Failure to Identify Thyroid Storm Results in Neurological Deficits

Case Summary

This case involves a 50-year-old male with no pertinent past medical history who experienced a syncopal event whilst running for the bus. Upon admission to the ER, he was found to be in Afib with rapid ventricular response. Lab studies were notable for hyperthyroidism and thyrotoxicosis. The consulted cardiologist suggested likely thyroid etiology as the cause of arrhythmia and recommended a referral to endocrinology. Under the care of hospital practitioners, antithyroid medications were prescribed. The patient was cardioverted although he remained in Afib. Approximately 7 days later a brain MRI noted a stroke which left the patient with severe neurological deficits. He was eventually diagnosed with thyroid storm.

Case Theory

The most common cardiac complication of hyperthyroidism is atrial fibrillation (Afib), affecting approximately 15% of patients. The cause of Afib is an abnormality of the electrical system of the heart characterized by an irregular heartbeat resulting from the two upper heart chambers not contracting properly. Atrial fibrillation with rapid ventricular response (RVR) is one of the most dangerous forms of arrhythmias that significantly increases an individual’s chances of having a heart attack, stroke, and irreversible organ damage. This critical condition can often be found as an exaggerated presentation of thyroid storm (thyrotoxicosis). A thyroid storm is a life-threatening complication of hyperthyroidism that involves multiple systems. Most of these patients require oral anticoagulation to prevent thromboembolic complications. In co-existing Afib with thyroid storm, the risk of cardiac and neurological events is high. Thyroid storm is estimated to have a mortality rate of up to 25% despite advances in treatment and supportive measures. Therefore, early recognition and aggressive resolution of the condition is critical. Thyroid storm coexisting with ischemic stroke increases mortality risk. Hemodynamic management of the disease is required to prevent mortality and morbidity. Hyperthyroidism and the thyroid storm are well-known causes of atrial fibrillation with RVR with up to 60% of patients presenting with symptoms of Afib. This makes it crucial for practitioners to know the symptoms of both conditions to reduce complications and mortality. Treatment relies on both appropriate anticoagulation and thyrotoxicosis management. When these conditions co-exist, adjustments in care management are key factors in survival. In this case, the failure to diagnose and properly treat both the thyroid storm and the co-existing Afib with RVR resulted in a poor outcome and neurological deficit in this patient.

Expert Witness Specialty/Specialties

Expert Specialty: Cardiology. An expert in cardiology with experience in cardio conversion and Afib is required in this case.

Expert Subspecialty: a subspecialty in cardiac electrophysiology is an appropriate expert for this case.

Questions for the Expert Witness

1. How is a thyroid storm diagnosed?
2. How is Afib with RVR due to thyroid storm treated?
3. How may a delay in treatment of thyroid storm impact an adverse outcome with the treatment of Afib?
4. What is the significance of thrombotic risk of hyperthyroid patients with atrial fibrillation with RVR?
5. What are the steps for management of thyrotoxic atrial fibrillation with RVR?

Expert Witness Involvement

An expert in cardiology with experience in electrophysiology can opine on the treatment of critically ill patients with hyperthyroidism and coexisting Afib with RVR. This expert can address the importance of anticoagulation, cardio conversion, stroke prevention, and the significance of hemodynamic stability in a similar, critically ill patient.