Endocrine Disorderd Flashcards
It is a network of glands throughout your body that make hormones.
The endocrine system
These are chemical messengers that travel through your bloodstream to your organs, tissues, and cells and regulate different bodily functions.
They are like a complex communication system that keeps everything working together.
Hormones
It connects the nervous system and endocrine system; controls hormones from the central nervous sytem
Hypothalamus
It produces melatonin that regulates sleep
Pineal Gland
It regulates metabolism and use of energy
Thyroid
It produces testosterone that controls male puberty and ability to produce sperm
Testis
It produces hormones that regulate blood glucose
Pancreas
It produces estrogen that controls female puberty and progesterone that manages fertility
Ovary
It produces hormones that help regulate metabolism and other body functions
Adrenal Gland
It monitors and regulates growth hormones; also controls reproductive glands
Pituitary Gland
It is a butterfly-shaped gland located in the front of your lower neck, just below your Adam’s apple.
The thyroid gland
The two active hormones secreted by the thyroid, and are iodinated derivatives of the amino acid tyrosine;
Thyroxine (T4; about 90% of output) containing four iodine atoms, and
Triiodothyronine (T3; about 10% of output) containing three iodine atoms.
There are several different thyroid function tests, but the most common ones measure the levels of:
● Thyroid-stimulating hormone (TSH)
● Thyroxine (T4)
● Free thyroxine (FT4)
● Triiodothyronine (T3)
It is usually the first test done because it is the most sensitive indicator of thyroid function. It measures the level of TSH in your blood.
TSH test
It is a hormone produced by the pituitary gland that stimulates the thyroid gland to produce T4.
TSH
It measures the level of total thyroxine in your blood.
T4 test
It is the main thyroid hormone produced by the thyroid gland.
T4
It measures the level of free thyroxine in your blood.
FT4 test
It is the active form of T4 that can enter your cells and affect your metabolism.
Free thyroxine
It measures the level of triiodothyronine in your blood.
However, this test is not usually done as part of a routine thyroid function test because the level of T3 in your blood can be affected by illness and other factors
T3 test
It is a more potent form of thyroid hormone than T4.
T3
A condition where the thyroid gland doesn’t produce enough thyroid hormone, slowing down metabolism.
Hypothyroidism
This is an autoimmune disease that is the most common cause of hypothyroidism.
It causes inflammation of the thyroid gland, which can damage the gland and reduce its ability to produce thyroid hormone.
Hashimoto’s thyroiditis
This is an inflammation of the thyroid gland that can be caused by a virus, bacteria, or a medication.
Thyroiditis
It is a mineral that is necessary for the production of thyroid hormone.
Severe deficiency is uncommon in developed countries because table salt is iodized, but it can still be a cause of hypothyroidism in some parts of the world.
Iodine
This is a rare condition that is present at birth.
It can be caused by a number of factors, including a developmental problem with the thyroid gland or a lack of iodine in the mother’s diet during pregnancy.
Congenital hypothyroidism
This is the most common type of hypothyroidism, and it occurs when the thyroid gland itself isn’t producing enough thyroid hormone.
Primary hypothyroidism
This is a less common type that occurs when the pituitary gland, a small gland at the base of the brain, doesn’t produce enough thyroid-stimulating hormone (TSH).
TSH tells the thyroid gland how much thyroid hormone to make.
Secondary hypothyroidism
This is a rare type that occurs when the hypothalamus, a part of the brain located above the pituitary gland, doesn’t produce enough thyrotropin-releasing hormone (TRH).
TRH tells the pituitary gland to make TSH.
Tertiary hypothyroidism
TSH (Thyroid-Stimulating Hormone):
○ Normal range:
0.5 to 5.0 mIU/L for adults
T4 (Thyroxine):
○ Normal range:
0.7 to 1.9 ng/dL for adults.
T3 (Triiodothyronine):
○ Normal range:
80 to 220 ng/dL for adults.
Medications that can Increase TSH:
Dopamine agonists
Steroids
Somatostatin analogs
Amiodarone
Psychiatric medications
Used to treat Parkinson’s disease and restless legs syndrome
Dopamine agonists: levodopa, cabergoline
It can temporarily elevate TSH levels.
