Endocrine Flashcards
Danger Signals
(5)
HYPOGLYCEMIA
TYPE 1 DIABETES MELLITUS
THYROID CANCER
PHEOCROMOCYTOMA
HYPERPROLACTINEMIA
Hypoglycemia
Hypoglycemia refers to blood glucose that is
Patient complains of ____ness, hand _____, and anxiety and feels like p_____ out. Difficulty concentrating. More common in people with type __ diabetes mellitus (DM; only 5%–10% of DM is type 1, average of two episodes per week). If severe hypoglycemia is uncorrected, it will progress to ___.
Hypoglycemia refers to blood glucose that is <50 mg/dL.
Patient complains of weakness, hand tremors, and anxiety and feels like passing out. Difficulty concentrating. More common in people with type 1 diabetes mellitus (DM; only 5%–10% of DM is type 1, average of two episodes per week). If severe hypoglycemia is uncorrected, it will progress to coma.
Hypoglycemia
Nondiabetic hypoglycemia is rare and is either reactive (diet related) or fasting (disease related).
For diabetic individuals, the American Diabetes Association (ADA) defines
- Level 1 hypoglycemia (glucose alert) as fasting blood sugar (FBS) of ≤___ mg/dL.
- Level 2 hypoglycemia is blood glucose of ≤___ mg/dL. A blood glucose of this level is sufficiently low to indicate serious, clinically important hypoglycemia.
Nondiabetic hypoglycemia is rare and is either reactive (diet related) or fasting (disease related).
For diabetic individuals, the American Diabetes Association (ADA) defines
- Level 1 hypoglycemia (glucose alert) as fasting blood sugar (FBS) of ≤70 mg/dL.
- Level 2 hypoglycemia is blood glucose of ≤54 mg/dL. A blood glucose of this level is sufficiently low to indicate serious, clinically important hypoglycemia.
Type 1 Diabetes Mellitus
School-age child with recent onset of persistent thirst (______) with frequent urination (_____) and weight ____. Feeling of hunger even though eating an increased amount of food; weight loss. May be accompanied by _____ vision (osmotic effect on the lens). Breath has a “____” odor. Large number of _____in urine.
Children may present with diabetic _______ (DKA) and neurologic symptoms, such as drowsiness and leth____, which can progress to ____. May report a recent viral-like illness before the onset of symptoms. Diagnosis peaks from ages __ to __ years and again from ages __ to __ years.
School-age child with recent onset of persistent thirst (polydipsia) with frequent urination (polyuria) and weight loss. Feeling of hunger even though eating an increased amount of food; weight loss. May be accompanied by blurred vision (osmotic effect on the lens). Breath has a “fruity” odor. Large number of ketones in urine.
Children may present with diabetic ketoacidosis (DKA) and neurologic symptoms, such as drowsiness and lethargy, which can progress to coma. May report a recent viral-like illness before the onset of symptoms. Diagnosis peaks from ages 4 to 6 years and again from ages 10 to 14 years.
Thyroid Cancer
A single thyroid nodule, usually located on the ____ half of one lobe in a patient, may be accompanied by enlarged _____ lymph node lump, swelling, or pain. May complain of h____ness and problems with sw______ (dysphagia, dyspnea, or cough).
- Higher incidence in the ____ race. ______ therapy during childhood for certain cancers (Wilms’s tumor, lymphoma, neuroblastoma) and/or a low-iodine diet increases risk.
- Higher prevalence in what gender (1) (3:1).
- Highest incidence from age__ to __ years. Positive _____ history of thyroid cancer. Metastasis is by ____ route.
A single thyroid nodule, usually located on the upper half of one lobe in a patient, may be accompanied by enlarged cervical lymph node lump, swelling, or pain. May complain of hoarseness and problems with swallowing (dysphagia, dyspnea, or cough).
- Higher incidence in the Asian race. Radiation therapy during childhood for certain cancers (Wilms’s tumor, lymphoma, neuroblastoma) and/or a low-iodine diet increases risk.
- Higher prevalence in women (3:1).
- Highest incidence from age 20 to 55 years. Positive family history of thyroid cancer. Metastasis is by lymph route.
Pheochromocytoma
=
- It generally occurs in persons aged __ to __ years but can appear at any age.
- Random episodes of ____ache (can be mild to severe), dia______, and _____ cardia accompanied by (1).
- Episodes resolve _________. In between attacks, patient’s vital signs are normal.
