DIABETES MELLITUS part 2 Flashcards
What is the underlying cause of type 1 diabetes?
The underlying cause of type 1 diabetes is unclear, but there may be a genetic component. Certain viruses, such as Coxsackie B and enterovirus, may trigger it.
What are the classic symptoms of hyperglycemia in type 1 diabetes?
The classic triad of symptoms of hyperglycemia in type 1 diabetes includes polyuria (excessive urine), polydipsia (excessive thirst), and weight loss (mainly through dehydration).
What is the role of insulin in glucose metabolism?
Insulin, produced by beta cellsin the Islets of Langerhans in the pancreas, is an anabolic hormone. It reduces blood sugar levels by causing cells in the body to absorb glucose from the blood and use it as fuel. It also prompts muscle and liver cells to absorb glucose from the blood and store it as glycogen in a process called glycogenesis. Without insulin, cells cannot take up and use glucose, leading to hyperglycemia.
What is glucagon, and what is its role in glucose metabolism?
Glucagon, produced by alpha cells in the Islets of Langerhans in the pancreas, is a catabolic hormone. It is released in response to low blood sugar levels and stress, working to increase blood sugar levels. Glucagon instructs the liver to break down stored glycogen and release it into the blood as glucose in a process called glycogenolysis. It also signals the liver to convert proteins and fats into glucose through gluconeogenesis.
When does ketogenesis occur, and what are ketones?
Ketogenesis, the production of ketones, occurs when there is insufficient glucose supply and glycogen stores are exhausted, as in prolonged fasting. Ketones are water-soluble fatty acids produced by the liver from fatty acids. They can be used as fuel, cross the blood-brain barrier to be used by the** brain**, and are normal and not harmful under fasting conditions or on very low carbohydrate, high-fat diets. Ketone levels can be measured in the urine with a dipstick test and in the blood using a ketone meter.
What is diabetic ketoacidosis (DKA), and when does it occur?
Diabetic ketoacidosis (DKA) occurs as a consequence of inadequate insulin. It can occur in the initial presentation of type 1 diabetes, when an existing type 1 diabetic is unwell for another reason, often with an infection, or when an existing type 1 diabetic is not adhering to their insulin regime. The three key features of DKA are ketoacidosis, dehydration, and potassium imbalance.
What is the pathophysiology of diabetic ketoacidosis (DKA)?
Diabetic ketoacidosis (DKA) occurs due to inadequate insulin. The lack of insulin leads to hyperglycemia, ketogenesis (production of ketones), and metabolic acidosis. DKA can be triggered by various scenarios in type 1 diabetes, resulting in life-threatening metabolic acidosis. The three key features of DKA are ketoacidosis, dehydration, and potassium imbalance.
What are the three key features of diabetic ketoacidosis (DKA)?
The three key features of diabetic ketoacidosis (DKA) are ketoacidosis, dehydration, and potassium imbalance.
What is the role of the kidneys in buffering ketones?
The kidneys buffer ketone acids (ketones) in healthy individuals, preventing the blood from becoming acidotic.
What is hyperglycaemic hyperosmolar syndrome (HHS)?
Hyperglycaemic hyperosmolar syndrome (HHS) is a severe hyperglycemia without significant ketosis, characteristic of type 2 diabetes.
How does the pathophysiology of HHS differ from DKA?
The pathophysiology of HHS is similar to DKA, but in HHS, there are still small amounts of insulin being secreted, preventing ketosis. However, the insulin level is not high enough to lower blood glucose to a safe level.
What are the clinical features of hyperglycaemic hyperosmolar syndrome?
Clinical features of HHS include dehydration due to polyuria, polydipsia, nausea, vomiting, and stupor/coma. The degree of impaired consciousness is directly related to the level of osmolarity.
What are the key investigations used to diagnose hyperglycaemic hyperosmolar syndrome?
HHS is characterized by profound hyperglycemia (glucose > 33.3 mmol/L), hyperosmolality (serum osmolarity > 320 mmol/kg, measured directly or calculated as 2 x Na+ + glucose +
What is the cause of ketoacidosis in the absence of insulin?
In the absence of insulin, the body’s cells cannot recognize glucose, leading to the liver producing ketones as an alternative fuel source. Over time, elevated levels of glucose and ketones result. Initially, the kidneys produce bicarbonate to counteract ketone acids and maintain a normal pH. However, prolonged ketone acid presence depletes bicarbonate, leading to ketoacidosis.
