Estimating the Frequency and Neuro-Hormonal Characteristics of Acute Hepatic Porphyria in Postural Tachycardia Syndrome
Postural Tachycardia Syndrome (POTS) is the most common autonomic disorder and is estimated to affect 3,000,000 individuals in the United States, with 80-85% of patients being women. The condition is characterized by a rapid increase in heart rate (HR) that occurs on standing, and chronic symptoms of cerebral hypoperfusion leading to lightheadedness, dizziness, and blurred vision. The acute hepatic porphyrias(AHP)are among the diseases that present with autonomic cardiovascular(tachycardia)and neurovisceral symptoms (abdominal pain) among others; they present with acute exacerbations Given that there is available treatment for AHP that change the natural progression of the disease, study focuses to investigate the occurrence of AHP in POTS and determine the clinical and neuro-hormonal characteristic of the POTS subgroup that will likely benefit from AHP screening. This study has one visit that involves, answering some questionnaires, coming to the lab for blood work, genetic testing, and some autonomic function tests. About 50 people will take part in this study.
⁃ Age 18 - 65 years
⁃ Individuals having an established diagnosis of POTS defined as the presence of presyncopal symptoms for more than 6 months and orthostatic tachycardia (>30 bpm increase in HR within 10 min after assuming upright position)
⁃ The present of one of the following criteria:
• 1 Family history of acute hepatic porphyria 3.2 Unexplained recurrent (more than one), prolonged (>24 hours) episode of severe, diffuse (poorly localized) abdominal pain AND at least TWO of the following:
⁃ Red to brownish urine.
⁃ Blistering skin lesions on sun-exposed areas.
⁃ Peripheral nervous system manifestations occurring around the time of abdominal pain (i.e., motor neuropathy (paresis), sensory neuropathy (numbness, tingling, limb pain).
⁃ Central nervous system manifestations occurring around the time of abdominal pain (i.e. confusion, anxiety, seizures, hallucinations).
⁃ Autonomic nervous system manifestations occurring around the time of abdominal pain (i.e. hyponatremia(Na<lower limit of normal)), tachycardia, hypertension, nausea and vomiting, constipation).