Type 1 diabetes is classified as type 1A and type 1B diabetes, which are considered to be caused by autoimmune and nonautoimmune (idiopathic) mechanisms, respectively (1). Fulminant type 1 diabetes is characterized by a rapid-onset diabetic ketoacidosis within a short period of time, normal to near-normal HbA1c level at onset, and complete β-cell destruction and was originally reported as a subtype of type 1B diabetes (2). Recently, the involvement of viral infections has been suggested to be the triggering mechanism of fulminant type 1 diabetes (3,4). The involvement of T-cell autoimmunity in this disease, however, has also been reported (5–8). Thus, its etiology is still unclear. Here, we report a case of fulminant type 1 diabetes and painless thyroiditis that presented simultaneously.
A 47-year-old woman was admitted to our hospital in a diabetic ketoacidotic coma. She suffered from fatigue and fever 2 days before admission. One day before admission, she visited a clinic and was given drugs for the common cold. On the day of admission, however, she became comatose and was transferred to our emergency room. Her arterial blood pH was 6.9 and bicarbonate was 1.5 mmol/l. She had markedly increased levels of ketone bodies and serum potassium (7.6 mEq/l). Computed tomography of the brain showed no abnormal findings. After admission, she went into cardiac arrest and was revived by cardiopulmonary resuscitation then treated in the intensive care unit. Her plasma glucose level was 56.3 mmol/l (1,013 mg/dl) and HbA1c was 6.5%. Serum and urinary C-peptide levels were very low (0.2 ng/ml and 3 μg/day, respectively). There was no increase in C-peptide following intravenous administration of 1 mg glucagon. She had no islet-associated autoantibodies (GAD antibody, islet cell antibody, or insulinoma-associated antigen-2 [IA-2] antibody. Her serum amylase was 7,492 IU/l (normal range 30–130). She had elevated lipase and trypsin levels (52 units/l [0–49] and 2,860 ng/ml [100–550], respectively). These findings were consistent with fulminant type 1 diabetes, and she was treated with intensive insulin therapy. The patient had HLA-A24, which is reported to be associated with β-cell destruction (9), and had a homozygous HLA-DR9-DQ3 haplotype, which is strongly associated with autoimmune (type 1A) diabetes (10).
After admission, she had persistent sinus tachycardia. Thirteen days after admission, an echocardiogram revealed paroxysmal atrial fibrillation. At that time, her thyroid hormones were elevated (fT3 10.4 pg/ml, fT4 4.4 ng/dl) and thyroid-stimulating hormone was suppressed (<0.03 μU/ml). Thyroid-stimulating hormone receptor antibody was negative, and a 99m-Tc–labeled thyroid scan revealed a decreased uptake (Tc RI uptake ratio 0.275% [normal range 0.4–3.0]). Thyroid-stimulating hormone measured at the previous clinic 1 day before her admission was within normal limits. Thus, the onset of fulminant type 1 diabetes and painless thyroiditis appeared to be simultaneous.
Cases of fulminant type 1 diabetes with thyroid disease or with thyroid-related antibody were previously reported (11,12), and these cases were suggested to have immunogenetic characteristics. Painless thyroiditis is also generally considered to be an autoimmune disorder (13). This case also suggests participation of autoimmune mechanisms at the onset of fulminant type 1 diabetes. On the other hand, the association of a viral infection cannot be excluded because of preceding symptoms of infection. In a nationwide survey (14), fulminant diabetes comprises ∼20% of Japanese type 1 diabetes with ketosis or ketoacidosis at the onset. This new subtype, however, might be a heterogeneous entity. This is the first case of fulminant type 1 diabetes associated with simultaneous painless thyroiditis. It is useful to follow such cases to elucidate fulminant type 1 diabetes etiology, and further study is required to clarify its entity.