How does dehydration occur in the context of hyperglycemia?
High blood glucose levels overwhelm the kidneys, causing glucose to leak into the urine. The osmotic diuresis, a process where glucose in the urine draws water out, leads to increased urine production (polyuria) and severe dehydration. Dehydration contributes to excessive thirst (polydipsia).
What role does insulin play in potassium balance?
Insulin normally drives potassium into cells. Without insulin, potassium is not added to and stored in cells. While serum potassium levels can be high or normal due to kidney balancing, total body potassium is low because no potassium is stored in the cells. Treatment with insulin can rapidly lead to severe hypokalemia (low serum potassium), posing a risk of fatal arrhythmias.
What are the key features of the presentation of diabetic ketoacidosis?
The presentation of diabetic ketoacidosis includes hyperglycemia, dehydration, ketosis, metabolic acidosis (with low bicarbonate), and potassium imbalance. Patients may experience symptoms such as polyuria, polydipsia, nausea and vomiting, acetone smell in the breath, weight loss, hypotension (low blood pressure), and altered consciousness.
What may trigger diabetic ketoacidosis, and why is it essential to investigate?
Diabetic ketoacidosis may be triggered by an underlying condition, such as an infection. It is crucial to investigate and look for signs of infections and other underlying pathology in any patient with DKA, as treating the underlying cause is essential for comprehensive management.
What are the diagnostic criteria for diabetic ketoacidosis (DKA)?
The diagnosis of DKA requires all three of the following criteria: hyperglycemia (e.g., blood glucose above 11 mmol/L), ketosis (e.g., blood ketones above 3 mmol/L), and acidosis (e.g., pH below 7.3).
What are the priorities in the treatment of diabetic ketoacidosis (DKA)?
The priorities in the treatment of DKA are fluid resuscitation to correct dehydration, electrolyte disturbance, and acidosis. The primary goal is to address dehydration, potassium imbalance, and acidosis, as these are life-threatening aspects of DKA.
What is the “FIG-PICK” mnemonic, and how does it aid in managing DKA?
The “FIG-PICK” mnemonic summarizes the principles of managing DKA: Fluids (IV fluid resuscitation with normal saline), Insulin (fixed-rate insulin infusion), Glucose (monitoring and adding glucose infusion when blood glucose is less than 14 mmol/L), Potassium (adding potassium to IV fluids and monitoring closely),** Infection (treating underlying triggers like infection)**, Chart fluid balance, and Ketones (monitoring blood ketones, pH, and bicarbonate). This aids in a systematic approach to DKA management.
What are the key complications during the treatment of DKA?
The key complications during the treatment of DKA include hypoglycemia (low blood sugar), hypokalemia (low potassium), cerebral edema (particularly in children), and pulmonary edema secondary to fluid overload or acute respiratory distress syndrome.
What considerations should be taken into account regarding potassium infusion in DKA treatment?
Under normal circumstances, the rate of potassium infusion should not exceed 10 mmol/hour to avoid inducing arrhythmia or cardiac arrest. However, in DKA, rates up to 20 mmol/hour may be used. Higher rates are only employed in specific scenarios under expert supervision with cardiac monitoring and through a central line rather than a peripheral cannula. Monitoring for potassium levels and ECG is crucial during the infusion.
Why are autoantibodies and serum C-peptide checked in some cases?
Autoantibodies and serum C-peptide are checked in cases where there is doubt about whether a patient has type 1 or type 2 diabetes. Autoantibodies associated with type 1 diabetes include anti-islet cell antibodies, anti-GAD antibodies, and anti-insulin antibodies. Serum C-peptide, a measure of insulin production, is helpful in distinguishing between low and high insulin production.
What are the components of long-term management for type 1 diabetes?
Long-term management of type 1 diabetes involves subcutaneous insulin, monitoring dietary carbohydrate intake, monitoring blood sugar levels upon waking, at each meal, and before bed, and monitoring and managing complications, both short and long term. Patient education is crucial for understanding and engaging with the condition, as type 1 diabetes is a lifelong condition that requires active patient involvement.
What is a basal-bolus regime in the context of insulin therapy for type 1 diabetes?
