Differential Diagnosis
Based on the provided symptoms and medical history, the following differential diagnoses are considered:
- Single most likely diagnosis
- Postural Orthostatic Tachycardia Syndrome (POTS): The patient's symptoms of dizziness, lightheadedness, and tachycardia upon standing, as well as a significant drop in blood pressure, are consistent with POTS. The patient's history of similar symptoms since childhood and the absence of other underlying conditions also support this diagnosis.
- Other Likely diagnoses
- Orthostatic Intolerance: The patient's symptoms of dizziness, lightheadedness, and weakness upon standing are consistent with orthostatic intolerance, which can be a feature of various conditions, including POTS, dehydration, and autonomic dysfunction.
- Anxiety Disorder: The patient's symptoms of shaking, tremors, and nausea in response to emotional stimuli, such as anxiety or stress, suggest an underlying anxiety disorder, which can contribute to or exacerbate orthostatic symptoms.
- Autonomic Dysfunction: The patient's symptoms of orthostatic intolerance, tremors, and nausea suggest autonomic dysfunction, which can be a feature of various conditions, including POTS, anxiety disorders, and other neurologic or systemic diseases.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Cardiac Arrhythmia: Although the patient's symptoms are more consistent with POTS or orthostatic intolerance, cardiac arrhythmias, such as supraventricular tachycardia or ventricular tachycardia, can cause similar symptoms and must be ruled out.
- Neurocardiogenic Syncope: The patient's history of presyncope and near-syncope episodes suggests neurocardiogenic syncope, which can be a feature of various conditions, including POTS, orthostatic intolerance, and cardiac arrhythmias.
- Adrenal Insufficiency: Although the patient's symptoms are not typical of adrenal insufficiency, this condition can cause orthostatic hypotension, tachycardia, and other symptoms that must be considered in the differential diagnosis.
- Rare diagnoses
- Dysautonomia: The patient's symptoms of orthostatic intolerance, tremors, and nausea suggest dysautonomia, a rare condition characterized by autonomic dysfunction.
- Mitochondrial Disease: The patient's symptoms of orthostatic intolerance, tremors, and nausea, as well as their history of similar symptoms since childhood, suggest mitochondrial disease, a rare condition characterized by defects in mitochondrial function.
- Ehlers-Danlos Syndrome (EDS) variant: Although the patient has been diagnosed with Hypermobile EDS (HEDS), other variants of EDS, such as vascular EDS, can cause similar symptoms and must be considered in the differential diagnosis.