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Abdominal Muscle Wall Pain

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Abdominal Muscle Wall Pain, Abdominal Wall Pain, Abdominal Wall Injury

  • Pathophysiology
  1. Abdominal Wall Muscles injured with direct Trauma
    1. Rectus Abdominis Muscle
    2. Rectus sheath hematoma
  2. Abdominal Wall Muscles Injured Indirectly (e.g. foreceful contraction or twisting)
    1. Internal Oblique Muscle
    2. External Oblique Muscle
    3. Transversus Abdominis Muscle
  • Symptoms
  1. Constant pain or fluctuating pain that is well localized
  2. Provocative maneuvers
    1. Posture changes and movement
    2. Worse with lifting, bending, straining
    3. Worse with flexing forward or rotating
    4. Abdominal Pain not related to bowel function
    5. Abdominal Pain not related to meals
  3. History of predisposing factors of Abdominal Wall Pain
    1. History of abdominal surgery, Abdominal Injury or Trauma
    2. History of Thoracolumbar back pain
    3. Diabetes Mellitus
    4. Obesity
  4. Discrete, small, coin size pain Trigger Point (can be localized with a finger)
    1. Lateral margins of rectus abdominis muscles
    2. Muscle or fascia attachments tender
  5. No symptoms suggestive of intra-abdominal process
    1. No Nausea or Vomiting
    2. No Diarrhea or Constipation
    3. No weight loss
    4. No fever
    5. No Rectal Bleeding or Anemia
    6. No urinary tract symptoms (Dysuria, urgency, Urinary Frequency)
  • Signs
  1. Carnett's Sign positive
  2. No signs suggestive of intra-abdominal source of pain
  3. Focal swelling or Ecchymosis may suggest rectus sheath hematoma
  • Labs
  1. Normal heparic enzymes
  2. Normal Urinalysis
  3. Normal inflammatory labs
    1. White Blood Cell Count (WBC) normal
    2. Erythrocyte Sedimentation Rate (ESR) normal
    3. C-Reactive Protein (CRP) normal
  1. Findings
    1. Abdominal Wall Mass
    2. Abdominal Wall Abscess
    3. Abdominal Wall Edema
    4. Abdominal Wall Hematoma (or rectus hematoma)
    5. Slipping Rib Syndrome
    6. Abdominal Wall Hernia
  2. Other indications
    1. Guidance for abdominal wall Trigger Point Injection
  1. Indicated in cases where intraabdominal injury cannot be excluded
  2. CT may demonstrate rectus sheath hematoma
  • Approach
  • Step 1 Evaluate for Visceral Pain
  1. See Acute Abdominal Pain
  2. Evaluate Carnett's Sign
    1. Positive (pain not improved with tensing Abdomen)
      1. Go to Step 2 below (Abdominal Wall Pain)
    2. Negative (Pain improves with tensing abdominal wall)
      1. See Acute Abdominal Pain
  • Approach
  • Step 2 Evaluate for Hernia
  1. If no scar or obvious Hernia, go to step 3
  2. Hernia palpable on exam
    1. Surgery Consultation
  3. Non-palpable Hernia suspected at scar
    1. No relief with Trigger Point Injection
    2. Consider imaging studies
    3. Consider surgery Consultation
  • Approach
  • Step 3 Musculoskeletal Cause
  1. Spinal movement increases pain
    1. Suspect intercostal nerve root irritation
  2. Anatomically localized pain
    1. Evaluate for abdominal wall Hernia, Inguinal Hernia or Femoral Hernia
    2. Evaluate for slipping rib syndrome (costal margin pain)
    3. Evaluate for cutaneous nerve entrapment
      1. Ilioinguinal Nerve Entrapment (groin incision pain)
      2. Anterior cutaneous nerve entrapment (lateral rectus muscle pain)
  3. Rectus abdominis pain
    1. Evaluate for Rectus sheath hematoma
    2. Evaluate for Myofascial pain
    3. Evaluate for Sports Hernia
  1. Local Trigger Point Injection indications
    1. Focal musculoskeletal cause (e.g. cutaneous nerve entrapment)
  2. Technique
    1. Lidocaine 1% or Bupivicaine 0.25% 5-10 ml injected into abdominal wall fascia or muscle
    2. Consider under Ultrasound guidance
    3. Added Corticosteroid may be considered
      1. Triamcinolone 10 mg
      2. Betamethasone 3-4 mg
      3. Methylprednisolone 40 mg
  • Management
  • Additional Measures
  1. Physical Therapy
  2. Massage
  3. Spray and Stretch
  4. Avoid provocative activities
    1. Avoid flexing, rotating or Stretching abdominal wall
  5. Systemic Medications
    1. See Chronic Pain Management
    2. Oral Analgesics (e.g. NSAIDS)
    3. Tricyclic Antidepressant
    4. Muscle relaxants
    5. Antispasmodics
  6. Local approaches for refractory pain
    1. First-line measures
      1. Local Trigger Point Injection with Corticosteroid (as above)
    2. Second-line measures
      1. Local injection of Onabotulinumtoxin A (Botox)
      2. Plane block (transversus abdominis, rectus sheath)
      3. Chemical neurolysis with phenol
      4. Radiofrequency denervation
    3. Third-line measures (refractory to above)
      1. Surgical neurectomy (surgical removal of entrapped nerve)
  7. Large rectus sheath hematomas
    1. Consult surgery
    2. Surgical drainage may be indicated
    3. Epigastric artery ligation may be indicated if continued blood accumulation