I have a similar situation: muscle atrophy in the right calf (gastroc) and thigh (quads). I was diagnosed five years ago with CIDP and the variant Lewis Sumner Syndrome (asymmetrical CIDP). Onset was over 35 years ago, so it had a long time to progress. IvIg and regular exercise have stabilized the situation, with some improvement. When I started IvIg, I had a slight increase in muscle mass, but it didn't continue. But without the IvIg, I'd probably be in a wheelchair by now. So the lesson is, treatment and exercise can help.

Atrophy is due to muscle wasting or disease process. PN is doubtful to effect your calf size.