Endocrinology Practice Questions

Q: What is the most common cause of hypercalcemic crisis?

Parathyroid adenoma. ***Parathyroid adenoma*** - **Primary hyperparathyroidism**, most often caused by a solitary parathyroid adenoma, is the leading cause of hypercalcemic crisis, though this is rare [1][2]. - The adenoma autonomously overproduces **parathyroid hormone (PTH)**, leading to increased calcium reabsorption from bone and kidneys, and enhanced intestinal calcium absorption [1]. *Carcinoma of the breast* - While breast carcinoma can lead to **hypercalcemia** through bony metastases or parathyroid hormone-related peptide (PTHrP) production, it's not the most common cause of hypercalcemic crisis. - Metastatic bone disease is a common cause of hypercalcemia in malignancy, but the extent of hypercalcemia varies. *Parathyroid hyperplasia* - **Parathyroid hyperplasia** is a rarer cause of primary hyperparathyroidism compared to adenoma, and thus less frequently causes hypercalcemic crisis [2]. - All four parathyroid glands are typically enlarged and overactive, leading to excessive PTH secretion. *Paget's disease* - **Paget's disease of bone** primarily causes localized areas of increased bone turnover and can lead to elevated **alkaline phosphatase** levels. - It rarely causes significant hypercalcemia, and even more rarely a hypercalcemic crisis, unless there is prolonged immobilization or coexisting hyperparathyroidism.

Q: A patient with hypertension presents with hypokalemia. Aldosterone levels and renin levels are both elevated. The most likely diagnosis is.

Renal Artery stenosis. ***Renal Artery stenosis*** - **Renal artery stenosis** leads to decreased renal perfusion, activating the **renin-angiotensin-aldosterone system (RAAS)** [2]. - This results in elevated **renin** and subsequent elevated **aldosterone** levels, causing hypertension and **hypokalemia** [3]. *Primary Hyperaldosteronism (Conn's syndrome)* - In **primary hyperaldosteronism**, the adrenal glands autonomously overproduce **aldosterone**, leading to high aldosterone levels [1]. - The high aldosterone levels suppress **renin** secretion, resulting in low renin levels, which contradicts the patient's presentation. *Addison's disease* - **Addison's disease** (primary adrenal insufficiency) is characterized by decreased production of all adrenal hormones, including **aldosterone** and **cortisol**. - This would lead to **hyponatremia**, **hyperkalemia**, and low blood pressure, not hypokalemia and hypertension. *Cushing's syndrome* - **Cushing's syndrome** results from excessive **cortisol** production, which can have mineralocorticoid effects and cause hypertension and hypokalemia. - However, **cortisol** excess does not directly cause elevated **renin** levels; renin is typically normal or suppressed in Cushing's.

Q: What would be the most probable diagnosis for a 50-year-old chronic smoker who presents with hemoptysis, truncal obesity, and hypertension, and has an elevated ACTH level that is not suppressible with high-dose dexamethasone?

Ectopic ACTH producing lung cancer. ***Ectopic ACTH producing lung cancer*** - The combination of **hemoptysis** in a **chronic smoker** points towards a pulmonary malignancy, which can produce **ectopic ACTH**, leading to Cushing's syndrome symptoms [2, 5]. - The **elevated ACTH** that is **not suppressible with high-dose dexamethasone** is characteristic of ectopic ACTH production, as the tumor cells do not respond to feedback inhibition [1]. *Adrenal adenoma* - An **adrenal adenoma** causes **ACTH-independent Cushing's syndrome**, meaning ACTH levels would be low [1]. - While it can cause symptoms like truncal obesity and hypertension, it does not explain the hemoptysis or elevated ACTH. *Bilateral adrenal hyperplasia* - **Bilateral adrenal hyperplasia** can cause Cushing's syndrome, but it is typically **ACTH-dependent** and often responsive to high-dose dexamethasone if it's pituitary-driven [1]. - It does not account for the hemoptysis or the **non-suppressible ACTH** level in this particular presentation. *Pituitary tumor* - A **pituitary tumor** (Cushing's disease) produces ACTH, causing Cushing's syndrome, and typically shows **suppression with high-dose dexamethasone** (though not always fully). - It would not explain the symptom of **hemoptysis** associated with a chronic smoker [2].

Q: In which condition is pre-tibial myxedema most commonly observed?

