Diabetes – Clinical Presentation

Comprehensive vocabulary flashcards covering the clinical presentation, diagnostic criteria, pathophysiology, pharmacotherapy considerations, and acute complications (DKA vs. HHS) of diabetes mellitus.

Type 1 Diabetes Mellitus (T1DM)

An autoimmune condition in which the body attacks its own pancreatic beta-cells, leading to insulin dependency; it often develops during childhood and has a genetic predisposition.

Type 2 Diabetes Mellitus (T2DM)

A metabolic disease characterized by insulin independency driven primarily by lifestyle factors; it is typically diagnosed in adulthood (with increasing childhood cases) and preventable via exercise and a healthy diet.

Gestational Diabetes Mellitus (GDM)

Diabetes diagnosed during the second or third trimester of pregnancy that was not clearly identified as diabetes prior to pregnancy.

Impaired Fasting Glucose (IFG)

A prediabetic state defined by a fasting plasma glucose (FPG) value between $100\,\text{mg/dL}$ ($5.6\,\text{mmol/L}$) and $125\,\text{mg/dL}$ ($6.9\,\text{mmol/L}$).

Impaired Glucose Tolerance (IGT)

A prediabetic state defined by a 2-hour plasma glucose value of $140\,\text{mg/dL}$ ($7.8\,\text{mmol/L}$) to $199\,\text{mg/dL}$ ($11.0\,\text{mmol/L}$) during a $75\text{-g}$ oral glucose tolerance test (OGTT).

Hemoglobin A1C Diagnostic Threshold for Diabetes

An A1C value of $\ge 6.5\%$ ($\ge 48\,\text{mmol/mol}$), performed in a laboratory using an NGSP-certified method standardized to the DCCT assay.

Fasting Plasma Glucose (FPG) Diagnostic Threshold for Diabetes

A fasting blood glucose measurement of $\ge 126\,\text{mg/dL}$ ($\ge 7.0\,\text{mmol/L}$), where fasting is defined as no caloric intake for at least $8\,\text{hours}$.

Oral Glucose Tolerance Test (OGTT) Diagnostic Threshold for Diabetes

A 2-hour plasma glucose level of $\ge 200\,\text{mg/dL}$ ($\ge 11.1\,\text{mmol/L}$) during an OGTT using the equivalent of $75\,\text{g}$ anhydrous glucose dissolved in water.

Random Plasma Glucose Diagnostic Threshold for Diabetes

A plasma glucose reading of $\ge 200\,\text{mg/dL}$ ($\ge 11.1\,\text{mmol/L}$) taken at any time of day regardless of meals, in an individual presenting with classic symptoms of hyperglycemia or hyperglycemic crisis.

The Three Classic Symptoms of Hyperglycemia

Polyuria (frequent urination), polydipsia (excessive thirst), and polyphagia (excessive hunger).

Self-Monitoring of Blood Glucose (SMBG) Routine

A primary glycemic assessment technique optimized by measuring blood glucose concentrations prior to meals, snacks, and possibly at bedtime.

Estimated Average Glucose (eAG)

A calculated average blood glucose value correlated with A1C; for instance, an A1C of $6.5\%$ corresponds to $140\,\text{mg/dL}$, $8.0\%$ corresponds to $183\,\text{mg/dL}$, and $10.0\%$ corresponds to $240\,\text{mg/dL}$.

Factors Impacting A1C Accuracy

Clinical factors and physiological conditions that distort glycated hemoglobin readings, including anemia types, erythropoiesis-stimulating drugs, recent blood transfusions, end-stage kidney disease, and pregnancy.

Diabetic Ketoacidosis (DKA)

An acute metabolic complication characterized by metabolic acidosis, ketone body accumulation, and serum glucose levels generally below $600\,\text{mg/dL}$ (mostly $350\text{--}500\,\text{mg/dL}$), where neurological complications are uncommon.

Hyperosmolar Hyperglycemic State (HHS)

An acute complication characterized by severe hyperglycemia (serum glucose usually $> 600\,\text{mg/dL}$), little to no ketoacid accumulation, and frequent neurological complications, resulting in coma in one-fourth to one-half of patients.

Ketogenesis

The biochemical pathway triggered by severe insulin deficiency where cells, unable to utilize glucose, break down fatty acids into acetyl-CoA, resulting in overproduction of ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone) and leading to ketoacidosis.

Dilutional Hyponatremia (Hyperglycemia-Induced)

A reduction in measured serum sodium caused by high intravascular glucose concentrations pulling free water osmotically from the intracellular space into the extracellular fluid.

Adult T2DM Screening Criteria

Screening recommended for all asymptomatic individuals aged $\ge 35\,\text{years}$, or in adults who are overweight or obese ($\text{BMI} \ge 25\,\text{kg/m}^2$) with at least one additional risk factor (such as family history, high-risk race/ethnicity, or comorbid conditions).

Pediatric T2DM Screening Criteria

Screening indicated in youth who are overweight ($\ge 85\text{th percentile}$) or obese ($\ge 95\text{th percentile}$) with one or more risk factors; testing begins after puberty onset or age $10\,\text{years}$ (whichever is earlier) and is repeated at minimum $3\text{-year}$ intervals.

One-Step Strategy for GDM

A screening protocol performing a $75\text{-g}$ OGTT after an overnight fast of $\ge 8\,\text{hours}$ at $24\text{--}28\,\text{weeks}$ of gestation; diagnosed if fasting $\ge 92\,\text{mg/dL}$, $1\text{-h} \ge 180\,\text{mg/dL}$, or $2\text{-h} \ge 153\,\text{mg/dL}$.

Two-Step Strategy for GDM

A diagnostic protocol using a nonfasting $50\text{-g}$ glucose load test (GLT) at $24\text{--}28\,\text{weeks}$; if $1\text{-h} \ge 130\text{--}140\,\text{mg/dL}$, a fasting $100\text{-g}$ OGTT is performed, with GDM confirmed if at least two Carpenter-Coustan thresholds are met.

DKA Glycemic Maintenance Target

The goal of maintaining blood glucose levels between $150\,\text{mg/dL}$ and $200\,\text{mg/dL}$ during acute insulin infusion until the patient is mentally alert and ketoacidosis resolves.

HHS Glycemic Maintenance Target

The goal of maintaining blood glucose levels between $250\,\text{mg/dL}$ and $300\,\text{mg/dL}$ during acute therapy until the patient is mentally alert and hyperosmolarity resolves.

IV and Subcutaneous Insulin Overlap Rule

The procedural requirement to continue IV insulin infusion for $2\text{--}4\,\text{hours}$ after administering the first subcutaneous insulin dose to prevent rebound hyperglycemia and ketoacidosis.

HHS Insulin Dose Titration Rule

The protocol requiring the IV insulin infusion dose to be doubled if serum glucose fails to decrease by $50\text{--}70\,\text{mg/dL}$ during the first hour of treatment.

Insulin Production and Action Regulation

The physiological feedback loop wherein high blood glucose postprandially stimulates pancreatic insulin release to store glucose as glycogen and produce energy, while low blood glucose stimulates pancreatic glucagon release to trigger glycogen breakdown into glucose.