Endocrinology — MCQs

A 45-year-old woman complains of tingling in her hands and feet, 24 hours after removal of follicular thyroid carcinoma. Her symptoms rapidly progress to severe muscle cramps, laryngeal stridor, and convulsions. Which of the following laboratory findings would be expected in this patient prior to treatment?

Q1629

A 28-year-old man presents to the emergency department with a severe headache, palpitations, excessive sweating, chest pain, visual disturbances, dyspnea, paresthesias, constipation, and a sense of impending doom, which occur primarily at night, over a period of two weeks. His blood pressure is 130/80 mmHg while supine and 90/60 mmHg while standing, and his blood sugar is 240 mg/dL. Which of the following is the most likely diagnosis?

Q1630

All of the following are features of Graves' disease except:

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1621: Which of the following conditions is not associated with Cushing syndrome?

A. Oat cell carcinoma of lung
B. Pituitary adenoma
C. Adrenal carcinoma
D. Medulloblastoma (Correct Answer)

Explanation: ***Medulloblastoma*** - **Medulloblastoma** is a primary **brain tumor** that arises in the cerebellum and is not typically associated with hormone production leading to Cushing syndrome. - Its symptoms are primarily neurological, related to increased **intracranial pressure** or cerebellar dysfunction, not systemic metabolic disturbances. *Adrenal carcinoma* - **Adrenal carcinoma** can directly produce excessive amounts of **cortisol**, leading to Cushing syndrome (specifically **primary adrenal Cushing's**) [1]. - This is a rare but aggressive tumor of the adrenal cortex. *Oat cell carcinoma of lung* - Also known as **small cell lung carcinoma**, this tumor can produce **ectopic ACTH** (adrenocorticotropic hormone), leading to paraneoplastic Cushing syndrome [1]. - The ectopic ACTH stimulates the adrenal glands to produce excess cortisol [1]. *Pituitary adenoma* - A **pituitary adenoma** that secretes ACTH is the most common cause of **Cushing's disease** (a specific type of Cushing syndrome) [1]. - This excess ACTH then stimulates the adrenal glands to overproduce cortisol [1].

Question 1622: All of the following statements about Nesidioblastosis are true, except:

A. Histopathology shows hyperplasia of islet cells
B. Hypoglycemic episodes may be seen
C. Diazoxide may be used for treatment
D. Occurs in adults more than children (Correct Answer)

Explanation: ***Occurs in adults more than children*** - **Nesidioblastosis** is a rare condition predominantly seen in **infants and children**, especially those with congenital hyperinsulinism. It is far less common in adults. - While adult forms can occur, the statement that it occurs more in adults than children is incorrect. *Hypoglycemic episodes may be seen* - Nesidioblastosis is characterized by **unregulated or excessive insulin secretion**, leading to recurrent episodes of severe **hypoglycemia**. - These hypoglycemic episodes can cause significant morbidity, particularly in infants. *Histopathology shows hyperplasia of islet cells* - The defining feature of nesidioblastosis is the **diffuse or focal hyperplasia of pancreatic islet cells**, particularly the beta cells. - These hyperplastic cells may be found budding off ducts or dispersed throughout the exocrine pancreas. *Diazoxide may be used for treatment* - **Diazoxide** is an ATP-sensitive potassium channel opener that reduces insulin secretion from pancreatic beta cells. - It is a common medical therapy used to manage hypoglycemia in patients with nesidioblastosis, especially in pediatric cases where it can sometimes avoid the need for surgery.

Question 1623: A 20-year-old average-weight female complains of oligomenorrhea along with facial hair. Preliminary investigation reveals raised free testosterone levels. Which of the following could be a likely etiology?

