Endocrine drugs (insulin, thyroid medications)

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 1: A 22-year-old woman with type 1 diabetes mellitus and mild asthma comes to the physician for a follow-up examination. She has had several episodes of sweating, dizziness, and nausea in the past 2 months that occur during the day and always resolve after she drinks orange juice. She is compliant with her diet and insulin regimen. The physician recommends lowering her insulin dose in certain situations. This recommendation is most important in which of the following situations?

• A. After a stressful exam
• B. During a viral infection
• C. Before exercise (Correct Answer)
• D. After large meals
• E. During pregnancy

Endocrine drugs (insulin, thyroid medications) Explanation: ***Before exercise*** - Exercise increases **glucose utilization** by muscles, which can lead to **hypoglycemia** in individuals taking insulin if the dose isn't adjusted. - The patient's symptoms (sweating, dizziness, nausea) are classic for **hypoglycemia**, which resolves with sugar intake (orange juice). *After a stressful exam* - **Stress** typically elevates **counter-regulatory hormones** (e.g., cortisol, epinephrine), which can increase blood glucose levels rather than cause hypoglycemia. - An insulin dose reduction is usually not necessary and could lead to **hyperglycemia** in this situation. *During a viral infection* - Infections, even viral ones, often trigger the release of **stress hormones**, increasing glucose production and leading to **hyperglycemia** and increased insulin requirements. - Insulin doses usually need to be *increased*, not decreased, during illness to manage elevated blood sugar. *After large meals* - Large meals, especially those rich in carbohydrates, would necessitate an **increased or consistent insulin dose** to cover the glucose intake and prevent **postprandial hyperglycemia**. - Reducing insulin after a large meal would likely lead to uncontrolled high blood sugar rather than prevent hypoglycemia. *During pregnancy* - While insulin requirements can fluctuate throughout pregnancy, they generally **increase** in the second and third trimesters due to increased **insulin resistance**. - Reducing insulin during pregnancy without careful monitoring could lead to uncontrolled **hyperglycemia**, posing risks to both mother and fetus.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 2: A 13-year-old girl presents after losing consciousness during class 30 minutes ago. According to her friends, she was doing okay since morning, and nobody noticed anything abnormal. The patient’s mother says that her daughter does not have any medical conditions. She also says that the patient has always been healthy but has recently lost weight even though she was eating as usual. Her vital signs are a blood pressure of 100/78 mm Hg, a pulse of 89/min, and a temperature of 37.2°C (99.0°F). Her breathing is rapid but shallow. Fingerstick glucose is 300 mg/dL. Blood is drawn for additional lab tests, and she is started on intravenous insulin and normal saline. Which of the following HLA subtypes is associated with this patient’s most likely diagnosis?