A pheochromocytoma is a rare hormone-releasing adrenal tumor.
- It generally occurs in persons aged 20 to 50 years but can appear at any age.
- Random episodes of headache (can be mild to severe), diaphoresis, and tachycardia accompanied by hypertension.
- Episodes resolve spontaneously. In between attacks, patient’s vital signs are normal.
Pheochromocytoma Triggers
- Physical ex______, anx____, str____, surgery, anesthesia, changes in body _____, or labor and delivery.
- Foods high in ______ (some cheeses, beers, wines, chocolates, dried or smoked meats)
- (1) drug class and st______ drugs are other triggers.
- Physical exertion, anxiety, stress, surgery, anesthesia, changes in body position, or labor and delivery.
- Foods high in tyramine (some cheeses, beers, wines, chocolates, dried or smoked meats)
- Monoamine oxidase inhibitors (MAOIs) and stimulant drugs are other triggers.
Hyperprolactinemia
Can be a sign of a ______ adenoma.
Serum prolactin is elevated
- _____ onset.
- Women may present with ______.
- _______ in both males and females.
- When the tumor is large enough to cause a ____ effect, the patient will complain of (2)
Can be a sign of a pituitary adenoma.
Serum prolactin is elevated.
- Slow onset.
- Women may present with amenorrhea.
- Galactorrhea in both males and females.
- When the tumor is large enough to cause a mass effect, the patient will complain of headaches and vision changes.
Normal Findings
The endocrine system works as a “_______feedback” system. If a ____ level of “_____” hormones occurs, it stimulates production. Inversely, if the level of hormones is high, it _____ production.
- (1) stimulates the
- (1) into producing the “_______ hormones” (such as follicle-stimulating hormone [FSH], luteinizing hormone [LH], thyroid-stimulating hormone [or thyrotropin; TSH]). These stimulating hormones tell the
- (1) (e.g., ovaries, thyroid) to produce “_____” hormones (e.g., estrogen, thyroid hormone).
High levels of these “active” hormones work in reverse. The hypothalamus directs the anterior pituitary into stopping production of the stimulating hormones (e.g., TSH, LH, FSH).
The endocrine system works as a “negative feedback” system. If a low level of “active” hormones occurs, it stimulates production. Inversely, if the level of hormones is high, it stops production.
- Hypothalamus stimulates the
- Anterior pituitary gland into producing the “stimulating hormones” (such as follicle-stimulating hormone [FSH], luteinizing hormone [LH], thyroid-stimulating hormone [or thyrotropin; TSH]). These stimulating hormones tell the
- Target organs (e.g., ovaries, thyroid) to produce “active” hormones (e.g., estrogen, thyroid hormone).
High levels of these “active” hormones work in reverse. The hypothalamus directs the anterior pituitary into stopping production of the stimulating hormones (e.g., TSH, LH, FSH).
Hypothalamus Releasing Hormones
(5)
- Thyroid Releasing Hormone (TRH)
- Gonadotropin Releasing Hormone (GnRH)
- Corticotropin Releasing Hormone (CRH)
- Growth Hormone Releasing Hormone (GHRH)
- Somatostatin
Somatostatin inhibits release of GH from pituitary gland
Anterior Pituitary Stimulating Hormones
(7)
- Thyroid Stimulating Hormone (TSH)
- Follicle Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
- Growth Hormone (GH)
- Adrenocorticotropic Hormone (ACTH)
- Melanocyte Stimulating Hormone (MSH)
- Prolactin
Posterior Pituitary Stimulating Hormones
(2)
Antidiuretic Hormones (ADH)
Oxytocin
Target Organs and Effects
- Thyroid (TSH) =
- Ovaries/Testes (FSH/LH) =
- Adrenal Cortex (ACTH) =
- Body (GH) =
- Uterus (Oxytocin) =
- Kidneys (Vasopressin (ADH)) =
- Pineal (melatonin) =
- Breast (Prolactin) =
- Thyroid (TSH) = T3 and T4
- Ovaries/Testes (FSH/LH) = Estrogen, Progesterone, Androgens, Testosterone
- Adrenal Cortex (ACTH) = Glucocorticoids, Mineralcorticoids
- Body (GH) = Somatic growth
- Uterus (Oxytocin) = Uterine contractions, bonding
- Kidneys (Vasopressin (ADH)) = Blood volume
- Pineal (melatonin) = Circadian rhythm
- Breast (Prolactin) = Milk production
Endocrine Glands
These glands form the (1) axis
Hypothalamus
Coordinates the n____ and end______ system by sending signals via the ______ gland. The gland interacts to form the HPA axis. Produces neurohormones that stimulate or stop production of pituitary hormones.