A basal-bolus regime involves a combination of background, long-acting insulin injected once a day and short-acting insulin injected 30 minutes before consuming carbohydrates (e.g., at meals). This regimen helps mimic the body’s natural insulin production pattern and provides better control over blood sugar levels throughout the day. Patients are advised to cycle their injection sites to avoid lipodystrophy, a condition where subcutaneous fat hardens and affects insulin absorption.
What are insulin pumps, and what are their advantages and disadvantages?
Insulin pumps are small devices that continuously infuse insulin at different rates to control blood sugar levels. They offer better blood sugar control, more flexibility with eating, and fewer injections. However, disadvantages include difficulties learning to use the pump, the need for constant attachment, potential blockages in the infusion set, and a small risk of infection. Tethered pumps have visible tubes connected to the pump, while patch pumps sit directly on the skin without visible tubes. Both types aim to provide convenient insulin delivery.
What is the purpose of a pancreas transplant, and when is it considered?
A pancreas transplant involves implanting a donor pancreas to produce insulin. It is considered in patients with severe hypoglycaemic episodes and those also requiring kidney transplants. The original pancreas is left in place for digestive enzyme production. The procedure is reserved for specific cases due to significant risks and the need for life-long immunosuppression to prevent rejection.
What is islet transplantation, and what role do islet cells play?
Islet transplantation involves inserting donor islet cells into the patient’s liver. Islet cells produce insulin and assist in managing diabetes. However, patients often still require insulin therapy after islet transplantation. This procedure is an alternative to pancreas transplantation and may be considered in specific cases.
What is the purpose of monitoring HbA1c levels in diabetes management?
HbA1c measures glycated hemoglobin, reflecting the average glucose level over the previous 2-3 months. It provides a long-term indicator of blood sugar control. Monitored every 3 to 6 months, HbA1c is a lab test that helps track average sugar levels, guiding diabetes management decisions.
How does a flash glucose monitor, such as FreeStyle Libre, work?
Flash glucose monitors, like FreeStyle Libre, use a sensor on the skin to measure glucose levels in the interstitial fluid. The sensor records readings at short intervals, providing an overview of glucose levels over time. Users swipe their mobile phones over the sensor to collect readings. These monitors offer convenience but have a 5-minute lag compared to blood glucose. Sensors need replacement every 2 weeks. If hypoglycemia is suspected, capillary blood glucose testing is necessary due to the delay.
What is the difference between continuous glucose monitors (CGM) and flash glucose monitors?
Continuous glucose monitors (CGM) and flash glucose monitors both use a sensor on the skin to monitor sugar levels in interstitial fluid. However, CGMs send readings over Bluetooth and do not require patients to scan the sensor manually. The key distinction lies in the automated transmission of readings, enhancing user convenience compared to flash glucose monitors.
What is a closed-loop system or artificial pancreas in diabetes management?
A closed-loop system, also known as an artificial pancreas, combines a continuous glucose monitor and an insulin pump. These devices communicate to automatically adjust insulin based on glucose readings. While the system aids in blood sugar control, patients need to input carbohydrate intake and adjust for activities like strenuous exercise. The closed-loop system represents an advanced approach to diabetes management.
What are short-term complications in diabetes management?
Short-term complications in diabetes management involve immediate issues with insulin and blood glucose. These include hypoglycemia (low blood sugar) and hyperglycemia (high blood sugar), which may lead to diabetic ketoacidosis (DKA). Hypoglycemia symptoms include hunger, tremor, sweating, irritability, and more. Severe hypoglycemia can result in reduced consciousness, coma, and death if untreated. Hyperglycemia, without DKA, may require adjustments to insulin doses, and DKA cases necessitate inpatient management.
What are long-term complications associated with chronic high blood glucose levels?
Chronic high blood glucose levels lead to long-term complications, including damage to endothelial cells of blood vessels.
Macrovascular complications involve
coronary artery disease,
peripheral ischemia, stroke, and hypertension.
Microvascular complications include
peripheral neuropathy,
retinopathy, and
kidney disease (glomerulosclerosis).
Additionally, chronic high glucose levels impair the immune system, increasing susceptibility to infections such as urinary tract infections, pneumonia, skin and soft tissue infections, and fungal infections like candidiasis. Monitoring and managing blood glucose levels are crucial to mitigate these complications.
