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Joined: 24 Mar 2013 01:28
Full Name: Govind Mohan
Name of Your College/Medical School: Madras Medical College


Post by gmohan »

orthostatic hypotension

Orthostatic hypotension (OH) or postural hypotension

occurs when mechanisms for the regulation of orthostatic BP control fails. Such regulation depends on the baroreflexes, normal blood volume, and defenses against excessive venous pooling.
OH is defined as a reduction of systolic BP of at least 20 mm Hg or diastolic blood pressure of at least 10 mm Hg within 3 minutes of standing up (3)

"Classic" postural hypotension occurs within three minutes of standing, "delayed" postural hypotension occurs after three minutes

Orthostatic hypotension (OH) occurs when mechanisms for the regulation of orthostatic BP control fail

such regulation depends on the baroreflexes, normal blood volume, and defenses against excessive venous pooling
there are many causes of OH
aging coupled with diseases such as diabetes and Parkinson's disease results in a prevalence of 10-30% in the elderly (1)
these conditions cause baroreflex failure with resulting combination of OH, supine hypertension, and loss of diurnal variation of BP

20% of community-dwelling adults over 60 years old and one in four people in long term residential care have postural hypotension (2)
about a quarter of patients with diabetes have postural hypotension (2)
High HbA1c, hypertension, and diabetic neuropathy increase its likelihood
third of patients with Parkinson's disease have postural hypotension (2)
Profiling with continuous blood pressure measurements have uncovered four major subtypes (4):

initial orthostatic hypotension
delayed blood pressure recovery
classic orthostatic hypotension
delayed orthostatic hypotension
clinical presentations are varied and range from cognitive slowing with hypotensive unawareness or unexplained falls to classic presyncope and syncope
neurogenic orthostatic hypotension might be the earliest clinical manifestation of Parkinson's disease or related synucleinopathies, and often coincides with supine hypertension
OH is associated with increased risk of (2):

heart failure
coronary heart disease
atrial fibrillation
all-cause mortality
increased risk of cognitive impairment, dementia, and depression
Postural hypotension should be investigated, especially if the patient is symptomatic.

Usually the patient will complain of blackouts and dizzy turns, the result of impaired cerebral perfusion.

Treatment of OH - management and prognosis vary according to the underlying cause, with the main distinction being whether orthostatic hypotension is neurogenic or non-neurogenic

is imperfect since it is impossible to normalize standing BP without generating excessive supine hypertension
practical goal is to improve standing BP so as to minimize symptoms and to improve standing time in order to be able to undertake orthostatic activities of daily living, without excessive supine hypertension.
possible to achieve these goals with a combination of fludrocortisone, a pressor agent (midodrine or droxidopa), supplemented with procedures to improve orthostatic defenses during periods of increased orthostatic stress. Such procedures include water bolus treatment and physical countermaneuvers

a systematic review (13 studies; n=513) concludes evidence about effects of fludrocortisone on blood pressure, orthostatic symptoms or adverse events in those with orthostatic hypotension and diabetes or Parkinson's is very uncertain, with lack of data on long-term treatment in other diseases

G Mohan.
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