From the Guidelines
Yes, Pelvic Inflammatory Disease (PID) can present similarly to pyelonephritis on a Computed Tomography (CT) scan.
Key Findings
- Contrast-enhanced CT can aid in the early diagnosis of PID, with findings such as pelvic fluid, loss of normal fat planes, and/or subtle enhancement of the endocervical canal or fallopian tubes 1.
- Fulminant PID on CT demonstrates fluid in the endometrial canal, distended and thickened fallopian tubes with wall enhancement, and ovarian enlargement 1.
- Late in the course of PID, a tubo-ovarian abscess may form, appearing as a complex cystic mass with thick enhancing walls on CT 1.
Differentiation from Pyelonephritis
While PID and pyelonephritis can have similar appearances on CT, certain features can help distinguish between the two conditions. For example, the presence of a complex cystic mass with thick enhancing walls and anterior displacement of the mesosalpinx is more suggestive of a tubo-ovarian abscess, which is a complication of PID 1.
- In contrast, pyelonephritis typically presents with findings such as renal enlargement, wedge-shaped areas of decreased attenuation, and/or a focal area of decreased enhancement in the affected kidney.
- However, in some cases, the CT findings may be non-specific, and clinical correlation and further evaluation may be necessary to establish a definitive diagnosis.
From the Research
Presentation of Pelvic Inflammatory Disease (PID) on CT Scan
- PID can present with various findings on a CT scan, including thickening of the uterosacral ligaments, pelvic fat stranding, reactive lymphadenopathy, and pelvic free fluid 2, 3.
- The CT findings of PID can be nonspecific and may mimic those of other pelvic and abdominal processes, such as pyelonephritis 2, 4.
- The diagnosis of PID can be challenging due to its nonspecific clinical manifestations, and CT is commonly the first imaging examination performed 2.
Differentiation from Pyelonephritis
- There is limited information available on the specific differentiation of PID from pyelonephritis on CT scan in the provided studies.
- However, the studies suggest that PID can present with a range of CT findings, including tubal thickening, pelvic fat stranding, and reactive lymphadenopathy, which may be similar to those seen in pyelonephritis 3, 5.
- A decision tree based on CT findings has been proposed to differentiate acute PID from acute appendicitis, but not specifically from pyelonephritis 6.
CT Findings in PID
- The most specific CT finding for the diagnosis of acute PID is tubal thickening of both fallopian tubes (95.1%) 5.
- The most sensitive CT finding is mid-pelvic fat stranding (60.4%) 5.
- Other CT findings in PID include obscuration of the normal pelvic floor fascial planes, thickening of the uterosacral ligaments, cervicitis, oophoritis, salpingitis, and accumulation of simple fluid in the endometrial canal, fallopian tubes, and pelvis 3.