Hi there, IgA nephropathy is associated with protein leak in urine. if protein leak is too much or associated with increase salt and water intake it can lead to rapid incraese in swelling. also if patient develops kidney dysfunction with rise in serum creatinine levels it can lead to decrease in urine and sudden increase in swelling. Iga nephropathy can be associated with HSP, a condition which can have progressive disease with knee pain. paient on steroids can develop infection which may present with knee pain . all these possibilities are there but a good examination by nephrologist and investigations will give the answer. contact your doctor as soon as posssible