A. Testosterone secreting tumour
B. Adrenal hyperplasia
C. Idiopathic hirsutism
D. PCOD (Correct Answer)

Explanation: ***PCOD*** - The triad of **oligomenorrhea**, **hirsutism** (facial hair), and **elevated free testosterone** levels is highly suggestive of **Polycystic Ovarian Disease (PCOD)** [1]. - **PCOD** is characterized by **anovulation**, leading to menstrual irregularities, and **hyperandrogenism** which causes hirsutism [1]. *Idiopathic hirsutism* - While idiopathic hirsutism causes **facial hair** and other androgenic symptoms, it is characterized by **normal androgen levels**, which contradicts the elevated free testosterone in this case. - **Oligomenorrhea** is not a typical feature of idiopathic hirsutism. *Adrenal hyperplasia* - **Adrenal hyperplasia**, particularly **Congenital Adrenal Hyperplasia (CAH)**, can cause hyperandrogenism and menstrual irregularities due to **enzymatic defects** in adrenal steroidogenesis. - However, it typically presents with **markedly elevated 17-hydroxyprogesterone** levels, which are not mentioned here, and often has an earlier onset or more severe virilization. *Testosterone secreting tumour* - A **testosterone-secreting tumor** (e.g., of the ovary or adrenal gland) would cause **sudden-onset**, rapid progression of **severe hirsutism** and **virilization**, often with **very high testosterone levels** [1]. - The gradual onset implied by "complains of" and the average weight of the patient make a tumor less likely than PCOD, though it would need to be ruled out if testosterone levels were extremely high [1].

Question 1624: Which of the following statements about pheochromocytoma is true?

A. Arises from chromaffin cells of adrenal medulla (Correct Answer)
B. Bilateral in 20% of all cases
C. Hypotension rules out pheochromocytoma
D. Almost always a malignant tumor

Explanation: ***Arises from chromaffin cells of adrenal medulla*** - **Pheochromocytomas** are rare neuroendocrine tumors that develop from **chromaffin cells** found in the adrenal medulla. - These cells are responsible for synthesizing and secreting **catecholamines**, explaining the characteristic symptoms of pheochromocytoma. *Bilateral in 20% of all cases* - While pheochromocytomas can be bilateral, this occurs in about **10% of cases**, mostly associated with genetic syndromes like **MEN 2**. - A higher percentage of bilaterality is seen in **familial forms** of the disease, but not in all cases. *Hypotension rules out pheochromocytoma* - Although **hypertension** is a hallmark symptom, **hypotension** can occur, particularly **orthostatic hypotension** due to volume depletion and impaired vasoconstriction. - Rarely, **pheochromocytoma crisis** can present with **shock** due to massive catecholamine release and subsequent myocardial dysfunction or vasoplegia. *Almost always a malignant tumor* - Most pheochromocytomas are **benign**; only about **10-15%** are malignant. - Malignancy is suggested by the presence of **metastatic disease**, as histology alone cannot reliably differentiate between benign and malignant forms.

Question 1625: Which one of the following is the MOST common complication of diabetes mellitus?

A. Diabetic Retinopathy
B. Diabetic Nephropathy
C. Peripheral Neuropathy (Correct Answer)
D. Cardiovascular Disease

Explanation: ***Peripheral Neuropathy*** - **Peripheral neuropathy** is the most common complication of diabetes, affecting up to 50% of patients with long-standing disease [1]. - It results from **nerve damage** due to chronic hyperglycemia, leading to symptoms like pain, numbness, and weakness, primarily in the extremities [1]. *Diabetic Retinopathy* - While a common microvascular complication, **diabetic retinopathy** occurs in about one-third of diabetic patients and is not as prevalent as peripheral neuropathy [2]. - It involves damage to the **blood vessels of the retina** and can lead to vision loss. *Diabetic Nephropathy* - **Diabetic nephropathy** is a serious complication affecting approximately 20-40% of diabetic patients, leading to kidney disease. - It is characterized by progressive **kidney damage** and can lead to end-stage renal disease, but it's less common than neuropathy [2]. *Cardiovascular Disease* - **Cardiovascular disease (CVD)**, including coronary artery disease, stroke, and peripheral artery disease, is a major cause of morbidity and mortality in diabetic patients [2]. - While highly significant, it is a macrovascular complication and its overall prevalence as a specific "complication" is not considered higher than peripheral neuropathy in terms of initial onset and detection.

