PSOAS abscess: an atypical initial presentation of Crohn's disease

A case report on delayed diagnosis of perforated Crohn's disease with recurrent intra-psoas abscess requiring omental patch

INTRODUCTION

Intra-abdominal abscesses associated with Crohn's disease (CD) can rarely occur in the psoas muscle. An intra-psoas abscess is prone to misdiagnosis because its location mimics other diseases, like appendicitis and diverticulitis [1].

PRESENTATION OF CASE

We present the case of a 25-year-old female with an 11-year history of CD, previously well-controlled on Remicade, who presented with right lower quadrant (RLQ) pain and CT findings of a right psoas abscess initially attributed to perforated appendicitis. Two percutaneous drainages pre-ileocecectomy, laparoscopic ileocecectomy, three percutaneous drainages post-ileocolectomy, and evidence of a recurrent abscess prompted diagnostic laparoscopy. The abscess was unroofed and debrided. A flap of omentum was used to fill the abscess cavity. A comprehensive literature search was performed using the terms 'Crohn's abscess', 'intra-psoas abscess', and 'omental patches' in Medline and on PubMed.

DISCUSSION

We attribute the abscess' recurrence to possible epithelialization of the abscess cavity. Intra-psoas abscesses, albeit rare, are a known manifestation of CD. Percutaneous drainage is the initial standard of care, although diagnosis can be difficult given its association with several diseases, which can delay definitive treatment. We summarize a recently proposed and agreed upon treatment scheme for the management of the Crohn's patient with an abdominal abscess. We also propose the novel technique of omental packing in abscess management.

CONCLUSION

Clinician awareness must be heightened for perforating CD in the setting of abscess refractory to either multiple drainage procedures, although care should be taken to individualize treatment to each CD patient who presents with an abdominal abscess.

[Pyogenic and tuberculous abscesses of the psoas muscle]

OBJECTIVES

To describe the clinical characteristics of patients with abscess on the psoas muscle (PA) and to identify the possible differences existing between pyogenic and tuberculous etiologies.

PATIENTS AND METHODS

A retrospective review of patients diagnosed of PA in one hospital was conducted (1983-2009). Two groups were established, that is pyogenic and tuberculous, and the clinical findings, analyses and evolution were compared.

RESULTS

Thirty PA were included, 83% pyogenic and 17% tuberculous, average age 53 years. On 9 occasions, 30% were primary and on 21 occasions, 70% secondary (to skeletal pathology in 8, to urological in 8 and to gastrointestinal in 8). No clinical differences were observed between both groups. Pyogenic and tuberculous etiologies were differentiated analytically through leukocyte values (13,871 vs. 8,560/mm(3), p=0.018), hemoglobin (11 vs. 14 g/dL, p=0.008) and erythrocyte sedimentation rate (ESR) (108 vs. 17 mm/h, p<0.0001). Abscesses were diagnosed by computed tomography (CT) in 29 patients (97%) and by magnetic resonance in 1 (3%), both with a diagnostic sensitivity of 100%, as opposed to 50% for ultrasound scanning. Left laterality was less frequent in pyogenic abscesses (44% vs. 100%, p=0.031). The blood cultures were positive in 22% and abscess pus culture in 82%. Gram negative bacilli, Streptococcus spp. and S. aureus were the most frequent isolations. A total of 67% were drained: transcutaneously 50%, surgically 13% and both techniques 3%. Two patients died (7%), both with pyogenic abscess.

CONCLUSIONS

Secondary pyogenic abscesses constitute the most frequent PA group. CT is the diagnostic procedure of choice. Leukocytosis, anemia, raised ESR and right laterality suggest pyogenic etiology. Transcutaneous drainage is substituting surgical drainage and also makes it possible to obtain diagnostic samples.