pneumonia

Just wondered if any of the medical people on here could throw any light on
this.
My 8yo has just been diagnosed with pneumonia. (Not swine flue related)
after complaining of a sore shoulder. The infection is in the top left lob,
which according to the doctor is unusual.
What I'm wondering is what exactly he means by unusual. Is it unusual for a
child, unusual without other areas being infected, or just unusual to get
that area infected at all? I'm going back tomorrow with her so I'll ask him
then, but I've been worrying a bit over it.
Debbie