What medications cause hyperglycemia ? these lead to reduced insulin and therefore increased blood sugar see slide 13 for the MOA

Diuretics: - Thiazides - Loop diuretics - Metalozone Atypical antipsychotics: - Olanzapine - Clozapine Beta-blockers: -Metoprolol Steroids/hormones: - Glucocorticoids - Oral contraceptives & estrogens - Thyroid hormones HIV therapies: - Protease inhibitors (navirs) - NRTIs (ex. tenofovir)

Module 4 - Endocrine Flashcards by Sam Myers

Low blood sugar promotes _____ release

glucagon

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High blood sugar promotes _____ release

insulin

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What is the best indicator of glucose homeostasis (regulation of catabolism and anabolism) ?

Fasting Plasma Glucose (FPG)

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FPG:

measures only at a ____ point in time (does not represent average)!

single

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FPG:
Patients should be instructed to ____ for at least 8 hours (8-12 is ideal), therefore overnight is most convenient (assay in the morning)

FAST

*only water can be consumed (no coffee, juices, gums, etc)

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Describe the Random Plasma Glucose test

Blood is taken at any time during the day regardless of food intake
Less valuable than fasting glucose in terms of diagnostic value (variable)

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What is the OGTT

Oral Glucose Tolerance Test:
-Testing the ability of the pancreas to secrete insulin to manage the glucose load and also the body’s response to the insulin

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Describe the OGTT in non-pregnant patients

Patient fasts (at least 8 hours)
Given 75g of glucose (drink in 5 mins)
Blood taken 2 hours after glucose given

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Describe the OGTT in pregnant patients

Patient fasts (at least 8 hours)
Givne 75g of glucose (drink in 5 mins)
Blood taken at both 1 and 2 hours after glucose given

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When does gestational diabetes usually show up?

at 24-28 weeks

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Who is screened for GDM ?

Every pregnant patient between 24 and 28 weeks gestation

*if there is a high risk of GDM based on multiple clinical factors, screening should be offered at any stage in the pregnancy

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What can increased blood glucose during pregnancy cause?

Fetal malformations (1st trimester)

- Metabolic complications and macrosomia (large babies) at birth

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What is the 1st step in screening for GDM?

50 g glucose challenge test with PG 1 hour later

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50 g glucose challenge test with PG 1 hour later:

If the result is <7.8 mmol/L what does that mean?

Normal value

Reassess at 24-28 weeks if tested earlier

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50 g glucose challenge test with PG 1 hour later:

If the result is 7.8-11.0 mmol/L what does that mean?

Perform a 75 g OGTT and measure FPG, 1hPG, and 2hPG

FPG > 5.3
1hPG > 10.6
2hPG > 9.0

If 1 value is met or exceeded

It means they have GDM

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50 g glucose challenge test with PG 1 hour later:

If the result is >11.0 mmol/L what does that mean?

Means they have GDM

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Describe the Glycosylated or Glycated Hemoglobin (Hgb A1C)

Glucose is irreversibly bound to hemoglobin in proportion to the average blood glucose
Lifespan of RBCs = 120 days therefore A1C reflects glucose over the last 2-3 months
Patients with persistently high glucose can have A1C’s as high as 20%

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What can cause an A1C to be falsely high?

Uremia
Alcoholism
Increased TGs
Splenectomy
Pregnancy

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What can cause an A1C to be falsely low?

Hemolysis

- Pregnancy

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What lab value indicates diabetes for FPG?

> 7 mmol/L

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What lab value indicates diabetes for random plasma glucose?

> 11.1 mmol/L

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What lab value indicates diabetes for a 2h OGTT ?

> 11.1 mmol/L

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What lab value indicates diabetes for A1C ?

> 6.5%

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What medications cause hyperglycemia ?

these lead to reduced insulin and therefore increased blood sugar
see slide 13 for the MOA

Diuretics:

Thiazides
Loop diuretics
Metalozone

Atypical antipsychotics:

Olanzapine
Clozapine

Beta-blockers:
-Metoprolol

Steroids/hormones:

Glucocorticoids
Oral contraceptives & estrogens
Thyroid hormones

HIV therapies:

Protease inhibitors (“navirs”)
NRTIs (ex. tenofovir)

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What is the 1st intervention for pre-diabetic patients?

diet and exericise

When do you re-test for pre-diabetic patients?

annually

Describe how thyroid hormones work (negative feedback loop)

- Hypothalamus in brain releases TRH (thyrotropin releasing hormone) - Anterior pituitary releases TSH (thyroid stimulating hormone) - Thyroid gland releases T4 (thyroxine) and T3 (triiodothyronine) *these hormones prevent the release of TRH and therefore TSH

How does cold affect TRH?

increases the amount of TRH, TSH and T3 and T4 to increase metabolic rate to compensate for the cold

How does stress affect TSH?

stress produces cortisol which decreases the amount of TSH and therefore the amount of thyroid hormones is decreased and hypothyroidism may develop

What is TSH ?

-A glycoprotein with an alpha and beta subunit similar to other hormones secreted by the anterior pituitary (LH and FSH)

Patients with primary hypothyroidism and major symptoms usually have elevations in TSH > ____ mU/L (mild symptoms 10-20 mU/L)

TSH may be falsely ____ in pregnancy

high

Why may TSH be falsely high in pregnancy?

because TSH and HCG are structurally similar

TSH reflects what?

long-term thyroid status (whereas T4 reflects short term)

TSH is ordered ______ before other thyroid tests

FIRST

Thyroxine is _____ T4

free

Thyroxine (Free T4): | Secreted by the _____ gland

thyroid

Thyroxine (Free T4): | How much T4 is normally produced daily by adults?

80 mcg

Thyroxine (Free T4): | ____ half life than T3 (7 days) but ____ potent

Longer half life Less potent

Thyroxine (T4): | Why must you read the lab report carefully?

T4 can be reported as total or free (total T4 measures both bound and free T4)

When is Thyroxine (Free T4) ordered?

if patient has signs and symptoms of hypothyroidism and TSH is normal or near normal

Triiodothyronine (Free T3): | ___% secreted by thyroid gland, remainder formed by deiodination of T4 by liver and kidneys

Triiodothyronine (Free T3): | How much of T3 is normally produced daily by adults

30 mcg

Triiodothyronine (Free T3): | ___x more potent than T4, but has a _____ half life (1 day)

3-4x more potent shorter half life

Triiodothyronine (Free T3): | Is it usually ordered?

Not usually ordered; only if hyperthyroidism is suspected, TSH is low and T4 is normal (T3 toxicosis)

List signs and symptoms of HYPOthyroidism

- lethargy/depression - constipation - weight gain - dry skin, hair and brittle nails - cold intolerance - paresthesias - slow deep tendon reflexes - decreased sweating - memory impairment - facial puffiness - slow motor activity

List signs and symptoms of HYPERthyroidism

- nervousness - fatigue - weight loss - heat intolerance - increased sweating - tachycardia - muscle atrophy - exophthalmos (bulging eyes)

Which drugs decrease thyroid hormones (T3 and T4)

- glucocorticoids - amiodarone - 6-MP - sulfonamides - lithium - phenobarb - antacids and binders

Which drugs increase thyroid hormones (T3 and T4)

- amphetamines - amiodarone - high dose propranolol - metoclopramide - high dose salicylates

What lab values will indicate sub-clinical HYPOthyroidism?

- Slight increase in TSH - Normal Free T4 - Normal Free T3

What is the explanation for sub-clinical HYPOthyroidism?

May occur in elderly patients, postpartum, inadequate replacement therapy etc. May or may not treat depending on symptoms and labs

What lab values will indicate primary HYPOthyroidism?

- High TSH - Low Free T4 - Low Free T3

What is the explanation for primary HYPOthyroidism?

Problem at the THYROID. | Thyroid is being stimulated but can't produce hormoens

What lab values will indicate central HYPOthyroidism?

- Normal or low TSH - Normal or low Free T4 - Normal or low Free T3

What is the explanation for central HYPOthyroidism?

Feedback mechanisms to pituitary or hypothalamus not working properly

What lab values will indicate HYPERthyroidism?

- Low TSH - High Free T4 - High Free T3

What is the explanation for HYPERthyroidism?

Graves's disease (60-90%) of cases - autoimmune disease activating the TSH receptor producing T3 and T4

How often should we monitor TSH and Free T4 after initiating therapy or changing dose?

-Reassess every 6-8 weeks after initiating therapy or changing dose (Css of TSH = about 6 weeks)

If patient on stable dose, how often should we monitor TSH and Free T4?

annually

If newly treated, symptoms such as fatigue, fast HR and puffiness tart to improve within _____ weeks, but anemia, skin/hair changes may take ______ to resolve

2-3 weeks months

If a hypothyroid patient becomes pregnant, monitor TSH and Free T4 every _____

trimester

If a hypothyroid patient becomes pregnant, their requirements ______

increase (up to 50% greater hormone requirements in pregnancy)

If a hypothyroid patient becomes pregnant and requires a dose increase, what dose increase do we recommend?

increase by 2 tablets of current dose per week

What is the TSH target range for first trimester (week 1-12)?

0.1-2.5 mU/L

What is the TSH target range for second trimester (week 13-26)?

0.2-0.3 mU/L

What is the TSH target range for third trimester (week 27 - end of pregnancy)?

0.3-3.0 mU/L

How do we manage hypothyroid patients after giving birth (post-partum) ?

- Reduce dose back to pre-conception dose | - Assess TSH levels 6-8 weeks postpartum for any dose adjustments

If someone has TSH that is 19.8 and Free T4 that is 6.2, what thyroid abnormality do they have and how do you know? What medication will they be started on?

primary HYPOthyroidism -TSH is high (stimulated thyroid) but thyroid is not producing enough hormones (T4 is low) - thyroid problem started on levothyroxine

Module 4 - Endocrine Flashcards

(68 cards)