Disease quickly spreading through young males often caused by extreme head trauma sustained in mosh pits. Symptoms include running around in circles at hardcore shows, using the word bro in situations where there are no bros around, and inserting the word "bro" in random words. For example, if you hear the word "brogurt" in conversation, you are talking to a sufferer.
One can recognize a sufferer of Browdown Syndrome by his track shorts and wife beaters. Often he listens to pseudo homosexual music about being loyal to his friends. Oddly, the severity of the condition is inversely affected by how good the music he moshes to is. For example, moshing to Converge is a mild case of Brodown Syndrome, while moshing to the local talentless musicians is intense Brodown Syndrome. Referring to oneself as "Broseidon" is an example of advanced Brodown Syndrome, and one should seek immediate medical attention if that word escapes one's lips.
Doctor: "So it says here you suffered a concussion while moshing in your best friend's basement?"
Bro: "Yeah dude we were listening to Four Year Strong while we were pumping iron but it wasn't long before a brodown broke out and we started moshing hardcore."
Doctor: "And you've been treated for this before?"
Bro: "Yeah my last doctor was a true friend and gave me some Brodeine for the pain but I didn't take it."
Doctor: "Yes, it seems you are suffering from Brodown Syndrome. Get some rest, take off the headband, put on some pants and a shirt, grow the fuck up and you'll be just fine."