Steroids: Prednisone and other corticosteroids
Used to treat acromegaly and some neuroendocrine tumors
Somatostatin analogs: octreotide, lanreotide
A medication used to treat certain heart rhythm problems can significantly alter thyroid function tests and requires careful monitoring.
Amiodarone
commonly used for bipolar disorder, can raise TSH levels and sometimes cause hypothyroidism.
Lithium
Medications that can Decrease TSH:
Levothyroxine
Dopamine antagonists
It is the synthetic form of T4 used to treat hypothyroidism.
Levothyroxine
Medications used for nausea and vomiting (e.g., metoclopramide, prochlorperazine) can suppress TSH.
Dopamine antagonists
Medications that can Increase T4 and FT4 levels:
Estrogens
Steroids
Medications that can Decrease T4 and FT4 levels:
Biotin supplements
Medications that can Affect T3 Levels:
Androgens
Glucocorticoids
Synthetic thyroid hormone to replace missing hormone. Long-term treatment, typically taken daily on an empty stomach.
Levothyroxine (Synthroid, Levothroid)
In cases where the patient’s body produces low levels of T3 and T4, we could give __ in the form of synthetic medications LT3 and LT4
hormone replacement therapies
It is the active form of thyroid hormone.
It directly affects cells throughout the body, influencing heart rate, breathing, digestion, and bone growth.
LT3 (liothyronine)
It is an inactive form of thyroid hormone. The body converts LT4 into LT3 in the liver and other tissues.
It is the primary hormone used in most thyroid replacement medications
LT4 (levothyroxine)
An overproduction of thyroid hormone, causing the body’s processes to speed up.
Hyperthyroidism
Causes of Hyperthyroidism
Graves’ disease (autoimmune)
thyroid nodules
excess iodine intake
Pharmaceutical Treatments:
• Antithyroid medications (Methimazole, Propylthiouracil)
• Beta-blockers (Propranolol, Atenolol
• Radioactive iodine therapy
• Thyroid surgery
Decrease thyroid hormone production. Regular monitoring needed to adjust dosage.
Antithyroid medications (Methimazole, Propylthiouracil)
Don’t affect thyroid function but manage symptoms like rapid heart rate and tremors.
Beta-blockers (Propranolol, Atenolol)
Destroys overactive thyroid tissue. May require lifelong thyroid hormone replacement later.
Radioactive iodine therapy
In severe cases, removal of part or all of the thyroid gland. Requires lifelong thyroid hormone replacement therapy.
Thyroid surgery
This is the preferred medication for most people with hyperthyroidism.
It can be taken once, twice, or three times a day depending on the dosage.
Methimazole
This medication may be used in specific situations, such as during pregnancy or if you cannot tolerate methimazole.
It’s typically taken two or three times a day.
Propylthiouracil (PTU)
How They Work:
● Both methimazole and PTU interfere with the incorporation of iodine into thyroid hormones.
A chronic condition affecting how your body regulates blood sugar (glucose) levels.
Diabetes Mellitus
Body cannot produce insulin (hormone that regulates blood sugar).
Type 1 diabetes
Body either doesn’t produce enough insulin or can’t use it effectively.
Type 2 diabetes
Autoimmune destruction of insulin-producing cells.
Type 1
Genetics, lifestyle factors (obesity, inactivity).
Type 2
● Measures the amount of glucose (sugar) in your bloodstream at a single point in time.
● Typically done after fasting for at least 8 hours, often overnight.
● Reflects your immediate blood sugar level and how well your body is regulating sugar
after not eating.
Fasting Blood Sugar (FBS)
● Measures the percentage of hemoglobin (protein in red blood cells) that has attached to glucose.
● Reflects your average blood sugar control over the past 2-3 months.
● Provides a broader picture of how well you’ve been managing your blood sugar levels
over time.
HbA1c (Hemoglobin A1c)
Normal Ranges:
● Fasting Blood Sugar (FBS):
○ Normal: Less than 100 mg/dL
○ Prediabetes: 100 to 125 mg/dL
○ Diabetes: 126 mg/dL or higher (on two separate tests)
Normal Ranges:
● HbA1c:
○ Normal: Below 5.7%
○ Prediabetes: 5.7% to 6.4%
○ Diabetes: 6.5% or higher
○ Often used as a screening tool for diabetes or prediabetes.
