute pyelonephritis 2, 3
- Obstruction of the bladder outlet, which can lead to impaired renal function 4
- Renal cell carcinoma, where perinephric fat features can predict disease progression 5
Clinical Implications
The presence of extensive perinephric fat stranding on a CT scan can have clinical implications, such as: