Diabetes Mellitus Type 1 for USMLE Step1 and USMLE Step 2
Handwritten Video Lectures on the pathophysiology, pathology, symptoms and treatment of Diabetes Mellitus Type 1 for USMLE Step 1 and Step 2.
PHYSIOLOGY OF DIABETES MELLITUS TYPE 1
Islet cells have beta cells in the central which secrete insulin and beta cells which secrete glucagon.
The beta cells has the GLUT2 transporter which transports glucose inside the cell. It is then acted upon by glucokinase which increases the level of ATP. ATP then deactivates KATP channels. Afterwards Calcium inlux activates vesicles of insulin to fuse with the membrane and release the insulin.
Insulin is synthesized in the Rough Endoplasmic reticulum as the preproinsulin. After removla of the pre and the post Peptides to form proinsulin. After the golgi aparatus the c peptide bends over and is removed after a bond is formed between the a and b peptide.
The c-peptide is a measure of endogenous insulin production.
PATHOPHYSIOLOGY OF DIABETES MELLITUS TYPE 1
Destruction of the Islet Cells of Langerhan leads to hypglycemia.
The genetic component of Diabetes Mellitus Type 1 involves HLA-DR3 and HLA-DR4.
Autoimmune is also invovled in Diabetes Mellitus Type 1. Islet cell autoantibodies target insulin or Anti GAD65. Also Diabetes Mellitus is associated with other autoimmune disease.
Viruses such as cocksackie virus also is known to cause Diabetes Mellitus.
DIAGNOSIS OF DIABETES MELLITUS TYPE 1
HbA1c level greater then 6.5 percent
2 hour fasting glucose greater than 126 mgdL
Oral Glucose Tolerance Test (OGTT) greater than 200
Random Plasma Glucose greater than 200 and symptomatic
Anyone 1 of the previous is a diagnosis of Diabetes Mellitus
SIGN AND SYMPTOMS OF DIABETES MELLITUS TYPE 1
Primary symptoms are polyuria polydypsia and weight loss occurs in approximately 90 percent of patients. Other symptoms include hyperphagia, perianal candidiasis.
Diabetic Ketoacidosis also has polyuria, polydipsia, fruity death and neurological symptoms
COMPLICATION OF DIABETES MELLITUS
Diabetic patients who do no manage their glucose well may get diabetic neuropathy, diabetic nephropathy, diabetic retinopathy, necrobiosis lipoidica and increase risk of atherosclerosis
MANAGEMENT OF DIABETES MELLITUS
Insulin therapy with a goal of keeping HbA1c below 7 percent.
Fast Acting Insulin includes Aspart, Lispro and Glulysine
Intermediate Acting Insulin such as regular insulin and NPH
Long acting insulin includes Glargine which has no peak, Determir which binds to albumin may all be using in different combination to manage glucose levels in Diabetic patients.