Microbiology and outcome of iliopsoas abscess in 124 patients

Imaging features of soft-tissue infections

Skin and soft tissues are among the most common sites of infections. Infections can involve the superficial epidermis to deep muscles and bones. Most infections spread through contiguous structures, although hematogenous spread can occur in the setting of an immunocompromised state and with atypical infections. While clinical diagnosis of infections is possible, it often lacks specificity, necessitating the use of imaging for confirmation. Cross-sectional imaging with US, CT, and MRI is frequently performed not just for diagnosis, but to delineate the extent of infection and to aid in management. Nonetheless, the imaging features have considerable overlap, and as such, it is essential to integrate imaging features with clinical features for managing soft tissue infections. Radiologists must be aware of the imaging features of different infections and their mimics, as well as the pros and cons of each imaging technique to properly use them for appropriate clinical situations. In this review, we summarize the most recent evidence-based features of key soft tissue infections.

A large iliopsoas abscess due to colon cancer complicated by bowel obstruction: A case report

INTRODUCTION

Iliopsoas abscesses (IPAs) associated with bowel obstruction due to colon cancer are rare, and there is no consensus regarding treatment strategies.

PRESENTATION OF CASE

A 63-year-old man presented with swelling and pain in the right iliac region. Imaging studies revealed an IPA expanding from the psoas major muscle and retroperitoneal space subcutaneously around the right ilium. After percutaneous drainage, the patient developed bowel obstruction secondary to colon cancer. Hemicolectomy and preventive ileostomy were performed at the gastrointestinal surgery department, and chemotherapy was administered at the medical oncology department after ileostomy closure. Three months later, local recurrence was confirmed in the right iliac region, and the recurrent lesion, including the ilium, was widely resected. One and a half years after the reoperation, there was no recurrence.

DISCUSSION

An IPA due to colorectal cancer without obvious perforation can also occur, and the treatment of IPAs depends on their size, location, shape, and presence of gas. Minimally invasive and staged treatment is preferable for IPAs due to colorectal cancer because the surgical mortality rate for colorectal cancer with local abscesses is high.

CONCLUSION

Colorectal cancer should be considered as a cause of IPAs. Treatment of IPAs caused by colon cancer should be performed in a less invasive manner after considering their size, location, shape, and the presence of gas. Cooperation between gastrointestinal surgeons and oncologists is essential for managing patients with an IPA due to colon cancer complicated by bowel obstruction.

Successful treatment of a unique case of solitary primary iliopsoas abscess caused by Streptococcus dysgalactiae subspecies equisimilis: A case report

RATIONALE

Iliopsoas abscess, mainly caused by Staphylococcus aureus, occurs via the bloodstream or spread from adjacent infected organs. Although a few cases regarding primary iliopsoas abscess caused by Streptococcus dysgalactiae subspecies equisimilis (SDSE) with accompanying disseminated foci have been reported to date, there has been no case report on solitary primary iliopsoas abscess caused by SDSE.

PATIENT CONCERNS

An 85-year-old Japanese woman presented with worsening right hip pain and fever after an exercise. Hip computed tomography revealed a right iliopsoas abscess (iliac fossa abscess), and intravenous cefazolin was started as a treatment based on the creatinine clearance level on admission.

DIAGNOSES

Blood cultures were positive for β-hemolytic Lancefield group G gram-positive cocci arranged in long chains, which were identified as SDSE by matrix-assisted laser desorption/ionization. No other disseminated foci were found upon performing whole computed tomography and transthoracic echocardiography. The patient was diagnosed with an SDSE solitary iliopsoas abscess.

INTERVENTIONS

The antimicrobial was appropriately switched to intravenous ampicillin on day 2, with the dosage adjusted to 2 g every 6 hours based on the preadmission creatinine clearance, followed by oral amoxicillin (1500 mg, daily).

OUTCOMES

The abscess disappeared without drainage on day 39, and the patient remained disease-free without recurrence or sequelae during a 6-month follow-up period.

LESSONS

SDSE can cause a solitary primary iliopsoas abscess, which can be successfully treated with an appropriate dose of antimicrobials without draining the abscess.

Invasive pneumococcal disease serotype 23B1 causing multifocal septic arthritis, myositis and retroperitoneal abscess

We describe a case of a previously healthy unvaccinated man in his 70s who developed penicillin-susceptible bacteraemic invasive pneumococcal disease due to non-vaccine serotype 23B with the unusual manifestations of multifocal myositis, intramuscular abscesses, polyarticular septic arthritis and synovitis. Blood cultures drawn prior to antibiotic therapy and culture of iliopsoas collection were helpful in making the diagnosis. At follow-up, he had persistent hip pain attributed to avascular necrosis of the head of femur, a possible late complication of his pyomyositis.

Campylobacter fetus-induced primary psoas abscess in patient with gouty arthritis: A case report and literature review

RATIONALE

Campylobacter fetus is rare pathogen with high mortality rate in immunosuppressive hosts. This study aimed to summarize clinical and pathological presentation of C fetus induced psoas abscess.

PATIENT CONCERNS

A 66-year-old male patient with long medical history of poorly-controlled gouty arthritis and steroid intake complained of a severe low back pain. Physical examination showed tenderness in his psoas.

DIAGNOSES

The patient underwent puncture biopsy to the lesion in the psoas under ultrasound guidance. The lesion was indicated as abscess by pathological examination, and its pathogen was indicated as C fetus by the next generation sequencing.

INTERVENTIONS

Meropenem 1 g q8.h were administered intravenously for 10 days. Then the antibiotic treatment was switched to amoxicillin/clavulanate potassium 0.375g q.8.h and levofloxacin 0.5g q.d oral administration when discharge.

OUTCOMES

The patient's fever and low back pain improved and infectious parameters declined. He was discharged in good general condition with advice for further monitoring and therapy. In the first month follow-up, the patient did not report recurrence or aggravation of his symptoms.

LESSONS

C fetus should be noticed in immunosuppressive patient with exposure to livestock who present with rare systematic or local invasive infection. We advocated the meropenem for the first-line treatment against C fetus.