What are the common chronic complications related to diabetes?
Common chronic complications related to diabetes include macrovascular complications such as coronary artery disease, peripheral ischemia, stroke, and hypertension. Microvascular complications involve peripheral neuropathy, retinopathy, and kidney disease (glomerulosclerosis). Infection-related complications encompass urinary tract infections, pneumonia, skin and soft tissue infections, and fungal infections, particularly oral and vaginal candidiasis. Chronic complications arise due to damage caused by prolonged high blood glucose levels. Monitoring and managing blood glucose are essential to prevent or mitigate these complications.
What is the simplified pathophysiology of Type 2 diabetes?
Repeated exposure to glucose and insulin leads to insulin resistance, requiring increased insulin production. Over time, the pancreas becomes fatigued and damaged, reducing insulin output. This, combined with a high carbohydrate diet, results in chronic high blood glucose levels (hyperglycaemia), leading to microvascular, macrovascular, and infectious complications similar to those in type 1 diabetes.
What are the risk factors for Type 2 diabetes?
Non-modifiable risk factors include older age, ethnicity (Black African or Caribbean, South Asian), and family history. Modifiable risk factors include obesity, a sedentary lifestyle, and a high carbohydrate (particularly sugar) diet.
What are the presenting features of diabetes?
Presenting features include tiredness, polyuria (frequent urination), polydipsia (excessive thirst), unintentional weight loss, opportunistic infections (e.g., oral thrush), slow wound healing, and glucose in urine (on a dipstick). Acanthosis nigricans, characterized by thickening and darkening of the skin, is often associated with insulin resistance.
What is pre-diabetes, and how is it indicated?
Pre-diabetes indicates that a patient is heading towards diabetes without fitting the full diagnostic criteria. An HbA1c of 42–47 mmol/mol suggests pre-diabetes. HbA1c measures average glucose levels over the previous 2-3 months.
How is type 2 diabetes diagnosed?
An HbA1c of 48 mmol/mol or above indicates type 2 diabetes. The sample is typically repeated after 1 month to confirm the diagnosis, unless there are symptoms or signs of complications. HbA1c is a blood test reflecting average glucose levels.
What are the NICE guidelines for managing type 2 diabetes?
NICE guidelines (updated 2022) recommend a structured education program, a low-glycaemic-index, high-fiber diet, exercise, weight loss (if overweight), antidiabetic drugs, and monitoring and managing complications for managing type 2 diabetes.
What are the treatment targets for HbA1c in type 2 diabetes?
The NICE guidelines recommend an HbA1c treatment target of 48 mmol/mol for new type 2 diabetics and 53 mmol/mol for patients requiring more than one antidiabetic medication. HbA1c is measured every 3 to 6 months until under control and stable.
What is the first-line medical management for type 2 diabetes?
The first-line is metformin, which increases insulin sensitivity and decreases glucose production by the liver. Metformin, a biguanide, does not cause weight gain or hypoglycemia. Notable side effects include gastrointestinal symptoms (pain, nausea, diarrhea) and lactic acidosis (e.g., secondary to acute kidney injury). Modified-release metformin can be considered for patients with gastrointestinal side effects with standard-release metformin.
What are second-line and third-line options for type 2 diabetes?
Second-line involves adding an SGLT-2 inhibitor (e.g., dapagliflozin) for patients with existing cardiovascular disease or heart failure. Second-line options also include a sulfonylurea, pioglitazone, DPP-4 inhibitor, or another SGLT-2 inhibitor. Third-line options include triple therapy with metformin and two second-line drugs or insulin therapy initiated by specialist diabetic nurses. In cases of triple therapy failure and BMI above 35 kg/m², switching one drug to a GLP-1 mimetic (e.g., liraglutide) is an option.
Why are SGLT-2 inhibitors increasingly recommended in type 2 diabetes?
SGLT-2 inhibitors are recommended due to their cardiovascular benefits, especially in older patients with a QRISK score above 10%. NICE suggests considering SGLT-2 inhibitors alongside metformin as part of the first-line treatment in type 2 diabetics at high risk of cardiovascular disease. SGLT-2 inhibitors are recommended second-line as part of dual therapy in these patients. Diabetic ketoacidosis is a potential side effect to be aware of.