• A. DR3 (Correct Answer)
• B. A3
• C. B8
• D. DR5
• E. B27

Endocrine drugs (insulin, thyroid medications) Explanation: ***DR3*** - The patient's presentation with **recent weight loss despite normal eating**, rapid but shallow breathing (**Kussmaul respiration** hinting at **metabolic acidosis**), elevated blood glucose (300 mg/dL), and loss of consciousness strongly suggests **Type 1 Diabetes Mellitus (T1DM)** presenting as **diabetic ketoacidosis (DKA)**. - **HLA-DR3** and **HLA-DR4** are the primary genetic markers most strongly associated with an increased susceptibility to Type 1 Diabetes Mellitus, an **autoimmune disease** affecting pancreatic beta cells. - **HLA-DR3** is the most direct answer as it is one of the two strongest HLA-DR associations with T1DM. *A3* - **HLA-A3** is primarily associated with **hemochromatosis**, a disorder of iron metabolism, and is not a common genetic marker for Type 1 Diabetes Mellitus. - The symptoms described in the patient (weight loss, hyperglycemia, DKA) are not characteristic of hemochromatosis. *B8* - **HLA-B8** is actually associated with Type 1 Diabetes Mellitus as part of the **extended haplotype A1-B8-DR3**, which shows strong linkage disequilibrium. - However, **HLA-B8 is not as directly or specifically associated with T1DM** as the HLA-DR subtypes (DR3 and DR4), which are considered the primary genetic markers. - When asking about HLA subtypes associated with T1DM, **DR3 or DR4** are the best answers as they show the strongest and most direct association. - HLA-B8 is also associated with other autoimmune conditions like **myasthenia gravis** and **Graves' disease**. *DR5* - While part of the **HLA-DR family**, **HLA-DR5** is less commonly associated with **Type 1 Diabetes Mellitus** compared to DR3 and DR4. - This subtype is more frequently linked with conditions like **pernicious anemia** or increased risk of certain infections. *B27* - **HLA-B27** is strongly associated with **seronegative spondyloarthropathies**, such as **ankylosing spondylitis** and **reactive arthritis**. - It has no known direct association with **Type 1 Diabetes Mellitus**.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 3: A 22-year-old woman with a history of type I diabetes mellitus presents to the emergency department with nausea, vomiting, and drowsiness for the past day. Her temperature is 98.3°F (36.8°C), blood pressure is 114/74 mmHg, pulse is 120/min, respirations are 27/min, and oxygen saturation is 100% on room air. Physical exam is notable for a confused and lethargic young woman. Initial laboratory values are notable for the findings below. Serum: Na+: 139 mEq/L Cl-: 100 mEq/L K+: 2.9 mEq/L HCO3-: 9 mEq/L BUN: 20 mg/dL Glucose: 599 mg/dL Creatinine: 1.1 mg/dL Ca2+: 10.2 mg/dL AST: 12 U/L ALT: 10 U/L An initial ECG is notable for sinus tachycardia. Which of the following is the best initial step in management for this patient?

• A. Normal saline and insulin
• B. Insulin and potassium
• C. Normal saline and potassium
• D. Normal saline, insulin, and potassium (Correct Answer)
• E. Normal saline, insulin, potassium, and sodium bicarbonate

Endocrine drugs (insulin, thyroid medications) Explanation: ***Normal saline, insulin, and potassium*** - This patient presents with signs and symptoms consistent with **diabetic ketoacidosis (DKA)**, including hyperglycemia (glucose 599 mg/dL), metabolic acidosis (HCO3- 9 mEq/L, respiratory compensation with elevated respiratory rate), and altered mental status. The initial management of DKA involves aggressive **intravenous fluid resuscitation** (normal saline), **insulin administration** to correct hyperglycemia and acidosis, and **potassium replacement** due to total body potassium depletion and anticipated further drop with insulin therapy. - Her **hypokalemia (2.9 mEq/L)**, even before insulin administration, necessitates immediate potassium repletion as insulin drives potassium intracellularly, which could worsen hypokalemia and lead to arrhythmias. *Normal saline and insulin* - While fluid resuscitation and insulin are crucial for DKA management, omitting **potassium replacement** in a patient with initial hypokalemia (K+ 2.9 mEq/L) would be inappropriate and potentially dangerous. - Failure to correct hypokalemia before or with insulin administration can precipitate life-threatening **cardiac arrhythmias**. *Normal saline, insulin, potassium, and sodium bicarbonate* - **Sodium bicarbonate** is generally not recommended for DKA unless pH is extremely low (typically <6.9), as it can worsen cerebral edema and hypokalemia. The patient's bicarbonate of 9 mEq/L and presumably higher pH does not warrant bicarbonate administration. - While fluids, insulin, and potassium are essential, the addition of sodium bicarbonate is usually reserved for severe, life-threatening acidosis (pH < 6.9). *Normal saline and potassium* - Administering only normal saline and potassium would address dehydration and hypokalemia but would fail to correct the underlying **hyperglycemia** and **ketoacidosis**, which are the core pathologies of DKA. - **Insulin** is critical to stop ketogenesis and lower blood glucose. *Insulin and potassium* - Administering insulin and potassium without **fluid resuscitation** would be inadequate. The patient is likely significantly dehydrated due to osmotic diuresis from hyperglycemia and vomiting. - **Fluid administration** is paramount in restoring circulating volume, improving renal perfusion, and reducing hyperglycemia by enhancing glucose excretion.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 4: An investigator is studying a drug that acts on the thyroid hormone pathway. Levels of serum free T3 and T4 in healthy participants are measured before and after administration of the drug. After administration, there is a decrease in the average serum free T3 level, while the average serum free T4 level is increased compared to initial serum studies. Inhibition of which of the following is the most likely mechanism of action of this drug?

