On Monday night, Kai stopped walking. He was complaining of pain in his right leg. We got worried, but decided to wait and see what happens in the morning.
Tuesday came, and he still couldn't walk. We brought him to the PD nearest our house, and luckily the doctor on duty that day was Terence's classmate. He diagnosed it as reactive arthritis (ReA).
According to Wikipedia, ReA is an autoimmune condition that develops in response to an infection in another part of the body. Kai had a viral fever about two weeks back, and that caused an inflammation of his right hip joints.
You can give ibuprofen to relieve the inflammation and pain, and usually it will go away in a matter of days. But the PD says if it doesn't, we will have to investigate further.
Luckily, ReA went away as quickly as it came. Kai was walking gingerly on Tuesday day and jumping on Wednesday.
The episode gave me quite a scare, and it made us sad to see our usually active boy limited by his inability to move. I can't imagine the pain felt by other parents whose kids have debilitating diseases; it must be terrible beyond words.