Thyroid Iodine Uptake (RAIU) Test Overview
32 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which condition is associated with an increased radioiodine uptake (RAIU)?

  • Silent Thyroiditis
  • Iodine-Induced Thyroiditis
  • Graves Disease (correct)
  • Subacute Thyroiditis

What is the optimal temperature for accurately determining the basal metabolic rate (BMR) of a subject who is undressed?

  • 24-26ºC (correct)
  • 18-20ºC
  • 26-28ºC
  • 20-22ºC

Which measurement device is used to determine body oxygen consumption during BMR assessment?

  • Benedict Spirometer (correct)
  • Pulse Oximeter
  • Thermal Calorimeter
  • Respirometer

What must be avoided for 12 hours prior to BMR determination?

<p>Protein intake (B)</p> Signup and view all the answers

Which of the following factors is NOT necessary for accurately determining BMR?

<p>Physical effort within the last week (D)</p> Signup and view all the answers

What is the primary principle behind the determination of the basal metabolic rate (BMR)?

<p>Direct relationship between body oxygen consumption and heat production (B)</p> Signup and view all the answers

In conditions of thyrotoxicosis, an early decline in thyroidal radioiodide content may indicate which phenomenon?

<p>Decreased urinary excretion (A)</p> Signup and view all the answers

To accurately assess BMR, how long should a subject avoid eating before the test?

<p>12 hours (D)</p> Signup and view all the answers

What is the primary purpose of the radioactive iodine uptake (RAIU) test?

<p>To quantify how much iodine the thyroid gland absorbs (D)</p> Signup and view all the answers

Which of the following factors can cause a decrease in RAIU values?

<p>Increased dietary intake of iodine (A), Usage of antithyroid medications (D)</p> Signup and view all the answers

Which time intervals are used for dosimetry readings in the RAIU test?

<p>2 hours and 24 hours (A)</p> Signup and view all the answers

What are the normal values for 24-hour RAIU?

<p>5 to 30 percent (B)</p> Signup and view all the answers

How does external application of iodide affect RAIU measurements?

<p>It suppresses radioiodide uptake (D)</p> Signup and view all the answers

What does the RAIU test measure in relation to kidney function?

<p>Thyroid clearance rate relative to the kidney (D)</p> Signup and view all the answers

Which condition is most likely associated with increased thyroidal RAIU?

<p>Excessive production of thyroid hormone (B)</p> Signup and view all the answers

What timing is crucial before taking the RAIU test?

<p>The patient should not eat for 2 hours before (A)</p> Signup and view all the answers

What is the maximum dose of glucose that a patient should consume during an OGTT?

<p>75 g (A)</p> Signup and view all the answers

What is the fasting duration required before the OGTT?

<p>8-14 hours (C)</p> Signup and view all the answers

If the one-hour glycemia level exceeds 140 mg/dl, what does it suggest?

<p>Abnormal insulin secretion (B)</p> Signup and view all the answers

When should the 2-hour blood sample be collected during the OGTT?

<p>At the completion of 2 hours post-ingestion (B)</p> Signup and view all the answers

What defines the 'ascendent slope' in the graphic representation of the OGTT results?

<p>Synthesis of insulin release (C)</p> Signup and view all the answers

What does a 2-hour glycemia level exceeding 120 mg/dl indicate?

<p>Insufficient insulin synthesis (A)</p> Signup and view all the answers

Which of the following is NOT a primary consequence of chronic hyperglycemia associated with diabetes mellitus?

<p>Hypoglycemia (D)</p> Signup and view all the answers

What should patients follow in their diet 3 days prior to the OGTT?

<p>Standard diet including 150 g sugars (D)</p> Signup and view all the answers

What is the primary function of the Benedict spirometer in the determination of oxygen consumption?

<p>To remove water vapors and carbon dioxide from the air (A)</p> Signup and view all the answers

How is the oxygen consumption calculated over 24 hours according to the provided calculations?

<p>By multiplying the volume consumed in 6 minutes by 10 and 24 (D)</p> Signup and view all the answers

What is the correct isocaloric coefficient for oxygen consumption, based on macronutrient metabolism?

<p>4.85 Kcal/l O2 (B)</p> Signup and view all the answers

What does an increased ΔBMR indicate in relation to thyroid function?

<p>Hyperthyroidism (A)</p> Signup and view all the answers

Which component is essential for calculating the Basic Metabolic Rate (BMR) using oxygen consumption data?