• A. Thyroid-stimulating hormone
• B. Follicular iodotyrosine deiodinase
• C. Follicular thyroid peroxidase
• D. Peripheral 5'-deiodinase (Correct Answer)
• E. Follicular thyroid proteases

Endocrine drugs (insulin, thyroid medications) Explanation: ***Peripheral 5'-deiodinase*** - Inhibition of **peripheral 5'-deiodinase** would decrease the conversion of **T4 to T3** in the periphery, resulting in lower **free T3** and higher **free T4** levels. - This enzyme is crucial for activating T4 into the more potent T3, and its blockade explains the observed changes in hormone levels. *Thyroid-stimulating hormone* - Inhibition of **TSH** would lead to a decrease in the production and release of both **T3 and T4** from the thyroid gland. - This contradicts the observed increase in **free T4** levels. *Follicular iodotyrosine deiodinase* - This enzyme is involved in recycling iodine from **monoiodotyrosine (MIT)** and **diiodotyrosine (DIT)** within the thyroid follicular cells, which is important for efficient thyroid hormone synthesis. - Its inhibition would primarily affect iodine availability and synthesis, not directly lead to increased T4 and decreased T3 in the periphery. *Follicular thyroid peroxidase* - **Thyroid peroxidase (TPO)** is critical for the **iodination of tyrosine residues** on thyroglobulin and the **coupling of MIT and DIT** to form T3 and T4. - Inhibition of TPO would decrease the synthesis of both **T3 and T4**, contrary to the observed increase in **free T4**. *Follicular thyroid proteases* - **Thyroid proteases** cleave thyroglobulin to release mature **T3 and T4** into the bloodstream. - Inhibition of these proteases would lead to a decrease in the release of both **T3 and T4**, which does not align with the observed increase in **free T4**.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 5: A 44-year-old woman presents to her physician’s office for weakness. She reports having some difficulty placing books on a high shelf and getting up from a seated position. She denies muscle pain or any new rashes. She has noticed a tremor that is worse with action and has been having trouble falling asleep and staying asleep. She has lost approximately 10 pounds unintentionally over the course of 2 months. Medical history is significant for type I diabetes mellitus managed with an insulin pump. Family history is notable for systemic lupus erythematosus in her mother and panic disorder in the father. Her temperature is 98.6°F (37 °C), blood pressure is 140/85 mmHg, pulse is 102/min, and respirations are 17/min. On physical exam, she is mildly diaphoretic and restless, she has notable lid retraction, and her hair is thin. She has 4/5 strength in the proximal upper and lower extremities. Biceps and patellar tendon reflexes are 3+. Which of the following laboratory findings are most likely present in this patient?

• A. Anti-Mi-2 antibody positivity
• B. Decreased thyroid-stimulating hormone (Correct Answer)
• C. Anti-nuclear antibody positivity
• D. Increased erythrocyte sedimentation rate
• E. Normal laboratory results

