Pathology Chapter 3: Carbohydrate & Lipid Disorders

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Questions and Answers

What is the primary difference between Type 1 and Type 2 diabetes mellitus?

Type 1 diabetes results in marked insulin deficiency, unlike Type 2 which involves insulin resistance. (correct)

Type 1 diabetes is more common in obese individuals than Type 2 diabetes.

Type 1 diabetes occurs predominantly in adults, while Type 2 occurs in children.

Type 1 diabetes is due to insulin resistance, while Type 2 is due to autoimmune destruction.

What is the fasting plasma glucose level that is considered diagnostic for diabetes mellitus?

≥200 mg/dL

≥126 mg/dL (correct)

≥100 mg/dL

≥150 mg/dL

What complications arise due to chronic hyperglycaemia in diabetes mellitus?

Muscle atrophy and joint pain

Microvascular complications such as retinopathy, nephropathy, and neuropathy (correct)

Increased appetite and weight gain

Hypoglycaemia and hypertension

Which condition is characterized by a fasting plasma glucose level lower than typical diabetes levels but higher than normal?

Impaired glucose tolerance Signup and view all the answers

Which of the following best describes the cause of Type 2 diabetes mellitus?

Insulin resistance coupled with inadequate insulin production Signup and view all the answers

What is one of the main characteristics of Type 1 Diabetes Mellitus?

Autoimmune destruction of beta cells Signup and view all the answers

Which of the following is a consequence of high levels of C-peptide?

More fat accumulation around the heart Signup and view all the answers

How is insulin secretion affected when glucose is administered intravenously compared to orally?

IV glucose results in lower insulin secretion initially. Signup and view all the answers

The natural history of type 2 diabetes often involves which of the following scenarios?

Excessive insulin secretion in the early stages. Signup and view all the answers

What role does incretin play in insulin regulation?

Stimulates the release of insulin. Signup and view all the answers

What is often a key difference between Type 1 and Type 2 diabetes in terms of insulin production?

Type 1 has an absence of insulin production. Signup and view all the answers

What can considerably elevate the risk of cardiovascular disease in individuals with obesity-related diabetes?

Increased lipid storage. Signup and view all the answers

Which of the following tests is primarily used to assess long-term glucose control in diabetes management?

Glycated hemoglobin (HbA1c). Signup and view all the answers

Which condition can lead to glucocorticoid-induced diabetes?

Both Type 1 and Type 2 diabetes Signup and view all the answers

What happens to glucose reabsorption in the kidneys during diabetes?

Excess glucose may appear in urine. Signup and view all the answers

What is a potential consequence of metabolic acidosis in type 1 diabetes?

Excess fat breakdown for energy. Signup and view all the answers

How does an increase in blood ketones affect a diabetic patient?

It increases the risk of metabolic acidosis. Signup and view all the answers

What type of deficits are responsible for maturity-onset diabetes of the young (MODY)?

Defects in insulin production due to beta cell function. Signup and view all the answers

Which hormone's actions are primarily lipogenic?

Insulin Signup and view all the answers

What characterizes the distinct insulin-related issue in Type 2 diabetes mellitus?

Insulin resistance with insufficient insulin production Signup and view all the answers

What is the significance of the fasting plasma glucose level of ≥126 mg/dL in diagnosing diabetes mellitus?

Identifies hyperglycaemia with risk of microvascular disease Signup and view all the answers

Which of the following is a likely effect of chronic hyperglycaemia due to diabetes mellitus?

Development of microvascular complications such as retinopathy Signup and view all the answers

What does 'impaired glucose tolerance' indicate about a patient's condition?

Higher than normal glucose but not qualifying for diabetes diagnosis Signup and view all the answers

What type of diabetic emergency can arise from high glucose levels combined with insufficient insulin?

Diabetic ketoacidosis Signup and view all the answers

Which of the following best describes the mechanism by which incretin influences insulin secretion?

