The 40-year-old died in his Inner Harbor condominium Sept. 23 from diabetic ketoacidosis, but there were no signs he was taking insulin to treat diabetes or that a doctor had ever diagnosed him with the disease, according to the state's chief medical examiner.
Close friends also said the 6-foot-7, 370-pound offensive tackle, who was nicknamed "Zeus," would not have let the disease go untreated.
"He would have taken care of himself to make sure he was around for his kids," said former Ravens linebackerBrad Jackson.
It is unusual for undiagnosed diabetes to prove fatal — an average of five or six Marylanders die that way each year, Fowler said.
Nationally, more than 1,700 people died from ketoacidosis in 2007, the latest federal health figures available. In Maryland, 45 people died from the condition that year.
The ailment, one of the most severe complications associated with diabetes, occurs when the body can't use glucose as fuel because there is no insulin being produced. Fat is used for fuel instead, which can lead to excessive acid build-up in the body.
The condition can be treated if caught early. But left untreated, ketoacidosis can lead to kidney failure, a build-up of fluid in the brain, a coma. Ultimately the body will shut down — and it can sometimes happen in a matter of weeks.
Symptoms such as severe nausea, abdominal pain and constant fatigue usually land people in the hospital or doctor's office before the condition gets too bad, diabetes and endocrinologist specialists said.
"It is not that common for people to develop diabetic ketoacidosis and die outside of the hospital," said Kristi Silver, associate professor of medicine and acting director of the University of Maryland Center for Diabetes and Endocrinology.
Fire officials found Brown dead in his apartment after family members hadn't heard from the man known for his fire on the field and gentleness off the field. He played for the Ravens from 1996 to 1998, and from 2003 to 2005.
Brown's family could not be reached for comment. His funeral service is scheduled for Friday.
Friends and former players who saw Brown in the two weeks before his death said he seemed healthy and didn't complain about feeling sick.
Jackson said he and Brown were together two weeks before his death at a team event where they signed autographs and talked "junk" to each other in between. Brown had talked about his oldest son, Little Zeus, a DeMatha Catholic High School football player who is being recruited by colleges.
Jackson said that if Brown had known he had diabetes, he would have treated it. Brown had a full life — he owned a Fatburger restaurant franchise in Elkridge, helped coach his son's football team, worked with current Ravens players and loved spending time with his two other sons and daughter as well, Jackson said.
Former Ravens offensive lineman Wally Williams knew Brown since their college days, when both played for historically black universities. They had parallel NFL careers, playing for the Ravens and the Cleveland Browns. They were roommates for a number of years and stayed in regular touch.
Williams saw Brown the Monday before he died. Brown was excited about the start of the new football season, and the two talked about getting together that weekend. Williams said diabetes ran in Brown's family, so he would have paid attention to if had known he had it.
"He never talked about having diabetes, never," Williams said.
Fowler said it is unclear what type of diabetes Brown had. Diabetic ketoacidosis is most commonly associated with Type 1 diabetes, which is found most often in children or young adults. The medical community thinks Type 1 is an autoimmune disorder, although the exact cause is not known. Type 2 diabetes is linked to diet habits andobesity.
Doctors said that because of Brown's age he didn't have the classic criteria for a Type 1 diagnosis, although it is possible. A ketoacidosis diagnosis from Type 2 diabetes, though uncommon, is more likely to occur in African-Americans, said Rita Kalyani, an assistant professor of medicine in the division of endocrinology and metabolism at Johns Hopkins.
Some doctors expressed surprise that Brown didn't show any of the symptoms of diabetes.
But athletes learn to push through the pain, so Brown may have had a higher tolerance for sickness.
"Professional athletes are used to feeling pain," Williams said. "It's almost a daily activity."
It is also possible that Brown could have confused some of the symptoms for general sickness. Thirst andfrequent urination are early signs of diabetic ketoacidosis. Other symptoms such as dry or flushed skin and shortness of breath later appear.
The medical examiner said over-the-counter flu medicine was found in Brown's apartment, giving some indication that he might have felt sick. But it was unclear how long the medicine had been there.
Fowler said that a relative indicated Brown might have been feeling sick for a few weeks.
"For someone who is undiagnosed, they may not know they have diabetes," Kalyani said. "The symptoms may occur gradually, and people may not recognize them."
Kalyani said some people wind up in the emergency room and are diagnosed there.
Marc I. Leavey, an internist with Mercy Medical Center's Lutherville Personal Physician's site, said the progression of the disease could have developed quickly. The condition can develop slowly but when vomiting occurs, the symptoms can quicken and in a few hours, according to the American Diabetes Association.
"You can develop rapidly onset diabetes," Leavey said. "If he didn't know it was there, the whole thing could have happened in a couple of weeks."
Kalyani said Brown's case demonstrates the need for continued diabetes education.
"We need to do as much as we can to build community awareness and patient education," she said. "We hope to reach those who may not know they have diabetes so we can prevent this kind of thing from happening."
Warning signs of ketoacidosis
The condition can develop slowly but when vomiting occurs can rapidly speed up.
Thirst or very drymouth
High blood glucose levels
High levels of ketones in the urine
Constantly feeling tired
Dry or flushed skin
Nausea, vomiting or abdominal pain
A hard time breathing
Fruity odor on breath
Difficulty paying attention, confusion
Source: American Diabetes Association