Endocrine drugs (insulin, thyroid medications) Explanation: **Decreased thyroid-stimulating hormone** - The patient exhibits classic symptoms of **hyperthyroidism**, including unintended weight loss, heat intolerance (diaphoresis), fine tremor, insomnia, tachycardia (pulse 102/min), and proximal muscle weakness. Lid retraction and thin hair are also characteristic signs. - In primary hyperthyroidism, the excessive production of thyroid hormones (T3 and T4) by the thyroid gland suppresses the pituitary's release of TSH, leading to a **decreased TSH level**. *Anti-Mi-2 antibody positivity* - **Anti-Mi-2 antibodies** are specific to **dermatomyositis**, which typically presents with a characteristic dermatological rash (e.g., heliotrope rash, Gottron papules) in addition to proximal muscle weakness. The patient explicitly denies new rashes. - While proximal weakness is present, the absence of skin findings and the presence of significant hyperthyroid symptoms make dermatomyositis less likely. *Anti-nuclear antibody positivity* - **Anti-nuclear antibodies (ANAs)** are often positive in **autoimmune connective tissue diseases** like systemic lupus erythematosus (SLE), Sjogren's syndrome, and scleroderma. While the mother had SLE, the patient's constellation of symptoms points more directly to thyroid dysfunction. - While ANA can be positive in autoimmune thyroid disease, it's not the most direct or specific laboratory finding for the dominant clinical picture presented. *Increased erythrocyte sedimentation rate* - An **increased ESR** is a non-specific marker of **inflammation** and can be elevated in various conditions, including infections, autoimmune diseases, and certain cancers. - While ESR can be elevated in some cases of hyperthyroidism, it is not as specific or as direct a diagnostic marker for the condition as thyroid hormone levels themselves. *Normal laboratory results* - Given the clear and numerous signs and symptoms of a pathological process, particularly **hyperthyroidism**, it is highly unlikely that all laboratory results would be normal. - The constellation of symptoms like weight loss, tremor, palpitations, insomnia, and muscle weakness strongly indicates a significant underlying medical condition requiring laboratory investigation.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 6: A patient presents to the emergency room in an obtunded state. The patient is a known nurse within the hospital system and has no history of any medical problems. A finger stick blood glucose is drawn showing a blood glucose of 25 mg/dL. The patient's daughter immediately arrives at the hospital stating that her mother has been depressed recently and that she found empty syringes in the bathroom at the mother's home. Which of the following is the test that will likely reveal the diagnosis?

• A. Fasting blood glucose
• B. Urine metanephrines
• C. Genetic testing
• D. 24 hr cortisol
• E. C-peptide level (Correct Answer)

Endocrine drugs (insulin, thyroid medications) Explanation: ***C-peptide level*** - A **low C-peptide level** in the presence of **hypoglycemia** and high insulin levels confirms the diagnosis of **exogenous insulin administration** (factitious hypoglycemia). - **C-peptide** is cleaved from **proinsulin** in equimolar amounts with endogenous insulin, making it an excellent marker to differentiate endogenous insulin production from exogenous insulin injection. - In this case: **Low C-peptide + High insulin + Hypoglycemia** = exogenous insulin administration. *Fasting blood glucose* - The patient already has documented **hypoglycemia (25 mg/dL)**, so an additional fasting blood glucose test would not provide further diagnostic information about the **cause** of hypoglycemia. - A single fasting blood glucose level indicates current glucose status but **does not differentiate** between endogenous insulin overproduction (insulinoma) and exogenous insulin administration. *Urine metanephrines* - **Urine metanephrines** are used to diagnose **pheochromocytoma**, a catecholamine-secreting tumor of the adrenal medulla. - Pheochromocytoma presents with **hypertension**, palpitations, headaches, and diaphoresis—**not hypoglycemia**. - This test is not relevant to the differential diagnosis of hypoglycemia. *Genetic testing* - **Genetic testing** might be considered for rare hereditary causes of hypoglycemia, such as congenital hyperinsulinism or genetic insulinoma syndromes (e.g., MEN1). - Given the clinical context (depressed nurse with access to insulin and empty syringes found at home), **exogenous insulin administration** is far more likely than a genetic condition. - Genetic testing is not the appropriate initial diagnostic step in this scenario. *24 hr cortisol* - A **24-hour urinary cortisol** test is used to diagnose **Cushing's syndrome** (cortisol excess), not hypoglycemia. - While **adrenal insufficiency** (cortisol deficiency) can cause hypoglycemia, it typically presents with **hypotension**, **hyponatremia**, **hyperkalemia**, and **hyperpigmentation**—features not described in this case. - The clinical presentation strongly suggests insulin-related hypoglycemia rather than adrenal insufficiency.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 7: A 43-year-old woman comes to the physician for an annual health maintenance examination. On questioning, she has had fatigue and headaches for the last month. A few weeks ago, she had to have her wedding ring resized because it had become too small for her finger. She has mild persistent asthma and anxiety disorder. She drinks 2–3 glasses of red wine per night and has smoked one pack of cigarettes daily for 16 years. She works a desk job in accounting and has recently been working long hours due to an upcoming company merger. Her father has a history of a pituitary adenoma. Current medications include alprazolam, a fluticasone inhaler, and an albuterol inhaler. She is 160 cm (5 ft 3 in) tall and weighs 81.6 kg (180 lb); her BMI is 32 kg/m2. Her temperature is 37.2°C (99°F), pulse is 92/min, and blood pressure is 132/80 mm Hg. Examination shows no abnormalities. Fasting laboratory studies show: Hemoglobin 13 g/dL Serum Na+ 135 mEq/L K+ 4.6 mEq/L Cl- 105 mEq/L HCO3- 22 mEq/L Urea nitrogen 17 mg/dL Glucose 160 mg/dL Creatinine 0.9 mg/dL Which of the following is the most likely underlying mechanism of this patient's hyperglycemia?

