Epidemics of various viral diseases

Type 1 Pathophysiology:Stage 1: Genetic predispositionStage 2: Environmental triggers (spring and fall epidemics of various viral diseases)Stage 3: Active autoimmunity (ICA’s and insulin antibodies progressively decrease the effective circulating insulin level)Stage 4: Progressive beta cell destructionStage 5: Overt Diabetes MellitusType 2 Pathophysiology:Insulin is a building (anabolic) hormone. Without it, 3 metabolic problems occur:- Decreased glucose utilization- Increased fat mobilization- Increased protein utilizationCells that require insulin as a carrier for glucose can take in only 25% of the glucose they require for fuel. Cells that do not require insulin for glucose transport include:- Nerve tissue- Adipose tissue- Erythrocytes- Skeletal muscle- Cells of intestines- Cardiac muscle- Liver- Kidney tubulesInadequate amounts of insulin lead to elevated levels of glucose. This elevation continues to rise because the liver cannot store glucose as glycogen without sufficient insulin levels. To return to homeostasis, the kidney excretes excess glucose, which acts as an osmotic diuretic, leading to increased water loss (fluid volume deficit).Increased Fat Mobilization:When glucose is unavailable, the body turns to fat stores for energy production.- Type 1 and Type 2 with severe stress: Fat metabolism causes breakdown products called ketones.- Ketones accumulate in the blood, are excreted through the kidney and lungs, and are measured in blood and urine.- High levels of ketones indicate uncontrolled diabetes.- Ketones interfere with the body’s acid-base balance by producing hydrogen ions, leading to decreased pH (metabolic acidosis).- Sodium follows excreted ketones, leading to sodium depletion and further acidosis.- Excreted ketones also increase osmotic pressure, leading to increased fluid loss.- Because fats are the primary source of energy, body lipids increase to 5x normal, leading to atherosclerosis.Increased Protein Utilization:Lack of insulin leads to protein wasting.- Without insulin to stimulate protein synthesis, the balance is altered, leading to catabolism.- Amino acids are converted to glucose in the liver, increasing glucose levels.- If left untreated, this leads to an emaciated appearance.Diagnosis of Diabetes:Physical exam, medical history, and labs.Labs:- Fasting Glucose >125- Casual Glucose >200- Postprandial >200- HbA1c- C-peptide