Definition and Overview
Autonomic dizziness is a condition in which cerebral perfusion is reduced when standing or abnormal fluctuations in heart rate and blood pressure occur due to dysregulation of the autonomic nervous system, resulting in dizziness, vertigo, and presyncope.
ICD-10 codes include R42 (dizziness and vertigo) and G90.8 (other autonomic nervous system disorders).
The main causes of autonomic dizziness are orthostatic hypotension, postural orthostatic tachycardia syndrome (POTS), and vasovagal syncope. It is important to differentiate it from structural causes such as stroke or cerebellar lesions, and most brain imaging tests show no obvious lesions.
Causes and Pathophysiology
Orthostatic hypotension
Orthostatic hypotension is a condition in which systolic blood pressure decreases by more than 20 mmHg or diastolic blood pressure decreases by more than 10 mmHg within 3 minutes after standing. Deterioration of the function of the autonomic efferent pathway causes a decrease in venous return volume and a decrease in cardiac output, resulting in a temporary drop in cerebral perfusion pressure.
Postural orthostatic tachycardia syndrome (POTS)
POTS is a syndrome in which the heart rate increases by more than 30 beats per minute or exceeds 120 beats per minute within 10 minutes of standing, accompanied by dizziness, palpitations, and presyncope. Abnormal peripheral vasoconstriction, decreased intravascular capacity, and excessive sympathetic nerve activity are all involved.
vasovagal syncope
Vasovagal syncope is a condition in which excessive parasympathetic nerve activation causes sudden bradycardia and a drop in blood pressure, resulting in loss of consciousness or presyncope. Pain, fear, and standing for long periods of time are triggering factors.
Other causes
Diabetic autonomic neuropathy, Parkinson's disease, multiple system atrophy (MSA), amyloidosis, and certain medications (antihypertensive drugs, tricyclic antidepressants, diuretics) can also cause autonomic dizziness.
symptoms
Symptoms of autonomic dizziness occur within 30 seconds to 3 minutes after standing up, and are characterized by improvement within a few minutes when sitting or lying down.
Main symptoms: - Feeling of lightheadedness or presyncope - Blurred vision or temporary scotoma - Ringing in the ears (tinnitus) - Palpitations (palpitations) - Sweating or facial pallor - nausea - Headache
In severe cases, loss of consciousness (syncope) may occur, and there is a risk of secondary damage due to falls.
diagnosis
History taking and physical examination
Check whether symptoms occur when standing up, how long the symptoms last, and triggering factors (after eating, hot environment, dehydration, certain medications). Measure blood pressure and pulse before and after standing.
Standing tilt table test
The standing tilt table test is a standard test that tilts the patient at a 70-degree angle and observes changes in heart rate and blood pressure for 20 to 45 minutes. It is used to differentiate orthostatic hypotension, POTS, and vasovagal syncope.
Heart rate variability (HRV) test
A decrease in heart rate variability is an indicator that reflects a decline in autonomic function. A decrease in HRV is commonly observed in patients with autonomic dizziness.
24-hour ambulatory blood pressure test
Assess nocturnal blood pressure dropping pattern (dipping/non-dipping) and diurnal blood pressure variability.
Differential diagnosis
- Benign paroxysmal positional vertigo (BPPV): Rotational vertigo that occurs when changing certain head positions.
- Vestibular neuritis: acute persistent rotatory vertigo, spontaneous nystagmus
- Cerebellum or brainstem lesions: with focal neurological signs
- Meniere's disease: Recurrent rotational dizziness + tinnitus + hearing fluctuations
treatment
Non-pharmacological treatment
Water and salt supplementation increases intravascular capacity and alleviates orthostatic blood pressure drops. Water intake of 2-3 L per day and appropriate salt intake (sodium 2-3 g/day) are recommended.
Compression stockings (length above the knee, 15 to 30 mmHg) reduce blood retention in the lower extremities and increase venous return.
It is also important to correct behavior such as slowly changing posture when standing, avoiding hot environments, and eating small meals to prevent low blood pressure after a meal.
exercise rehabilitation
Aerobic exercise and lower extremity muscle strengthening exercises are effective in improving symptoms in patients with POTS and orthostatic hypotension. Initially, start with exercises that have a low standing load, such as lying down or swimming.
medication
- Midodrine: peripheral vasoconstrictor, first-line drug for orthostatic hypotension
- fludrocortisone: Increases intravascular capacity through sodium retention
- Pyridostigmine: Orthostatic hypotension associated with POTS and autonomic neuropathy.
- Beta-blockers: For heart rate control in some POTS patients.
In a clinical study, it was reported that systolic blood pressure significantly increased and symptoms improved in patients with orthostatic hypotension after midodrine administration.
Treatment of underlying disease
Active treatment of underlying causes such as diabetes, Parkinson's disease, and autonomic neuropathy is important for the long-term prognosis of autonomic dizziness.
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This information is provided for medical educational purposes and is not a substitute for individual medical care or treatment. If you have any symptoms, be sure to seek professional advice. Inquiries: Osang Neurosurgery 1599-5453 | osns.co.kr