NS 3310: Hyperglycemic Crises in Diabetes
31 Cards in this Set
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Structure of Islets of Langerhands
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Within pancreatic tissue
Islets have alpha cells on the periphery and beta cells in the center, with a capillary running through
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What does GLUT2 do in the beta cell?
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GLUT2 is an insulin-independent glucose transporter found in many beta cells, liver, and intestinal cells.
GLUT2 is a highly efficient transporter of glucose, and minorly transports glucosamine.
Once ATP is formed in beta cells from intake of glucose, cell is depolarized, and insuli…
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What hormones are released when plasma glucose is low?
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Glucagon is released first when plasma glucose drops below 100mg/dL
Then, epinephrine and growth hormone are released
Lastly, cortisol is produced
All of these hormones prevent serum glucose from dropping too low during fasting
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What hormones protect against hyperglycemia?
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Only one: insulin
(Contrast with hypoglycemia, with 4 hormones)
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What would a patient presenting with excessive thirst, frequent urination, and acidic pH be diagnosed with?
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Type 1 diabetes
This patient is in "diabetic ketoacidosis" (DKA)
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How does Diabetic Ketoacidosis develop?
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Hormone sensitive lipase, involved in lipolysis is inhibited by insulin.
In the absence of insulin, the FA released from lipolysis cannot be stored in the liver or exported as VLDL - so the excess Acetyl CoA leads to ketogenesis.
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Kussmaul breathing
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Typical symptom of diabetic ketoacidosis; a labored breathing that is an attempt to rid the bloodstream of carbon dioxide and increase the pH of the blood
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What pathologic process of DKA is dehydration/hypokalemia related to?
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Osmotic diuress
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What pathologic process of DKA is hyperglycemia/hyperlipidemia related to?
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Insulin absence and glucagon persistence
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What pathologic process of DKA is metabolic acidosis related to?
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Ketoacid production
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What pathologic process of DKA is abdominal pain/hyperkalemia related to?
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Metabolic acidosis
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What pathologic process of DKA is tachypnea (Kussmaul breathing) related to?
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Respiratory Alkalosis
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If an obese patient presented with normal blood pH, normal serum ketones, elevated sodium, and elevated glucose, what would she be diagnosed with?
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Type II diabetes
Type II diabetes often presents as hyperosmolar, hyperglycemic, and non-ketotic
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Why does ketoacidosis rarely occur in Type II diabetes?
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There is usually enough insulin in the body to supress the production of ketones.
However, not enough insulin is produced to absorb glucose by adipose and muscle tissues.
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How does a clamp study measure insulin resistance?
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This method works by infusing a constant rate of serum glucose, and raising the amount of insulin, and measuring the amount of glucose it takes for their body to no longer be able to maintain it's blood glucose levels.
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Why is HHS the defining feature of Type II diabetes?
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Instead of DKA in TII, patients have a hyperosmolar, hyperglycemic state.
The blood sugar in TII is higher than in TI.
Type II diabetics can tolerate higher blood sugar because they have enough insulin to supress ketone production.
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How can clinicians distinguish HHS from DKA?
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Based on blood sodium levels (higher in Type II), osmolality (higher in Type II), C-peptide (not present in Type I), and pH and ketone levels
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What is c-peptide and how does it relate to diabetes?
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C-peptide is a cleavage product of pro-insulin that is produced in equal amounts to insulin but degraded more slowly.
C-peptide levels are a way of detecting that patients are able to produce their own insulin (i.e. T2D)
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How is DKA treated?
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Give fluids and choose infusion rate based on dehydration level.
Next, give patient potassium because total potassium stores are very low.
Next give, insulin. It is very important to monitor potassium levels throughout this time because insulin forces potassium into cells.
If the pat…
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If a patient presented with high fasting glucose, ketones in urine, low c-peptide, positive for GAD65 antibody, but no complaints, how would he be diagnosed?
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The fasting glucose is 3x the normal fasting glucose of a healthy individual, and it is spilling into the urine.
The patient is ketotic but not in ketosis.
This is a version of Type I diabetes known as "Latent Autoimmune Diabetes of Adults"
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What is LADA?
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"Latent autoimmune diabetes of adults"
LADA patients have symptoms of type I, but milder and present in adulthood
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Describe the alpha-beta system used for determining the type of LADA
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Alpha+ means there is antibodies present for GAD or IA-2
Beta+ means that c-peptide is present
A patient can be A+B+
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What is "Ketosis-Prone Diabetes" (KPD)?
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Hybrid between Type I and Type II because both the high blood sugar and ketones are elevated
It is a result of the death of beta cells from glucotoxicity
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Symptoms of ketosis-prone diabetes (KPD)
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Nausea, polyuria, weight loss, insulin resistance, low pH, positive urine and serum ketones, elevated serum glucose, low but present C-peptides, negative antibodies
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What occurs in glucotoxicity?
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When serum glucose is elecated, GLUT2 expression in beta cells is decreased and proapoptotic genes are expressed.
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What is the "threshold effect?"
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Occurs in Type II diabetes where beta cells fail to function during sever hyperglycemia, but once the hyperglycemia is corrected, the beta cells recover
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What is the "honeymoon period?"
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Seen in Type I diabetes after initiation of insulin therapy, where beta cells will begin to produce insulin, but eventually they all die.
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Positive insulin, positive ketones
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Ketosis-Prone Diabetes (KDP)
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Negative Insulin Positive Ketones
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Type I diabetes
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Positive insulin, negative ketones
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Type II diabetes
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Negative insulin, negative ketones
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LADA
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NS 3310: Final Exam