Lecture Notes: Diabetes Mellitus by Dr. Priyanka Sachdev

Introduction

• Instructor: Dr. Priyanka Sachdev
• Topic: Diabetes Mellitus (DM)
• Approach: Integrated teaching covering anatomy, physiology, pathogenesis, clinical features, complications, and pharmacology of DM.

Anatomy and Physiology

Pancreas Overview

• Dual Function:
  • Exocrine: Secretes digestive enzymes
  • Endocrine: Secretes hormones like insulin and glucagon
• Histology:
  • Exocrine part consists of acini
  • Endocrine part consists of islets of Langerhans

Islets of Langerhans

• Composed of various cell types:
  • Alpha cells: Secrete glucagon
  • Beta cells: Secrete insulin
  • Delta cells: Secrete somatostatin
  • Pancreatic polypeptide cells: Secrete pancreatic polypeptide
  • Minor cells: D1 (secrete VIP) and enterchromaffin cells (secrete serotonin)
• Identification: Immunoperoxide staining differentiates cells based on hormone secretion
• Electron Microscopy: Shows structural differences among cell types

Diabetes Mellitus Overview

Definition

• A group of disorders characterized by hyperglycemia (high blood glucose levels)
• Normal blood glucose levels:
  • Fasting: 80-100 mg/dL
  • Post-meal: up to 140 mg/dL

Pathophysiology

• Issue with Insulin:
  • Either absent or non-functional
  • Results in high blood glucose (hyperglycemia) and low cellular glucose availability
• Consequences:
  • Blood Complications: Affects retina, nerves, kidneys (diabetic retinopathy, nephropathy, neuropathy)
  • Cellular Complications: Cellular starvation despite high blood glucose levels

Classification of Diabetes

Types

1. Type 1 Diabetes
   • Juvenile Onset: Diagnosed in young age
   • Insulin Dependent: Requires insulin injections
   • Accounts for 10% of diabetes cases
2. Type 2 Diabetes
   • Maturity Onset: Common in middle age or older
   • Non-Insulin Dependent: Treated with lifestyle changes, oral hypoglycemics, and sometimes insulin
   • Accounts for 90% of diabetes cases
3. Genetic Defects in Beta Cells
   • Known as MODY (Maturity Onset Diabetes of the Young)
   • Six types based on specific genetic defects
4. Gestational Diabetes
   • Diabetes occurring during pregnancy
5. Others
   • Caused by genetic defects in insulin, infections, drugs, syndromes
   • Infections: Cytomegalovirus, Coxsackie B, Rubella
   • Drugs: Steroids, thyroid hormone, beta agonists
   • Syndromes: Down syndrome, Turner syndrome

Risk Factors

• Family history
• Obesity
• Physical inactivity
• Race and ethnicity (blacks, Asians, Pacific Islanders)
• Previous impaired glucose regulation
• History of gestational diabetes or high birth weight babies
• Hypertension
• Dyslipidemia (low HDL, high LDL/triglycerides)
• PCOD
• Acanthosis nigricans

Insulin Regulation and Diabetes Pathophysiology (To be covered in Part 2)

• Insulin Synthesis and Action
• Pathogenesis of type 1 and type 2 diabetes
• Clinical Features: Polyuria, polydipsia, polyphagia
• Complications: Ketoacidosis, hyperosmolar coma
• Diagnosis: Criteria and methods
• Pharmacology: Anti-diabetic drugs and insulin types

Conclusion and Next Steps

• Next Session: Detailed coverage of insulin regulation, pathogenesis, clinical features, and complications of diabetes, followed by pharmacology.
• Feedback: Importance of student feedback and upcoming sessions announcements.

Note: Join the next session for a deeper dive into the pathogenesis and treatment of diabetes mellitus, and remember to provide feedback for improvement.