Dusty, IGA is not an EMI of Crohn's and it actually has EMI's of it's own. From what I understand it is a separate auto-immune disorder. Or auto immune reaction, the IGA antibody release is somehow activated during a respiratory infection and for some reason makes deposits of IGA stuck in the glomeruli of the kidneys. The IGA release is not originated from the lymph tissue but from the bone marrow. The Dr remarked that Johnny's pneumonia attacked his bone marrow because his WBC went down to a 2 during his illness and normally would have gone up because of infection. The pediatrician said some viruses attack the bone marrow and that although uncommon, it is not unheard of.
The Dr. said that about 30% of pediatric diagnosis of IGA will result in a quick decline of kidney function and dialysis within a year. Another 30% will have a slow decline, respond to steroids, immune suppressants and blood pressure meds and will lose kidney function slowly over 10-20 years. The other 30% will never progress into kidney failure, although it is possible to leak protein and blood in the urine for decades after diagnosis. He said the level will ebb and flow, which is somewhat consistent with what we are seeing with Johnny as his levels have gone up and down since his urine was first tested. But that kidney damage will never occur in that group.
They don't really know what category someone will fall into when diagnosed. Some good prognostic indicators are having a normal blood pressure, proteinuria <1gram per day, and normal GFR (Glomular filtration rate). Johnny has normal blood pressure, his proteinuria was 47.3 mg/dL, and had a normal GFR. His protein was only a one time drop, so I am assuming it is low enough that they don't need to do a 24 hour urine drop. The only indicator that the nephrologist was uncomfortable with was that he had casts in his urine. I don't think at this point they would even treat him, but he is already on immune suppressants for his crohn's. It is such a slow progressing disease they usually follow protein and blood in the urine and blood pressure hoping that disease progression will not take place. I think they are pretty certain that Johnny will not fall into the 30% that quickly deteriorates so they will regularly check him knowing that any changes that take place will happen slowly enough that more aggressive treatments will be started if the disease begins to progress.
If his blood pressure goes up, the protein or blood increases or his GFR drops they will use prednisone and stronger immune suppressants. Hopefully, we won't have to go there. Johnny's IGA serum protein profile was normal and I know it is high in auto immune kidney diseases so I think that is a good sign too. I know we would get more information about the prognosis if we had a biopsy but there are risks involved and he is already on the treatment they prescribed so both the GI and nephrologist felt it was best not to do the biopsy at this point. I completely agree, although I do have a few more questions about it.
I only had a phone conversation with the nephrologist after all Johnny's labs came back so I didn't get a chance to get a lot of information. We will be seeing the nephrologist again in 4 weeks and I will have a better chance to ask more questions. The nephrologist said he will treat 10's of thousands of kids with IGA and the GI will treat 10's of thousands of kids with crohn's but together they will treat only a handful of kids with both in their careers. I know they have already been in discussion about how to treat these diseases, but I have a feeling that there is not a regular treatment protocol. I do however have complete confidence in both Dr.'s they have both gone above and beyond.
The journal article the nephrologist sent me is from Feb. 2014, "The Histopathlologic Spectrum of Kidney Biopsies in Patients with Inflammatory Bowel Disease". It's so new I am not sure it would be available online yet.