• A. Decreased insulin production
• B. Adverse effect of medication
• C. Stress
• D. Insulin resistance (Correct Answer)
• E. Hypersecretion of ACTH

Endocrine drugs (insulin, thyroid medications) Explanation: ***Insulin resistance*** - The patient's **obesity (BMI 32 kg/m2)**, **sedentary lifestyle**, and **fasting hyperglycemia** (glucose 160 mg/dL) indicate **insulin resistance**, which is the underlying mechanism of hyperglycemia in **type 2 diabetes**. - The **ring resizing due to finger enlargement**, **fatigue**, **headaches**, and **family history of pituitary adenoma** raise suspicion for **acromegaly** (growth hormone excess), which also causes hyperglycemia through **insulin resistance** - growth hormone antagonizes insulin action at peripheral tissues. - Regardless of whether this represents type 2 diabetes or acromegaly, **insulin resistance is the direct mechanism** causing the hyperglycemia in this patient. *Decreased insulin production* - Decreased insulin production is characteristic of **type 1 diabetes** or late-stage type 2 diabetes with beta-cell exhaustion. - The patient's **obesity** and typical metabolic risk factors suggest **insulin resistance** rather than decreased production as the primary mechanism. - No clinical features suggest autoimmune destruction or significant pancreatic damage. *Adverse effect of medication* - The patient's medications (**alprazolam**, **fluticasone inhaler**, **albuterol**) are unlikely to cause significant fasting hyperglycemia. - While high-dose systemic **corticosteroids** can cause hyperglycemia, **inhaled fluticasone** at typical asthma doses has minimal systemic absorption and is not a common cause of sustained hyperglycemia. - **Alprazolam** and **albuterol** do not typically cause hyperglycemia. *Stress* - **Acute stress** can transiently elevate blood glucose through counter-regulatory hormones (cortisol, catecholamines). - However, the **fasting glucose of 160 mg/dL** suggests a chronic metabolic derangement rather than acute stress response alone. - Work-related stress may be a contributing factor but is not the primary underlying mechanism. *Hypersecretion of ACTH* - **ACTH hypersecretion** (Cushing's disease) causes excess cortisol production, leading to hyperglycemia, weight gain, and fatigue. - This patient lacks classic features of Cushing's syndrome: **central obesity with thin extremities**, **moon facies**, **buffalo hump**, **purple striae**, **skin thinning**, or **easy bruising**. - While the patient is obese, the distribution appears generalized rather than the characteristic centripetal pattern of Cushing's syndrome.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 8: A 14-year-old boy is rushed to the emergency room after he became disoriented at home. His parents say that the boy was doing well until 2 days ago when he got sick and vomited several times. They thought he was recovering but today he appeared to be disoriented since the morning. His vitals are normal except shallow rapid breathing at a rate of 33/min. His blood sugar level is 654 mg/dL and urine is positive for ketone bodies. He is diagnosed with diabetic ketoacidosis and is managed with fluids and insulin. He responds well to the therapy. His parents are told that their son has type 1 diabetes and insulin therapy options are being discussed. Which of the following types of insulin can be used in this patient for the rapid action required during mealtimes?

