What is the treatment for rigors?

Management of Rigors

For patients experiencing rigors, prompt treatment with antipyretics, NSAIDs, and opioid medications is recommended as first-line therapy to alleviate symptoms and prevent complications. 1

Definition and Causes

• Rigors are intense shivering episodes often accompanied by fever, chills, and autonomic symptoms that commonly occur in infectious conditions but can also be medication-induced 2
• Common causes include bacteremia, cholangitis, protozoan infections, viral infections, and reactions to medications such as amphotericin B or IL-2 therapy 2, 3, 1
• Rigors may be an early sign of sepsis, especially when accompanied by fever and hypotension 4

First-Line Management

• Antipyretics:

  • Acetaminophen 650 mg PO every 4 hours scheduled when fever exceeds 100.5°F (38°C) 1

• NSAIDs:

  • Indomethacin 50-75 mg every 6 hours (discontinue if serum creatinine >2 mg/dL, decreased urine output, or platelets <50,000) 1

• Opioid medications for severe rigors:

  • Meperidine 25 mg IV with option to repeat another dose within 30 minutes as needed (25-50 mg IV every 4 hours PRN) 1
  • Hydromorphone 0.5 mg IV every 15 minutes as needed, may repeat up to 3 total doses 1

Additional Supportive Measures

• Ensure adequate hydration with IV fluids if hypotension develops 1
• For hypotension not responding to initial fluid boluses (250-500 mL), consider:
  • Additional fluid boluses 1
  • In severe cases with persistent hypotension, vasopressors may be considered 1
• Monitor oxygen saturation and provide supplemental oxygen if saturation falls below 92% 1

Special Considerations

• For medication-induced rigors:

  • Dantrolene sodium can be considered for severe amphotericin B-induced rigors refractory to conventional measures 3
  • For IL-2 therapy-induced rigors, preparation should be made beforehand so intervention is possible in a timely fashion 1

• For infection-related rigors:

  • Obtain appropriate cultures (blood, urine, etc.) before starting antibiotics 1
  • Initiate empiric antibiotics promptly if infection is suspected, particularly in cases with fever and hypotension 1, 4
  • For suspected acute bacterial cholangitis with rigors, antibiotics and subsequent biliary decompression if an underlying stricture is present are strongly recommended 1

Monitoring and Follow-up

• Monitor vital signs, particularly temperature, blood pressure, and oxygen saturation 1
• Assess for signs of end-organ damage or deterioration 1
• Evaluate for potential complications such as hypotension, decreased urine output, or respiratory distress 1
• In elderly patients with rigors and altered mental status, consider additional evaluation for delirium and its underlying causes 5

Pitfalls and Caveats

• Rigors alone do not cause increases in muscle or liver enzymes; such changes are associated with the underlying cause 2
• Do not mistake a Jarisch-Herxheimer reaction (which can present with rigors, fever, and hypotension following antibiotic treatment for spirochete infections) for septic shock 4
• Constitutional symptoms like fever, chills, and rigors are poorly sensitive for conditions like septic arthritis and should not be used to rule out serious infections 6
• In immunocompromised patients, rigors may signal serious infections requiring prompt evaluation and treatment 1