Arteriovenous Malformation (AVM) Causes Collapse of Baseball Manager

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On June 13, 1999, the Houston Astros baseball team manager Larry Dierker suffered a "seizure" during a game with the San Diego Padres.

"In a frightening scene, Dierker collapsed in the dugout in the eighth inning and members of the Astros and paramedics rushed to his aid," according to Reuters news service. "With players openly weeping and praying for his recovery, Dierker was removed from the field via ambulance."

An Astros spokesman said Dierker had suffered a grand mal seizure, "which affects the entire body," adding that the "condition is not heart-related....His blood sugar was normal, which is also an encouraging sign...(and Dierker) had been attempting to reduce his use of chewing tobacco."

On June 15, the Associated Press reported that Larry Dierker had successful surgery to remove a tangled mass of blood vessels in his brain that caused him to have the seizure in the dugout two days earlier.

"Dr. Rob Parrish said the 5 1/2-hour procedure to remove the mass, called an arteriovenous malformation, went smoothly." The area of malformed vessels had been removed. "Having an AVM that ruptures is certainly life threatening."

An arteriovenous malformation (AVM) is a congenital disorder, which means that is present at birth or really well before birth. The disorder involves blood vessels in the brain, brainstem, or spinal cord. There is characteristically a complex tangle of abnormal arteries and veins that are connected by one or more abnormal pathways (fistulas).

The fistulas in the AVM permit high-speed, high-flow shunting of blood from the arterial to the venous side of the circulation. This shunting causes low blood pressure (hypotension) in the arterial vessels feeding the AVM and neighboring areas of the brain that they normally supply with blood.

AVMs typically cause problems before the age of 40. The most common symptoms of AVM include bleeding (hemorrhaging), seizures, headaches, and neurological problems such as paralysis or loss of speech, memory, or vision. The frequency of hemorrhage occurence, depending on the particular study, has been reported to range from 30- 82%. AVM rupture accounts for 2% of all strokes.

There are three general forms of treatment for AVM:

  • Surgery is the best-known and longest-standing treatment for AVM. Surgery for an AVM involves identifying the margins of the malformation, tying off (ligating) or clipping the feeder arterial vessels, eliminating the draining veins, and removing or obliterating the nidus (the nest) of the AVM ;
  • Endovascular occlusion is a procedure which involves closing off the vessels of the AVM by one of various nonsurgical means. Catheters can deliver closing or occlusive agents that include permanent balloons, clogging (thrombosing) coils, hardening (sclerosing) drugs, and fast-acting embolization glue (embolization is often used before surgery); and
  • Radiosurgery involves focusing multiple radiation beams on the AVM so as to injure and clog or thrombose the AVM. The result of radiosurgery takes weeks to months to become fully effective.

A real danger of radiosurgery is damage to normal brain or spinal cord tissue around the AVM. Therefore, radiosurgery is usually reserved for AVMs that are relatively small (less than 3 cm in diameter), situated so deep beneath important brain tissue that the surgical approach is hazardous, or have so many feeder arteries that embolization is not feasible.

Most people (perhaps 80% or more) with AVMs never experience problems. However, AVMs that hemorrhage can lead to serious neurological problems and, sometimes, death.

After the baseball manager Larry Dierker had surgery at Methodist Hospital in Houston (Texas), surgeon Rob Parrish said Mr. Dierker would be in intensive care overnight, stay in the hospital 5-10 days, and that recovery time would be least four weeks.

On June 23, Larry Dierker went home from the hospital. The next day he visited his team's practice at the Astrodome to the delight of his players.

For further reading about AVM, see: Arteriovenous Malformations in Adults, by the Arteriovenous Malformation Study Group. New England Journal of Medicine 340: 1812-1818, June 10, 1999.


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