Incretin stimulates beta cells to secrete insulin in response to food intake. Signup and view all the answers

What occurs to the levels of C-peptide in a patient with Type 1 diabetes?

Almost zero due to lack of insulin production. Signup and view all the answers

In type 2 diabetes, what effect does prolonged high insulin secretion have on the beta-cells?

Leads to beta-cell destruction and possible insulin deficiency. Signup and view all the answers

Which metabolic pathway is primarily affected by insulin's action as a lipogenic hormone?

Fatty acid and triglyceride synthesis. Signup and view all the answers

Which test provides insight into long-term glucose control in diabetic patients?

Glycated hemoglobin (HbA1c) test. Signup and view all the answers

What happens to glucose reabsorption in the kidneys when diabetes is present?

Glucose reabsorption is impaired, leading to glucose in urine. Signup and view all the answers

What could lead to glucocorticoid-induced diabetes?

Elevated blood glucose from glucocorticoid therapy. Signup and view all the answers

What is a common characteristic of patients with metabolic acidosis in type 1 diabetes?

Breakdown of fatty acids for energy. Signup and view all the answers

How does an acute phase of insulin secretion differ from a later phase in response to oral glucose intake?

The acute phase occurs first, followed by a more sustained but lower insulin release. Signup and view all the answers

Which of the following conditions occurs due to significantly elevated ketones in diabetic patients?

Diabetic ketoacidosis. Signup and view all the answers

What is a significant risk factor for cardiovascular disease associated with obesity-related diabetes?

Increased levels of C-peptide. Signup and view all the answers

What is an autoimmune marker commonly associated with Type 1 diabetes?

Islet autoantibodies. Signup and view all the answers

Which condition is characterized by a failure of insulin to promote glucose entry into cells?

Type 2 diabetes due to insulin resistance. Signup and view all the answers

Study Notes

Carbohydrate & Lipid Metabolism Disorders

This presentation covers the approach to patients with disorders of carbohydrate and lipid metabolism.
It is part of a third-year General Pathology course.

Roadmap

The roadmap outlines a sequence of topics:
- Diabetes management
- Diabetes emergencies (diabetic ketoacidosis, hyperglycemic hyperosmolar state, hypoglycemia)
- Lipid metabolism
- Mixed hyperlipidaemia
- Hypercholesterolaemia and hypertriglyceridemia

Diabetes Mellitus

Diabetes mellitus is a clinical syndrome characterized by elevated plasma blood glucose (hyperglycemia).
Type 1 diabetes mellitus (T1DM) is typically caused by autoimmune destruction of insulin-producing beta cells in the pancreas, leading to significant insulin deficiency.
Type 2 diabetes mellitus (T2DM) is characterized by reduced sensitivity to insulin and an inadequate insulin secretion to overcome 'insulin resistance'.

Diabetes Mellitus (Detailed)

High glucose and lack of insulin cause acute symptoms, metabolic decompensation, and hospitalization. These acute issues are particularly prevalent in type 1 diabetes.
Chronic hyperglycemia leads to diabetes-related microvascular complications affecting eyes (retinopathy), kidneys (nephropathy), and feet (neuropathy).
Blood glucose levels are continuously distributed, without a clear division between normal and abnormal values.
Diagnostic criteria for diabetes mellitus involve a fasting plasma glucose of ≥126 mg/dL or glucose of ≥200 mg/dL two hours after an oral glucose challenge.
Less severe hyperglycemia is called "impaired glucose tolerance."

Diabetes Mellitus (Mechanisms - Diagrams)

Healthy cells efficiently take up glucose from the bloodstream using insulin receptors.
In Type 1 diabetes, the pancreas fails to produce insulin, resulting in reduced glucose uptake.
In Type 2 diabetes, cells do not respond properly to insulin, making glucose uptake inefficient.

