Differential Diagnosis

The patient's complaint of a persistent heart rate over 100 since the age of 10 suggests a chronic condition. Here's a differential diagnosis organized into categories:

• Single Most Likely Diagnosis

  • Hyperthyroidism: This condition, characterized by an overproduction of thyroid hormones, can lead to an increased heart rate, among other symptoms. The long-standing nature of the patient's symptoms makes this a plausible diagnosis, as hyperthyroidism can present at any age and persist if untreated.

• Other Likely Diagnoses

  • Anxiety Disorder: Despite the patient's denial, anxiety can cause a persistent increase in heart rate, especially if the anxiety is chronic. It's essential to consider this diagnosis, as anxiety disorders can manifest at a young age and persist into adulthood.
  • Chronic Stress: Similar to anxiety, chronic stress can lead to a sustained increase in heart rate due to the body's ongoing "fight or flight" response.
  • Deconditioning or Poor Physical Conditioning: A sedentary lifestyle or lack of physical fitness can result in an elevated resting heart rate.

• Do Not Miss Diagnoses

  • Pheochromocytoma: A rare tumor of the adrenal gland that produces excess adrenaline, leading to high blood pressure, rapid heart rate, and other symptoms. Although uncommon, missing this diagnosis could be fatal due to the risk of hypertensive crises.
  • Thyrotoxic Crisis: A life-threatening complication of untreated or undertreated hyperthyroidism, characterized by an extreme exacerbation of hyperthyroid symptoms, including a very rapid heart rate.
  • Cardiac Conditions (e.g., Hypertrophic Cardiomyopathy, Arrhythmias): Certain heart conditions can cause an elevated heart rate and are critical to diagnose due to their potential impact on the patient's quality of life and survival.

• Rare Diagnoses

  • Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT): A rare genetic disorder that affects the heart's rhythm, potentially causing an elevated heart rate and increased risk of sudden cardiac death.
  • Familial Dysautonomia (Riley-Day Syndrome): A rare genetic disorder that affects the development of the autonomic nervous system, potentially leading to various symptoms, including an abnormal heart rate.
  • Other Rare Endocrine Disorders: Such as multiple endocrine neoplasia type 2 (MEN2), which can include pheochromocytoma and hyperthyroidism among its manifestations.