Case Report: A spinal infection with bilateral psoas abscesses was treated with NPWT to enhance the local infection by increasing the infiltration of neutrophil cells and draining the pus

Treatment of spinal brucellosis with bilateral psoas abscess is a challenging clinical endeavor. We retrospectively evaluated a case of lumbar infection and bilateral psoas abscess, and was effectively managed through a unilateral extreme lateral approach with the aid of NPWT for bilateral drainage. We hypothesize that NPWT can influence the Piezo1 receptor of neutrophils and further influence the interaction between neutrophils and endothelial cells to promote the clearance of infected lesions, and this phenomenon is also observed in pathological slides. This proves that NPWT can rapidly enhance the recruitment of neutrophils in the infected area and improve the local immune response, and after a year of reassessment and tracking, Bilateral drainage using NPWT via a unilateral Extreme Lateral Approach could acquire satisfactory surgical outcomes, can be used as a treatment modality for lumbar infection with bilateral psoas abscesses.

Iliopsoas Hematoma Progression to Abscess in the Setting of Diabetic Ketoacidosis

Iliopsoas hematomas (IPH) are defined as a spontaneous or traumatic retroperitoneal collection of blood involving the iliopsoas muscle. In some cases, intramuscular hematomas can progress to abscesses and put the patient at risk for further complications. Our objectives are: to describe the etiology of intramuscular hematoma and psoas abscess, to describe the clinical signs and treatment of intramuscular hematoma and psoas abscess, and to analyze the association between uncontrolled diabetes mellitus and psoas abscess progression, which we achieve through retrospective case analysis and associated literature review on symptom constellation. We present the case of a 40-year-old male patient with a history of diabetes mellitus and alcohol abuse who presented with three days of increasing back and left lower extremity pain, confusion, auditory hallucinations, and fever found to be in diabetic ketoacidosis. Six days prior, the patient presented to the Emergency Department (ED) after being struck by a motor vehicle while ambulating found to have bruising, weakness in his lower extremities, and an L2 vertebrae fracture found on CT. During the presentation, the patient was found to have decreased muscle strength, leukocytosis with elevated lactate, and CT findings suggestive of a left psoas abscess drained by interventional radiology. Vancomycin and Cefepime were used as an empiric antibiotic regimen. The culture of the wound was then found to grow Methicillin-susceptible Staphylococcus aureus (MSSA) bacteria and antibiotics were then adjusted to Vancomycin and Cefazolin. During the patient's hospital stay, he developed two more abscesses on his bilateral psoas muscles, which were promptly percutaneously drained by interventional radiology. This case describes an uncommon progression of an Iliopsoas hematoma to a psoas abscess, likely due to his immunocompromised status secondary to his uncontrolled diabetes mellitus. Uncontrolled diabetes mellitus has been shown in various studies to be an independent risk factor of intramuscular hematoma progress to psoas abscess. We suggest that patients displaying fever, chills, flank pain, limited hip movement, and indications of uncontrolled diabetes should be approached with a high degree of suspicion for a psoas abscess.

Clinical Characteristics and In-Hospital Outcomes in Patients with Iliopsoas Abscess: A Multicenter Study

(1) Background: Iliopsoas abscess (IPA) is usually overlooked due to its nonspecific symptoms and signs. The resulting delayed diagnosis and treatment can increase morbidity and mortality. The purpose of the present study was to identify the risk factors for the unfavorable outcomes associated with IPA. (2) Methods: We included patients who presented to the emergency department and were diagnosed with IPA. The primary outcome was in-hospital mortality. Variables were compared, and the associated factors were examined with Cox proportional hazards model. (3) Results: Of the 176 patients enrolled, IPA was of primary origin in 50 patients (28.4%) and of secondary origin in 126 (71.6%). Skeletal origin was the most common source of secondary IPA (n = 92, 52.3%). The most common pathogens were Gram-positive cocci. Eighty-eight (50%) patients underwent percutaneous drainage, 32 (18.2%) patients underwent surgical debridement, and 56 (31.8%) patients received antibiotics. Multivariate analyses indicated that age > 65 (year) (HR = 5.12; CI 1.03-25.53; p = 0.046), congestive heart failure (HR = 5.13; CI 1.29-20.45; p = 0.021), and platelet < 150 (103/μL) (HR = 9.26; CI 2.59-33.09; p = 0.001) were significant independent predictors of in-hospital mortality in Model A, while the predictors in Model B included age > 65 (year) (HR = 5.12; CI 1.03-25.53; p = 0.046) and septic shock (HR = 61.90; CI 7.37-519.46; p < 0.001). (4) Conclusions: IPA is a medical emergency. Our study reported that patients with advanced age, congestive heart failure, thrombocytopenia, or septic shock had a significantly higher risk of mortality, and the recognition of the associated factors may aid in risk stratification and the determination of the optimal treatment plan for IPA patients.

Presentation, management and outcomes of iliopsoas abscess at a University Teaching Hospital in Nepal

Objectives

Iliopsoas abscess (IPA) is an uncommon clinical disease and is often missed to diagnose due to vague clinical presentation. Early treatment with drainage and appropriate antibiotic therapy is necessary before sepsis sets in and become lethal. We conducted this study to evaluate clinical features, etiology, management strategies, and outcomes in patients with IPA from a University Teaching Hospital in Nepal.

Methods

A retrospective analysis of 32 consecutive IPA cases managed at Tribhuvan University Teaching Hospital, Nepal for the period of January 2019 to February 2022 was carried out.

Results

The mean age was 42.5 ± 19.1 years (range, 19-75 years) and the male: female ratio was 2.2:1. Two-thirds or more patients presented with fever, limp, fixed flexion deformity and/or low back pain. Ultrasonography (US) was diagnostic in 27 (84.4%) patients. Eighteen (56.3%) patients had primary IPAs, and 14 (43.7%) had secondary IPAs. Thirty (93.7%) patients were managed with US guided percutaneous drainage (PCD) and 2 (6.2%) patients underwent open surgical drainage. Drainage procedures were combined with antibiotics in all patients. Pus culture showed Staphylococcus aureus growing in the majority of cases (10 of 23, 43.5%). The hospital stay was longer in patients treated via surgical drainage compared to those who received PCD: 13 days (range 12-14 days) vs. 6.6 days (range 4-13 days), respectively. Recurrence of abscess was seen in 4 (12.5%) cases and all were successfully managed via a second PCD. There was no mortality.

Conclusions

Varying clinical presentation of iliopsoas abscess demand a high index of suspicion for early diagnosis. Initial imaging modality in suspected case of IPA is US. US-guided PCD along with the appropriate antibiotics is a successful frontline treatment of IPAs with shorter hospital stay.

