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Year : 2014  |  Volume : 7  |  Issue : 4  |  Page : 525-528  

Unusual presentation of psoas abscess as an abdominal lump

Department of Surgery, MGM Medical College and Hospital, Navi Mumbai, Maharashtra, India

Date of Web Publication25-Jun-2014

Correspondence Address:
Vishal Yadav
Department of Surgery, MGM Medical College and Hospital, Navi Mumbai - 410 206, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0975-2870.135299

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Psoas abscess is a collection of pus in the iliopsoas compartment that has traditionally been classified as primary or secondary according to its origin. Psoas abscess is an uncommon clinical entity that can be primary following hematogenous dissemination of an etiologic agent, the source of which is usually occult or secondary as a result of local extension of an infectious process near the psoas muscle. We report a case of primary pyogenic psoas abscess caused by β-hemolytic streptococci presenting as a lump in the abdomen and subsequently varying treatment regimens. We present the details of this case as well as a literature review to compare various presentations, etiologies and potential treatment modalities.

Keywords: b-hemolytic streptococci, lump in abdomen, percutaneous drainage, primary pyogenic psoas abscess

How to cite this article:
Yadav V, Sengol J, Yadav V, Bansal P. Unusual presentation of psoas abscess as an abdominal lump. Med J DY Patil Univ 2014;7:525-8

How to cite this URL:
Yadav V, Sengol J, Yadav V, Bansal P. Unusual presentation of psoas abscess as an abdominal lump. Med J DY Patil Univ [serial online] 2014 [cited 2024 Feb 24];7:525-8. Available from:

  Introduction Top

Psoas abscess is regarded as a rare disease in the medical literature. The reported incidence is 0.4/100,000, but it has probably increased in recent years. [1] The causes of psoas abscess in India have also changed in the last decades. At the beginning of the 20 th century, psoas abscess was mainly caused by tuberculosis of the spine (Pott's disease). With the decline of Mycobacterium tuberculosis as a major pathogen in developed countries, a psoas abscess was mostly seen secondary to diseases of the digestive tract. [2] In recent years, a primary psoas abscess due to hematogenous spread from an occult source is more common, especially in immunocompromised and older patients. [2],[3] In addition, tuberculosis is on the increase again due to immigration and human immunodeficiency virus (HIV) infections in risk groups. We present clinical case histories, demonstrating the various clinical presentations of psoas abscess. In this report, we describe a patient of psoas abscess presenting as a lump in the abdomen, which is a rare presentation.

  Case Report Top

This was a case report of a 45-year-old male patient presented with a lump in the lower abdomen since 7 days with pain radiating to the ipsilateral hip and thigh since 4 days. He also had a complaint of decreased urine output. Palpable soft-tissue mass over the right iliac fossa (RIF), hypogastric and inguinal areas was noted 1 week before admission. He had right fixed flexion deformity.

His medical history was negative. There was no history of trauma, cutaneous or other infection. Patient denied fever, back pain, gastrointestinal or genitourinary symptoms, weight loss or weakness. On admission, his general condition was good and he was not febrile. The chest was clear to auscultation and no adenopathy was found. Examination of the RIF and hypogastrium showed a fluctuant, warm, mildly tender mass, measuring 20 cm × 15 cm. Flexion and external rotation of the ipsilateral hip was painful. The neurological examination was normal [Figure 1].
Figure 1: Fluctuant, warm, mildly tender mass, measuring 20 cm × 15 cm lump in right iliac fossa

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A complete blood examination showed a white blood cell count of 13,500/mm 3 (89% neutrophils) and 9.5 mg/dl hemoglobin. Urine analysis was normal. Throat cultures, urine cultures and stool cultures were sterile. The chest X-ray was normal. There was no clinical evidence of other organs involvement, namely the lung, the spine, the hip or the gastrointestinal or genitourinary tracts, which was also confirmed by radiological studies. Serologic HIV testing was negative.

Ultrasonography revealed the presence of mixed echogenic, predominantly hyperechogenic well-circumscribed mass noted measuring approximately 20 cm × 20 cm in the hypogastric region. Mass is extending from anterior abdominal wall to the urinary bladder wall and it shows no vascularity.

