Thyroid Research Centre, Institute of Nuclear Medicine and
Allied Sciences (INMAS), Lucknow Road, Timarpur, New Delhi-110054
Abstract- An unusual cause of spontaneous hypoglycemia
is Insulin Autoimmune Syndrome (IAS) or Hirata Disease, characterized by
high levels of insulinemia and circulating autoantibodies to insulin in
subjects without prior insulin administration. Till 2009, more than 200
cases from Japan and as many as 60 cases in Caucasians and 20 cases in
East Asians have been reported. To the best of our knowledge, this is
the second case of IAS reported from India.
Keywords - Hirata Disease, Insulin Autoimmune Syndrome,
Autoimmunity, Hypoglycemia, Insulin Autoantibodies
Key Clinical Message - Hirata disease is an autoimmune
syndrome rarely seen due to carbimazole/methimazole use in
thyrotoxicosis. However, a clinician should keep it in mind when using
these drugs and appropriate instructions to the patients should be
issued.
Introduction- Insulin Autoimmune Syndrome (IAS) or Hirata
Disease (HD), was first described by Hirata in 1970 and is characterized
by spontaneous hypoglycemic episodes, a high titre of insulin
autoantibodies and increased levels of immune reactive insulin in
patients those who are not treated with insulin or oral hypoglycemic
agents previously. There is a significant genetic predisposition to IAS
as suggested by its association with specific HLA class II alleles, and
it is often associated with previous exposure to drugs such as
sulfhydryl group in their chemical structures such as Methimazole/
carbimazole. The majority of cases as reported in Japan, IAS is the
third leading cause of hypoglycemia (325 patients diagnosed at the end
of 2007).1 The syndrome is rare in non-Japanese
population: 60 cases in Caucasians and 20 cases in East Asians have been
reported till date.2, 3 To best of our knowledge, it
is the second case reported in India.