A Case Report of Iliopsoas Abscess Secondary to Small Bowel Fistula

Iliopsoas abscesses (IPAs) are rare infections in the musculature that can be difficult to diagnose due to nonspecific presentations. These abscesses are most commonly caused by either the hematogenous spread of a separate infectious source in the body or secondary to Crohn's disease and are typically treated with antibiotic therapy and percutaneous drainage. For cases complicated by bowel disease, multiloculated psoas abscess, or gas-forming organisms, surgical drainage may be indicated. We present the case of an 81-year-old female with a history of colon cancer status post-cecum resection who presented with back pain, thigh pain, and constipation. Computerized tomography imaging showed concurrent small bowel obstruction and a right IPA extending down to the right thigh. Laparoscopic exploration revealed a small bowel fistulization to the right iliopsoas as the source of infection. Resection of the small bowel and surgical incision and drainage of the abscess were necessary for her treatment. The patient was discharged with vacuum-assisted closure of her wound after a hospital course complicated with chronic diarrhea. Bowel fistulization should be considered a potential cause of IPAs in patients with a complicated gastrointestinal history.

Rare extension of pancreatic pseudocyst with Mycobacterium abscessus into the iliopsoas muscle

Pancreatic pseudocyst is a well-known complication of both acute and chronic pancreatitis. Although extension into other anatomical sites is common, extension into the retrofascial space causing an iliopsoas abscess is exceedingly rare. Although its low incidence creates a diagnostic challenge for clinicians, early diagnosis is essential to prevent significant complications and poor patient outcomes. We present a case of iliopsoas abscess with unusual culture fluid growth in the setting of acute on chronic pancreatitis secondary to extension of a pancreatic pseudocyst. We also offer a brief review of the literature and pathophysiology of the condition.

Prognostic nutritional index as outcome predictor in patients with iliopsoas abscess

Cases with iliopsoas abscess (IPA) in a single hospital-based cases were reviewed and compared with clinical profiles of published hospital-based IPA series. To verify usefulness of prognostic nutritional index (PNI) used to predict outcome and severity of IPA, this study was performed. This study consists of 2 parts: Study 1 - Case review of IPA series in a single hospital: 7 cases with IPA treated in a single hospital in sequential 5 years were collected (series 1) and their clinical profiles compared. Study 2 - Review of hospital-based literature: A search of the PubMed database from 1990 to the present was performed, using the Boolean expression ([Psoas OR iliopsoas] AND [abscess] AND [hospital-based]). Two hospital-based case series were collected. The clinical profiles of 2 series were compared with series 1 to draw predictive factors of outcome and deciding treatment modality, medical or surgical. Study 1 - Analyzing 7 IPA cases, average age was 76.7 years old (varying from 64 to 91) and the lifesaving rate was 86%. PNI < 45, calculated with serum albumin (Alb) and total lymphocyte count, and larger cumulative abscess volume (CAV) measured by computed tomography seem outcome predictors. Study 2 - Analyzing 2 hospital-based IPA series (series 2 and 3), series 2 reviewed isolated IPA cases without any comorbidities and series 3 reviewed IPA cases with cardiovascular disorders. Among 3 series including ours, series 1 showed oldest case and longer length of hospitalization. Series 3 showed the highest mortality among 3 because it collected IPA with cardiovascular comorbidities. PNI seems predictors of outcome and disease activity in patients with IPA and might indicate treated with surgical intervention.

Musculoskeletal tuberculosis with multifocal muscle abscesses in a healthy young adult

Musculoskeletal tuberculosis represents 1% of total tuberculosis cases. It affects young adults from endemic countries or immunocompromised patients, and may lead to severe functional impairment. We report a case of a 27-year-old male from an endemic country presenting with a 4-month history of fever, a major pectoralis abscess, and low back pain. A lumbar spine MRI revealed osteolytic lesions in multiple vertebral bodies along with a large iliopsoas abscess. Both abscesses were drained and the diagnosis was established by positive polymerase chain reaction assay for tuberculosis. The patient was initiated on anti-tuberculous treatment for 9 months. Musculoskeletal tuberculosis is rarely found in Western countries. If left intreated, it can lead to severe complications which may require surgical intervention.

A missed psoas abscess diagnosis: A forensic case report

Psoas abscess is a rare pathology that usually presents with non-specific signs and rare clinical features. These characteristics can delay the diagnosis leading to complications and death. We report a forensic autopsy case of a 65-year-old male, alcoholic, smoker, with a history of hypertension, and urinary infection, who presented to the emergency room for anorexia and consciousness disorder. On physical examination, the patient was febrile and confused. Laboratory exams revealed leukocytosis and elevated C-reactive protein (CRP). Two days later, he died despite extensive resuscitation. Forensic autopsy revealed a large amount of green pus in the left psoas muscle extending to the muscles of the thigh of the same side with multiple cavities. The pus extended to the left kidney with destructive parenchyma and coralliform lithiasis. Histological examination showed destroyed renal tissue by lesions of chronic and acute pyelonephritis with dilatation of the pyelocaliceal cavities. Bacteriological analysis of the pus showed the presence of Escherichia coli. The psoas abscess was secondary to pyonephrosis favored by the immunodeficiency. Thus, death was attributed to a septic shock secondary to a psoas abscess complicating pyonephrosis.

Iliopsoas Pyomyositis With Bacteremia at an Early Stage of Presentation in a Temperate Region

A psoas abscess, a collection of pus in the psoas muscle, is rare but the incidence is increasing with the use of computed tomography (CT) and magnetic resonance imaging (MRI). Pyomyositis, a muscular infection that does not lead to abscess formation, is well known as tropical pyomyositis because it is highly prevalent in tropical areas. We encountered a case of iliopsoas pyomyositis and bacteremia without abscess formation. The blood culture was positive despite the early stage of presentation and no abscess formation on MRI. Imaging is the gold standard for diagnosing iliopsoas abscesses. There are cases similar to ours wherein the blood culture is positive before the formation of an abscess. Regardless of whether an abscess is found on MRI or not, we need to consider the possibility of false negatives at the early stage of presentation. A suspicion of this disease is essential during a physical examination for early diagnosis and treatment, especially in rural areas, where medical resources are limited. Furthermore, pyomyositis is a common disease in tropical regions, but in recent years, case reports of occurrences in temperate regions have increased. This case indicates the need to consider pyomyositis as a differential diagnosis of fever and hip joint pain even in temperate regions.

