American gymnastic legend Kurt Thomas passed away June 5 at the age of 64. Thomas died nearly two weeks after , which led to a severe stroke. His wife Beckie Thomas told the: "Yesterday I lost my universe, my best friend and my soul mate of twenty-four years. Kurt lived his life to the extreme, and I will be forever honored to be his wife."
Former Olympic teammate Bart Conner said: "I am completely devastated to hear this. Kurt was a fierce rival, who went on to become a cherished friend."
In 1978, Thomas became the first American male gymnast ever to win a gold medal in floor exercise at the World Championships. In 1979, he set the record for the most medals (six) won at a single world competition, a record that stood until Simone Biles matched it in 2018.
He was known for his original moves, two of which were named for him: "Thomas Flair" on pommel horse, and the "Thomas Salto" on floor exercise. He later went on to work as a TV sports analyst for ABC Sports during the 1984 Olympics. He starred in the 1985 movie "."
He and Beckie went on to own and operate Kurt Thomas Gymnastics in Frisco, Texas. He was inducted into the International Gymnastics Hall of Fame in 2003.
Posterior Cerebral Circulation
Although the brain comprises only 2% of the total body mass, it uses nearly 50% of the body's glucose. As the most energy-intensive organ in the body, it follows that the brain is also the most perfused organ in the body. Therefore, some knowledge of the cerebral circulatory system is important in understanding how perturbations in blood flow to the brain can affect the entire body.
Oxygenated blood leaves the left side of the heart into the aorta. The aortic arch gives rise to three branches. The first (and largest) is the brachiocephalic trunk, the second, the left carotid artery, and the third, the left subclavian artery.
Blood supply to the brain is normally divided into anterior and posterior segments, relating to the different arteries that supply the brain. The internal carotid arteries supply the anterior brain and the vertebral arteries supply the brainstem and posterior brain. Although the vertebral arteries frequently arise as the most proximal ascending branch of the subclavian artery on each side of the body, several variations in their origin and distribution are well documented.
The anterior and posterior cerebral circulations are interconnected via bilateral posterior communicating arteries, which form part of the Circle of Willis. This arrangement creates redundancy for collateral circulation in the cerebral circulation. If one part of the circle becomes blocked or narrowed (stenotic), or one of the arteries supplying the circle is blocked or narrowed, blood flow from the other blood vessels can often preserve the cerebral perfusion well enough to avoid the symptoms of ischemia.
The vertebral arteries leave the Circle of Willis and combine to form the basilar artery, which then divides into the posterior cerebral arteries. Main branches of the basilar artery include:
- Posterior inferior cerebellar artery
- Anterior inferior cerebellar artery
- Pontine branches
- Superior cerebellar artery
The posterior circulation supplies blood to the brainstem, midbrain, pons, cerebellum, and the posterior cerebrum. Several of the cranial nerves also receive blood supply from the posterior circulation.
Posterior Circulation and Basilar Strokes
Each year, approximately 800,000 people in the United States have a stroke. Stroke is the fifth leading cause of death in the U.S. and is a major cause of serious disability in adults.
In general, there are two forms of stroke: ischemic and hemorrhagic. An ischemic stroke, which accounts for 87% of strokes, is caused by a blockage of a blood vessel supplying the section of brain supplied by that vessel. A hemorrhagic stroke is caused by bleeding into or around the brain. High blood pressure and aneurysms are examples of conditions that can cause hemorrhagic stroke.
Basilar artery infarct or occlusion results from the obliteration of blood supply to the posterior circulation or vertebrobasilar system of arteries to the brain. Approximately 20%-25% of all acute strokes occur in the posterior circulation. The most common causes are atherosclerosis or thromboembolism.
The presentation of symptoms of posterior circulatory stroke (PCS) largely depends on its cause. Up to 50% of patients with thrombotic stroke have a period of waxing and waning symptoms in the form of transient ischemic attacks prior to occlusion of the blood vessel. This period can last from days to weeks. On the other hand, those with an embolic or hemorrhagic stroke typically have an acute onset of symptoms.
Symptoms of PCS depend upon the location of the infarct/hemorrhage and can vary greatly. Classic dogma stated that the "sine qua non" of PCS was the presence of "crossed deficits." This means ipsilateral (same side) cranial nerve deficits with contralateral (opposite side) extremity deficits. However, according to a , "in reality, the presence of crossed deficits is not sensitive, occurring in only 3%-4% of PCS."
Other common symptoms include:
- Vertigo/dizziness
- Nausea and/or vomiting
- Abnormal oculomotor signs such as nystagmus (repetitive, uncontrolled eye movements)
- Limb weakness (unilateral, hemiparesis, or quadriparesis)
- Abnormal level of consciousness
- Blurry vision and/or visual field deficits
- Ataxia
- Sensory loss in the face and scalp
- Cranial nerve weakness including dysarthria (the speech muscles are damaged, paralyzed, or weakened), dysphagia (difficulty swallowing), dysphonia (poor voice quality), and facial muscle weakness.
Patients with PCS commonly have more than one symptom at a time and may present with groups of signs and symptoms recognized as distinct clinical syndromes. describe three of these syndromes:
"Top-of-the-basilar" syndrome involves occlusion in the rostral part of the basilar artery, resulting in ischemia affecting the upper brainstem and the thalamus. Clinical manifestations include behavioral changes, hallucinations, somnolence, visual changes, and oculomotor disturbances.
Locked-in syndrome involves occlusion at the proximal and middle part of the basilar artery, sparing the tegmentum of the pons. The patient is thus conscious and oculomotor function is preserved, but other voluntary muscles of the body are affected. These patients cannot move or talk, but consciousness is evident because of vertical eye movement, which is an oculomotor nerve function.
Pontine warning syndrome is a basilar artery atherosclerotic disease characterized by motor and speech disturbances that occur in a waxing and waning manner. These patients typically experience recurrent on-and-off attacks of hemiparesis and dysarthria. This syndrome is indicative of an imminent basilar artery branch occlusion with infarction of the supplied region.
Prognosis
Unfortunately, the prognosis for patients with PCS is not good. There is a mortality rate of more than 85% and survivors are often left with significant neurologic deficits. Survivors also have a 10%-15% risk of recurrent stroke.
Patients with successful recanalization after thrombolysis or angioplasty have a lower mortality rate of 33% to 50%, versus 74% to 100% in patients without thrombectomy or failed reperfusion.
Michele R. Berman, MD, and Mark S. Boguski, MD, PhD, are a wife and husband team of physicians who have trained and taught at some of the top medical schools in the country, including Harvard, Johns Hopkins, and Washington University in St. Louis. Their mission is both a journalistic and educational one: to report on common diseases affecting uncommon people and summarize the evidence-based medicine behind the headlines.