<p>Body surface area in square meters (D)</p> Signup and view all the answers

What physiological process does the oral glucose tolerance test primarily evaluate?

<p>Insulin response to carbohydrate intake (D)</p> Signup and view all the answers

Which factor contributes to the variation in the calculated BMR compared to theoretical values?

<p>The percentage difference (ΔBMR) (C)</p> Signup and view all the answers

The height of the graphic showing oxygen consumption is multiplied by which factor to determine the volume consumed?

<p>The area of the spirometer cylinder (C)</p> Signup and view all the answers

Flashcards

Radioactive Iodine Uptake (RAIU) Test

A test that uses a radioactive tracer to measure how much iodine the thyroid gland absorbs from the blood.

Radioactive Iodine (131I)

A radioactive isotope of iodine used in RAIU tests to measure thyroid gland function.

Thyroidal Radioactive Iodine Uptake (RAIU)

The percentage of radioactive iodine absorbed by the thyroid gland within a specific timeframe (usually 24 hours).

Dietary Iodine Intake and RAIU

High levels of iodine in the diet can suppress RAIU values, potentially making the test results less accurate.

Signup and view all the flashcards

RAIU and Thyroid Conditions

Increased RAIU usually suggests hyperthyroidism, whereas decreased RAIU often indicates hypothyroidism.

Signup and view all the flashcards

External Iodine Sources and RAIU

Iodine-containing substances, such as contrast media, antiseptics, and certain drugs, can interfere with RAIU by suppressing iodine uptake.

Signup and view all the flashcards

High RAIU and Iodine Intake

High RAIU due to excessive iodine intake may not necessarily indicate hyperthyroidism.

Signup and view all the flashcards

Low RAIU and Iodine Intake

Low RAIU due to low iodine intake may not necessarily indicate hypothyroidism.

Signup and view all the flashcards

Basal Metabolic Rate (BMR)

The minimal amount of energy required to sustain basic life functions at rest.

Signup and view all the flashcards

BMR Determination

The process of measuring the body's oxygen consumption to determine BMR. It involves a closed system where the subject breathes pure oxygen for a set duration, and the oxygen consumed is measured.

Signup and view all the flashcards

Benedict Spirometer

A device used to measure oxygen consumption in BMR determination. It uses a closed system with a cylinder filled with pure oxygen, and the oxygen consumed is measured by the change in volume within the cylinder.

Signup and view all the flashcards

Rest Conditions

A condition essential for accurate BMR determination, where the subject is at complete rest, free from physical or mental exertion.

Signup and view all the flashcards

Fasting Condition

A condition vital for precise BMR measurement, where the subject has not consumed food for 12 hours before the test.

Signup and view all the flashcards

Comfort Temperature

A condition required for accurate BMR measurement, ensuring the body temperature is optimal (20-22°C for dressed subjects and 24-26°C for undressed subjects) to avoid energy expenditure for thermoregulation.

Signup and view all the flashcards

Emotional Calmness

A condition critical for precise BMR measurement, where the subject is in a relaxed and stress-free environment.

Signup and view all the flashcards

Oxygen Consumption Measurement

The process of measuring the amount of oxygen consumed by the body during the BMR test.

Signup and view all the flashcards

Oxygen Caloric Coefficient

The amount of energy released by 1 liter of oxygen when metabolizing sugars, proteins, or lipids.

Signup and view all the flashcards

h

The height of the graphic recorded on the Benedict spirometer, which represents the amount of oxygen consumed.

Signup and view all the flashcards

VO2 / 6 min

The volume of oxygen consumed in 6 minutes, calculated by multiplying the height "h" by the cylinder surface area.

Signup and view all the flashcards

VO2 / 24 hours

The volume of oxygen consumption per 24 hours, calculated by multiplying the 6-minute oxygen consumption by 40.

Signup and view all the flashcards

Isocaloric Coefficient

The average caloric coefficient of sugars, proteins, and lipids, representing the energy released per liter of oxygen.

Signup and view all the flashcards

Energy Consumption/24 hours

The energy consumption per 24 hours calculated by multiplying the daily oxygen consumption (VO2/24 hours) by the isocaloric coefficient.

Signup and view all the flashcards

BMR

The basal metabolic rate (BMR) is the minimum energy required by the body to function at rest, calculated by dividing the energy consumption per 24 hours by the body surface area.