Primary Psoas Abscess in a Pediatric Patient: A Case Report

A psoas abscess is described as a collection of pus in the iliopsoas muscle compartment, which comprises the psoas and iliacus muscles located in the extraperitoneal space. It can be considered a primary abscess due to hematogenous or lymphatic seeding from a distant site, primarily occurring in children in tropical or developing countries. These primary infections are typically due to a single microorganism, most commonly, Staphylococcus aureus. Secondary spread develops due to the direct spread of infection of the psoas muscle from an adjacent structure (hip, vertebrae, gastrointestinal tract, aorta, genitourinary tract), developing due to trauma or instrumentation of the inguinal region, lumbar spine, or hip region. The secondary infections can be either mono- or polymicrobial and include enteric and anaerobic organisms. We present a case of psoas abscess in a five-year-old female who presented with a progressively worsening pain in the right hip for three days with refusal to bear weight and no history of trauma. Hip x-ray imaging yielded no abnormal results, but laboratory values prompted further investigation, leading to identifying a right psoas abscess via MRI with surrounding edema and enhancement. Imaging modality choice has proven to be instrumental in identifying psoas abscess and is key to achieving a diagnosis.

Epidural phlegmon and iliopsoas abscess caused by Salmonella enterica bacteremia: A case report

INTRODUCTION AND IMPORTANCE

Iliopsoas abscesses (IPA) are rare and typically present with a non-specific triad of fever, back pain, and antalgic gait. Staphylococcus aureus is the organism responsible for nearly 90 % of IPA cases. We present a case of primary IPA with progression to osteomyelitis and discitis due to Salmonella enterica bacteremia, an exceedingly rare etiology occurring in an otherwise healthy individual.

CASE PRESENTATION

This patient presented with fever, back pain, and hip pain. Initial imaging and laboratory workup did not reveal any source of infection. He became septic within 72 h of admission, and blood cultures were confirmed as Salmonella enterica. However, the etiology of the infection remained unclear. Computed Tomography (CT) imaging revealed a right-sided psoas abscess measuring 7 mm × 7 mm and an epidural phlegmon. He was discharged home with intravenous ceftriaxone and levofloxacin. However, the patient was readmitted due to L2-L3 osteomyelitis and discitis with an eccentric disc bulge causing compression of the right L3 nerve root and neutropenia.

CLINICAL DISCUSSION

This case in unique in the fact that this occurred in a healthy patient with no significant risk factors or exposure to this bacteria. Additionally, this case highlights the rapid progression of IPA and the spread to adjacent spinal structures with the potential to cause nerve compression with successful medical management.

CONCLUSION

Salmonella enterica is rare cause of iliopsoas abscess. This case emphasizes the importance of including iliopsoas abscesses as a differential diagnosis in patients with a high index of clinical suspicion.

Minimally invasive outpatient management of iliopsoas muscle abscess in complicated spondylodiscitis

BACKGROUND

Iliopsoas muscle abscess (IPA) and spondylodiscitis are two clinical conditions often related to atypical presentation and challenging management. They are both frequently related to underlying conditions, such as immunosuppression, and in many cases they are combined. IPA can be primary due to the hematogenous spread of a microorganism to the muscle or secondary from a direct expansion of an inflammatory process, including spondylodiscitis. Computed tomography-guided percutaneous drainage has been established in the current management of this condition.

AIM

To present a retrospective analysis of a series of 8 immunocompromised patients suffering from spondylodiscitis complicated with IPA and treated with percutaneous computed tomography-guided drainage and drain insertion in an outpatient setting.

METHODS

Patient demographics, clinical presentation, underlying conditions, isolated microorganisms, antibiotic regimes used, abscess size, days until the withdrawal of the catheter, and final treatment outcomes were recorded and analyzed.

RESULTS

All patients presented with night back pain and local stiffness with no fever. The laboratory tests revealed elevated inflammatory markers. Radiological findings of spondylodiscitis with unilateral or bilateral IPA were present in all cases. Staphylococcus aureus was isolated in 3 patients and Mycobacterium tuberculosis in 2 patients. Negative cultures were found in the remaining 3 patients. The treatment protocol included percutaneous computed tomography-guided abscess drainage and drain insertion along with a course of targeted or empiric antibiotic therapy. All procedures were done in an outpatient setting with no need for patient hospitalization.

CONCLUSION

The minimally invasive outpatient management of IPA is a safe and effective approach with a high success rate and low morbidity.

A case report of minimally invasive percutaneous ultrasound guided tuberculous iliopsoas abscess drainage in an immunocompromised patient

Introduction and importance

Iliopsoas abscess is a collection of pus that presents with nonspecific features with often delays in diagnosis however cause significant morbidity and mortality with Mycobacterium tuberculosis to be considered as causative agent in at risk individuals in tuberculous endemic regions. Management involves drainage and initiation of adequate antibiotics with radiological guided percutaneous approach considered the appropriate initial approach.

Case presentation

50-year-old immunosuppressed presenting with left iliopsoas abscess who underwent ultrasound guided drainage and placement of pigtail catheter successfully without the need for open surgical drainage. Our experience of interventional radiology for diagnosis of causative agent and treatment in a sub-Saharan Africa.

Clinical discussion

We concur with the recommendation to analyse fluid for tuberculosis in at risk individuals with minimally invasive procedures via interventional radiology as an adequate first line diagnostic and treatment option of psoas abscess. Ultrasound guided catheter placement and drainage successfully drained the abscess by day 10 similarly seen as the average duration in a case series from India.

Conclusion

The importance of the role of interventional radiology in treatment for complex abdominal pathologies in sub-Saharan Africa with its ability to diagnose and treat via minimally invasive procedures at highest precision and lowest risks and complications while maintaining a high level of suspicion for tuberculosis as the underlying etiology is highlighted.

