TY - JOUR
T1 - No increased herniation of the cerebellar tonsils in a group of patients with orthostatic intolerance
AU - Garland, Emily M.
AU - Anderson, James C.
AU - Black, Bonnie K.
AU - Kessler, Robert M.
AU - Konrad, Peter E.
AU - Robertson, David
PY - 2002/12
Y1 - 2002/12
N2 - Orthostatic intolerance, seen predominantly in young women, is characterized by symptoms of lightheadedness, fatigue and palpitations in the upright posture. With standing, plasma norepinephrine levels rise dramatically and heart rate often increases by more than 30 beats per minute, although blood pressure does not usually fall. A theory recently popularized in the media suggests that some cases of orthostatic intolerance are related to hindbrain compression, with or without a Chiari I malformation. As a preliminary investigation of this hypothesis, head or cervical spine MRI scans from 23 females with orthostatic intolerance were reviewed. The cerebellar tonsils averaged 0.3 ± 1.9 mm below the foramen magnum. These results were compared to measurements from a control group averaging 0.4 ± 2.6 mm above the foramen magnum (P > 0.05). Tonsillar depression of at least 3 mm occurred in 13 % of both the patient group and the control group. Tonsillar herniation was not found to influence supine or upright blood pressure, heart rate or plasma norepinephrine levels in the patients. We conclude that herniation of the cerebellar tonsils is not a common cause of orthostatic intolerance. However, the single measurement of tonsillar depression might underestimate the number of patients with hindbrain compression.
AB - Orthostatic intolerance, seen predominantly in young women, is characterized by symptoms of lightheadedness, fatigue and palpitations in the upright posture. With standing, plasma norepinephrine levels rise dramatically and heart rate often increases by more than 30 beats per minute, although blood pressure does not usually fall. A theory recently popularized in the media suggests that some cases of orthostatic intolerance are related to hindbrain compression, with or without a Chiari I malformation. As a preliminary investigation of this hypothesis, head or cervical spine MRI scans from 23 females with orthostatic intolerance were reviewed. The cerebellar tonsils averaged 0.3 ± 1.9 mm below the foramen magnum. These results were compared to measurements from a control group averaging 0.4 ± 2.6 mm above the foramen magnum (P > 0.05). Tonsillar depression of at least 3 mm occurred in 13 % of both the patient group and the control group. Tonsillar herniation was not found to influence supine or upright blood pressure, heart rate or plasma norepinephrine levels in the patients. We conclude that herniation of the cerebellar tonsils is not a common cause of orthostatic intolerance. However, the single measurement of tonsillar depression might underestimate the number of patients with hindbrain compression.
KW - Autonomic nervous system
KW - Cerebellar herniation
KW - Chiari I malformation
KW - Orthostatic intolerance
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U2 - 10.1007/s10286-002-0051-9
DO - 10.1007/s10286-002-0051-9
M3 - Article
C2 - 12598952
AN - SCOPUS:12244304168
SN - 0959-9851
VL - 12
SP - 472
EP - 476
JO - Clinical Autonomic Research
JF - Clinical Autonomic Research
IS - 6
ER -