Endocrinology Practice Questions

Q: A 28-year-old female presents with panic attacks, palpitations, sweating, and chest pain. EKG shows sinus tachycardia. Labs reveal decreased TSH and increased FT4. Analyze and choose the most likely diagnosis.

Hyperthyroidism. ***Hyperthyroidism*** - The combination of **panic attacks**, **palpitations**, **sweating**, and **chest pain** are classic symptoms of **hyperthyroidism**, often mimicking anxiety [1]. - The lab results of **decreased TSH** and **increased free T4 (FT4)** are definitive for hyperthyroidism, indicating an overactive thyroid gland [2]. *GAD* - While **Generalized Anxiety Disorder (GAD)** can present with anxiety, palpitations, and sweating, it would not explain the **abnormal thyroid function tests**. - GAD is a diagnosis of exclusion in the presence of an underlying medical condition causing anxiety-like symptoms. *Panic Disorder* - **Panic disorder** is characterized by recurrent, unexpected panic attacks with physical symptoms like palpitations and chest pain. - However, **panic disorder** would not account for the **decreased TSH** and **increased FT4** found in the lab results. *Mitral valve prolapse* - **Mitral valve prolapse** can cause **palpitations** and sometimes atypical chest pain but does not typically cause the widespread symptoms of panic attacks or sweating. - It would not lead to **abnormal thyroid hormone levels** seen in the lab findings.

Q: A 38-year-old woman presents with visual field defects and galactorrhea. An MRI reveals a pituitary mass. Which class of drugs would be most appropriate for treating this condition?

Dopamine agonist. ***Dopamine agonist*** - **Galactorrhea** suggests hyperprolactinemia, often caused by a **prolactinoma** [3] (a type of pituitary adenoma), which can be effectively treated with dopamine agonists [1]. - Dopamine agonists (e.g., **bromocriptine, cabergoline**) mimic dopamine's inhibitory effect on prolactin secretion, leading to a reduction in prolactin levels and tumor shrinkage, thus resolving visual field defects [1],[2]. *Beta-blocker* - **Beta-blockers** are primarily used to treat conditions like hypertension, angina, and anxiety, and do not directly address pituitary tumors or hyperprolactinemia. - They work by blocking the effects of adrenaline and do not influence prolactin secretion or tumor size. *Serotonin antagonist* - **Serotonin antagonists** are used in various conditions, including migraine prophylaxis and treatment of carcinoid syndrome, but they have no role in managing pituitary masses or high prolactin levels. - These drugs target serotonin receptors and do not affect dopamine pathways relevant to prolactin regulation. *Acetylcholinesterase inhibitor* - **Acetylcholinesterase inhibitors** are used to treat conditions like Alzheimer's disease and myasthenia gravis by increasing acetylcholine levels in the brain. - They are not indicated for the treatment of pituitary tumors or hyperprolactinemia, as their mechanism of action is unrelated to prolactin regulation.

Q: A 45-year-old woman presents with fatigue, dry skin, and constipation. Physical examination reveals a delayed relaxation phase of deep tendon reflexes. Laboratory tests show elevated TSH and low free T4. What is the most likely diagnosis?

Primary hypothyroidism. ***Primary hypothyroidism*** - The constellation of **fatigue, dry skin, constipation**, and a **delayed relaxation phase of deep tendon reflexes** are classic symptoms of hypothyroidism [1]. - **Elevated TSH** and **low free T4** confirm primary hypothyroidism, indicating the thyroid gland itself is underactive [1]. *Hyperthyroidism* - This condition presents with symptoms opposite to those described, such as **weight loss, heat intolerance, diarrhea**, and **tachycardia** [1]. - Laboratory findings would typically show **low TSH** and **elevated free T4** or free T3 [1]. *Subclinical hypothyroidism* - Characterized by an **elevated TSH** but **normal free T4** levels; patients may be asymptomatic or have mild symptoms. - The patient's **low free T4** explicitly rules out subclinical hypothyroidism. *Thyroiditis* - Though thyroiditis can cause hypothyroidism (e.g., Hashimoto's thyroiditis), the term itself refers to inflammation of the thyroid. - While it's a potential cause, **primary hypothyroidism** is the most direct diagnostic classification based on the presented symptoms and lab results.

Q: A 65-year-old woman with a history of hyperthyroidism presents with fever, tachycardia, and confusion. What is the most likely diagnosis?

Thyroid storm. ***Thyroid storm*** - **Thyroid storm** is a life-threatening exacerbation of hyperthyroidism characterized by symptoms such as **fever**, **tachycardia**, and altered mental status like **confusion** [1]. - The patient's history of **hyperthyroidism** makes this diagnosis highly probable in the context of these severe symptoms [1]. *Myxedema coma* - **Myxedema coma** is the extreme manifestation of **hypothyroidism**, not hyperthyroidism, and would present with symptoms such as **hypothermia**, **bradycardia**, and severe lethargy, which contradict the patient's presentation. - The patient's history of **hyperthyroidism** also makes myxedema coma an unlikely diagnosis. *Sepsis* - While **fever**, **tachycardia**, and **confusion** can be seen in sepsis, the underlying history of **hyperthyroidism** and the acute, severe presentation points more specifically to thyroid storm [1]. - Sepsis would typically have a clear infectious source, which is not mentioned in this scenario, and would not solely account for the severe systemic hypermetabolic state described. *Pheochromocytoma* - **Pheochromocytoma** is a tumor that typically presents with paroxysmal episodes of **hypertension**, **palpitations**, and **sweating** due to excessive catecholamine release. - Although it can cause **tachycardia**, the symptom complex including **fever** and a history of hyperthyroidism makes it less likely than a thyroid storm.