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Minimally invasive procedure for drainage of a tuberculous iliopsoas abscess

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Image guided diagnosis and therapy

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Interventional radiology experience in sub-Saharan Africa

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Level of suspicion of tuberculous iliopsoas abscess in at risk individuals

Detection of mecA and 16S rRNA Genes Using Real-Time PCR Can Be Useful in Diagnosing Iliopsoas Abscess, Especially in Culture-Negative Cases: RT-PCR for Iliopsoas Abscess

The rapid detection of etiological agents is important for the successful treatment of iliopsoas abscess (IPA). The purpose of this study was to investigate the clinical utility of a real-time polymerase chain reaction (PCR) that targets the mecA gene for methicillin-resistant staphylococci (MRS) and the 16S rRNA gene for pan-bacteria. Our retrospective diagnostic study included 22 patients exhibiting IPAs and four patients with noninfectious iliopsoas mass regions who underwent computerized tomography or ultrasonography-guided biopsy and/or surgical treatment. Clinical symptoms, serum data, imaging analysis, and tissue microbiological culture were utilized for the diagnosis of IPA. The diagnostic accuracy of real-time PCR was determined based on the diagnosis of IPA and microbiological culture results. The microbiological culture was positive for 12 IPA cases that included 2 MRSA infections. Among 12 culture-positive IPA cases, 16S rRNA-PCR was positive in 12 and MRS-PCR in two. Among 10 culture-negative IPA cases, including 3 TB cases, 16S rRNA-PCR was positive in 8 and MRS-PCR in 2. In noninfectious iliopsoas mass patients, neither 16S rRNA nor MRS-PCR detected bacterial DNA. The sensitivity, specificity, positive predictive, and negative predictive values of 16S rRNA-PCR for diagnosing IPA were 0.91, 1.00, 1.00, and 0.67, respectively, while those for the diagnosis of MRS infection with MRS-PCR were 1.00, 0.92, 1.00, and 0.50, respectively. Real-time PCR targeting bacterial DNA can detect bacterial DNA in culture-negative cases and offer improved detectability of MRS infection in IPA patients.

Characteristics and Outcomes of Psoas Abscess: Experience From a Tertiary Care Center in North India

Background

Psoas abscess (PA) is an uncommon disease involving infection of the psoas muscle with abscess formation. The evidence concerning clinical and diagnostic characteristics of PA and its outcomes is limited. The literature is heterogenous, with varying presentations and outcomes in different regions worldwide. We present a retrospective analysis of the clinical, radiological, and laboratory characteristics of PA, its management, and outcomes from a tertiary care center in North India.

Methodology

We reviewed the clinical records of confirmed cases of PA treated in our institute from January 2016 to December 2020 with a minimum follow-up of one year. Further, we performed a descriptive analysis of demographic characteristics, clinical features, laboratory parameters, radiological investigations, the basis of diagnosis confirmation, causative microorganisms, definitive management, treatment outcomes, and complications.

Results

We reviewed 33 cases with a mean age of 29.9 ± 16.8 years. Overall, 48.4% of PAs were right-sided, and 24.2% were bilateral. Abdominal discomfort was the most common presenting symptom. Blood laboratory parameters were mostly within the near-normal range except for the elevated erythrocyte sedimentation rate, C-reactive protein, and neutrophil-to-lymphocyte ratio. Ultrasonography was the most commonly performed radiological investigation and was the basis of diagnosis confirmation. Mycobacterium tuberculosis was the most common causative microorganism. Most patients required percutaneous drainage, and around one-fourth required open drainage. All patients had symptomatic as well as radiological improvement and no major complications.

Conclusions

Tuberculosis is the most prevalent cause of PA in the North Indian population. Most patients respond well to the less invasive treatment with percutaneous therapeutic drainage and antitubercular drugs, with few patients requiring open drainage. However, tissue diagnosis may remain inconclusive in a few patients, and antitubercular treatment may need to be initiated based on the clinicoradiological evaluation. Nevertheless, the rate of complications is low, with nil mortality probably related to the mild-to-moderate disease course of tuberculosis.

Risk Factors of Coexisting Septic Spondylitis and Arthritis: A Case-Control Study in a Tertiary Referral Hospital

Introduction: In patients under immunosuppression or severe sepsis, it is sometimes manifested as coexisting septic arthritis and spondylitis. The aim of this study is to evaluate and investigate the risk factors of infectious spondylitis associated with septic arthritis. Methods: The study retrospectively reviewed the patients diagnosed with infectious spondylitis between January 2010 and September 2018 for risk factors of coexisting major joint septic arthritis. Results: A total of 10 patients with infectious spondylitis and coexisting septic arthritis comprised the study group. Fifty matched patients with solely infectious spondylitis were selected as the control group. Major risk factors include preoperative C-reactive protein (p = 0.001), hypoalbuminemia (p = 0.011), history of total joint replacement (p < 0.001), duration of preoperative antibiotics treatment (p = 0.038) and psoas muscle abscess (p < 0.001). Conclusion: Infectious spondylitis and septic arthritis are thought of as medical emergencies due to their high mortality and morbidity. Our study evaluated 5 risk factors as significant major findings: hypoalbuminemia (<3.4 g/dL), higher preoperative CRP (>130 mg/L), psoas muscle abscess, longer preoperative antibiotics treatment (>8 days) and history of total joint replacement. Clinicians should pay attention to the patients with those five factors to detect the coexisting infections as early as possible.

Indication for drainage for a hematogenous iliopsoas abscess: Analysis of patients initially treated without drainage

BACKGROUND

This study aimed to determine the indications for drainage in extended haematogenous iliopsoas abscesses (IPAs), which include both primary and vertebral osteomyelitis-related IPAs.

METHODS

Sixty-three IPA patients who were initially treated with only antibiotics and no drainage were enrolled. The success (S) group included patients who were cured without drainage, while the failure (F) group included those who required open or percutaneous drainage or died.

RESULTS

Compared with patients in the S group, patients in the F group (n = 15) had a higher incidence of end-stage renal disease on hemodialysis, compromised immunity, vertebral osteomyelitis of the cervicothoracic spine, other musculoskeletal infections, and multilocular abscesses. The IPAs in the F group had larger transverse and longitudinal diameters. In receiver operating characteristic curve analyses for the diameter of IPAs, the most valuable cut-off points predicting the F group were a longitudinal diameter of 5.0 cm (sensitivity, 1.0; specificity, 0.67) and a transverse diameter of 2.3 cm (sensitivity, 0.73; specificity, 0.73). A combination of both diameter cut-offs had high specificity (sensitivity, 0.73; specificity, 0.90).

