A Case of Late Diagnosis of Latent Autoimmune Diabetes in Adults

Abstract

Latent autoimmune diabetes of adults (LADA) is a type of autoimmune diabetes that begins in adulthood (usually after the age of 35 years); its main feature is the presence of diabetes-associated autoantibodies (most often autoantibody against glutamic acid decarboxylase), which leads to progressive destruction of the islets of Langerhans. This is a heterogeneous condition that presents with clinical and laboratory manifestations common to type 1 diabetes and type 2 diabetes. We report a case of a 71-year-old man diagnosed with type 2 diabetes two years ago, poorly controlled with oral antidiabetic therapy, and worsening in the third year. He had a positive family history of type 2 diabetes in two second-degree relatives (nephews). No pathologic findings at the physical examination were found. His body mass index was 23 kg/m² and glycated hemoglobin was 10.6%. Laboratory workup revealed low basal C-peptide (<0.1 ng/mL) and positive glutamic acid decarboxylase antibodies, and the LADA diagnosis was confirmed. This case highlights the importance of being aware of this disease, especially in patients previously diagnosed with type 2 diabetes who remain uncontrolled with diet and oral hypoglycemic agents. LADA is often confused with type 2 diabetes, and therefore, the management is frequently inadequate. An early diagnosis and treatment are crucial to delaying disease progression.

Keywords: autoantibodies; c-peptide; diabetes mellitus; insulin; latent autoimmune diabetes.