Introduction: Insulin autoimmune syndrome (IAS), or Hirata syndrome, is characterized by hyperinsulinemic hypoglycemia resulting from the presence of high titers of insulin autoantibodies (IAAs) in the absence of exogenous insulin. We present a rare case of IAS. Case: A 75-year-old female with underlying hypertension, dyslipidemia, and osteoporosis presented with symptoms suggestive of spontaneous hypoglycemia of 3 months duration. She was non-diabetic with no history of antidiabetic agents or exogenous insulin use. Notably, she had taken traditional medications 1 month prior to onset of symptoms. Her fasting blood glucose was 2 mmol/L. Serum insulin was significantly elevated at >1,000 iui/mL and serum C peptide was 2,950 pmol/L, consistent with hyperinsulinemic hypoglycemia. Blood sulfonylurea level was not available. Her complete blood count and renal and liver function were normal. Thyroid function test was normal, and a short corticotropin stimulation test showed adequate cortisol response. Computed tomography (CT) pancreas, endoscopic ultrasound and PET-CT scan with Galium-68 DOTATATE showed no evidence of insulinoma. Serum IAAs were raised at 175 IU/mL, which confirmed a diagnosis of IAS. The patient was managed with dietary modifications and advised for frequent, small meals with low glycemic index, incorporating oral raw cornstarch. She was also started on oral diazoxide 100 mg twice daily (3 mg/kg/day) due to persistent hypoglycemia. She responded well to diazoxide with no more spontaneous hypoglycemia, however, developed fluid retention which was managed with oral diuretics. Subsequently, we managed to taper and stop the diazoxide after 18 months of treatment. Patient remains well with no further episodes of hypoglycemia. Conclusion IAS may be triggered by medications or viral infections, occurs more frequently in people with autoimmune conditions, and shows genetic predisposition. However, as in our patient, IAS may be idiopathic, and the cause remains unknown. IAS is frequently self-limiting, and our patient experienced spontaneous remission with no further hypoglycemic episodes after discontinuation of treatment.
Hypoglycemia ; Insulins

Introduction: Subacute thyroiditis (SAT) and acute suppurative thyroiditis (AST) are two distinct inflammatory conditions but share many overlapping clinical and biochemical features, which may pose a diagnostic challenge. We report a case of SAT mimicking AST. Case: A 39-year-old female presented with a 3-week history of painful neck swelling and symptoms of thyrotoxicosis, including palpitations, heat intolerance, and diaphoresis. She had no family history of thyroid disease. On examination, she was febrile and had a smooth and tender goiter. Her blood tests showed leukocytosis with elevated erythrocyte sedimentation rate and C-reactive protein. Her thyroid function test (TFT) showed thyroid-stimulating hormone of 0.023 mIU/L and free thyroxine 4 of 32.15 pmol/L. An urgent ultrasound revealed a large, ill-defined heterogeneously hypoechoic lesion predominantly at the left lobe of the thyroid gland with mild intralesional vascularity. These were reported as features of thyroiditis with infective or early suppurative changes. Fine needle aspiration (FNA) of the lesion was attempted by the radiologist but was unsuccessful. She was treated with intravenous antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs), but symptoms persisted. Repeated ultrasound and computed tomography scans about 1 week later confirmed an enlarged thyroid gland with no obvious lesion or collection within the gland. The diagnosis was revised to SAT, and prednisolone 15 mg OD was started. This resulted in rapid improvement in her symptoms and inflammatory markers. Four weeks later, she remained asymptomatic, and prednisolone was gradually tapered off. Serial TFT monitoring showed a classic triphasic pattern with an initial hyperthyroid phase, followed by hypothyroidism before returning to euthyroidism. Conclusion SAT can present with a focal lesion on the ultrasound during the early stage of the disease, making it difficult to distinguish from a thyroid abscess due to overlapping features. Good clinical judgement guided by FNA and appropriate follow-up imaging may be helpful in differentiating between the two conditions.
Thyroiditis, Subacute ; Thyroiditis, Suppurative