CONCLUSIONS

Drainage should be applied in case of a larger abscess with transverse diameter ≥ 2.3 cm and longitudinal diameter ≥ 5.0 cm. Conversely, IPAs with longitudinal diameter <5 cm do not require drainage. Haemodialysis, compromised immunity, vertebral osteomyelitis of the cervicothoracic spine, and musculoskeletal infections are risk factors of conservative treatment failure.

Bilateral iliopsoas abscess presenting with abdominal wall cellulitis and left-sided empyema thoracis: a rare presentation

Iliopsoas abscess is common in immunocompromised patients and rarely presents with empyema thoracis. We present a 26-year-old male with no comorbidities who presented with a 3-day history of abdominal pain, fever and dyspnoea. There was no history of tuberculosis or recent contact with a tuberculous patient. On examination, the patient had facial dysmorphism and abdominal wall cellulitis extending bilaterally from flank to the inguinoscrotal region. Chest X-ray showed a left pleural effusion. Ultrasonography and contrast-enhanced CT also showed bilateral iliopsoas abscess with a left massive pleural empyema. The patient underwent bilateral abscess open drainage, thoracostomy for left empyema thoracis and intravenous antibiotic therapy. The patient had an uneventful course postoperatively and was discharged.

A Case of Psoas Muscle Abscess With Hematuria, Detected Initially by Point-of-Care Ultrasound in the Emergency Department

BACKGROUND

Psoas muscle abscess (PMA) is a collection of pus in the psoas muscle. It is considered a rare clinical entity and is often misdiagnosed due to highly vague symptoms. We report that point-of-care ultrasound (POCUS) serves as a useful and noninvasive tool for early detection of PMA.

CASE REPORT

Our patient was a 35-year-old man without any past medical illness who visited the emergency department due to right lower back pain and hematuria for 8 months. He denied fever, trauma, or recreational drug use. On arrival, the patient's vital signs were stable and had no fever. Laboratory tests showed white blood cell count 12,800/μL with neutrophil segment 83.2%, C-reactive protein 0.2 mg/dL, and normal renal function. Urine routine showed red blood cells > 100/high-power field. Kidney-ureter-bladder radiograph revealed a positive psoas sign on the right. POCUS showed a mixed echogenic mass adjacent to the right kidney. Subsequently, contrast abdominal computed tomography revealed T10-T11 collapsed vertebral bodies with disc erosion and right psoas muscle abscess at the right kidney level. The patient received open drainage of psoas muscle abscess and T11-T12 laminectomy. He was discharged 13 days post admission. Why ShouldanEmergency PhysicianBe Aware of This? Early and accurate diagnosis of PMA is important because, if left untreated, mortality rate can reach 100%. A potential pitfall in our case is the presence of hematuria with flank pain that could lead to incorrect diagnosis of renal calculi, a much more common condition. This case illustrates the importance of using POCUS in any patient with back or flank pain, with or without hematuria.

Phlegmonous Psoas Muscle Infection Causing Sepsis and Death With Missing Postmortem Computed Tomography Scan Correlation

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.

Chronic active non-lethal human-type tuberculosis in a high royal Bavarian officer of Napoleonic times-a mummy study

In paleopathology, morphological and molecular evidence for infection by mycobacteria of the M. tuberculosis complex (MTC) is frequently associated with early death. In the present report, we describe a multidisciplinary study of a well-preserved mummy from Napoleonic times with a long-standing tuberculous infection by M. tuberculosis senso stricto who died at the age of 88 years of focal and non-MTB related bronchopneumonia. The well-preserved natural mummy of the Royal Bavarian General, Count Heinrich LII Reuss-Köstritz (1763–1851 CE), was extensively investigated by macro- and histomorphology, whole body CT scans and organ radiography, various molecular tissue analyses, including stable isotope analysis and molecular genetic tests. We identified signs for a long-standing, but terminally inactive pulmonary tuberculosis, tuberculous destruction of the second lumbar vertebral body, and a large tuberculous abscess in the right (retroperitoneal) psoas region (a cold abscess). This cold abscess harboured an active tuberculous infection as evidenced by histological and molecular tests. Radiological and histological analysis further revealed extensive arteriosclerosis with (non-obliterating) coronary and significant carotid arteriosclerosis, healthy bone tissue without evidence of age-related osteopenia, evidence for diffuse idiopathic skeletal hyperostosis and mild osteoarthrosis of few joints. This suggests excellent living conditions correlating well with his diet indicated by stable isotope results and literary evidence. Despite the clear evidence of a tuberculous cold abscess with bacterioscopic and molecular proof for a persisting MTC infection of a human-type M. tuberculosis strain, we can exclude the chronic MTC infection as cause of death. The detection of MTC in historic individuals should therefore be interpreted with great caution and include further data, such as their nutritional status.

Psoas abscess during treatment with intravenous tocilizumab in a patient with rheumatoid arthritis: a case-based review

Interleukin-6 receptor antagonist tocilizumab is a biologic drug used for treating patients with active rheumatoid arthritis (RA) who failed to respond to synthetic or other biologic disease-modifying antirheumatic drugs or where they were contraindicated. Interleukin-6 receptor blockade results in a decrease of disease activity but has some potential adverse effects, the most common being infections. We present a case of a 75-year-old female patient with long-lasting RA, several comorbidities and multiple prior therapies, who developed back pain and general malaise during tocilizumab intravenous treatment. The laboratory findings were typical of toxemia, and the imaging findings revealed large psoas muscle abscess. Surgical and antibiotic treatment was performed with a good outcome. To our knowledge, this has been the first case of a psoas abscess in a patient with RA treated with tocilizumab described in the literature so far. We also present a review of the literature regarding infection, and particularly abscess formation in patients treated with biological disease-modifying antirheumatic drugs, tocilizumab included.

Epidemiological features and outcomes of patients with psoas abscess: A retrospective cohort study

Background

Psoas abscess (PA) is an uncommon disease. Although PA is associated with significant morbidity and mortality, its epidemiology and clinical characteristics remain unknown. This study aimed to evaluate the epidemiological and clinical features and outcomes of patients with PA in a prefectural-wide study.

Materials and methods

This was a multicenter retrospective cohort study conducted between 2010 and 2012 in the Miyagi prefecture with a population of 2,344,062 in 2011. Adult patients with PA were enrolled from 71 secondary and tertiary care hospitals.