• A. Insulin detemir
• B. Insulin degludec
• C. NPH insulin
• D. Insulin glargine
• E. Insulin lispro (Correct Answer)

Endocrine drugs (insulin, thyroid medications) Explanation: ***Insulin lispro*** - **Insulin lispro** is a **rapid-acting insulin analog** designed to be taken immediately before or with a meal, offering quick onset (5-15 minutes) and short duration of action. - Its rapid action helps to control **postprandial glucose spikes**, closely mimicking the physiological insulin response to food, which is crucial for mealtime coverage in **Type 1 diabetes**. *Insulin detemir* - **Insulin detemir** is a **long-acting insulin analog** used for basal insulin coverage, providing a relatively constant insulin level over an extended period (12-24 hours). - It is not suitable for **mealtime insulin coverage** due to its slow onset of action and prolonged duration, which would not effectively manage postprandial glucose excursions. *Insulin degludec* - **Insulin degludec** is an **ultra-long-acting basal insulin analog** with a duration of action exceeding 42 hours, providing stable basal coverage. - Its extremely slow onset and prolonged duration make it unsuitable for **prandial (mealtime) insulin**, as it cannot address the rapid rise in blood glucose following a meal. *NPH insulin* - **NPH (Neutral Protamine Hagedorn) insulin** is an **intermediate-acting insulin** that provides basal insulin coverage, with an onset of 2-4 hours and a peak effect around 6-10 hours. - Its slow onset and prolonged action make it unsuitable for **mealtime insulin coverage**, as it would not adequately prevent the rapid rise in blood sugar immediately after eating. *Insulin glargine* - **Insulin glargine** is a **long-acting insulin analog** used for **basal insulin coverage**, providing a relatively flat and peakless insulin profile over 24 hours. - It is not used for **prandial (mealtime) insulin** because its slow onset and sustained action would not effectively counteract the rapid rise in blood glucose following a meal.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 9: A 3-year-old girl swallowed a handful of pills after her grandmother dropped the bottle on the ground this afternoon. She presents to the ER in a very drowsy but agitated state. She is clutching her abdomen, as if in pain, her skin is dry and flushed, and she does not know her name or where she is. Her pupils are dilated. Her grandmother reports that she has not urinated in several hours. The grandmother's medical history is significant for allergic rhinitis and osteoarthritis, both of which are treated with over the counter medications. What is the appropriate treatment for this child?

• A. N-acetylcysteine
• B. Naloxone
• C. Physostigmine (Correct Answer)
• D. Deferoxamine
• E. Atropine

Endocrine drugs (insulin, thyroid medications) Explanation: ***Physostigmine*** is the correct answer. - The patient's presentation with **dry, flushed skin**, **dilated pupils**, agitation, drowsiness, abdominal pain, and urinary retention is highly suggestive of **anticholinergic toxicity**. - **Physostigmine** is a **cholinesterase inhibitor** that increases acetylcholine levels, directly reversing the effects of anticholinergic poisoning. *N-acetylcysteine* - **N-acetylcysteine** is the specific antidote for **acetaminophen overdose**, which is not indicated by the patient's symptoms. - The symptoms described do not match the typical presentation of acetaminophen toxicity (e.g., hepatic damage). *Naloxone* - **Naloxone** is used to reverse **opioid overdose**, which typically presents with respiratory depression and miosis (pinpoint pupils), contrary to this patient's dilated pupils and lack of respiratory compromise. - The clinical picture does not suggest opioid intoxication. *Deferoxamine* - **Deferoxamine** is a chelating agent used to treat **iron overdose**, which can cause gastrointestinal symptoms but does not typically present with the anticholinergic signs seen here. - There are no indications of iron toxicity in the patient's history or symptoms. *Atropine* - **Atropine** is an **anticholinergic agent** itself and would worsen the patient's symptoms by further blocking acetylcholine receptors. - It is used to treat cholinergic crises, not overdose of anticholinergic drugs.

Endocrine drugs (insulin, thyroid medications) US Medical PG Question 10: A 44-year-old woman comes to the physician because of a 6-month history of fatigue, constipation, and a 7-kg (15.4-lb) weight gain. Menses occur irregularly in intervals of 40–50 days. Her pulse is 51/min, and blood pressure is 145/86 mm Hg. Examination shows conjunctival pallor and cool, dry skin. There is mild, nonpitting periorbital edema. Serum thyroid-stimulating hormone concentration is 8.1 μU/mL. Treatment with the appropriate pharmacotherapy is initiated. After several weeks of therapy with this drug, which of the following hormonal changes is expected?

