Endocrine Diagnostics

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Questions and Answers

Which diagnostic test is most commonly used for monitoring long-term glucose control in patients with diabetes mellitus?

Hemoglobin A1C (correct)

Oral glucose tolerance test

C-Peptide

Fasting glucose

In Type 1 Diabetes Mellitus, what is the primary issue?

Lack of endogenous insulin (correct)

Overproduction of insulin

Problem with insulin utilization by cells

Insulin resistance

Which test provides information on concentration of thyroid hormones and can continual assessment of thyroid disorder treatment as well as screen for thyroid/ pituitary/ hypothalamus disorders?

Urinalysis

Fasting glucose

Liver function tests

TSH, T3/T4 (correct)

Which age group is usually diagnosed with Type 2 Diabetes Mellitus?

Older adults (>40yo) Signup and view all the answers

What lab test is used for the diagnosis and monitoring of DM2 as well as screening for hypoglycemia?

Fasting plasma glucose Signup and view all the answers

Which parameter represents normal fasting plasma glucose levels?

70-99 mg/dL Signup and view all the answers

Which test is crucial for assessing for elevated level of triglycerides and lower HDL and small LDL particles in patients with diabetes and other endocrine disorders?

Lipid panel Signup and view all the answers

Which hormone is released from the anterior pituitary gland to stimulate the thyroid to release mostly T4 and some T3?

TSH Signup and view all the answers

Which test is commonly used in screening for hyperthyroidism when used in combination with TSH?

T4 Signup and view all the answers

Which lab parameter is essential to assess before verifying abnormal calcium levels in patients with suspected parathyroid disorders?

Serum albumin levels Signup and view all the answers

What is the gold standard for the evaluation and management of Diabetes?

Hemoglobin A1C Signup and view all the answers

Which test checks the average blood sugar levels over the last 3 months?

Hemoglobin A1C Signup and view all the answers

What is the main reason for performing an Oral Glucose Tolerance Test (OGTT)?

To assess how the body processes sugar Signup and view all the answers

Which test requires fasting for at least 8 hours before its administration?

Oral Glucose Tolerance Test (OGTT) Signup and view all the answers

What is typically looked for in a urinalysis for patients with ambiguous symptoms or to help diagnosis or monitor patient's with DM?

Protein, Ketones, and Glucose Signup and view all the answers

What is measured by a C-Peptide test?

The protein byproduct of pancreas making insulin Signup and view all the answers

In what context would an Oral Glucose Tolerance Test be conducted for 1 hour or 3 hours?

For screening gestational DM Signup and view all the answers

What is the A1C range for prediabetes?

5.7%-6.4% Signup and view all the answers

What is the A1C that indicates diabetes?

>6.5 Signup and view all the answers

Why is it important to monitor liver function as a progression of Diabetes?

A and C Signup and view all the answers

What is NOT a concern of hyperglycemia in the kidneys?

Increase protein trapping Signup and view all the answers

Elevation in which lab could be a early sign of renal damage?

microalbumin Signup and view all the answers

LABS - DKA? HHS?

hyperglycemia around 250, hyperkalemia, hyponatremia = DKA hyperglycemia >600, serum osmolality >310 = HHS Blood pH greater than 7.3, positive ketones and blood in urine = DKA Elevated BUN and creatinine, no acidosis = HHS Signup and view all the answers

What is the initial test for cortisol insufficiency / Addison's Disease?

Morning Blood Cortisol level Signup and view all the answers

What is a first-line test for high cortisol disorders such as Cushing's?

B and C Signup and view all the answers

The definitive test for Cushing's or high cortisol adrenal disorder is the Dexamethasone suppression test.

True Signup and view all the answers

ADH disorders: Diabetes Insipidus or SIADH

High Urine output with LOW ADH = central DI High ADH with hyponatremia = SIADH HYPERnatremia and dehydrated = central DI Retain too much fluid and over-hydrated = SIADH Signup and view all the answers

Compare Central DI and Nephrogenic DI

Hypernatremia, dehydration, and fluid loss = Central and Nephrogenic DI Low ADH = Central DI High ADH = Nephrogenic DI Overhydrated with retained fluids and high ADH = SIADH Signup and view all the answers

Study Notes

Diabetes Mellitus

Regulation of blood glucose:
- Glucose serves as fuel for cellular functions
- Absorbed in the GI tract and metabolized into glucose from carbohydrates
- Stored in liver as glycogen
- Pancreas produces, stores, and releases insulin to facilitate glucose move into cells and out of bloodstream when plasma glucose is high
- Pancreas produces, stores, and releases glucagon to facilitate glucose breakdown and export into plasma when plasma glucose is low

Types of Diabetes Mellitus

Type 1:
- Lack of endogenous insulin
- Abrupt onset, usually in children
- Prone to ketoacidosis due to metabolism of fatty acids
- Treatment focused on glycemic control with diet and exogenous insulin
Type 2:
- Endogenous insulin present but problem with insulin utilization or release
- Usually diagnosed at older age (>40yo)
- Associated with obesity and dyslipidemia
- Not prone to ketoacidosis due to insulin presence
- Treatment focused on glycemic control with diet, exercise, weight loss, etc.

