Orthostatic hypotension (also known as postural hypotension), is said to exist when there si a fall of 20mms systolic or 10mms diastolic blood pressure for at least 3 minutes, in standing position in a symptomatic patient. This is to be distinguished from sluggish baro-receptor response in may elderly individuals lasting for a few seconds to a minute. The cause is autonomic dysfunction.
The usual causes are Neuropathies (especially in diabetic), parkinson’s disease, tabes, multiple cerebral infarcts, vascular lesions involving mid brain and hypothalamus.
Many drugs in common use can use cause orthostatic hypotension including hypotensives (diuretics, sympatholytics) anti-depressants 9amitryptalline, imipramine), and anxilolytics (chlorpromazine, thoriadazine). Elderly patients are the most affected.
The resultant clinical features include light-headedness, dizziness, and syncope. In the presence of associated lesion of the parasympathetic system, these symptoms are not apparent immediately and the patient continues to stand leading to profound weakness, breathlessness, heavingess of legs, confusion and staggering, and incontinence.
The symptoms occur most classically in the morning on getting off bed. Food, alcohol, exercise, hot environment, anemia, diarrhea and poor nutritional state worsen symptoms.
Treatment
Treat specific etiology if present. Stop, lower the dosage or change offending medicaton. For example, prefer calcium channel blockers, beta blockers, and Ace inhibitors for hypetension, desipramine or nortryptaline for depression, Haloperidol or Fluphenazine for anxiety
Increasing salt intake – extra salt in cooking and more consumption of salted drinks like buttermilk, and salty snacks. Enteric coated salt tablets for those with poor food intake (salt intake can be increased to 10gms a day)
Head tit up when sleeping by 6-10 inches, by placing bricks under legs of the cot at the head end.
Pre-standing and standing exercises like isometric exercise of upper extremities, plantar dorsi-flexion of legs, and abdominal tensing.
NSAIDs like indomethacin, ibuprofen, that act by increasing plasma volume, and reducing circulating vasodilating prostaglanding.
Fludrocortisone acetate that acts by sodium retention (starting with 0.1mg daily and increasing on weekly basis up to 0.5mg bid). Adequate salt intake continues to be part of therapy. This drug can lead to hypokalemia, dependent edema, and congestive failure.
Education of patient – When getting up in the morning, to rise slowly from supine to sitting, and then to stand up after a few minutes. Dim lighting of bed rooms, bedside urine bottle, and bedside commode are useful additions
