Endocrinology · USMLE Step 1 and Step 2

Diabetes Mellitus Type 2 song

Type 2 Diabetes - Pathophysiology & Complications, as a song. Hear the short teaser here. The full song is on YouTube and Spotify.

Diabetes Mellitus Type 2

Full song on YouTube ↗Spotify ↗

Key points in this song10

Type 2 DM is characterized by insulin resistance in peripheral tissues (muscle, fat, liver) combined with progressive pancreatic beta-cell dysfunction, leading to relative insulin deficiency.
Insulin resistance causes decreased GLUT4 translocation in skeletal muscle and adipose tissue, impairing glucose uptake despite normal or elevated insulin levels.
The liver fails to suppress gluconeogenesis in the insulin-resistant state, contributing to fasting hyperglycemia; this is the primary driver of elevated fasting glucose in Type 2 DM.
Compensatory hyperinsulinemia initially maintains euglycemia, but chronic beta-cell overstimulation leads to beta-cell exhaustion, amyloid deposition (IAPP/amylin), and progressive loss of first-phase insulin secretion.
Visceral obesity drives insulin resistance via excess free fatty acids and adipokine dysregulation, including decreased adiponectin and increased TNF-α, IL-6, and resistin.
Glucotoxicity and lipotoxicity create a vicious cycle, where chronic hyperglycemia and elevated free fatty acids further impair beta-cell function and worsen insulin resistance.
Incretin effect is significantly reduced in Type 2 DM; GLP-1 secretion from intestinal L-cells is blunted, decreasing glucose-dependent insulin release and increasing glucagon levels.
Hyperglucagonemia from dysregulated alpha-cell function is a key pathogenic feature, driving excessive hepatic glucose output even in the postprandial state.
Strong genetic component with high heritability; associated with TCF7L2 gene variants, the most reproducible genetic risk factor identified in genome-wide association studies.
Unlike Type 1 DM, Type 2 DM is not autoimmune; C-peptide levels are detectable (reflecting endogenous insulin production), and GAD65/islet cell antibodies are absent.