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%)

DDX

RLQ Pain

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

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

Diagnosis

Clinical Features

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

Workup

• CT is imaging study of choice

Treatment

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

See Also

• Abdominal Pain

Source

• Tintinalli