Laboratory Tests for Diabetes Mellitus

Plasma Glucose:
- Fasting (normal 70-99 mg/dL)
- Random (normal 70-140 mg/dL)
- Finger stick for screening or self-monitoring
- Used for diagnosis and monitoring of DM Type 2
Hemoglobin A1C:
- Venipuncture blood draw
- Checks average blood sugar over the last 3 months
- Gold standard for evaluation and management of Diabetes
C-Peptide:
- Protein byproduct of pancreas making insulin
- Measures amount of c-peptide in blood or urine
- Used in evaluation and management of Type 1 DM
Oral Glucose Tolerance Test (OGT T):
- Measures body's ability to process large amount of sugar
- Must fast for at least 8hrs before test
- Result is glucose level at the end of the test
- Used for screening and diagnosis of Type 2 DM
Urinalysis:
- Screening test for ambiguous symptoms
- Used to diagnose or monitor patients with DM
- Looks for protein, ketones, and glucose
Liver Function Tests:
- Follows liver function as a measure of diabetes progression
- Concerns include high insulin levels causing hepatocyte injury and development of fatty liver leading to increased insulin resistance
Renal Function Tests:
- Follows renal function as a measure of diabetes progression
- Concerns include nephropathy and potential kidney damage

Diabetic Ketoacidosis (DKA) vs. Hyperosmolar Hyperglycemic State (HHS)

Diabetic Ketoacidosis (DKA):
- Type 1 DM
- Precipitated by infection
- More severe illness
- Ketoacidosis
- Short prodromal symptoms (polyuria/polydipsia, N/V, drowsiness)
- Mortality 5-10%
Hyperosmolar Hyperglycemic State (HHS):
- Type 2 DM
- More common
- Uncommon
- Longer prodromal symptoms (days to weeks of weakness, polyuria/polydipsia, poor fluid intake)
- Mortality 40-60%

Laboratory Tests for DKA vs. HHS

DKA:
- Labs to get: BMP, blood glucose, UA for ketones (if positive then serum ketone), arterial blood gas
- Findings: hyperglycemia, positive ketones in urine and blood, blood pH < 3.10, no acidosis, anion gap, elevated BUN and Cr
HHS:
- Labs to get: BMP, blood glucose, UA for ketones (if positive then serum ketone), arterial blood gas
- Findings: hyperglycemia, no acidosis, anion gap, elevated BUN and Cr

Thyroid Disorders

Thyroid Function Tests:
- Purpose: measure concentration of hormones going to/secreted by the thyroid
- Screen for thyroid/pituitary/hypothalamus
- Continual assessment of thyroid disorder treatment
- Detecting antibodies to thyroid tissue
TSH:
- Released from anterior pituitary gland as part of a negative feedback loop from T4/T3
- Causes thyroid to release mostly T4 and some T3
- Uses: screening for thyroid disease and assessing thyroid function while on treatment
FT4:
- Measures the unbound serum T4
- Uses: in combination with TSH, used to screen for hypo/hyperthyroidism
- Monitoring disease progression and medical treatment for thyroid conditions
Thyroid Antibody Labs:
- Thyroglobulin (Tg) Antibody
- Thyroid Peroxidase (TPO) antibody: positive in Hashimoto's thyroiditis
- Thyrotropin Receptor Antibody's (TrAb): Thyroid stimulating immunoglobulin (TSI) - Grave's Disease

Parathyroid Disorders

Parathyroid Hormone (PTH):
- Regulates calcium and phosphate levels
- Produced by parathyroid glands
Things to Check:
- Calcium: normal range 8.5-10.2mg/dL
- First, verify abnormal calcium
- Total calcium corrected for albumin
- PTH
- Vitamin D
- Phosphorus
- Corrected calcium = serum calcium + (0.8 x [4.0 - serum albumin])
Pattern to Check:
- Start with corrected calcium
- If abnormal (high or low), then check PTH
- Correlate calcium level (high or low) with PTH level (high or low)
- Differentiate primary, secondary, and tertiary with other labs/PMH
- Vit D, Magnesium, etc.
Example Pattern:
- Hyperparathyroidism:
  - Primary (problem with the gland itself)
    - PTH elevated
    - Calcium elevated
    - Vit D normal/elevated
    - Phosphorus normal/low
- Secondary (problem with end organ, aka bone or kidneys)
  - PTH elevated
  - Calcium low/normal
- Tertiary (chronic stimulation leading to overproduction of PTH)
  - PTH elevated
  - Calcium low/normal

Adrenal Disorders

Cortisol insufficiency:
- Low cortisol
- Labs: morning blood cortisol level
- Addison's disease

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Description

Explore the regulation of blood glucose levels in the body, focusing on the role of insulin and glucagon in managing high and low blood sugar levels. Learn how glucose is absorbed, metabolized, and stored in the body to maintain optimal cellular function.

Endocrine Diagnostics - Skills