Chapter 1
Chapter 1
A sixty-eight-year-old man presents with a complaint of lightheadedness on standing that is worse after meals and in hot environments. Symptoms started about four years ago and have slowly progressed to the point that he is disabled. He has fainted several times, but always recovers consciousness almost as soon as he falls. Review of symptoms reveals slight worsening of constipation, urinary retention out of proportion to prostate size, and decreased sweating. He is otherwise healthy with no history of hypertension, diabetes, or Parkinson's disease. Because of his urinary retention, he was placed on the alpha one antagonist tamsulosin but he could not tolerate it because of worsening of orthostatic hypotension. Physical examination revealed a blood pressure of one hundred sixty-seven over eighty-four millimeters of mercury supine and one hundred six over fifty-five millimeters of mercury standing. There was an inadequate compensatory increase in heart rate (from eighty-four to eighty-eight beats per minute), considering the degree of orthostatic hypotension. Physical examination is otherwise unremarkable with no evidence of peripheral neuropathy or parkinsonian features. Laboratory examinations are negative except for plasma norepinephrine, which is low at ninety-eight picograms per milliliter (normal is two hundred fifty to four hundred picograms per milliliter for his age). A diagnosis of pure autonomic failure is made, based on the clinical picture and the absence of drugs that could induce orthostatic hypotension and diseases commonly associated with autonomic neuropathy. What precautions should this patient observe in using sympathomimetic drugs? Can such drugs be used in his treatment?
One. What is pure autonomic failure?
One. What is pure autonomic failure?
Pure autonomic failure is a rare, neurodegenerative disorder of the peripheral autonomic nervous system characterized primarily by a severe drop in blood pressure when standing up.