Question 1626: Which of the following is the most useful investigation for thyroid function?

A. TSH (Correct Answer)
B. T3
C. T4
D. Thyroglobulin

Explanation: TSH - **Thyroid-Stimulating Hormone (TSH)** is the most sensitive and specific test for assessing thyroid function as it reflects the feedback loop between the pituitary gland and the thyroid [1]. - An abnormal TSH level usually indicates either **hypothyroidism** (high TSH) or **hyperthyroidism** (low TSH), even before changes in T3 or T4 are apparent [1]. *T3* - **Triiodothyronine (T3)** is primarily used to confirm a diagnosis of hyperthyroidism, especially when T4 levels are normal but TSH is suppressed [1]. - It is less reliable for initial screening due to its **short half-life** and significant diurnal variation. [1] *T4* - **Thyroxine (T4)** is a good indicator of thyroid hormone production, but its levels can be affected by **protein binding** and non-thyroidal illnesses. - While total T4 is often included in a thyroid panel, **free T4** is more accurate as it reflects the metabolically active hormone not bound to proteins [1]. *Thyroglobulin* - **Thyroglobulin** is primarily used as a tumor marker for monitoring recurrence in patients with differentiated thyroid cancer after thyroidectomy [1]. - It plays no significant role in the initial **assessment of general thyroid function** or diagnosis of hyper/hypothyroidism [1].

Question 1627: Hyperglycemia occurs after what % of beta cell mass is destroyed:

A. 40%
B. 80% (Correct Answer)
C. 60%
D. 20%

Explanation: ***80%*** - **Hyperglycemia** typically manifests only after a significant portion of **beta cell mass** (around 80-90%) has been destroyed. - This extensive loss of **insulin-producing cells** compromises the body's ability to maintain normal glucose levels [1]. *20%* - A 20% destruction of beta cell mass is generally **insufficient** to cause clinical hyperglycemia. - The remaining beta cells can usually compensate for this relatively small loss through increased insulin secretion. *40%* - While 40% loss represents a considerable reduction, it's often still within the compensatory capacity of the pancreas. - At this stage, individuals might experience **impaired glucose tolerance** but not overt hyperglycemia [1]. *60%* - Even with a 60% loss, the body may still be able to maintain near-normal glucose levels, especially in the early stages of beta cell destruction [1]. - Hyperglycemia is more likely to develop as the destruction progresses beyond this point.

Question 1628: A 45-year-old woman complains of tingling in her hands and feet, 24 hours after removal of follicular thyroid carcinoma. Her symptoms rapidly progress to severe muscle cramps, laryngeal stridor, and convulsions. Which of the following laboratory findings would be expected in this patient prior to treatment?

A. Decreased serum calcium and decreased PTH (Correct Answer)
B. Decreased serum calcium and increased PTH
C. Increased serum calcium and decreased PTH
D. Increased serum calcium and increased PTH

Explanation: ***Decreased serum calcium and decreased PTH*** - The symptoms of **tingling**, **muscle cramps**, **laryngeal stridor**, and **convulsions** are classic signs of **hypocalcemia**. [1] - Following thyroidectomy, **parathyroid glands** can be inadvertently removed or damaged, leading to **hypoparathyroidism**, which results in decreased parathyroid hormone (PTH) levels and subsequent hypocalcemia. [1] *Decreased serum calcium and increased PTH* - This pattern is characteristic of **secondary hyperparathyroidism**, where low calcium levels stimulate increased PTH production. [1] - However, in this case, the hypocalcemia is a direct result of parathyroid damage during surgery, leading to *decreased* PTH. *Increased serum calcium and decreased PTH* - This pattern is characteristic of **primary hyperparathyroidism**, where an adenoma or hyperplasia of the parathyroid glands causes excessive PTH production, leading to hypercalcemia. [1] - This patient is experiencing symptoms consistent with hypocalcemia, not hypercalcemia. *Increased serum calcium and increased PTH* - This combination is rare and could suggest conditions like **familial hypocalciuric hypercalcemia**, where inappropriately high PTH is seen despite elevated calcium. [1] - However, the patient's symptoms are of hypocalcemia, and the history points towards iatrogenic hypoparathyroidism.

