Why is Lou Gehrig's disease usually result from respiratory infection secondary to respiratory infection?

Question

Explain why.

Answer 1

Maybe it is the other way around.

Lou Gehrig's disease has an unknown cause, there is a tendency to choke on liquids due to lack of muscle control.

Choking on liquids can lead to pneumonia.

see:

http://www.merck.com/mmpe/sec16/ch223/ch...

Some brain diseases are thought to be due to a slow viral infection, the above link (which is not exhaustive of the subject) does not list this on the intial page.