Pituitary Gland
Located at the sella turcica (_____of the brain). Stimulated by the hypothalamus into producing the ______ hormones such as FSH, LH, TSH, adrenocorticotropic hormone (ACTH), and growth hormone (GH).
These glands form the Hypothalamic-Pituitary-Adrenal (HPA) axis
Hypothalamus
Coordinates the nervous and endocrine system by sending signals via the pituitary gland. The gland interacts to form the HPA axis. Produces neurohormones that stimulate or stop production of pituitary hormones.
Pituitary Gland
Located at the sella turcica (base of the brain). Stimulated by the hypothalamus into producing the stimulating hormones such as FSH, LH, TSH, adrenocorticotropic hormone (ACTH), and growth hormone (GH).
Anterior Pituitary Gland (Adenohypophysis)
It has two lobes (anterior and posterior). The _____ pituitary gland produces hormones that directly regulate the target ____ (e.g., ovaries, testes, thyroid, adrenals).
It has two lobes (anterior and posterior). The anterior pituitary gland produces hormones that directly regulate the target organs (e.g., ovaries, testes, thyroid, adrenals).
FSH:
- Stimulates the ______ to enable growth of follicles (or ____)
- Production of _______
LH:
- Stimulates the ovaries to ______
- Production of _______ (by corpus luteum)
- In males, LH stimulates the testicles (____cells) to produce ______
FSH:
- Stimulates the ovaries to enable growth of follicles (or eggs)
- Production of estrogen
LH:
- Stimulates the ovaries to ovulate
- Production of progesterone (by corpus luteum)
- In males, LH stimulates the testicles (Leydig cells) to produce testosterone
TSH:
- Stimulates ____ gland
- Production of _______ (T3) and _____ (T4)
- GH*:
- Stimulates (1) of the body
TSH:
- Stimulates thyroid gland
- Production of triiodothyronine (T3) and thyroxine (T4)
- GH*:
- Stimulates somatic growth of the body
ACTH:
- Stimulates the ______ glands (two portions of gland: _____ and _____)
- Production of glucocorticoids (_____) and mineralocorticoids (______)
- Stimulates the adrenal glands (two portions of gland: medulla and cortex)
- Production of glucocorticoids (cortisol) and mineralocorticoids (aldosterone)
- Prolactin:*
- Affects lactation and ____ production
- Melanocyte-stimulating hormone:*
- Production of ______ in response to UV light; highest levels at night between __ p.m. and __ a.m.
- Prolactin:*
- Affects lactation and milk production
- Melanocyte-stimulating hormone:*
- Production of melatonin in response to UV light; highest levels at night between 11 p.m. and 3 a.m.
Posterior Pituitary Gland
Secretes ________ hormone (vasopressin) and _____, which are made by the hypothalamus but st____ and sec______ by the posterior pituitary.
Secretes antidiuretic hormone (vasopressin) and oxytocin, which are made by the hypothalamus but stored and secreted by the posterior pituitary.
Thyroid Gland
A butterfly-shaped organ (two lobes) located below the prominence of the thyroid _____(Adam’s apple). It is __inches long, and the lobes are connected by the _____. Uses _____to produce T3 and T4.
A butterfly-shaped organ (two lobes) located below the prominence of the thyroid cartilage (Adam’s apple). It is 2 inches long, and the lobes are connected by the isthmus. Uses iodine to produce T3 and T4.
Parathyroid Glands
Located _____ the thyroid glands (two glands behind each lobe). Produces (1) hormone, which is responsible for the _____ balance of the body by regulating the calcium loss or gain from the b____, k_____, and G______ tract (calcium absorption).
Located behind the thyroid glands (two glands behind each lobe). Produces parathyroid hormone (PTH), which is responsible for the calcium balance of the body by regulating the calcium loss or gain from the bones, kidneys, and gastrointestinal (GI) tract (calcium absorption).
Pineal Gland
Pea-sized gland located inside the ____ that produces _____. Melatonin regulates the sleep–wake cycle. _____ stimulates melatonin production, and ____ suppresses it.
Pea-sized gland located inside the brain that produces melatonin. Melatonin regulates the sleep–wake cycle. Darkness stimulates melatonin production, and light suppresses it.
