Diabetes Mellitus and Insulin's Role

• Diabetes Mellitus is a chronic multisystem disease related to abnormal insulin production, impaired insulin utilization, or both.
• Diabetes is a leading cause of end-stage renal disease, adult blindness, and non-traumatic lower limb amputations.
• It is a major contributing factor to heart disease and stroke.
• Types of diabetes mellitus include type 1, type 2, MODY, and gestational diabetes.
• The pancreas creates insulin; it has endocrine and exocrine functions. In diabetes, the endocrine system's insulin and glucagon (produced by beta cells) are affected
• Glucagon has the opposite effect of insulin: insulin reduces blood sugar, while glucagon raises it.

The Problem of Diabetes

• Cells need sugar to function; when you consume sugar, it is supposed to be stored or transported to the cells.
• In diabetes, sugar stays in the bloodstream instead of being stored or transported.
• This alerts the pancreas to secrete insulin, but in diabetes, either insulin is not produced or it is produced in insufficient quantities.
• Type 1 diabetes (formerly known as insulin-dependent diabetes mellitus) involves no insulin production.
• Type 2 diabetes occurs when not enough insulin is produced or when there's insulin resistance, requiring extra insulin.
• The three main issues in diabetes are: no insulin production, insufficient insulin production, or insulin resistance.
• When sugar isn't stored properly and remains in the bloodstream, it can cause blockages in small and large vessels and lead to amputations due to bacterial infections and poor circulation.

Complications

• Potential complications include amputations, bacterial infections, nerve damage, kidney failure (dialysis), and blindness.
• Poor circulation and high sugar levels contribute to bacterial infections and neuropathy, and can cause tingling and loss of sensation.
• Occlusion of the blood supply to the small vessels can result in diabetic retinopathy and potential blindness.
• Affecting the large blood vessels, macrovascular complications from diabetes can cause heart disease and stroke.
• The kidneys may not receive enough blood supply, leading to chronic end-stage renal disease, also called diabetic nephropathy.
• Complications typically arise after years of uncontrolled blood sugar levels so good glycemic control helps prevent complications.
• Gangrene is a condition with decreased blood supply, leading to necrotic tissue.
• Type 1 diabetes is insulin-dependent, while type 2 is not, and often requires medication (oral pills).
• Genetics plays a significant role in both type 1 and type 2 diabetes.
• Gestational diabetes is due to hormonal changes during pregnancy.
• Prediabetes indicates a person is at risk for diabetes, requiring teaching and regular screening.
• Certain medications, such as prednisolone and steroids, can cause high blood sugar.
• The adrenal gland produces cortisol when it needs energy to fight off infections, which can release blood sugar.
• Stress can also elevate blood sugar levels.
• Conditions like Crohn's disease, cancer, asthma, and rheumatoid arthritis treated with steroids can lead to secondary diabetes due to cortisol stimulation (Cushing's syndrome).

Etiology and Pathophysiology

• Genetics play a significant role in type 2 diabetes.
• Type 1 diabetes is an autoimmune condition where the body attacks and kills its own beta cells.
• Normal blood sugar levels: 74-106.
• Insulin's function is to decrease blood sugar levels.
• Extra sugar is stored in the liver and muscles, but without insulin, the body cannot use this stored sugar properly.
• Without insulin, abnormal muscle breakdown (gluconeogenesis) can occur, leading to the production of ketones.
• A lack of insulin leads to the production of ketones, resulting in diabetic ketoacidosis (DKA) in both type 1 and type 2 diabetes, causing metabolic acidosis.
• Even small amounts of insulin prevent gluconeogenesis.
• Individuals with type 2 diabetes who produce a small amount of insulin are less prone to ketoacidosis, but can develop hyperosmolar hyperglycemic nonketotic syndrome (HHNS).
• Insulin drives sugar into cells, and with abnormal breakdown ketones, an acidic and poisonous state occurs.
• Counterregulatory hormones counteract insulin's effects to increase blood sugar; these include glucagon, growth hormone, cortisol, and epinephrine.
• Symptoms like diaphoresis, unresponsiveness, restlessness, and anxiety necessitate checking blood sugar.
• Hypoglycemia can mimic a stroke.
• If a patient is unresponsive, administer D50W (dextrose 50%) intravenously.
• If IV access is unavailable or has infiltrated, administer a glucagon shot.