Graves' disease. ***Graves' disease*** - **Pre-tibial myxedema** is a pathognomonic dermatological manifestation almost exclusively seen in **Graves' disease**, which is an autoimmune hyperthyroid condition [1]. - It involves the deposition of **glycosaminoglycans** and hyaluronic acid in the dermis, leading to non-pitting edema and thickened skin on the shins. *Hypothyroid* - While generalized **myxedema** (non-pitting edema) can occur in severe hypothyroidism, it is diffuse and not typically localized to the pre-tibial area as a distinct condition like pre-tibial myxedema. - The skin changes are usually more widespread, affecting the face, hands, and feet, and are due to widespread mucin deposition not specific to the shins. *Hyperthyroidism* - This is a general term for an overactive thyroid gland. While **Graves' disease** is a type of hyperthyroidism, pre-tibial myxedema is not a feature of all forms of hyperthyroidism (e.g., toxic multinodular goiter, thyroiditis) [1], [2]. - The presence of pre-tibial myxedema narrows the diagnosis specifically to Graves' disease among the hyperthyroid conditions [1]. *Hashimoto* - **Hashimoto's thyroiditis** is an autoimmune disease primarily causing hypothyroidism, though it may have a transient hyperthyroid phase. - It is not typically associated with **pre-tibial myxedema**; rather, patients often present with symptoms of hypothyroidism, such as fatigue, weight gain, and dry skin.

Q: Which of the following statements about gynaecomastia is false?

Subcutaneous mastectomy is the initial treatment of choice. ***Subcutaneous mastectomy is the initial treatment of choice*** - **Subcutaneous mastectomy** is a surgical intervention, which is typically reserved for cases that are severe, persistent, or resistant to more conservative medical management. - The initial approach usually involves identifying and treating the underlying cause, or pharmacologic therapy if needed, before considering surgery. *Seen in liver disease* - **Liver disease**, particularly advanced states like cirrhosis, impairs the liver's ability to metabolize **estrogen**, leading to increased circulating levels. - This **estrogen excess**relative to **androgen** can stimulate breast tissue growth in males. *There may be estrogen/testosterone imbalance* - **Gynaecomastia** results from an imbalance between **estrogen** (which promotes breast tissue growth) and **androgen** (which inhibits it) [1]. - Conditions that increase **estrogen** levels, decrease **testosterone** levels, or block **androgen receptors** can cause this imbalance [1]. *Can be drug induced* - Many medications can cause **gynaecomastia** as a side effect, including **anti-androgens** (e.g., spironolactone, flutamide), **estrogens**, some **antidepressants**, and certain **cardiovascular drugs** (e.g., digoxin, calcium channel blockers) [1]. - These drugs can directly affect hormone levels or receptor activity, leading to breast tissue proliferation [1].

Q: Which of the following factors contributes to the development of diabetic gangrene?

All of the options contribute to diabetic gangrene. ***All of the options contribute to diabetic gangrene*** - Diabetic gangrene is a complex complication resulting from a combination of **vascular impairment**, **neuropathy**, and **immunological dysfunction** in diabetic patients [1]. - Each of the individual factors listed plays a significant and interconnected role in its pathogenesis, making a multifactorial etiology. *Ischemia due to reduced blood supply* - **Peripheral arterial disease (PAD)** is common in diabetes, leading to narrowed blood vessels and reduced blood flow to the extremities [1]. - This **ischemia** deprives tissues of oxygen and nutrients, making them vulnerable to injury and infection and impairing healing. *Altered host defense mechanisms and neuropathy* - **Diabetic neuropathy** can lead to loss of sensation, causing unnoticed injuries and breakdown of skin integrity [1]. - **Impaired immune function** in diabetes makes patients more susceptible to infections, which can rapidly progress and lead to gangrene. *Increased blood glucose levels leading to tissue damage* - **Hyperglycemia** directly contributes to macrovascular and microvascular complications, worsening **ischemia** and **neuropathy** [2]. - High glucose levels also impair **wound healing** and **immune responses**, facilitating infection and tissue destruction.

Q: Which of the following is not a clinical feature of hyperprolactinaemia?

Ambiguous genitalia. ***Ambiguous genitalia*** - **Ambiguous genitalia** refers to a condition where external genitalia do not clearly identify an infant as male or female [4]. This is usually due to **congenital adrenal hyperplasia (CAH)** or other developmental disorders, not hyperprolactinemia [3]. - Hyperprolactinemia primarily affects reproductive function and milk production, not the determination of sex characteristics during fetal development. *Oligomenorrhea* - **Oligomenorrhea** (infrequent menstruation) is a common clinical feature of hyperprolactinemia. Elevated prolactin levels can disrupt the **hypothalamic-pituitary-gonadal axis**, inhibiting GnRH pulsatility and subsequent ovarian function [2]. - This hormonal imbalance leads to irregular or absent menstrual periods [2]. *Galactorrhea* - **Galactorrhea** (inappropriate milk production) is a classic symptom of hyperprolactinemia [1]. Prolactin's primary physiological role is to stimulate milk synthesis [5]. - Pathologically high levels of prolactin result in milk discharge from the breast unrelated to childbirth or nursing [2]. *Recurrent abortions* - Hyperprolactinemia can lead to **recurrent miscarriages** or abortions due to its impact on the menstrual cycle and the potential for a **luteal phase defect**. - High prolactin can interfere with adequate progesterone production needed to maintain an early pregnancy by disrupting follicular development and corpus luteum function [2][5].

