How can I calculate the difference between the largest and smallest value row-wise, for each column when there are plenty of NA?

Let’s assume this is my data:

   a   b   c  d   e



A  1   NA  3  NA  NA



B  0   NA  6  NA  2



C  3   2   1  NA  3



C  NA  NA  3  NA  0

For each column, I want to find the difference between the row with the highest value and the row with the lowest value – the result should look like this:

3 0 5 NA 3

I have hundreds of columns to analyse so I need a code that is easy to handle (eg: I won’t need to manually input the column names).

Any help will be greatly appreciated!