Vertebrobasilar insufficiency

Vertebrobasilar insufficiency (VBI) or vertebral-basilar ischemia, also called beauty parlour syndrome (BPS), is a temporary set of symptoms due to decreased blood flow (ischemia) in the posterior circulation of the brain. The posterior circulation supplies blood to the medulla, cerebellum, pons, midbrain, thalamus, and occipital cortex (responsible for vision). Therefore, the symptoms due to VBI vary according to which portions of the brain experience significantly decreased blood flow (see image of brain ). In the United States, 25% of strokes and transient ischemic attacks occur in the vertebrobasilar distribution. These must be separated from strokes arising from the anterior circulation, which involves the carotid arteries. Vertebrobasilar insufficiency (VBI) or vertebral-basilar ischemia, also called beauty parlour syndrome (BPS), is a temporary set of symptoms due to decreased blood flow (ischemia) in the posterior circulation of the brain. The posterior circulation supplies blood to the medulla, cerebellum, pons, midbrain, thalamus, and occipital cortex (responsible for vision). Therefore, the symptoms due to VBI vary according to which portions of the brain experience significantly decreased blood flow (see image of brain ). In the United States, 25% of strokes and transient ischemic attacks occur in the vertebrobasilar distribution. These must be separated from strokes arising from the anterior circulation, which involves the carotid arteries. Vertigo, the sensation of spinning even while a person is still, is the most recognizable and quite often the sole symptom of decreased blood flow in the vertebrobasilar distribution. The vertigo due to VBI can be brought on by head turning, which could occlude the contralateral vertebral artery and result in decreased blood flow to the brain if the contralateral artery is occluded. When the vertigo is accompanied by double vision (diplopia), graying of vision, and blurred vision, patients often go to the optometrist or ophthalmologist. If the VBI progresses, there may be weakness of the quadriceps and, to the patient, this is felt as a buckling of the knees. The patient may suddenly become weak at the knee and crumple (often referred to as a “drop attack”). Such a fall can lead to significant head and orthopedic injury, especially in the elderly. Transient ischemic attacks due to VBI will, by definition, have symptoms resolved within 24 hours. More often, however, the symptoms are very brief, lasting a few seconds to half an hour. The evaluation for VBI starts with a history and physical exam, with great emphasis on the cardiovascular and neurologic exam. It also includes a work-up to exclude benign conditions (such as labyrinthitis, vestibular neuronitis, and benign paroxysmal positional vertigo) that have overlapping signs and symptoms. However, the exact work-up largely depends on the patient’s age and known risk factors. For middle-aged patients, a cardiovascular risk factor evaluation is important. This often includes a cholesterol level, lipid profile (see this to determine what your cholesterol level means), ECG, and echocardiogram. If a person with VBI is under age 45 and has no evidence for atherosclerosis, a work-up for hypercoagulable states (Lupus anticoagulant, anti-cardiolipin antibodies, is indicated. Screening for protein C, protein S, or antithrombin III deficiency is sometimes recommended but these are more usually responsible for venous thrombosis than arterial problems. Imaging studies are rarely required to diagnose VBI, but sometimes computed tomography (CT) is performed first. The CT is extremely sensitive in detecting hemorrhage. However, magnetic resonance imaging (MRI) is superior to the CT in detecting ischemic changes in the vertebrobasilar distribution. Magnetic resonance angiography (MRA) also can be used to identify vertebrobasilar stenoses or occlusions, but it can often overestimate the degree of stenosis, or wrongly show stenosis as an occlusion. Intracranial MRA is mostly sufficient to evaluate vertebrobasilar arteries, while extracranial vertebral arteries are better diagnosed using contrast-enhanced MRA, which is less dependent on flow phenomena and more accurate in evaluating stenosis. CT angiography is also highly accurate in evaluation vertebrobasilar vessels, but ionizing radiation and use of nephrotoxic contrast media make it less suitable both in elderly with chronic kidney disease and young adults because of radiation exposure. Moreover, vessel wall calcification and beam-hardening artifacts due to dense bones or metal fillings sometimes cause strong CT-image degradation.