Thyroid Gland Tests
- (1)* Used to detect goiter (generalized enlargement of gland), multinodular goiter, single nodule, and solid versus cystic masses
- (1):* Used as a diagnostic test for thyroid cancer
- (1):* Shows metabolic activity of thyroid gland
- Thyroid gland ultrasound:* Used to detect goiter (generalized enlargement of gland), multinodular goiter, single nodule, and solid versus cystic masses
- Fine-needle biopsy:* Used as a diagnostic test for thyroid cancer
- Thyroid scan (24-hour thyroid scan with RAIU):* Shows metabolic activity of thyroid gland
- RAIU = Radioactive iodine uptake test*
Laboratory Findings of Thyroid Disease
- _____ spot: Not metabolically active (more worrisome; rule out thyroid cancer); next step is to do?
- ____ spot: Metabolically active nodule with homogeneous uptake; usually benign; helpful in diagnosing recurrent disease
- Cold spot: Not metabolically active (more worrisome; rule out thyroid cancer); fine-needle aspiration biopsy
- Hot spot: Metabolically active nodule with homogeneous uptake; usually benign; helpful in diagnosing recurrent disease
TSH (thyroid-stimulating hormone or thyrotropin):
- Normal range: TSH of ____ to ____ mU/L (third-generation test).
- TSH is used for both screening and monitoring response to treatment.
- Recheck TSH every ___ to __ weeks. Dose of levothyroxine (Synthroid) is based on the TSH level. Goal is a TSH __ 5.0 mU/L.
- When TSH is stable, recheck every __ to __ months.
- Normal range: TSH of 0.5 to 5.0 mU/L (third-generation test).
- TSH is used for both screening and monitoring response to treatment.
- – Recheck TSH every 6 to 8 weeks. Dose of levothyroxine (Synthroid) is based on the TSH level. Goal is a TSH <5.0 mU/L.
- – When TSH is stable, recheck every 6 to 12 months.
What Thyroid Disorder do these labs show?
- TSH > 5.0
- Free T4 = Low
- T3 = Low
Hypothyroidism
What Thyroid Disorder do these labs show?
- TSH < 0.05
- Free T4 High
- T3 High
Hyperthyroidism
What Thyroid Disorder do these labs show?
- TSH >5.0
- Free T4 Normal
- T3 Normal
Subclinicial Hypothyroidism
What Thyroid Disorder do these labs show?
- TSH <0.05
- Free T4 Normal
- T3 Normal
Subclinical Hyperthyroidism
Primary Hyperthyroidism (Thyrotoxicosis)
(1) Disease =
The classic finding is a very ____ (or undetectable) TSH with _______ in both serum-free T4 and T3 levels.
Graves Disease
Chronic autoimmune disorder that is the most common cause for hyperthyroidism (60%–80%) in the United States
The classic finding is a very low (or undetectable) TSH with elevations in both serum-free T4 and T3 levels.
Graves’ Disease
Graves’ disease accounts for __% to __% of all types of hyperthyroidism. An ________ disorder causing hyperfunction and production of ______ thyroid hormones (T3 and T4).
- Higher incidence in what gender? (7:1 ratio).
- These women are also at higher risk for other autoimmune diseases such as rheumatoid arthritis (RA) and pernicious anemia (PA) and for osteopenia/osteoporosis due to increased metabolism.
Graves’ disease accounts for 60% to 80% of all types of hyperthyroidism. An autoimmune disorder causing hyperfunction and production of excess thyroid hormones (T3 and T4).
- Higher incidence in women (7:1 ratio).
- These women are also at higher risk for other _____ diseases such as (1) and (1) and for ____penia/porosis due to increased metabolism.
Classic Case of Graves Disease
______-aged woman ____ a large amount of weight rapidly with anxiety and insomnia. Cardiac symptoms (due to overstimulation) are pal_____, hypertension, atrial ______, or premature atrial contractions. W____ and m______ skin with increased pers______. May present with ________ and lid lag (Graves’ ophthalmopathy). More ______ bowel movements (looser stools). ____orrhea and (1) temperature intolerance. Enlarged thyroid (g_____) and/or thyroid nod______ present. May be accompanied by pretibial myx_____ (thickening of the skin usually located in the shins and gives an orange-peel appearance).
