Diabetes Mellitus Type 2 for USMLE Step 1 and USMLE Step 2
Handwritten video lecture looking at Pathophysioloy, Pathology, symptoms and treatment of Diabetes Mellitus Type 2 for the USMLE Step 1 and the USMLE Step 2
Diabetes Type 2 has either a decrease in insulin secretion or increase in insulin resistance. Insulin is secreted from the Islets Cells of Langerhand specifically from the beta cells. Glucose enters the beta cell via the GLUT2 and is activated by glucokinase. This increases ATP which deactivates KATP pump. This leads to an influx of calcium and release of vesicles with insulin. OSU and repaglinide inhibit the same KATP channel.
Insulin is synthesized in Rough Endoplasmic Reitculum. Preproinsulin has a c,b,a pre and post section. When pre and post is removed then it is known as pro insulin. Pro insulin moves on to Golgi Apparatus where the c peptide curve. a peptide and b peptide forms bond and the c peptide is removed
PATHOPHYSIOLOGY OF DIABETES MELLITUS TYPE 2
Genetic causes of diabetes mellitus focuses on MODY1, MODY3, MODY5 associated with HNF. MODY2 is associated iwth glucokinase mutation and MODY4 is associated with INsulin promotor factor (IPF-1).
Environmental influences includes obesity which causes releases of adipokinse such as leptin, adiponetin, TNF, resistin.
SYMPTOMS OF DIABETES MELLITUS TYPE 2
Diabetes is often times asymptomatic. Most common presentation is polyuria, polydypsia, and weight loss. Other patients with Diabetes Type 2 present with blurred vision, vulvovaginits because diabetes is an immunosuppressed state. Often times it may present Hyperosmolar Hyperglycemic state associated with severe glucose level and hyperosmolality. Diabetes type 2 may also be associated with Diabetic Ketoacidosis.
DIAGNOSTIC CRITERIA FOR DIABETES MELLITUS TYPE 2
The American Diabetes Association has four factor for diagnosing diabetes. HbA1c is greater than 6.5 percent is diagnosed as having diabetes. If the fast plama glucose is greater than 125 then the patient is diagnosed as having diabetes. OGTT includes giving 75g of glucose and then checking blood sugar. If patient has greater than 200mgdL than patient is diagnosed as having diabetes. If random plasma glucose is greater than 200 and the patient is symptomatic than that is enough to diagnose the patient was diabetic.
SCREENING PATIENTS FOR DIABETES MELLITUS TYPE 2
Screen patient for diabetes if patient is greater than 45 years old, sedentary lifestyle, primary family history, high LDL, Low HDL, signs of insulin resistance and certain ethnicities.
Screen children for diabetes if they are greater than 10 years old and overweight, family history, gestational diabetes of mother and signs of hyperinsulinemia.
MANGEMENT OF DIABETES MELLITUS TYPE 2
Primary focus of management is control of blood glucose. Initial therapy focuses on Diet, Exercise and Metformin. If after three months the HbA1c is greater than 7 than add another drug to control the diabetes. If after three months the HbA1c is still not below 7, than add another drug for triple therapy.
The current diet for diabetics is medical nutrition therapy (MNT). This individualized diets has been seen to be the most effective for diabetic patients.
Diabetic children should get at least 60 minutes a day, while adults should have 150 minutes a week.
Diabetic patients should be screened for complications of diabetes. Nephropathy check for albuminuria and start treatment for ACE inhibitor if positive. Diabetic Retinopathy can be check with routine ophthalmologic exams. Neuropathy is also common in diabetic patients. Check for sensation of arms and legs. Foot Exam is also important and should be done in every visit. Cardovascular assessment is also important in diabetic patients because they are at risk. Check for blood pressure, dyslipidemia and consider aspirin