Computed tomography (CT) established the diagnosis of a loculated fluid-density mass, measuring 20 cm of length, beginning on the RIF, extending anteriorly up to rectus sheath involving the psoas muscle and extending inferiorly through the inguinal region until the root of the tight, with discrete infiltration of the subcutaneous tissue [Figure 2].
Figure 2: Computed tomography abdomen showing loculated fluid-density mass, measuring 20 cm of length, beginning on the right iliac fossa, extending anteriorly up to rectus sheath involving the psoas muscle and extending inferiorly through the inguinal region until the root of the tight, with discrete infiltration of the subcutaneous tissue

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Patient was operated with lower midline incision and abscess cavity, which was lying just beneath the anterior abdominal wall, was opened and approximately 1500 ml of foul smelling frank pus was aspirated [Figure 3]. The cavity extending up to the retroperitoneum, but the peritoneum was not opened. A dependent drain was left in situ and the abdomen was closed.
Figure 3: Lower midline incision and abscess cavity which was lying just beneath the anterior abdominal wall

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The microbiological study of blood, sputum and urine was also negative. Abscess culture was positive for β-hemolytic streptococci. In vitro susceptibility test showed: Penicillin 30 mm, imipenem 30 mm, piperacillin 30 mm, cefepime 30 mm, cefotaxim 25 mm and clarithomycin 22 mm.

Pus for acid-fast bacteria and gram stain-negative. Adenosine deaminase-negative.

Patient was given injection piperacillin tazobactam and injection levofloxacin antibiotic cover. Post-operative ultrasonography on day 7 showed no collection. Drain was less than 30 ml on the post-operative day 8 and was removed on the post-operative day 10 and suture on day 14, had an uneventful recovery and was discharged on 20 th day of hospitalization.

He was symptom free at 1-year follow-up.

  Discussion Top

The iliopsoas compartment is an extraperitoneal space, which contains the iliopsoas and iliacus muscles. The psoas muscle lies in close proximity to organs such as the sigmoid colon, appendix, jejunum, ureters, abdominal aorta, kidneys, pancreas, spine and iliac lymph nodes. Hence infections in these organs can spread to the iliopsoas muscle. [4] On the other hand, abundant blood supply of the muscle is believed to predispose it to hematogenous spread from occult sites of infection. [2] A primary psoas abscess occurs from hematogenous dissemination of a distant infection and is now the predominant form. [1],[2] A secondary abscess arises by contiguous spread of a local infective process and inflammatory or neoplastic diseases of the bowel, kidney and spine, such as Crohn's disease and appendicitis, contribute the majority of secondary cases. [2] Impairment of immunocompetence by infection, iatrogenic immunosuppression or following surgery predisposes to IPA formation-particularly primary cases. The clinical presentation of psoas abscess is often variable and can be non-specific. The classical clinical triad consisted fever, back pain and limp. Other symptoms are vague abdominal pain, malaise, nausea and weight loss. [5] However, the classical clinical symptoms are rarely present in its entirety and prompt diagnosis continues to rely upon retaining a high degree of suspicion as the signs and symptoms may be diffuse chronic and non-specific. The pus from retroperitoneal space tracks down along the psoas muscle in the extraperitonial space and intraperitonial cavity is never involved. The pus got accumulated extraperitonial in the parietal wall of the abdomen and mimic as abdominal lump, which is rare presentation as in our case. Plain film radiography, ultrasonography, CT scan, magnetic resonance imaging (MRI) or fluorodeoxyglucose-positron emission tomography may be used to diagnose these infections. [6],[7] However, CT scan is considered the "gold standard" for definitive diagnosis. [2],[5] Some of the authors believe that MRI images are superior to CT scans because of better discrimination of soft-tissues and the ability to visualize the abscess wall and the surrounding structures without using an intravenous contrast medium. However Gallium-67 scanning is also an effective method of detecting inflammatory lesions, especially abscesses. [6] Other laboratory findings include anemia, an elevation of the white blood cell count and increases in the C-reactive protein level and erythrocyte sedimentation rate (ESR). There was an increase in the leukocytosis and ESRs of our case. Blood cultures may be positive and pus culture through image-guided or surgical aspiration should be carried out. The microbiology of psoas abscess depends on a primary or secondary etiology. In 1° psoas abscess Staphylococcus aureus is the predominant organism, although infections from Pseudomonas, Hemophilus and Proteus species are also reported. [2] The bacteriology of secondary psoas abscess usually reflects the underlying condition and enteric organisms (Escherichia coli, Enterobacter and Salmonella) predominate. [8] The purulent abscess that appeared was drained from right psoas muscles of our case. Unfortunately, whilst the isolation of enteric organism strongly suggests a secondary abscess, cases of primary abscess yielding gut organisms and conversely S. aureus from secondary abscesses have both been reported. [9],[10] In areas, where tuberculosis remains a concern, mycobacterial infection must be considered. The treatment of a psoas abscess involves the use of appropriate antibiotics along with drainage of the abscess. Patients with a suspected psoas abscess should be treated with antibiotics as an empirical treatment even before the culture results are known. Drainage of the abscess should be performed. It may be carried out through surgical drainage or image-guided percutaneous drainage (PCD), but hospital stay is significantly longer compared with open drainage. [2] On the other hand, literature, however, has been inconsistent as to whether open or PCD is more effective. [11] Definitive surgery to treat the underlying cause and if borne in mind when planning the initial treatment, open drainage can be combined with a definitive surgery, minimizing hospital stay and the need for further admissions. In the event of infection with an undetected source or prolonged fever, as well as abdominal solid organs, peritoneal cavity and retroperitoneal region should also be carefully examined. Abscess drainage along with antibiotic treatment constitutes the basis of treatment. First-line PCD appears to be the best approach at the present time, reserving open surgery for very large abscesses. [12] In this case, open drainage of abscess was done.