Results

There were 57 patients with adult PA in the Miyagi prefecture. The median age of the patients was 72 years, and 67% patients were male. Fever and flank pain were the primary symptoms in 82% and 74% of patients, respectively. Ten patients (18%) had septic shock, and the hospital mortality rate was 12%. Secondary PA was present in 72% of cases, and the most common origin was pyogenic spondylitis. Of the patients with secondary PA, 44% had an epidural abscess. The most common pathogens were Staphylococcus aureus, and 11% (6 cases) of the cases were caused by methicillin-resistant S. aureus.

Conclusion

In the Miyagi prefecture of Japan, the estimated prevalence of PA was 1.21/100,000 population years and hospital mortality was 12%. Secondary PA accounted for more than 70% of the cases, and S. aureus was the most common causative pathogen.

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The hospital mortality rate of psoas abscess (PA) was 12% in Japan.

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Estimated prevalence of PA was 1.21/10,000 population years between 2010 and 2012.

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Secondary PA: >70% of cases with the most common origin as pyogenic spondylitis.

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Epidural abscess formed in 44% of patients.

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The most common pathogen was Staphylococcus aureus.

Lumbosacral spondylodiscitis complicated by sepsis, osteomyelitis, epidural abscess formation and deep vein thrombosis

A 71-year-old man presented with a 3-month history of low back pain radiating to his right hip and thigh associated with lower limb weakness and constitutional symptoms. Imaging confirmed a lumbosacral spondylodiscitis at L2-3 and L5-S1 as well as a right-side psoas abscess which was treated with urgent CT-guided drainage and intravenous antibiotics. His admission was complicated by a number of issues, including the development of osteomyelitis with vertebral body destruction at multiple sites, epidural abscess formation and deep vein thrombosis. Additionally, the patient developed severe sepsis which necessitated admission to the intensive care unit. The patient's clinical condition improved gradually with intravenous antibiotics until he was well enough for transfer to a rehabilitation centre, where he underwent regular occupational and physical therapy. Repeat imaging showed overall resolution of the aforementioned pathologies and is currently being followed up by the spinal surgeons on an outpatient basis.

Retroperitoneoscopic Drainage of Psoas Abscess: A Systematic Review

BACKGROUND

Psoas abscess is a relatively rare clinical condition that can occur worldwide, is difficult to diagnose, and has a severe clinical course. Conventional treatment ranges from antibiotic therapy alone to computed tomography (CT)-guided and/or open surgical drainage. Retroperitoneoscopic drainage represents a minimally invasive and potentially definitive therapeutic option.

MATERIALS AND METHODS

A systematic review of the literature on minimally invasive extraperitoneal access for drainage of psoas abscess was conducted through PUBMED, EMBASE, and COCHRANE databases, according to the PRISMA statement guidelines. We considered only studies in English and with a full text. The quality of all selected articles was assessed for the risk of methodological bias. Additional literature sources were used to put into context the indications and limits of retroperitoneoscopic drainage.

RESULTS

Seven papers published between 2004 and 2020, including a total of 56 patients, met the eligibility criteria and were included in the qualitative analysis. Causative agents of psoas abscess included Mycobacterium tuberculosis, Klebsiella pneumoniae, Enterobacter aerogenes, Staphylococcus aureus, and Streptococcus spp. Tuberculous abscess was more common than pyogenic abscess (92.8% vs. 7.2%). Main clinical findings were back pain (76.8%) and fever (53.6%). All patients were preoperatively evaluated by CT or magnetic resonance imaging. Only 4 patients (7.1%) had previously undergone CT-guided percutaneous drainage. Retroperitoneoscopic drainage was combined with antibiotic therapy in all cases. No Clavien-Dindo grade >3 complications occurred, and there was no 30-day postoperative mortality. The recurrence rate was 1.8% at a mean follow-up of 21 months.

CONCLUSION

Retroperitoneoscopic surgical drainage is a safe and effective approach for the treatment of psoas abscess.

Why-not-doing-high-tech-test Syndrome

A 69-year-old man presented with fever, chill, and malaise. A thorough physical examination brought the correct diagnosis of psoas abscess to light. In this case, a physical examination is the only way to correct diagnosis.

Atypical Cause of Sepsis from Bilateral Iliopsoas Abscesses Seeded from Self-mutilation: A Case Report

INTRODUCTION

An iliopsoas abscess (IPA) is an abscess located adjacent to the iliopsoas and iliacus muscles. Although rare, their variable clinical presentations often lead to a delay in diagnosis.

CASE REPORT

We present a case of sepsis secondary to multiple IPAs that was missed despite multiple healthcare encounters. The patient had no classical risk factors for an IPA, and the abscesses were found to be seeded via hematogenous spread from self-inflicted cutting.

CONCLUSION

This case illustrates the importance of obtaining a complete history, including psychiatric screen, and performing a thorough examination when evaluating patients with low back pain to rule out overlooked sources of bacteremia.

Infectious disease consultations and newly diagnosed cancer patients: A single-center retrospective observational study

Noninfectious diseases may be diagnosed during infectious disease (ID) consultations. Among non-IDs, cancer diagnosis is important; however, epidemiological data describing the relationship between ID consultations and newly diagnosed cancer patients are scarce. This study described the frequency and tendency of new cancer diagnoses in patients after ID consultation.This retrospective study included adult inpatients who underwent ID consultations between October 2016 and March 2018. The demographic data and clinical manifestations of each case are described.Among the 380 inpatients who underwent ID consultations, 6 (1.6%) received a new cancer diagnosis after ID consultation. Among the initial most likely diagnoses, 3 patients were diagnosed with IDs and 3 were diagnosed with non-IDs. The initial most likely ID diagnosis was important for new cancer diagnoses (P = .004, odds ratio: 11.1, 95% confidence interval: 2.11-57.2); diagnostic errors, as judged by the physicians, occurred in 2 of the 6 cases.While the frequency of establishing new diagnoses during ID consultations is low, coexisting infection and cancer is possible. ID specialists should identify any patterns related to new cancer diagnosis in patients to prevent diagnostic error and improve the quality of diagnosis.