Type 1 Diabetes

• Typically manifests in individuals younger than 40 years old with symptoms like polyuria, polyphagia, and polydipsia.
• It involves progressive destruction of pancreatic beta cells by the body's own T cells.
• Patients require exogenous insulin to sustain life; without it, they can collapse.
• A complication of Type 1 diabetes is diabetic ketoacidosis (DKA), which is life-threatening.
• DKA is a state of shock characterized by low blood pressure (e.g., 80/70), high heart rate (e.g., 120 bpm), low pH (e.g., 7.12), low CO2 (e.g., 25), and low bicarbonate (e.g., 8), leading to metabolic acidosis with compensatory high respiration rate (e.g., 40 breaths per minute).
• Blood sugar levels during DKA can range from 300 to 600 mg/dL.
• Regular insulin IV is administered during ketoacidosis.
• Common symptoms include thirst, hunger, and frequent urination (polyuria, polyphagia, and polydipsia).

Prediabetes

• Indicates an increased risk for developing diabetes.
• Fasting glucose levels range from 100 to 125 mg/dL.
• The A1C test (glycated hemoglobin) measures the average blood sugar attached to hemoglobin in red blood cells (which have a lifespan of 120 days) over a period of 3 months.
• The A1C test is the most confirmatory method.
• A risk factor is obesity.

Type 2 Diabetes

• Typically occurs in adults, often over 30 years of age.
• Characterized by insufficient insulin production or insulin resistance, without ketone production, but with the potential complication of a hyperosmolar nonketotic state.
• Risk factors include obesity.
• Individuals may produce insulin but at very low levels.
• There is a gradual onset that can take several years, leading to long-term complications such as nephropathy and neuropathy.

Manifestations

• Include a hyperosmolar hyperglycemic nonketotic state (HHNS) or hyperosmolar hyperglycemic syndrome (HHS), characterized by thick, concentrated blood with sugar levels ranging from 500 to 1500 mg/dL, hypertonic blood, and osmotic fluid/electrolyte imbalances.
• Initial management includes significant rehydration
• Fluid replacement can lead to electrolyte imbalances through urination.
• Blood pressure may be low (e.g., 80/70), heart rate high (e.g., 120 bpm), respiratory rate normal (e.g., 18 breaths per minute due to the absence of ketones), and oxygen saturation normal.
• Treatment involves electrolyte replacement, a massive bolus of isotonic fluid (normal saline), IV insulin, and priority IV line placement.
• Extracellular fluid loss leads to intracellular fluid loss as the body attempts to rehydrate the cells.
• Other manifestations include lethargy, fatigue, recurrent infections, and recurrent vaginal yeast or monilia infections.
• Retinopathy, nephropathy, stroke, and neuropathy may occur.

Goals of Diabetes Mellitus Management

• Decrease symptoms and prevent long-term complications through drug therapy, specifically insulin for type 1 diabetes.
• Type 2 diabetes may require insulin during stressful situations such as fever, infection, or surgical procedures when oral medications are insufficient.
• Because it cannot be taken orally, insulin is administered via subcutaneous injection for self-administration or IV.
• Insulin pumps provide continuous infusion and monitor blood glucose levels.
• Example case: An 18-year-old with type 1 diabetes using an insulin pump presents with fatigue and potential DKA due to neglected pump maintenance, resulting in insufficient insulin levels.
• Potassium imbalances are common. Normally, insulin helps potassium enter cells; without insulin, potassium accumulates outside the cells (hyperkalemia), potentially leading to cardiac arrhythmias or arrest.
• In cases of kidney problems and hyperkalemia, IV insulin is administered to help draw potassium back into the cells.
• Ventilator support with 100% oxygen may be necessary.
• Hypoglycemia symptoms include anxiety, irritability, restlessness, fatigue, and sweating.
• Insulin injection site rotation is important.
• The Somogyi effect occurs when insulin is taken at night, causing blood sugar to drop and then rebound high so taking a snack before bed can stabilize levels
• The dawn phenomenon is due to hormonal changes leading to high blood sugar levels in the morning.
• Oral agents are used in type 2 diabetes to stimulate the pancreas to produce more insulin.
• Common oral agents include sulfonylureas and biguanides.
• Sulfonylureas may cause weight gain, while biguanides do not.
• Nutritional therapy encompasses managing high cholesterol, high potassium, and metabolic syndrome.
• Management includes diet teaching, the plate method, exercising after meals, and having a snack before exercise.
• Self-glucose monitoring is important and should occur before and after bedtime.