• A. Increased TRH
• B. Increased T3
• C. Decreased T4
• D. Increased T4
• E. Decreased TSH (Correct Answer)

Endocrine drugs (insulin, thyroid medications) Explanation: ***Decreased TSH*** - The patient has **primary hypothyroidism** (elevated TSH 8.1 μU/mL, symptoms of fatigue, constipation, bradycardia, weight gain, cool dry skin) and is treated with **levothyroxine (synthetic T4)**. - The phrase **"after several weeks of therapy"** is key: while T4 levels rise within days of starting levothyroxine, **TSH takes 6-8 weeks to normalize** due to the negative feedback loop. - As circulating thyroid hormone levels are restored, the **hypothalamic-pituitary-thyroid axis** re-establishes negative feedback, leading to **decreased TSH secretion** from the pituitary. - **Decreased TSH is the primary clinical marker** used to assess adequacy of thyroid hormone replacement after several weeks of therapy. *Increased T4* - While T4 levels do increase with levothyroxine therapy, this occurs **rapidly (within days)**, not over "several weeks." - The question's timeframe of "several weeks" directs attention to the **delayed TSH response**, which is what clinicians monitor at 6-8 weeks to adjust dosing. - T4 elevation is immediate; TSH normalization takes weeks and is the endpoint being tested. *Increased T3* - T3 levels will increase as **T4 is peripherally converted to the active form T3**, but this is not the primary hormonal change being monitored after several weeks. - The question asks about expected hormonal changes in the context of treatment monitoring, where **TSH is the gold standard**. *Increased TRH* - **Thyrotropin-releasing hormone (TRH)** from the hypothalamus stimulates TSH release. In primary hypothyroidism, both TRH and TSH are elevated. - With thyroid hormone replacement, negative feedback would lead to **decreased TRH**, not increased. *Decreased T4* - This is the opposite of what occurs with levothyroxine therapy. - The goal of treatment is to **increase** deficient T4 levels to the physiological range.

Endocrine drugs (insulin, thyroid medications) Flashcard 1 of 10

Question: Which type(s) of diabetes may be treated with pramlintide (amylin analogs)? _____

Answer: T1DM and T2DM

Endocrine drugs (insulin, thyroid medications) Flashcard 2 of 10

Question: -blocker toxicity is treated with _____, saline, or atropine

Answer: glucagon

Endocrine drugs (insulin, thyroid medications) Flashcard 3 of 10

Question: What is a possible off-label use of the thyroid hormone replacement therapy (e.g. levothyroxine and triiodothyronine)? _____

Answer: weight loss supplement

Endocrine drugs (insulin, thyroid medications) Flashcard 4 of 10

Question: _____ is a class III anti-arrhythmic that can produce hyper or hypothyroidism.

Answer: Amiodarone

Endocrine drugs (insulin, thyroid medications) Flashcard 5 of 10

Question: Glulisine, aspart, and lispro (rapid acting insulin) are useful for controlling the _____ glucose spike

Answer: postprandial

Endocrine drugs (insulin, thyroid medications) Flashcard 6 of 10

Question: GLP-1 analogs cause increased _____ release and satiety

Answer: insulin

Endocrine drugs (insulin, thyroid medications) Flashcard 7 of 10

Question: mestranol

Answer: estrogen

Extra Information: hypognadism, ovarian failure, menstrual abnormalities, HRT in postmenopausal women, androgen-dependent prostate cancerestrogen receptor-positive breast cancer, hx DVTbinds estrogen receptorincreased risk of endometrial cancer, vaginal bleeding in postmenopausal women

Endocrine drugs (insulin, thyroid medications) Flashcard 8 of 10

Question: clompihene

Answer: SERM

Extra Information: infertility and PCOSpartial agonist at estrogen receptor, prevents feedback inhibitionhot flashes, ovarian enlargement, multiple pregnancy, visual disturbances

Endocrine drugs (insulin, thyroid medications) Flashcard 9 of 10

Question: tamoxifen

Answer: SERM

Extra Information: ER-positive breast cancerantagonist at estrogen receptor; specific for breast tissue

Endocrine drugs (insulin, thyroid medications) Flashcard 10 of 10

Question: raloxifene

Answer: SERM

Extra Information: osteoporosis (reduces bone resorption)agonist at estrogen receptor; specific to bone