Middle-aged woman loses a large amount of weight rapidly with anxiety and insomnia. Cardiac symptoms (due to overstimulation) are palpitations, hypertension, atrial fibrillation, or premature atrial contractions. Warm and moist skin with increased perspiration. May present with ophthalmopathy and lid lag (Graves’ ophthalmopathy). More frequent bowel movements (looser stools). Amenorrhea and heat intolerance. Enlarged thyroid (goiter) and/or thyroid nodules present. May be accompanied by pretibial myxedema (thickening of the skin usually located in the shins and gives an orange-peel appearance).
Objective Findings of Graves Disease
- Thyroid: ______ enlarged gland (goiter), toxic ad_____, or multi______r goiter. May be tender to palpation or asymptomatic
- Extremities: Fine _____ on both hands, _____ palms, pretibial ______
- Eyes: Lid ___; ________in one or both eyes
- Cardiac: ______cardia, atrial ______, congestive heart failure, cardiomyopathy
- Integumentary: ____ hair, _____ skin
- Neurologic: _____ deep tendon reflexes
- Thyroid: Diffusely enlarged gland (goiter), toxic adenoma, or multinodular goiter. May be tender to palpation or asymptomatic
- Extremities: Fine tremors on both hands, sweaty palms, pretibial myxedema
- Eyes: Lid lag; exophthalmos in one or both eyes
- Cardiac: Tachycardia, atrial fibrillation, congestive heart failure, cardiomyopathy
- Integumentary: Fine hair, warm skin
- Neurologic: Brisk deep tendon reflexes
Graves Disease Labs
Look for very low ___(
- If Graves’ disease, will have positive (1) antibodies, which is also known as the (1) immunoglobulins
- The (1) antibody is positive with Graves’ disease as well as Hashimoto’s disease.
Look for very low TSH (<0.05 mU/L) with elevated serum-free T4 and T3.
- If Graves’ disease, will have positive thyrotropin receptor antibodies (TRAb), which is also known as the thyroid-stimulating immunoglobulins (TSIs)
- The thyroid peroxidase antibody (TPO) is positive with Graves’ disease as well as Hashimoto’s disease.
Graves Disease Workup
- Check (1).
- If low, order thyroid _____. Look for very ___ TSH (<0.05 mU/L) with ______ serum-free T4 and elevated T3. (In some patients with very low TSH, only either the serum T4 or the serum T3 will be elevated.)
- Next step is to order ______ tests to confirm whether Graves’ disease is present ( (1) and (1) or (1)).
If thyroid has a single palpable mass/nodule, order thyroid ______. Refer to ________for management.
- Check TSH.
- If low, order thyroid panel. Look for very low TSH (<0.05 mU/L) with elevated serum-free T4 and elevated T3. (In some patients with very low TSH, only either the serum T4 or the serum T3 will be elevated.)
- Next step is to order antibody tests to confirm whether Graves’ disease is present (TRAb and TPO or TSI).
- If thyroid has a single palpable mass/nodule, order thyroid ultrasound. Refer to endocrinologist for management.
Graves Disease Imaging Studies
- Thyroid ______
- (1) (RAIU) shows diffuse uptake (goiter).
- If solitary toxic nodule, shows warm or “__” nodule or “____” nodule. Absolute contraindications for this test are pr_____ and breast_______.
- Thyroid ultrasound
- 24-hour radioactive iodine uptake (RAIU) shows diffuse uptake (goiter).
- If solitary toxic nodule, shows warm or “hot” nodule or “cold” nodule. Absolute contraindications for this test are pregnancy and breastfeeding.
Graves Treatment
- Rx (1)**:* Shrinks thyroid gland/decreases hormone production.
- Rx (1)**:* Shrinks thyroid gland/decreases hormone production.
Which one is the preferred treatment for moderate to severe hyperthyroidism? (can cause _____ failure).
- Methimazole (Tapazole):* Shrinks thyroid gland/decreases hormone production.
- Propylthiouracil (PTU)**:* Shrinks thyroid gland/decreases hormone production.
PTU is preferred treatment for moderate to severe hyperthyroidism (can cause liver failure).
Side Effects of Methimazole and Propylthiouracil (PTU)
What 2 labs are important to monitor?
Skin ____
granulocyto____/aplastic ____, ______cytopenia - check (1)
______ necrosis - check (1)
Skin rash, granulocytopenia/aplastic anemia, thrombocytopenia (check complete blood count [CBC] with platelets), hepatic necrosis (monitor CBC, liver function tests [LFTs]).
