Differential Diagnosis for Respiratory Distress, Bradycardia, and SVT after IVIG in Myasthenia Gravis Patient

• Single Most Likely Diagnosis
  • Anaphylactic Reaction to IVIG: This is a common adverse reaction to IVIG, which can cause respiratory distress, cardiovascular instability (including bradycardia and tachycardia), and can be life-threatening if not promptly treated.
• Other Likely Diagnoses
  • Thromboembolic Event: IVIG can increase blood viscosity, potentially leading to thromboembolic events such as pulmonary embolism, which can cause respiratory distress and cardiac arrhythmias.
  • Fluid Overload: Rapid infusion of IVIG can lead to fluid overload, especially in patients with pre-existing heart conditions, causing respiratory distress and potentially leading to arrhythmias.
  • Acute Hemolysis: Although rare, IVIG can cause hemolysis, leading to acute kidney injury, which might indirectly cause fluid overload and electrolyte imbalances contributing to arrhythmias.
• Do Not Miss Diagnoses
  • Cardiac Ischemia: Myocardial infarction or ischemia can present with arrhythmias and should be considered, especially if the patient has risk factors for coronary artery disease.
  • Pulmonary Embolism: As mentioned, this is a critical diagnosis to consider due to its high mortality if untreated.
  • Sepsis: Although less likely, sepsis can cause a wide range of symptoms including respiratory distress and arrhythmias, and is critical to identify and treat promptly.
• Rare Diagnoses
  • Aseptic Meningitis: A rare side effect of IVIG, which could potentially cause respiratory and cardiac symptoms indirectly through increased intracranial pressure or systemic inflammation.
  • Renal Failure: IVIG can cause or exacerbate renal failure, potentially leading to fluid overload, electrolyte imbalances, and subsequent arrhythmias.
  • Transfusion-Related Acute Lung Injury (TRALI): Although more commonly associated with blood transfusions, TRALI is a rare but potentially life-threatening complication that could occur with IVIG, causing respiratory distress.