Friday, November 23, 2012

Misdiagnoses Happen... and Sometimes They Matter

Recently I read a piece on a man who was diagnosed with type 1 diabetes at the age of 60, in France. He had gone to his doctor because he had lost 20 lb without trying, and he was thirsty. His random blood sugar was in the 300s, but his A1c was only 7.2%, indicating that he'd had a rapid onset of diabetes. So his doctor put him on insulin, and he felt better. His doctor did not test c-peptide or antibodies; he didn't see a reason.

Except that one month later this newly diagnosed diabetic went to the emergency room with extreme stomach pain, and was diagnosed autoimmune pancreatitis. Autoimmune pancreatitis is a rare condition mostly seem in middle aged men, and it usually gets a lot better when the person is put on steroids. So this guy was put on prednisolone for three months. After two months of prednisolone, he went off of insulin. Three years later, he is not on any medication at all, and his A1c is below 6%.

This particular misdiagnosis- autoimmune pancreatitis misdiagnosed as type 1 diabetes- is not common. For one thing, AIP is not common, and for another, the diabetes is usually not the first symptomatic part of it. And most doctos looking at a middle aged or elderly person with new diabetes are not going to leap to the assumption that it's type 1.
But misdiagnoses in general are common. Some of them are very serious- as when diabetes is the first thing seen in what turns out to be pancreatic cancer, and the doctor only diagnoses diabetes. Or as when somebody is diagnosed with type 2 diabetes, treated only with oral medications, and goes into ketoacidosis before getting insulin. Or when diabetes is misdiagnosed altogether as the flu. Or when a person with diabetes responsive to sulfonyureas is put on insulin only (if you were diagnosed with diabetes before the age of one year, for your own sake please get tested).

The following things make misdiagnosis more likely:
- Neither antibodies nor c-peptide were tested.
- A diagnosis was made that doesn't fit the c-peptide or antibody results.
- The person making the diagnosis was not an endocrinologist, and the patient has never seen an endocrinologist.
- The person is a young adult when symptoms start.
- The person is a baby when symptoms start.
-  The person first went to see a doctor early on.

If you were diagnosed with type 1 diabetes without ever having either a positive antibody test or a low cpeptide (and not low for blood sugar, but actually low), it might be a good idea to get your cpeptide levels tested. More than a few people have found that they've been on insulin for a long time without needing to be.

I find it comforting to know that my cpeptide is nil and my antibodies are positive. There are no doubts about my diagnosis.

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