Q: Which type of hypercholesterolemia is characterized by a genetic defect in the LDL receptor, leading to markedly elevated LDL levels?

Type IIa. ***Type IIa*** - This type of hypercholesterolemia, also known as **familial hypercholesterolemia (FH)**, is caused by a genetic defect in the **LDL receptor gene**. - The dysfunctional or absent LDL receptors lead to impaired clearance of **LDL particles** from the blood, resulting in markedly elevated **LDL cholesterol levels**. *Type I* - Type I hypercholesterolemia (also called familial chylomicronemia syndrome) is characterized by a deficiency in **lipoprotein lipase (LPL)** or its cofactor **apoC-II**. - This leads to a severe accumulation of **chylomicrons** and **very-low-density lipoprotein (VLDL)**, causing extremely high triglyceride levels, not primarily elevated LDL. *Type IIb* - Type IIb hypercholesterolemia, or **familial combined hyperlipidemia**, involves elevated levels of both **LDL** and **VLDL**. - It is typically associated with overproduction of VLDL and impaired clearance of VLDL and LDL, but the primary defect is not specifically in the LDL receptor. *Type III* - Type III hypercholesterolemia, or **familial dysbetalipoproteinemia**, is characterized by a defect in **apoE**, leading to impaired clearance of **chylomicron remnants** and **VLDL remnants (IDL)**. - This results in elevated levels of both cholesterol and triglycerides, primarily due to the accumulation of these specific remnant lipoproteins, not a defect in LDL receptors.

Question 1

What is the most common cause of hypercalcemic crisis?

Accepted Answer

Parathyroid adenoma

Answer

Carcinoma of the breast

Answer

Parathyroid hyperplasia

Answer

Paget's disease

Question 2

A patient with hypertension presents with hypokalemia. Aldosterone levels and renin levels are both elevated. The most likely diagnosis is.

Accepted Answer

Renal Artery stenosis

Answer

Primary Hyperaldosteronism {Conn's syndrome}

Answer

Addison's disease

Answer

Cushing's syndrome

Question 3

What would be the most probable diagnosis for a 50-year-old chronic smoker who presents with hemoptysis, truncal obesity, and hypertension, and has an elevated ACTH level that is not suppressible with high-dose dexamethasone?

Accepted Answer

Ectopic ACTH producing lung cancer

Answer

Adrenal adenoma

Answer

Bilateral adrenal hyperplasia

Answer

Pituitary tumor

Question 4

In which condition is pre-tibial myxedema most commonly observed?

Accepted Answer

Graves' disease

Answer

Hypothyroid

Answer

Hyperthyroidism

Answer

Hashimoto

Question 5

Which of the following statements about gynaecomastia is false?

Accepted Answer

Subcutaneous mastectomy is the initial treatment of choice

Answer

Seen in liver disease

Answer

There may be estrogen/testosterone imbalance

Answer

Can be drug induced

Question 6

Which of the following factors contributes to the development of diabetic gangrene?

Accepted Answer

All of the options contribute to diabetic gangrene

Answer

Ischemia due to reduced blood supply

Answer

Altered host defense mechanisms and neuropathy

Answer

Increased blood glucose levels leading to tissue damage

Question 7

Which of the following is not a clinical feature of hyperprolactinaemia?

Accepted Answer

Ambiguous genitalia

Answer

Oligomenorrhea

Answer

Galactorrhea

Answer

Recurrent abortions

Question 8

Diabetic ketoacidosis is said to be present if:

Accepted Answer

Hyperglycemia, heavy glycosuria, ketonemia, ketonuria, and acidosis are present.

Answer

Hyperglycemia, glycosuria, hyperkalemia, and hypocalcemia are present.

Answer

Hypoglycemia, hypokalemia, hypercalcemia, and ketonemia are present.

Answer

Hypoglycemia, ketonemia, ketonuria, and hypokalemia are present.

Question 9

Which type of hypercholesterolemia is characterized by a genetic defect in the LDL receptor, leading to markedly elevated LDL levels?

Accepted Answer

Type IIa

Answer

Type I

Answer

Type IIb

Answer

Type III

Question 10

The diagnosis of diabetes mellitus is certain in which of the following situations?

Accepted Answer

Successive fasting plasma glucose concentrations of 8, 9, and 8.5 mmol/L in an asymptomatic, otherwise healthy individual.

Answer

Abnormal oral glucose tolerance in a 24-yrs-old woman who has been dieting

Answer

A serum glucose level >7.8 mmol/L in a woman in her twenty-fifth week of gestation after a 50-g oral glucose load

Answer

Persistent asymptomatic glycosuria in a 30-yrs-old woman

Endocrinology — MCQs

Endocrinology — MCQs

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