Diabetic Ketoacidosis (DKA)

DKA is an acute, life-threatening complication of diabetes, primarily in type 1 diabetes, which is characterized by insufficient insulin.
DKA is characterized by hyperglycemia, ketogenesis, metabolic acidosis (low bicarbonate, pH below 7.3), and dehydration.
Underlying causes include infection, stress response, and missed/inadequate insulin doses. Infections can heavily exacerbate the condition.

Hyperglycemic Hyperosmolar State (HHS)

HHS is an acute complication in type 2 diabetic patients characterized by severe hyperglycemia, hyperosmolarity (high serum osmolarity, often above 320 mOsmol/kg), and dehydration without significant ketoacidosis. There is little to no ketone body production.

Hypoglycemia

Hypoglycemia is a potentially dangerous condition with abnormally low blood glucose (below 70 mg/dL).
Symptoms include sweating, trembling, and rapid heart rate, and the condition is potentially serious, especially if left untreated.

Chronic Complications of Diabetes

Chronic complications include:
- Microvascular problems: retinopathy, nephropathy, neuropathy.
- Macrovascular problems: CVD, stroke, PAD.
- Foot complications: neuropathies, ulcers. Charcot foot is a serious complication from the loss of sensation in the feet.

Lipoproteins

Lipids, such as fatty acids, cholesterol, and triglycerides, are hydrophobic molecules that bind to proteins for transport.
These lipids are transported as lipoproteins, which have a hydrophobic core and an amphiphilic surface monolayer.
The different types of lipoproteins include chylomicrons, VLDL, IDL, LDL, and HDL.

Disorders of Lipid Metabolism

Proteins and receptors on lipoproteins guide lipid metabolism.
Dyslipidemia is a common disorder characterized by defects in lipoprotein synthesis and catabolism, affecting lipoprotein levels.
Treatment of dyslipidemia can improve cardiovascular health.

Hypercholesterolemia

Hypercholesterolemia is a common condition characterized by elevated LDL cholesterol.
Physical signs like corneal arcus and xanthelasma may indicate hypercholesterolemia.
The risk of CVD is linked to the severity of LDL cholesterol rise.

Hypertriglyceridemia

Hypertriglyceridemia is often linked to genetic factors, high alcohol consumption, medications, diabetes, impaired glucose tolerance, and other factors including obesity.
Increased triglycerides can correlate with postprandial hyperlipidemia, decreased HDL cholesterol, and thus higher CVD risk.

Mixed Hyperlipidaemia

Mixed hyperlipidemia involves higher levels of both triglycerides and LDL cholesterol.
Treatment of extreme triglyceride elevation may temporarily disguise it as a mixed hyperlipidemia.
The condition frequently develops with diabetes, impaired glucose intolerance, high BMI, and other insulin resistance problems.

Evolution of Atherosclerotic Plaque

Atherosclerotic plaque development involves multiple steps including LDL accumulation, inflammation, and smooth muscle proliferation. Cells adhering to the vascular endothelium, macrophages picking up oxidized LDL, and other inflammatory responses are part of the progression.

Life History of Atheroma

Atheroma formation progresses from normal artery, early atheroma and vulnerable plaque, to stabilized plaque, and ruptured plaque/thrombosis.

Non-pharmacological Management of Lipid Disorders

Dietary changes including reducing saturated fat and cholesterol, incorporating unsaturated fats, controlling carbohydrate consumption, increasing physical activity and increasing fruit and vegetable intake are critical.

Pharmacological Management of Lipid Disorders

Treatment choices vary based on the predominant lipid abnormality.
Statins, fibrates, and other drugs are frequently utilized.

Diabetic Foot Disease

Peripheral neuropathy and vascular disease are major factors in development of diabetic foot issues. Poor blood flow and reduced sensation greatly increase risk.

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Description

This quiz explores carbohydrate and lipid metabolism disorders as part of the General Pathology curriculum. Key topics include diabetes management, lipid metabolism, and related emergencies. Assess your understanding of diabetes mellitus, its types, and associated metabolic consequences.