Question 1629: A 28-year-old man presents to the emergency department with a severe headache, palpitations, excessive sweating, chest pain, visual disturbances, dyspnea, paresthesias, constipation, and a sense of impending doom, which occur primarily at night, over a period of two weeks. His blood pressure is 130/80 mmHg while supine and 90/60 mmHg while standing, and his blood sugar is 240 mg/dL. Which of the following is the most likely diagnosis?

A. Familial dysautonomia syndrome
B. Opiate withdrawal syndrome
C. Pheochromocytoma (Correct Answer)
D. Alcohol withdrawal syndrome

Explanation: **Pheochromocytoma** - This patient presents with a classic triad of symptoms: **headaches**, **sweating**, and **palpitations**, often referred to as the "PHE" symptoms, which are highly suggestive of **pheochromocytoma**. - Additional findings such as **orthostatic hypotension**, **hyperglycemia**, and nocturnal episodes further support the diagnosis of a **catecholamine-secreting tumor**. *Familial dysautonomia syndrome* - This is a rare genetic disorder affecting the **autonomic nervous system**, primarily seen in individuals of Ashkenazi Jewish descent, and typically presents in infancy or early childhood. - While it involves autonomic dysfunction, it is not characterized by paroxysmal episodes of severe hypertension and acute symptoms like those described, nor by a new onset of these symptoms in a 28-year-old. *Opiate withdrawal syndrome* - Symptoms of opiate withdrawal include **muscle aches**, **nausea**, **vomiting**, **diarrhea**, **dilated pupils**, and **piloerection**, often accompanied by psychological distress. - The presented symptoms, particularly the severe headache, chest pain, visual disturbances, and significant hyperglycemia, are not typical features of opiate withdrawal. *Alcohol withdrawal syndrome* - This syndrome can cause **tremors**, **autonomic hyperactivity** (e.g., sweating, elevated heart rate, hypertension), **anxiety**, and in severe cases, **seizures** or **delirium tremens**. - While some autonomic symptoms overlap, the highly specific triad of severe headache, palpitations, and profuse sweating, along with significant hyperglycemia and orthostatic hypotension, points away from alcohol withdrawal as the primary diagnosis.

Question 1630: All of the following are features of Graves' disease except:

A. More common in males (Correct Answer)
B. Pretibial myxoedema
C. Intolerance to heat
D. Tremor

Explanation: ***More common in males*** - **Graves' disease** is significantly **more common in females** than males, with a female-to-male ratio of approximately 5-10:1. [2] [3] - This option presents a characteristic that is **not a feature** of Graves' disease, as the prevalence is much higher in women. *Tremor* - **Tremor** is a common symptom of **hyperthyroidism**, often described as a fine, rapid tremor, especially in the hands. [3] - It is caused by the **increased adrenergic stimulation** and metabolic rate associated with excess thyroid hormones. *Pretibial myxoedema* - **Pretibial myxoedema** (also known as Graves' dermopathy) is a specific dermatological manifestation of **Graves' disease**. [1] [2] - It involves **localized thickening and discoloration** of the skin, typically on the shins, due to the accumulation of glycosaminoglycans. *Intolerance to heat* - **Heat intolerance** is a classic symptom of **hyperthyroidism** and is a common finding in patients with Graves' disease. [3] - This occurs due to the **increased basal metabolic rate** and excessive heat production stimulated by high levels of thyroid hormones.

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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