Acute Complications

• Include diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic syndrome (HHS).
• DKA is characterized by hyperglycemia, ketosis, acidosis, and dehydration and urine ketones.
• DKA often occurs in type 1 diabetes due to a lack of insulin and excessive breakdown of fat stores.
• The body compensates for metabolic acidosis by increasing respiration rate.
• Management of DKA:

Management of DKA

• Check for ketones and administer regular insulin IV, manage polyuria by rehydrating.
• Signs of dehydration: poor skin turgor, orthostatic hypotension, sweet fruity breath odor.
• An unconscious 18-year-old with type 1 diabetes found in a parking lot requires airway management as a priority, IV fluids for low BP and insulin due to risk of acute renal failure stemming from hyperkalemia.
• Administer an insulin drip with normal saline and insulin each hour and add 5% dextrose when glucose is below 250 mg/dL to prevent hypoglycemia.
• Replace low potassium; in Metabolic acidosis Sodium bicarbonate may be necessary.
• Hyperosmolar hyperglycemic syndrome (HHS):
• A life-threatening condition more common in type 2 diabetes is marked by lethargy, unconsciousness, severe dehydration, neurological manifestations, and high serum osmolality.
• Sugar levels can range from 600-1000+ mg/dL.
• Symptoms include altered mental status, confusion, dry oral mucosa, dry warm skin, polyuria or oliguria, nausea, and vomiting.
• Ketone bodies are absent or minimal.
• IV fluids are a crucial intervention.
• Signs include tachycardia, fever, dehydration, thirst, dizziness, and poor skin turgor.

Hypoglycemia

• Defined as blood glucose levels less than 70 mg/dL, causing irritability, restlessness, vision disturbances, cool clammy skin, stroke-like symptoms, coma, or seizures.
• If the patient is alert and able to swallow, provide fruit juice, and check blood sugar after 15 minutes and again after 45 minutes.
• If the patient is NPO or not alert, administer 50% dextrose IV push or, if IV access is not available, administer glucagon IM or subcutaneously.

Angiopathy (Damage to Blood Vessels)

• Macrovascular:
• Affects large vessels, leading to stroke, heart attack, and peripheral artery disease; risk factors include obesity, smoking, hypertension, high-fat intake, and a sedentary lifestyle.
• Microvascular:
• Affects small vessels such as arterioles and capillaries, leading to retinal damage (retinopathy), nerve damage (neuropathy), kidney damage (nephropathy), and skin conditions (dermopathy); it typically manifests 10-20 years after the onset of type 2 diabetes.

Diabetic Nephropathy

• Causes damage to small vessels that supply the kidneys, potentially leading to end-stage renal failure.
• Management includes medications (ACE inhibitors to manage hypertension and increase insulin sensitivity), monitoring albumin levels in the urine, monitoring serum creatinine levels, and following up with a doctor.
• A high amount of albumin in urine is cause for concern.

Diabetic Neuropathy

• Can cause pain (described as pins and needles) and loss of sensation in the feet, potentially leading to non-traumatic amputations.
• A patient with a diabetic ulcer may develop sepsis (blood infection) or osteomyelitis in the feet.
• Sensory neuropathy and peripheral arterial disease can also lead to foot complications.
• Medication:
• Antiseizure and antidepressant medications can be used to manage nerve excitability.
• Oxygenation is crucial to promote healing.

Explore the critical role of insulin in glucose metabolism and the consequences of its deficiency or excess in diabetes mellitus. Questions cover the effects of insulin and glucagon, symptoms, potential complications and treatments. Test your knowledge on diabetes and related hormones.