A Microbiologist's Mexico Trip Ends with Multiple Tiny Ring-Like Pelvic Abscesses

Patient: Female, 22-year-old

Final Diagnosis: Iliacus muscle abscess

Symptoms: Back pain • diarhea • leg weakness

Medication:—

Clinical Procedure: Joint aspiration

Specialty: Infectious Diseases • General and Internal Medicine

Laparoscopic drainage as a minimally invasive treatment for a psoas abscess: A single-center case series and literature review

A psoas abscess is a rare but potentially devastating condition that is associated with risks of neurological deficits, septic shock, and even death. The current first-line treatment is percutaneous catheter drainage (PCD) under imaging guidance, combined with broad-spectrum antibiotics. Surgical drainage should be considered if PCD fails or is impossible.Although many studies on PCD and open surgical drainage have appeared, the outcomes of laparoscopic drainage have rarely been reported. Thus, we laparoscopically drained the psoas abscesses of 6 patients; drainage was complete and we encountered no recurrence or complication. All patients were evaluated by plain radiography, contrast-enhanced computed tomography, and laboratory tests; all were followed-up for 1 year. Laparoscopic drainage is a good treatment option when PCD fails, affording all the advantages of open surgery (complete drainage, resection of infected tissue, and contermporaneous treatment of concomitant lesions). Also, laparoscopic drainage is minimally invasive, requires a smaller incision, and allows rapid recovery.

[Infectious myositis]

Infectious myositis is a rare condition that can be caused by bacteria, viruses, parasites or fungi. Muscle pain or weakness are symptoms shared by all type of myositis. Diagnosis is made on clinical presentation: fever and poor general state is found in bacterial myositis, diffuse muscle pain with flu-like symptoms in viral causes, eosinophilia and a tropical travel history can be related to parasitic etiology, and immunocompromising condition suggests fungal infection. Rhabdomyolysis, leukocytosis and elevated C-reactive protein are common. Imaging (computed tomography or magnetic resonance imaging) can be useful to detect which muscle is affected. The causative organism can be identified on blood cultures, skeletal muscle biopsy, serology or any other pathogen specific test. Treatment depends on the causative organism. Open surgical or imaging-guided drainage is usually necessary in bacterial myositis.

Metastatic infection during Staphylococcus aureus bacteremia

Staphylococcus aureus causes various infections, including skin and soft tissue infections and pneumonia via both, community-associated and nosocomial infection. These infectious diseases can lead to bacteremia, and may subsequently result in metastatic infections in several cases. Metastatic infections are critical complications in patients with S. aureus bacteremia, since the optimal duration of the antimicrobial treatment differs in patients with and without metastatic infection. Notably, two weeks of antimicrobial treatment is recommended in case of uncomplicated S. aureus bacteremia, whereas in patients with S. aureus bacteremia-associated endocarditis or vertebral osteomyelitis, six weeks of antimicrobial administration is vital. In addition, misdiagnosis or insufficient treatment in metastatic infection is associated with poor prognosis, functional disability, and relapse. Although echocardiography is recommended to examine endocarditis in the patients with S. aureus bacteremia, it remains unclear which patients should undergo additional examinations, such as CT and MRI, to detect the presence of other metastatic infections. Clinical studies have revealed that permanent foreign body and persistent bacteremia are predictive factors for metastatic infections, and experimental studies have demonstrated that the virulence factors of S. aureus, such as fnbA and clfA, are associated with endocarditis; however, these factors are not proven to increase the risk of metastatic infections. In this review, we assessed the incidence, predictive factors, diagnosis, and treatment for metastatic infections during S. aureus bacteremia.

Secondary psoas abscess after an open cholecystectomy and a common bile duct exploration

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Psoas abscesses are rare, with a worldwide incidence of only 12 new cases per year.

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Kocher maneuver increases risk of perforation and consequent inoculation of the retroperitoneal space with microorganisms.

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External contamination may occur either through use of contaminated instruments or inadequate asepsis of the surgical area.

Background

A psoas abscess presents a diagnostic challenge, due to its rarity, non-specific clinical manifestations and wide range of etiologies.

Case report

We describe a case of a secondary psoas abscess containing Staphylococus aureus following open cholecystectomy and common bile duct exploration in a woman who had no history or evidence of comorbidity.

Conclusions

Two possible causes of this abscess are performance of the Kocher maneuver during the surgical procedure and external contamination. This case adds cholecystectomy and cholecystitis to the list of known causes of psoas abscesses.

Iliopsoas Abscess in Hemodialysis Patients With End-Stage Kidney Disease

Iliopsoas abscess in HD patients is rare. We examined nine HD patients with iliopsoas abscess (six men and five diabetes mellitus cases) treated between 2005 and 2015. Mean age and dialysis vintage at onset were 72 years and 109 months, respectively. Of the nine patients, four had lumbar orthopedic diseases, and two had all components of the classic triad of iliopsoas abscess at onset. All nine patients underwent percutaneous drainage, while seven underwent antimicrobial therapy. The most common pathogenic bacterium was methicillin-resistantStaphylococcus aureus(MRSA) (n = 5). Four patients had multilocular recurrence on the same side as the initial abscess and did not undergo CT before drainage catheter removal. Five patients died in the hospital, in which three died due to infectious diseases by MRSA. We suggest percutaneous drainage as the first-line therapy for HD patients with iliopsoas abscess and recommend combining antimicrobial therapy for MRSA, because of poor prognosis.

An iliopsoas abscess caused by Parvimonas micra: a case report

BACKGROUND

Parvimonas micra, a Gram-positive anaerobic coccus, is a rare pathogen for psoas abscess. We describe a case of a patient with iliopsoas abscess caused by P. micra.

CASE PRESENTATION

An 81-year-old Asian man presented to our department with complaints of fever since the preceding day. Abdominal computed tomography revealed the presence of a low-density mass in the right iliopsoas muscle indicative of a psoas abscess. Computed tomography-guided percutaneous drainage of the psoas abscess was performed. Results of organism cultures of the abscess and blood were positive for P. micra. However, our patient had no known primary focus of infection. On the basis of these findings, a primary psoas abscess caused by P. micra was diagnosed, and treatment with ampicillin/sulbactam 1.5 g, administered intravenously every 8 h, was initiated. By day 7, the patient's white blood cell count normalized. By day 20, his C-reactive protein level was decreased to 0.35 mg/dl.

CONCLUSION

Iliopsoas abscesses caused by anaerobic bacteria are relatively rare, and iliopsoas abscesses caused by P. micra are especially rare. Our patient's case revealed that P. micra can cause iliopsoas abscess. Therefore, clinicians should be aware of the possibility that P. micra may cause iliopsoas abscess.