Psoas muscle abscess

Psoas muscle abscess and fluid collections are located in the retrofascial space, rather than in the retroperitoneal space, because the psoas muscles are located in the iliopsoas compartment posterior to the transversalis fascia, which is the posterior boundary of the retroperitoneum.

Psoas muscle abscess may present with fever, flank pain, abdominal pain or limp. Other symptoms are nausea, malaise and weight loss.

Psoas muscle abscess may be classified as primary or secondary depending on the presence or absence of underlying disease.

Primary psoas muscle abscess occurs probably as a result of haematogenous spread of an infectious process from an occult source in the body. Primary psoas muscle abscess can occur in patients with:

Spread of infection from gastrointestinal disease (e.g. appendicitis, diverticulitis, Crohn disease or perforated colon carcinoma) is the most common source of a secondary psoas muscle fluid collection. 

Renal disease is the second most common source.

They may also occur as a result of a neighboring spondylodiskitis.

Cross-sectional imaging is the modality of choice for abscess detection in the psoas muscle. Extension from the psoas muscle into the iliacus muscle is a common sequela.

It is diagnostic in only 60% of cases of psoas abscess, compared with 80% to 100% for CT. 

Appropriate antibiotics along with drainage of the abscess are the treatment of choice. This is often treated with image-guided percutaneous drainage, typically CT, due to the retroperitoneal location.

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Article information

rID: 21395
Synonyms or Alternate Spellings:
  • Iliopsoas abscesses
  • Psoas abscesses
  • Psoas abscess
  • Psoas abscesses
  • Psoas muscle abscesses
  • Iliopsoas abscess

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Cases and figures

  • Case 1
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  • Psoas abscess and...
    Case 2: psoas abscess and left sided renal cyst
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  • Case 3: SIJ and psoas abscess
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  • Case 4: due to splenic tuberculomas
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  • Case 5: on ultrasound
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  • Case 6: due to tuberculous spondylo-diskitis
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  • Case 7
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  • Case 8: postoperative psoas collection
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  • Case 9: complicating renal abscess
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  • Case 10
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  • Case 11
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  • Case 12
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  • Case 13
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