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Updated: Dec 3, 2025
Posterior Approach for Debridement of the Psoas Abscess
Published on: March 2, 2020
Phlegmonous Psoas Muscle Infection Causing Sepsis and Death With Missing Postmortem Computed Tomography Scan
Jack Garland1, Kate O'Connor2, Mindy Hu3
1From the Forensic and Analytical Science Service, NSW Health Pathology, New South Wales, Australia.
Abstract:
Infection of the psoas muscle is a rare pathology, which carries a high risk of sepsis and is a potential cause of death. Classic symptoms include back pain and fever and it may be diagnosed premortem on computed tomography or magnetic resonance imaging, where abscess formation may be identified as a discrete rim enhancing and low-attenuation lesion. Infections without abscess formation, such as phlegmonous infection, may be more difficult to identify however, particularly if there is absence of other nonspecific findings, such as gas bubbles. We report a case of Staphylococcus aureus phlegmonous psoas muscle causing sepsis and death with no postmortem computed tomography scan correlation, where clinical history of back pain and an unknown source of sepsis was the only prompt for psoas dissection. This case highlights a potential postmortem computed tomography blind spot in abdominal pathology and we recommend dissecting the psoas muscle if sepsis is suspected but a definitive septic focus is unable to be identified.
Insights
Psoas muscle infection, though rare, poses a high sepsis risk. This case highlights phlegmonous infection without abscess, emphasizing the need for psoas dissection in unexplained sepsis cases.
Area of Science:
- Medical Pathology
- Infectious Diseases
- Radiology
Background:
- Psoas muscle infections are rare but life-threatening, often presenting with back pain and fever.
- Abscess formation is typically identified via CT or MRI, but non-abscess infections like phlegmon can be challenging to diagnose.
- Early diagnosis is crucial to prevent sepsis and mortality.
Observation:
- A case of Staphylococcus aureus phlegmonous psoas muscle infection leading to sepsis and death is presented.
- The infection lacked typical abscess findings and was not identified on postmortem CT.
- Clinical presentation of back pain and an unidentified sepsis source prompted psoas muscle dissection.
Findings:
- Phlegmonous psoas muscle infection can cause severe sepsis and death without clear radiological signs of abscess.
- Computed tomography (CT) may miss non-abscess psoas infections, representing a potential diagnostic blind spot.
- Clinical suspicion is paramount when a septic focus remains unidentified.
Implications:
- This case underscores the importance of considering psoas muscle infection in patients with unexplained sepsis and back pain.
- Routine psoas muscle dissection should be considered in postmortem examinations when sepsis is suspected but the source is unclear.
- Improved diagnostic strategies for non-abscess psoas infections are needed to enhance patient outcomes.
