Differential Diagnosis for a 91 Year Old Female Patient with Episodes of Tachycardia
The patient's symptoms of waking up in the middle of the night with a racing heart could be attributed to various causes. Here's a categorized differential diagnosis:
Single Most Likely Diagnosis
- Plavix-induced Orthostatic Hypotension: The patient was recently started on Plavix (clopidogrel), which can cause orthostatic hypotension, especially in the elderly. This could lead to reflex tachycardia, particularly when changing positions at night. The fact that her heart rate returns to normal within an hour without intervention supports this possibility.
Other Likely Diagnoses
- Nocturnal Hypoglycemia: Although not mentioned, if the patient is diabetic or on medications that can cause hypoglycemia, nocturnal hypoglycemia could lead to tachycardia and other symptoms.
- Anxiety or Stress: Episodes of anxiety or stress, possibly related to the recent stent placement, could cause the patient to wake up with a racing heart.
- Sleep Apnea: This condition is common in the elderly and can cause nocturnal awakenings with tachycardia due to transient hypoxia.
- Dehydration or Electrolyte Imbalance: Dehydration or electrolyte imbalances, such as hypokalemia or hypomagnesemia, can cause tachycardia, especially in elderly patients.
Do Not Miss Diagnoses
- Myocardial Ischemia or Infarction: Although the patient recently had a stent placed, it's crucial not to miss the possibility of myocardial ischemia or infarction, especially given her history of arterial clot.
- Pulmonary Embolism: This is a life-threatening condition that could present with tachycardia and nocturnal awakenings.
- Cardiac Arrhythmias (e.g., Atrial Fibrillation): Certain arrhythmias could cause episodes of tachycardia, and it's essential to rule out these conditions.
Rare Diagnoses
- Pheochromocytoma: A rare tumor that can cause episodic tachycardia and hypertension.
- Thyroid Storm: Although rare, thyroid storm can cause tachycardia, among other symptoms, and is more common in elderly patients with untreated or undertreated hyperthyroidism.
- Catecholamine-producing Tumors: Other rare tumors, such as paragangliomas, can cause episodic tachycardia due to excessive catecholamine production.