[Orthostatic hypotension: 2nd part. Epidemiology, complications and treatments]. / L'hypotension orthostatique: 2ème partie. Epidémiologie, complications et traitements.

Orthostatic hypotension (OH) is a rather common phenomenon in clinical practice. It may occur in 5-10 % of normal individuals, but its prevalence increases with age and various pathologies, so that it may rise above 35 % in certain subgroups of patients. OH is associated with various comorbidities, in particular cardio-cerebro-vascular accidents and falls (especially in the elderly), and may even increase mortality. It is, however, difficult to determine whether OH is simply a marker of frailty or whether it is really a risk factor. OH treatment involves physical manoeuvres or medications, which aim at inducing a peripheral vasoconstriction (midodrine, etilefrine) or an increase of circulating blood volume (9-alpha-fluohydrocortisone). However, their use should be cautious, because of a risk of arterial hypertension in supine position.

[Orthostatic hypotension: definition, symptoms, assessment and pathophysiology]. / L'Hypotension orthostatique: 1ère partie: definition, symptomatologie, évaluation et physiopathologie.

Orthostatic hypotension (OH) is defined by a drop in arterial blood pressure (BP) of at least 20 mmHg for systolic BP and 10 mmHg for diastolic BP after standing. Symptoms are generally quite typical, but may also be rather vague. Diagnosis may be easily made by the physician in his/ her office, and confirmed, if necessary, by more sophisticated measurements. Pathophysiology is generally rather complex, but mostly involves a defect in the autonomic nervous system, in its sympathetic component. Failure of peripheral vasoconstriction seems to play a more important role than the defect in reflex tachycardia. Causes of OH are multiples. OH may occur in healthy subjects, when exposed to exceptional circumstances, but is more generally associated with various diseases, either neurological disorders or pathologies characterized by hypovolemia. Medications can also aggravate the risk of OH, among which some antihypertensive or psychotropic agents. Elderly people, especially frailty subjects, are exposed to a high risk of OH, whose origin is often multifactorial, and this complication may have serious medical consequences.