What are the symptoms of a psoas abscess?

Symptoms of Psoas Abscess

The classic symptoms of psoas abscess include fever, flank or lower back pain, and limitation of hip movement, though most patients do not present with this complete triad. 1, 2

Clinical Presentation

Common Symptoms

• Pain:

  • Localized pain in the flank or lower back area (most common symptom) 1, 2
  • Hip pain with possible radiation to the thigh 2
  • Pain worsens with hip extension (psoas sign) 2

• Systemic Manifestations:

  • Fever and chills (present in majority of cases) 1, 2
  • Malaise and weight loss 3
  • Leukocytosis (most common laboratory finding) 2

• Physical Examination Findings:

  • Palpable mass in the lower abdomen or inguinal area 2
  • Limited hip movement with flexion contracture 3
  • Tenderness at the costovertebral angle 4
  • Limp or antalgic gait 2

Severity Indicators

• Septic shock (seen in severe cases) 2, 5
• Diffuse cellulitis 6
• Systemic inflammatory response syndrome 6

Diagnostic Challenges

• Subacute Presentation:

  • Symptoms often present for >7 days before diagnosis 1
  • Only 1 in 11 patients presented with the classic triad of fever, flank pain, and limited hip movement in one study 2

• Varied Clinical Picture:

  • Symptoms may be nonspecific and mimic other conditions 2, 7
  • In some cases, psoas abscess may be the first indication of underlying disease (e.g., Crohn's disease) with absent gastrointestinal symptoms 3

Primary vs. Secondary Psoas Abscess

Primary Abscess

• No definite etiology, spread hematogenously from distant occult site 7
• Staphylococcus aureus is the most common pathogen 1, 2

Secondary Abscess

• Associated with underlying conditions:
  • Spondylodiscitis and pyelonephritis (most common) 1
  • Crohn's disease 3
  • Appendicitis or diverticulitis 7
  • Colon neoplasms 5
  • Osteomyelitis 5

Diagnostic Approach

• CT scan is the gold standard for diagnosis 1, 2, 5
• Ultrasound may show negative findings initially in some cases 2
• MRI provides better soft tissue definition in complex cases 6
• Laboratory findings typically include leukocytosis and elevated inflammatory markers (ESR, CRP) 6, 2
• Blood cultures may be positive in up to 28% of cases 6

Clinical Pearls

• High clinical suspicion is crucial for early diagnosis due to nonspecific presentation 2
• Delayed diagnosis can lead to septic shock and increased mortality 5
• Consider psoas abscess in patients with unexplained fever, back/flank pain, and hip movement limitations, especially with risk factors for secondary abscess 2, 3

Prompt recognition of these symptoms and appropriate imaging can lead to earlier diagnosis, proper drainage (surgical or percutaneous), appropriate antibiotic therapy, and improved outcomes in patients with psoas abscess.