○ May be used to monitor blood sugar control in people with diabetes, especially if they experience symptoms of high or low blood sugar.
Fasting Blood Sugar
○ The preferred test for diagnosing diabetes by most healthcare organizations.
○ Used to monitor blood sugar control in people with diabetes and adjust treatment
plans as needed.
HbA1c
Injectable hormone to regulate blood sugar levels. Types and regimens vary depending on the type and severity of diabetes.
Insulin
● Starts working within minutes (5-15 minutes) of injection.
● Peak effect is typically within 1-2 hours.
● Duration of action lasts for 3-4 hours.
Rapid-acting insulin
Rapid-acting insulin Examples:
lispro (Humalog®)
aspart (NovoLog®)
glulisine (Apidra®)
l● Starts working within 30-60 minutes of injection.
● Peak effect is typically within 1-3 hours.
● Duration of action lasts for 6-8 hours.
Short-acting insulin
Often used to cover mealtime blood sugar spikes.
Rapid-acting Insulin
Often used before meals to prevent blood sugar spikes.
Short-acting Insulin
● Starts working within 1-2 hours of injection.
● Peak effect is typically within 4-8 hours.
● Duration of action lasts for up to 18 hours.
Intermediate-acting insulin
Often used to provide background insulin coverage throughout the day or night.
Immediate-acting Insulin
Intermediate-acting insulin Example:
NPH (Neutral Protamine Hagedorn) insulin (Humulin N®)
● Starts working slowly, typically within 1-2 hours.
● Doesn’t have a distinct peak effect.
● Duration of action can last for 24 hours or more.
Long-acting insulin
Often used to provide basal insulin coverage throughout the day and night.
Long-acting insulin
Long-acting insulin Examples:
glargine (Lantus®)
detemir (Levemir®)
● Newest type of long-acting insulin with an even slower onset of action.
● Provides consistent basal insulin coverage.
Ultra long-acting insulin
● Starts working within 6 hours of injection.
● Doesn’t have a distinct peak effect.
● Duration of action can last up to 42 hours.
Ultra long-acting insulin
Ultra long-acting insulin Example:
degludec (Tresiba®)
● Combinations of rapid-acting and intermediate-acting insulin in a single injection.
● Offers both mealtime coverage and background insulin.
● Ratios of rapid-acting to intermediate-acting insulin can vary depending on the product.
Pre-mixed insulin
● May not be suitable for everyone and require specific dosing strategies.
● Examples: Humulin 70/30® (70% NPH, 30% regular), NovoMix 30® (30% aspart, 70%
protamine aspart)
Pre-mixed Insulin
Can help the body produce or use insulin more effectively.
Combinations may be used.
Oral medications
● This is a newer class of medication not typically considered an oral antidiabetic agent, but it’s important to be aware of.
● They work by causing the kidneys to remove excess sugar through the urine. They are not taken orally and are a separate medication class.
SGLT2 Inhibitors
● How they work: Enhance the body’s natural incretin hormones, which stimulate insulin release and suppress glucagon secretion (glucagon raises blood sugar).
● Not technically classified as oral antidiabetic agents, but are sometimes taken orally.
DPP-4 Inhibitors (Incretin Mimetics)
Delay the absorption of carbohydrates from the small intestine, leading to a slower rise in blood sugar after meals.
Alpha-Glucosidase Inhibitors
Improve insulin sensitivity in muscle and fat tissues.
Thiazolidinediones (TZDs)
● How they work: Primarily work by reducing glucose production in the liver and improving insulin sensitivity in muscle cells.
● Example: Metformin
Biguanides
● How they work: Similar to sulfonylureas, they stimulate insulin secretion but have a shorter duration of action.
● Examples: repaglinide and nateglinide
Meglitinides
● How they work: Stimulate the pancreas to release more insulin.
● Examples: glimepiride, glipizide, gliclazide, and glyburide
Sulfonylureas