If a pregnant woman has hyperthyroidism? What is the preferred medication? Can you take care of this patient by yourself?
For hyperthyroidism, PTU is preferred treatment, if needed. For high-risk pregnancy, refer to obstetrician.
Graves Disease Adjunctive Treatment
Rx (1)-(3)
Given to alleviate the symptoms of hyperstimulation (i.e., anxiety, tachycardia, palpitations
Betablockers are effective (e.g., propranolol, metoprolol, atenolol).
When using Radioactive Iodine to treat Graves - what conditions is it contraindicated to give radioactive iodine? What does radioactive iodine do to the thyroid gland? What will the person need for life?
Contraindicated during pregnancy or lactation. Permanent destruction of thyroid gland results in hypothyroidism for life (needs thyroid supplementation for life).
(1)
Complication of Graves Disease where an individual’s heart rate, blood pressure, and body temperature can soar to dangerously high levels. Acute worsening of symptoms due to stress or infection. Look for decreased level of consciousness (LOC), fever, abdominal pain. Lifethreatening. Immediate hospitalization needed.
Thyroid Storm (Thyrotoxicosis)
Primary Hypothyroidism
(1) Most common disease in the US
The classic lab finding for hypothyroidism is a ____ TSH with ____free T4 levels (do not confuse with total T4). Diagnosis is based on the lab findings.
Some of the most common causes are ______ thyroiditis, post_____ thyroiditis, and thyroid ablation with (1) (to treat hyperthyroidism).
Hashimoto’s Thyroiditis
The classic lab finding for hypothyroidism is a high TSH with low free T4 levels (do not confuse with total T4). Diagnosis is based on the lab findings.
Some of the most common causes are Hashimoto’s thyroiditis, postpartum thyroiditis, and thyroid ablation with radioactive iodine (to treat hyperthyroidism).
Hashimoto’s Thyroiditis
A chronic ______ disorder of the thyroid gland. There is generally no ____ with this thyroid swelling. The body produces destructive antibodies (1) against the thyroid gland that gradually destroys them. Almost all patients (90%) with Hashimoto’s thyroiditis have elevated TPOs. Most patients have developed a goiter. More common in (1) gender with ratio of 8:1.
A chronic autoimmune disorder of the thyroid gland. There is generally no pain with this thyroid swelling. The body produces destructive antibodies (TPOs) against the thyroid gland that gradually destroys them. Almost all patients (90%) with Hashimoto’s thyroiditis have elevated TPOs. Most patients have developed a goiter. More common in women with ratio of 8:1.
Classic Case of Hashimoto’s Thyroiditis
A middle-aged-to-older woman who is overweight complains of f____, weight ____, ____ intolerance, cons______, and menstrual abnormalities. May have alopecia on the outer one-third of both eyebrows. Serum ch______ is elevated. May have a history of another ______disorder (e.g., RA, PA).
A middle-aged-to-older woman who is overweight complains of fatigue, weight gain, cold intolerance, constipation, and menstrual abnormalities. May have alopecia on the outer one-third of both eyebrows. Serum cholesterol is elevated. May have a history of another autoimmune disorder (e.g., RA, PA).
(1)
Severe hypothyroidism is an endocrine emergency that is now rare (mortality rate 30%–40%). Patient presents with cognitive symptoms such as slowed thinking, poor short-term memory, depression (or dementia), hypotension, and hypothermia
Myxedema - Myxedema Coma
Hashimoto’s Thyroiditis Labs
- Order _____ first (TSH >___ mU/L).
- If elevated, order TSH again with (1) (free thyroxine).
- If TSH is ___ and serum-free T4 is ___, the diagnosis is hypothyroidism.
- Next step is to order (1): If elevated, confirms Hashimoto’s thyroiditis (gold-standard test for diagnosing Hashimoto’s thyroiditis).
- Order TSH first (TSH >5.0 mU/L).
- If elevated, order TSH again with free T4 (free thyroxine).
- If TSH is high and serum-free T4 is low, the diagnosis is hypothyroidism.
- Next step is to order TPOs: If elevated, confirms Hashimoto’s thyroiditis (gold-standard test for diagnosing Hashimoto’s thyroiditis).
(1)
Diagnosis If TSH is >5 mU/L (elevated), but serum-free T4 is within normal range, person is (asymptomatic to mild symptoms of hypothyroidism).
