Psoas abscess

Background

• Psoas muscle is susceptible to infection from distant sites due to rich blood supply, proximity to overlying retroperitoneal lymphatic channels
• S. aureus is most common pathogen (80%)

Clinical Features

• Abdominal pain radiating to hip, flank
• Pain with thigh flexion (esp against resistance)
• Limp
• Fever
• Nausea

Differential Diagnosis

Hip pain

• Femur fracture
• Hip dislocation
• Hip bursitis
• Psoas abscess
• Piriformis syndrome
• Meralgia paresthetica
• Septic Arthritis (Hip)
• Obturator nerve entrapment
• Pelvic fractures
  • Acetabular pelvic fractures
  • Open book pelvic fracture
  • Straddle pelvic fracture
  • Pelvic avulsion fracture
• Avascular necrosis of hip

RLQ Pain

• Appendicitis
• Abdominal aortic aneurysm
• Crohn's disease (terminal ileitis)
• Diverticulitis (cecal, Asian patients)
• Ectopic
• Endometriosis
• Epiploic appendagitis
• Herpes zoster
• Inguinal hernia
• Ischemic colitis
• Meckel's diverticulum
• Mesenteric lymphadenitis
• Mittelschmerz
• Ovarian cyst
• Ovarian torsion
• PID
• Psoas abscess
• Testicular torsion
• Kidney stone
• Neutropenic enterocolitis (typhlitis)

LLQ Pain

• Diverticulitis
• Kidney stone
• UTI
• Pyelonephritis
• Ectopic Pregnancy
• Infectious colitis
• Inflammatory bowel disease (Crohn's Disease, Ulcerative Colitis)
• Inguinal Hernia
• Mesenteric Ischemia
• Epiploic appendagitis
• Mittelschmerz
• Ovarian cyst
• Ovarian torsion
• PID
• Psoas abscess
• Testicular torsion
• Appendicitis
• Abdominal aortic aneurysm
• Herpes zoster
• Endometriosis
• Colon cancer
• Irritable bowel syndrome
• Small bowel obstruction

Evaluation

• CT is imaging study of choice

Management

• Antibiotics
  • Vancomycin +
  • One of the following
    • Piperacillin/tazobactam 3.375g, OR
    • Ceftriaxone + Metronidazole
• Surgical consultation

See Also

• Abdominal Pain

References

Authors

Jordan Swartz, Ross Donaldson, Daniel Ostermayer, Neil Young