Q: What is the diagnosis of a 55-year-old woman with chronic low backache?

Osteoporosis. ***Osteoporosis*** - The image shows **loss of bone density** and **vertebral compression fractures**, especially visible in the lumbar spine, which are characteristic findings in osteoporosis. - Osteoporosis is common in post-menopausal women, and **chronic low backache** is a frequent symptom due to microfractures or vertebral collapse. *Hurler's syndrome* - This is a lysosomal storage disease (mucopolysaccharidosis type I) that primarily affects **children** and presents with distinct **skeletal deformities** (dysostosis multiplex), facial features, and organ involvement. - It would not typically present as chronic low backache in a 55-year-old woman, and the radiological findings are not consistent with Hurler's syndrome. *Paget’s disease* - Paget's disease of bone involves abnormal bone remodeling, leading to **enlarged and weakened bones**, often with a characteristic **cotton wool appearance** on X-ray, which is not seen here. - While it can cause bone pain and affect the spine, the primary radiological features seen in this image are more consistent with generalized bone density loss and fractures rather than focal expansion and abnormal bone architecture. *Renal osteodystrophy* - This condition occurs in patients with **chronic kidney disease** and results from imbalances in calcium, phosphate, and parathyroid hormone. - Radiographic features include **osteosclerosis (rugger jersey spine)**, bone erosions, or osteomalacia, which are different from the generalized osteopenia and compression fractures observed in this X-ray.

Q: What is the primary pathophysiological consequence of Graves' disease?

Results in hyperthyroidism. Graves' disease is an **autoimmune disorder** where antibodies stimulate the **TSH receptor**, leading to excessive thyroid hormone production [1], [2]. This overproduction of T3 and T4 results in a **hypermetabolic state** characteristic of hyperthyroidism [2]. Graves' disease is significantly more common in **females** than in males, with a female-to-male ratio as high as 5-10:1 [1], [2]. This gender predisposition is consistent with many other **autoimmune diseases**.

Q: In which condition would elevated calcium levels be most likely to occur, potentially triggering calcitonin secretion?

Hyperparathyroidism. ***Hyperparathyroidism*** - **Primary hyperparathyroidism** is characterized by excessive secretion of parathyroid hormone (PTH), which leads to increased reabsorption of calcium from bones, increased intestinal absorption of calcium, and increased renal tubular reabsorption of calcium, resulting in **hypercalcemia** [1]. - The elevated calcium levels would then trigger a compensatory increase in **calcitonin secretion** from the thyroid gland as calcitonin acts to lower blood calcium. *Hyperthyroidism* - While hyperthyroidism can sometimes lead to mild hypercalcemia due to increased bone turnover, it is generally **not the primary cause of significant elevated calcium levels** that markedly trigger calcitonin [2]. - The **pathophysiology of calcium elevation** is different and less pronounced compared to hyperparathyroidism. *Hypoparathyroidism* - This condition involves **insufficient secretion of PTH**, leading to decreased blood calcium levels (**hypocalcemia**). - Therefore, it is the opposite of what would cause elevated calcium and subsequent calcitonin secretion. *Cushing Syndrome* - Cushing syndrome is characterized by **excess cortisol**, which can paradoxically lead to **decreased bone formation** and **increased bone resorption**, sometimes causing mild hypercalcemia. - However, **significant hypercalcemia** triggering calcitonin is not a primary or characteristic feature of Cushing syndrome.

Q: In which condition is radioiodine preferred for treatment?

Post-surgery for differentiated thyroid cancer. ### Post-surgery for differentiated thyroid cancer - **Radioiodine (radioactive iodine, I-131)** is preferentially used after surgery for **differentiated thyroid cancer** to ablate any remaining thyroid tissue or metastatic disease [1]. - This therapy targets and destroys thyroid cells that absorb iodine, effectively reducing recurrence risk and improving survival rates [1]. *Hyperthyroidism in young patients* - While radioiodine can be used in hyperthyroidism, it's generally reserved for older patients or those who fail antithyroid medications due to concerns about potential long-term effects, such as **hypothyroidism** for which replacement will be required lifelong [1]. - Younger patients often start with **antithyroid drugs** (e.g., methimazole or propylthiouracil) as the initial treatment option [1]. *Hyperthyroidism during pregnancy* - **Radioiodine therapy is absolutely contraindicated during pregnancy** because it can cross the placenta and damage the fetal thyroid gland, leading to **fetal hypothyroidism**. - **Antithyroid drugs** (specifically propylthiouracil in the first trimester, then methimazole in later trimesters) are the preferred treatment options [1]. *Recent onset of hyperthyroidism with toxic goiter* - For recent onset hyperthyroidism, especially with a **toxic goiter**, initial treatment typically involves **antithyroid medications** to control thyroid hormone levels [1]. - Radioiodine might be considered later if medical therapy fails or is not tolerated, but it's not usually the primary choice for *recent onset* cases due to the potential for a temporary exacerbation of hyperthyroidism after treatment.

Q: Which of the following conditions is least likely to be associated with osteoporosis?

Hypoparathyroidism. ***Hypoparathyroidism*** - This condition is characterized by **low parathyroid hormone (PTH)** levels, leading to **hypocalcemia** and **hyperphosphatemia**. - Without sufficient PTH, the normal regulation of bone turnover is impaired, typically resulting in **increased bone density** rather than osteoporosis. *Thyrotoxicosis* - **Excess thyroid hormone** directly stimulates bone remodeling, leading to an **increased rate of bone resorption** over bone formation. - This imbalance results in a net loss of bone mass and can significantly increase the risk of osteoporosis. *Rheumatoid arthritis* - Chronic inflammation in **rheumatoid arthritis** releases pro-inflammatory cytokines that directly promote osteoclast activity and bone loss (local and systemic) [1]. - Reduced physical activity, systemic effects of the disease, and the use of glucocorticoids for treatment can all contribute to **secondary osteoporosis** [1]. *Steroid therapy* - **Glucocorticoids** (steroids) inhibit osteoblast function, reduce calcium absorption in the gut, and increase renal calcium excretion [1]. - Long-term use of systemic steroids is a well-established major risk factor for **steroid-induced osteoporosis** and fractures [1].

Question 1

A 28-year-old female presents with panic attacks, palpitations, sweating, and chest pain. EKG shows sinus tachycardia. Labs reveal decreased TSH and increased FT4. Analyze and choose the most likely diagnosis.

Accepted Answer

Hyperthyroidism

Answer

GAD

Answer

Panic Disorder

Answer

Mitral valve prolapse

Question 2

A 38-year-old woman presents with visual field defects and galactorrhea. An MRI reveals a pituitary mass. Which class of drugs would be most appropriate for treating this condition?

Accepted Answer

Dopamine agonist

Answer

Beta-blocker

Answer

Serotonin antagonist

Answer

Acetylcholinesterase inhibitor

Question 3

A 45-year-old woman presents with fatigue, dry skin, and constipation. Physical examination reveals a delayed relaxation phase of deep tendon reflexes. Laboratory tests show elevated TSH and low free T4. What is the most likely diagnosis?

Accepted Answer

Primary hypothyroidism

Answer

Hyperthyroidism

Answer

Subclinical hypothyroidism

Answer

Thyroiditis

Question 4

A 65-year-old woman with a history of hyperthyroidism presents with fever, tachycardia, and confusion. What is the most likely diagnosis?

Accepted Answer

Thyroid storm

Answer

Myxedema coma

Answer

Sepsis

Answer

Pheochromocytoma

Question 5

What are the endocrine and autoimmune mechanisms involved in a 55-year-old female presenting with palpitations, tremors, weight loss, high free T4, and low TSH?

Accepted Answer

Graves' disease leading to hyperthyroidism due to autoimmune stimulation of the thyroid.

Answer

Hashimoto's thyroiditis causing autoimmune destruction of the thyroid and resulting in hypothyroidism.

Answer

Adrenal insufficiency resulting in decreased cortisol and aldosterone levels.

Answer

Primary hyperparathyroidism leading to increased calcium and PTH secretion.

Question 6

What is the diagnosis of a 55-year-old woman with chronic low backache?

Accepted Answer

Osteoporosis

Answer

Hurler's syndrome

Answer

Paget’s disease

Answer

Renal osteodystrophy

Question 7

What is the primary pathophysiological consequence of Graves' disease?

Accepted Answer

Results in hyperthyroidism

Answer

Results in hypothyroidism

Answer

Equally common in both sexes

Answer

Common in Male

Question 8

In which condition would elevated calcium levels be most likely to occur, potentially triggering calcitonin secretion?

Accepted Answer

Hyperparathyroidism

Answer

Hyperthyroidism

Answer

Hypoparathyroidism

Answer

Cushing Syndrome

Question 9

In which condition is radioiodine preferred for treatment?

Accepted Answer

Post-surgery for differentiated thyroid cancer

Answer

Hyperthyroidism in young patients

Answer

Hyperthyroidism during pregnancy

Answer

Recent onset of hyperthyroidism with toxic goiter

Question 10

Which of the following conditions is least likely to be associated with osteoporosis?

Accepted Answer

Hypoparathyroidism

Answer

Thyrotoxicosis

Answer

Steroid therapy

Answer

Rheumatoid arthritis

Endocrinology — MCQs

Endocrinology — MCQs

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