S. aureus is found in 90% of the cases of primary psoas abscess followed by E. coli (3%). [7] In the literature, there are other reported causes of primary psoas abscess such as brucellosis, trichinosis, typhilitis, pneumococcus or MT. [13] Alexandru et al. reported case of primary psoas abscess caused by β-hemolytic streptococci. [14]

The present case points out a unique cause of psoas abscess presenting as lump in abdomen caused by β-hemolytic streptococci.

  References Top

1.Garner JP, Meiring PD, Ravi K, Gupta R. Psoas abscess-not as rare as we think? Colorectal Dis 2007;9:269-74.  Back to cited text no. 1
2.Walsh TR, Reilly JR, Hanley E, Webster M, Peitzman A, Steed DL. Changing etiology of iliopsoas abscess. Am J Surg 1992;163:413-6.  Back to cited text no. 2
3.Santaella RO, Fishman EK, Lipsett PA. Primary vs secondary iliopsoas abscess. Presentation, microbiology, and treatment. Arch Surg 1995;130:1309-13.  Back to cited text no. 3
4.Procaccino JA, Lavery IC, Fazio VW, Oakley JR. Psoas abscess: Difficulties encountered. Dis Colon Rectum 1991;34:784-9.  Back to cited text no. 4
5.Mallick IH, Thoufeeq MH, Rajendran TP. Iliopsoas abscesses. Postgrad Med J 2004;80:459-62.  Back to cited text no. 5
6.Lebouthillier G, Lette J, Morais J, Aubin B, Picard M. Ga-67 imaging in primary and secondary psoas abscess. Clin Nucl Med 1993;18:637-41.  Back to cited text no. 6
7.Yago Y, Yukihiro M, Kuroki H, Katsuragawa Y, Kubota K. Cold tuberculous abscess identified by FDG PET. Ann Nucl Med 2005;19:515-8.  Back to cited text no. 7
8.Liao YS, Shih HN, Hsu RW. Salmonella psoas abscess - A case report. Changgeng Yi Xue Za Zhi 1995;18:170-5.  Back to cited text no. 8
9.Afaq A, Jain BK, Dargan P, Bhattacharya SK, Rauniyar RK, Kukreti R. Surgical drainage of primary iliopsoas abscess - Safe and cost-effective treatment. Trop Doct 2002;32:133-5.  Back to cited text no. 9
10.Hamano S, Kiyoshima K, Nakatsu H, Murakami S, Igarashi T, Ito H. Pyogenic psoas abscess: Difficulty in early diagnosis. Urol Int 2003;71:178-83.  Back to cited text no. 10
11.Yacoub WN, Sohn HJ, Chan S, Petrosyan M, Vermaire HM, Kelso RL, et al. Psoas abscess rarely requires surgical intervention. Am J Surg 2008;196:223-7.  Back to cited text no. 11
12.Conde Redondo C, Estebanez Zarranz J, Rodrigues Toves A, Amon Sesmero J, Simal F, Martinez Sagarra JM. Treatment of psoas abscess: Percutaneous drainage or open surgery. Prog Urol 2000;10:418-23.  Back to cited text no. 12
13.Ricci MA, Rose FB, Meyer KK. Pyogenic psoas abscess: Worldwide variations in etiology. World J Surg 1986;10:834-43.  Back to cited text no. 13
14.Alexandru C, Emilia N, Karina B, Doru B. Primary psoas abscess. Timisoara Med J 2004;54:374-6.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3]


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