Rare Cause of Recurrent Hypoglycemia: Insulin Autoimmune Syndrome

Table 1

Laboratory investigation during initial and subsequent follow-up period.

Lab	Time after the 2nd episode
	1st day	4th month	6th month	12th month	15th month
FPG (mg/dL)	44	96	87	93	92
HbA1c (%)	5.7	5.7	5.8	5.7	5.8
Fasting insulin level (µU/mL)	2628	50.77	26.11	18.17	12.62
C-peptide level (ng/mL)	8.3	—	1.95	2.23	2.16
Insulin autoantibody level (nmol/L)	10.7	—	—	—	—
Anti-thyroperoxidase Ab (U/mL)	88.84	—	62.10	43.35	35.11
Anti-thyroglobulin Ab (U/mL)	169.26	—	114.11	68.11	72.40
Antinuclear Ab titer	1 : 320	—	1 : 320	1 : 100	—

obtained during the hypoglycemic episode.