(Human bio lesson ->) Pleurisy's the inflammation of the lining of the lungs and causes sharp pains in the chest. Apparently the main cause for it are infections but I can't say for sure what caused it in Dongho's case.
So, just saying, if you're a KissMe or a Dongholic please show your support for Dongho! If you didn't read the alkpop article, it states that Dongho might need to undergo surgery. Let's pray and hope that he won't need it and will recover shortly!
We KissMes will support you every step of the way!