Decision to treat with Synthroid should be individualized. Some choose not to treat but recheck same labs again in 12 months.
- Subclinical Hypothyroidism*
- (nonpregnant adults)*
Hashimoto’s Thyroiditis Treatment
Rx (1)
Dose Range __-__ mcg/day
Increase Synthroid dose every few weeks until TSH is normalized (
Recheck TSH every __ to __ weeks until TSH is normalized (TSH <5.0 mU/L). When under control, check TSH every __ months.
Levothyroxine (Synthroid)
Dose Range 25-50 mcg/day
Increase Synthroid dose every few weeks until TSH is normalized (<5.0 mU/L).
Recheck TSH every 6 to 8 weeks until TSH is normalized (TSH <5.0 mU/L). When under control, check TSH every 12 months.
Levothyroxine Side Effects
Advise patient to report if pal_____, n_____ness, or tr______ because this means that Synthroid dose is too high (decrease dose until symptoms are gone and TSH is in normal range).
Start with _____ dose for older adults or patients with history of heart disease (watch for ang______, acute ____, atrial _______)
Advise patient to report if palpitations, nervousness, or tremors because this means that Synthroid dose is too high (decrease dose until symptoms are gone and TSH is in normal range).
Start with lowest dose for older adults or patients with history of heart disease (watch for angina, acute myocardial infarction [MI], atrial fibrillation).
Exam Tips
- Learn to diagnose (1) (TSH elevated with normal free T4).
- If patient has elevated TSH (>5.0 mU/L), workup needed for ________ (e.g., order ___, free ___).
- Start older patients at low dose of Synthroid (___–___ mcg/day) and gradually increase to avoid adverse ______ effects from overstimulation (palpitations, angina, MI).
- Patient with normal free T4 but with elevated TSH—do ___ treat (subclinical hypothyroidism). Recheck TSH in about __ months.
- Learn to diagnose subclinical hypothyroidism (TSH elevated with normal free T4).
- If patient has elevated TSH (>5.0 mU/L), workup needed for hypothyroidism (e.g., order TSH, free T4).
- Start older patients at low dose of Synthroid (12.5–25 mcg/day) and gradually increase to avoid adverse cardiac effects from overstimulation (palpitations, angina, MI).
- Patient with normal free T4 but with elevated TSH—do not treat (subclinical hypothyroidism). Recheck TSH in about 6 months.
Exam Tips
- Check TSH every __ to __ weeks (do not order earlier than 6 weeks) to monitor treatment response. If TSH is ___ to ____ mU/L, it is within normal limits and the patient is at the right dose (Synthroid).
- (1) treatment results in hypothyroidism for life. Supplement with thyroid hormone for life.
- If TSH is suppressed (TSH <0.05 mU/L), workup needed for _______.
- Chronic amenorrhea and hypermetabolism result in ______. Supplement with (1) and (1) 1,200 mg; engage in weight-bearing exercises.
- Check TSH every 6 to 8 weeks (do not order earlier than 6 weeks) to monitor treatment response. If TSH is 0.05 to 5.0 mU/L, it is within normal limits and the patient is at the right dose (Synthroid).
- Radioactive iodine treatment results in hypothyroidism for life. Supplement with thyroid hormone for life.
- If TSH is suppressed (TSH <0.05 mU/L), workup needed for hyperthyroidism.
- Chronic amenorrhea and hypermetabolism result in osteoporosis. Supplement with calcium and with vitamin D 1,200 mg; engage in weight-bearing exercises.
Clinical Pearls
- Many patients with subclinical hypothyroidism will eventually develop?
- Advise patient to _____ Synthroid tablets with teeth before swallowing with ____for better absorption. These tablets are synthetic T4 (levothyroxine).
- Alternative medicine practitioners are more likely to prescribe _____ thyroid tablets (desiccated thyroid glands from pigs), which contain _____ T3 and T4 for hypothyroidism.
- All _____thyroid patients should be referred to an endocrinologist as soon as possible.
- Many patients with subclinical hypothyroidism will eventually develop overt hypothyroidism.
- Advise patient to crush Synthroid tablets with teeth before swallowing with water for better absorption. These tablets are synthetic T4 (levothyroxine).
- Alternative medicine practitioners are more likely to prescribe Armour thyroid tablets (desiccated thyroid glands from pigs), which contain natural T3 and T4 for hypothyroidism.
- All hyperthyroid patients should be referred to an endocrinologist as soon as possible.