Title : Psoas abscess due to group B streptococcus presenting as diabetic ketoacidosis
Abstract:
Introduction: Psoas abscess is an uncommon infection that typically presents with fever and back pain. The most frequently identified pathogen is Staphylococcus aureus. We present a diabetic patient presenting with Diabetic Ketoacidosis (DKA) due to a Streptococcus agalactiae psoas abscess.
Case: A 60-year-old male with a past medical history of type 2 diabetes mellitus presented to the hospital with a chief complaint of right-sided back and leg pain. He also reported polyuria and polydipsia but denied any fevers or chills. He also reported abdominal pain and a 30-pound weight loss over the last month. On presentation, his physical exam revealed no abdominal tenderness but some weakness in the right leg. He was found to be in DKA and started on insulin and IV fluid infusion but his DKA failed to resolve despite appropriate treatment. A CT of the abdomen and pelvis was performed and revealed a 4.5 x 4.7 cm right psoas muscle abscess and an adjacent 5.2 x 2.5 cm right inferior posterior pararenal abscess with concurrent right hydronephrosis. A urine culture revealed mixed urogenital flora with 5,000-10,000 CFU of S. agalactiae and he was started on ceftriaxone and metronidazole. Percutaneous drainage of the abscess also grew S. agalactiae. His symptoms and DKA resolved following these interventions and he was later discharged on oral cephalexin for 8 weeks with plans to have repeat imaging as an outpatient.
Discussion: Psoas abscesses typically occur either through hematogenous spread from another infection site or direct spread from another closely located structure such as in vertebral osteomyelitis, diverticulitis, appendicitis, and pyelonephritis. Signs and symptoms can often be nonspecific and include fevers as well as abdominal, back, and leg pain. As with our patient, the lack of specific symptoms may delay the diagnosis. As always in patients presenting with DKA, underlying infection should be ruled out. Streptococcus agalactiae is an uncommon pathogen, causing 1% of psoas abscesses but invasive group B streptococcus infections are increased among diabetics. Clinicians should consider appropriate imaging in patients with back pain and an increased suspicion of underlying infection such as in patients presenting with DKA.
Audience Take Away Notes
- Provide an example of an atypical presentation of infection which was not diagnosed initially at presentation and how to recognize similar cases
- Explore the common pathogens, presentations, and sequelae of psoas abscesses including potential spread to nearby structures and the importance of timely diagnose due to morbidity and mortality
- Discuss how a symptoms of leg pain can be a sign of numerous intra-abdominal pathologies and infections
- Discuss the value and significance of the Psoas Sign on a physical examination, and how it can be used as a sign of not just appendicitis