Signup and view all the flashcards

Oral Glucose Tolerance Test (OGTT)

A test that measures how well the body regulates blood sugar levels after consuming a sugary drink.

Signup and view all the flashcards

Fasting Glycemia

The amount of glucose in the blood before eating.

Signup and view all the flashcards

1-hour Glycemia

The amount of glucose in the blood one hour after drinking the sugary drink.

Signup and view all the flashcards

2-hour Glycemia

The amount of glucose in the blood two hours after drinking the sugary drink.

Signup and view all the flashcards

Diabetes Mellitus

A condition where the body either doesn't produce enough insulin or can't use it properly, resulting in high blood sugar levels.

Signup and view all the flashcards

Insulin

A hormone that helps the body use glucose for energy.

Signup and view all the flashcards

Insulin Sensitivity

The body's ability to use insulin effectively.

Signup and view all the flashcards

Type 1 Diabetes

A condition where the body doesn't produce enough insulin.

Signup and view all the flashcards

Study Notes

Thyroid Iodine Uptake (RAIU) Test

  • The RAIU test measures how much radioactive iodine the thyroid gland absorbs from the blood.
  • This is used to assess thyroid function.
  • A tracer (131I) is administered orally.
  • Gamma scintillation counters are used to measure uptake at 4 and 24 hours.
  • Patients should fast for 2 hours before the test and avoid antithyroid medication for 5-7 days prior.
  • Radioactive iodide (11 µCu) is administered orally or intravenously.
  • The percentage of thyroidal iodide uptake (RAIU) is calculated from the counts per constant time unit at 2 and 24 hours.
  • The 24-hour RAIU percentage is typically the most valuable measurement.
  • Normal 24-hour RAIU values range from 5% to 30%.
  • Low values can be due to increased dietary iodine intake (e.g., iodized bread).
  • High iodine intake (e.g., from contrast media or amiodarone) can suppress RAIU, affecting results.
  • Increased uptake may indicate hyperthyroidism (overactive thyroid) or diseases affecting renal function.
  • Decreased uptake may indicate hypothyroidism (underactive thyroid) or iodine-induced suppression.
  • RAIU does not measure hormone production; it assesses thyroid uptake of iodine.

Basal Metabolic Rate (BMR)

  • BMR represents the minimum energy needed to sustain basic vital processes like respiration and circulation.
  • Accurately determining BMR requires specific conditions: rest (no physical or mental exertion in the previous day), fasting (12 hours prior) , avoiding protein rich meals, and maintaining comfortable temperature (20-22°C for dressed, 24-26°C for undressed persons).
  • A Benedict spirometer measures oxygen consumption to calculate BMR.
  • The patient breathes pure oxygen in a closed system for 6 minutes.
  • The apparatus tracks oxygen usage and the height of the slope is calculated.
  • The oxygen consumption is converted to energy units (kcaloules).
  • The energy consumption over 24 hours is calculated by multiplying the 6-minute oxygen consumption by a constant (to convert).
  • The amount of energy (kcal/m^2 body surface) is the BMR.
  • The obtained BMR value is compared to standard values for similar sex and age (Harris-Benedict tables) to evaluate if the BMR is within a healthy range.
  • Deviations from normal BMR may indicate hyperthyroidism (elevated BMR) or hypothyroidism (decreased BMR).

Oral Glucose Tolerance Test (OGTT)

  • The OGTT evaluates the body's response to glucose by measuring blood glucose and insulin levels after glucose intake.

  • The test entails giving a specific amount of glucose (usually 75g) and collecting blood samples routinely at various time intervals (e.g. 0, 30, 60, 90 and 120 minutes).

  • Blood glucose concentration is directly measured for each time point

  • Blood insulin concentrations are also directly measured to follow metabolic response.

  • Normal blood glucose response following the glucose load should increase, but then gradually return to baseline, so that values return close to the preload glucose concentrations over time.

  • A high glucose level one hour or two hours after the ingestion of glucose can indicate impaired glucose tolerance, or diabetes mellitus.

  • Values outside the normal ranges can indicate underlying issues like diabetes.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Thyroid Iodine Uptake PDF

Description

This quiz focuses on the Radioactive Iodine Uptake (RAIU) Test, which measures how much radioactive iodine is absorbed by the thyroid gland. It assesses thyroid function and offers details about the procedure, considerations, and interpretation of results. Participants will learn about normal range values and factors that may affect the test outcome.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser