Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1531: In which condition is Vanillylmandelic Acid (VMA) excreted in urine?

A. Alkaptonuria
B. Neuroblastoma
C. Pheochromocytoma (Correct Answer)
D. Cushing's syndrome

Explanation: ***Pheochromocytoma*** - **Vanillylmandelic Acid (VMA)** is a breakdown product of catecholamines (epinephrine and norepinephrine), which are overproduced in **pheochromocytoma** [2]. - Elevated VMA levels in urine are a key diagnostic marker for this **adrenal medulla tumor** [3]. *Alkaptonuria* - This is an inherited disorder of **tyrosine metabolism**, leading to the accumulation of **homogentisic acid**. - It causes **ochronosis** (darkening of cartilage and connective tissue) and dark urine upon standing, but not elevated VMA. *Neuroblastoma* - While neuroblastoma also involves **catecholamine overproduction**, it typically leads to elevated levels of **homovanillic acid (HVA)** and **VMA**, but is primarily characterized by HVA in children. - Neuroblastoma is a childhood cancer, distinct from the adrenal tumor seen in adults with pheochromocytoma. *Cushing's syndrome* - This condition is characterized by chronic **excess cortisol** production, leading to symptoms like central obesity, moon facies, and hypertension [1]. - It does not involve alterations in catecholamine metabolism or elevated VMA levels.

Question 1532: In which condition would elevated calcium levels be most likely to occur, potentially triggering calcitonin secretion?

A. Hyperthyroidism
B. Hypoparathyroidism
C. Cushing Syndrome
D. Hyperparathyroidism (Correct Answer)

Explanation: ***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.

Question 1533: What percentage of patients with primary hyperparathyroidism have parathyroid adenomas?

A. 50%
B. 60%
C. 70%
D. 80% (Correct Answer)

Explanation: 80% - **Parathyroid adenomas** are the most common cause of **primary hyperparathyroidism**, accounting for approximately 80% of cases [1]. - This typically involves a **single enlarged gland** producing excess parathyroid hormone (PTH) [1]. *50%* - This percentage is too low; **parathyroid adenomas** constitute a significantly higher proportion of primary hyperparathyroidism cases. - Such a low percentage would imply a much higher prevalence of other causes, which is not accurate. *60%* - While a majority, 60% still underestimates the true prevalence of **parathyroid adenomas** in primary hyperparathyroidism presentations. - This figure does not accurately reflect the strong predominance of **single adenomas** as the underlying pathology. *70%* - This value is closer but still slightly below the accepted frequency for **parathyroid adenomas** in the context of primary hyperparathyroidism. - Most sources and clinical experience point to a prevalence that is higher than 70%.

Question 1534: Which of the following conditions is least likely to be associated with osteoporosis?

A. Thyrotoxicosis
B. Steroid therapy
C. Rheumatoid arthritis
D. Hypoparathyroidism (Correct Answer)

Explanation: ***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 1535: A 25-year-old patient presents with thinning of the outer third of the eyebrows. Which condition is most likely associated with this finding?

A. Cutaneous TB
B. Lichen planus
C. Psoriasis
D. Hypothyroidism (Correct Answer)

Explanation: ### Hypothyroidism - **Thinning of the outer third of the eyebrows** (also known as the **Hertoghe sign**) is a classic dermatological manifestation of **hypothyroidism**. - Other common symptoms of hypothyroidism include fatigue, weight gain, cold intolerance, and dry skin [1]. *Cutaneous TB* - **Cutaneous tuberculosis** presents with various skin lesions, such as lupus vulgaris, scrofuloderma, or papulonecrotic tuberculid, but typically does not manifest as isolated thinning of the eyebrows. - Eyebrow loss in this context would usually be part of a broader immune response or severe systemic disease, not a specific diagnostic sign. *Lichen planus* - **Lichen planus** can affect hair follicles, leading to scarring alopecia, particularly on the scalp, but it is not typically associated with isolated thinning of the outer third of the eyebrows [1]. - It usually presents with **pruritic, purple, polygonal papules** on the skin, wrists, and ankles, and can affect mucous membranes. *Psoriasis* - **Psoriasis** is a chronic inflammatory skin condition characterized by **red, silvery-scaled plaques** and can affect the scalp, but it does not specifically cause thinning of the outer third of the eyebrows. - Eyebrow involvement in psoriasis would typically present as scaly plaques within the eyebrow area, not hair loss conforming to the Hertoghe sign.

Question 1536: Which of the following is used in quantifying hirsutism?

A. Bishop score
B. Rotterdam criteria
C. Ferriman-Gallwey score (Correct Answer)
D. All of the options

Explanation: Detailed assessment of androgen excess requires specific clinical tools. ***Ferriman-Gallwey score*** - The **Ferriman-Gallwey score** is a semi-quantitative method used to assess the degree of **hirsutism** by evaluating hair growth in nine body areas [1]. - Each area is scored from 0 (no terminal hair) to 4 (extensive terminal hair growth), and the total score indicates the severity of hirsutism [1]. *Bishop score* - The **Bishop score** is used to assess cervical ripeness and predict the likelihood of successful vaginal birth induction. - It evaluates cervical dilation, effacement, consistency, position, and fetal station, not hair growth. *Rotterdam criteria* - The **Rotterdam criteria** are diagnostic criteria for **polycystic ovary syndrome (PCOS)** [1]. - They require the presence of at least two out of three criteria: **oligo- or anovulation**, clinical or biochemical signs of **hyperandrogenism** (including hirsutism), and polycystic ovaries on ultrasound [1]. *All of the options* - This option is incorrect because only the **Ferriman-Gallwey score** is specifically designed for quantifying hirsutism directly. - The other options pertain to different clinical assessments unrelated to the direct measurement of hair growth severity.

Question 1537: In which condition is radioiodine preferred for treatment?

A. Post-surgery for differentiated thyroid cancer (Correct Answer)
B. Hyperthyroidism in young patients
C. Hyperthyroidism during pregnancy
D. Recent onset of hyperthyroidism with toxic goiter

Explanation: ### 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.

Question 1538: What is the initial treatment for most patients with growth hormone-secreting pituitary adenoma?

A. Transphenoidal surgical resection (Correct Answer)
B. Somatostatin analogs
C. Dopamine agonists
D. GH receptor antagonists

Explanation: ***Transphenoidal surgical resection*** - This is the **preferred initial treatment** for most growth hormone (GH)-secreting pituitary adenomas, as it offers the best chance for **cure** and rapid reduction in GH levels [1]. - Success rates are high, especially for **smaller tumors** (microadenomas), and it can quickly relieve mass effect symptoms [1]. *Somatostatin analogs* - These are typically used as **second-line therapy** if surgery is unsuccessful or contraindicated, or in patients not surgical candidates. - They work by **inhibiting GH secretion** but do not usually achieve a complete cure like surgery. *GH receptor antagonists* - These medications, such as pegvisomant, **block the action of GH** at its receptor, normalizing IGF-1 levels. - They are primarily used when other treatments, including surgery and somatostatin analogs, have failed to control GH excess. *Dopamine agonists* - While dopamine agonists (e.g., cabergoline) can **sometimes reduce GH secretion** in a minority of patients, they are significantly less effective for GH-secreting tumors compared to prolactinomas [1]. - They are occasionally used as **adjunctive therapy** or in specific cases where the GH-secreting tumor also co-secretes prolactin [1].

Question 1539: Azoospermia with normal FSH would indicate?

A. Hypothalamic failure
B. Testicular failure
C. Obstruction of vas deferens (Correct Answer)
D. None of the options

Explanation: ***Obstruction of vas deferens*** - **Azoospermia** with **normal FSH** and normal testicular size strongly suggests an obstructive cause, as the testes are producing sperm but it cannot exit [2]. - This scenario means the **gonadal axis** (hypothalamus-pituitary-testis) is functioning correctly, hence normal FSH, but there is a physical block in the reproductive tract [1], *Hypothalamic failure* - This would lead to secondary hypogonadism, characterized by **low FSH** and **low testosterone**, which is not seen here. - Reduced stimulation of the testes would result in decreased or absent sperm production, but the hormonal profile would be different. *Testicular failure* - Primary testicular failure (e.g., Klinefelter syndrome) would lead to **azoospermia** accompanied by **high FSH** due to lack of negative feedback from the damaged testes [1]. - This condition implies the testes themselves are unable to produce sperm, prompting the pituitary to release more FSH in an attempt to stimulate them. *None of the options* - Obstruction of the vas deferens is a specific and accurate explanation for the given clinical presentation. - Therefore, one of the provided options is indeed correct.

Question 1540: What is the ideal treatment for macroprolactinoma?

A. Bromocriptine (Correct Answer)
B. Surgical excision
C. Stereotactic radiosurgery
D. Watchful waiting

Explanation: **Bromocriptine** - **Dopamine agonists** like bromocriptine are the **first-line treatment** for macroprolactinomas, effectively reducing tumor size and prolactin levels [1]. - These medications are successful in **over 80%** of patients, often leading to significant clinical improvement and avoiding the need for surgery [2]. *Surgical excision* - Surgical excision is typically reserved for cases where **dopamine agonists are ineffective**, poorly tolerated, or if there is rapid neurological deterioration not managed by medical therapy [2]. - Surgical removal of macroprolactinomas can be challenging and carries risks, including **hypopituitarism** and damage to surrounding structures. *Stereotactic radiosurgery* - **Radiosurgery** is generally considered a **secondary or tertiary treatment option** for macroprolactinomas failing medical therapy or surgery, or in cases of residual tumor [1]. - While effective in controlling tumor growth and hormone secretion, its effects are **delayed**, and it can lead to **hypopituitarism** over time. *Watchful waiting* - **Watchful waiting** is generally not appropriate for **macroprolactinomas** due to their potential for continued growth, which can lead to significant mass effect symptoms like **visual field defects** and headaches [1]. - This approach is more commonly applied to **microprolactinomas** that are asymptomatic and do not show significant growth [1].

Practice by Chapter

Diabetes Mellitus

Practice Questions

Thyroid Disorders

Practice Questions

Adrenal Gland Disorders

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Pituitary Disorders

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Calcium and Bone Metabolism

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Reproductive Endocrinology

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Lipid Disorders

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Endocrine Hypertension

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Multiple Endocrine Neoplasia

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Obesity and Metabolic Syndrome

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Neuroendocrine Tumors

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Endocrine Emergencies

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