Endocrinology — MCQs

A 56-year-old man presents with increased thirst, increased urinary volume, and frequency, along with new symptoms of constipation and generalized aches and pains. He has no significant past medical history and a normal physical examination. Initial investigations reveal a normal complete blood count, fasting blood glucose, and urinalysis, with normal sodium, urea, and creatinine levels, but an elevated calcium level of 12.4 mg/dL (8.4-10.2 mg/dL). Further testing shows an elevated PTH level. What is the most likely cause of the patient's polyuria?

Q1667

Which is the most common cause of death in type 1 diabetes mellitus?

Q1668

All of the following statements regarding diabetes mellitus are true, except one:

Q1669

Which condition is primarily associated with tetany?

Q1670

Among the following, which is a feature of testicular feminization syndrome?

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1661: The endocrine disorder associated with generalized lymphadenopathy is?

A. Addison's disease
B. Carcinoid syndrome
C. Hyperthyroidism (Correct Answer)
D. Cushing's syndrome

Explanation: ***Hyperthyroidism*** - **Generalized lymphadenopathy** can be a clinical manifestation of **hyperthyroidism**, particularly in conditions like **Graves' disease** [1]. - This is thought to be due to **immunological overactivity** often associated with autoimmune thyroid conditions [2]. *Addison's disease* - **Addison's disease** is characterized by **adrenal insufficiency** and typically presents with symptoms like **fatigue**, **skin hyperpigmentation**, and **hypotension**. - It is not commonly associated with **generalized lymphadenopathy**. *Cushing's syndrome* - **Cushing's syndrome** results from **prolonged exposure to high levels of cortisol**, leading to symptoms like **central obesity**, **moon facies**, and **hirsutism**. - **Lymphadenopathy** is not a feature of **Cushing's syndrome**; in fact, chronic cortisol excess can cause **lymphopenia**. *Carcinoid syndrome* - **Carcinoid syndrome** is caused by **neuroendocrine tumors** secreting **vasoactive substances** like serotonin, leading to symptoms such as **flushing**, **diarrhea**, and **bronchospasm**. - **Lymphadenopathy** is not typically part of the carcinoid syndrome, although tumor metastasis to lymph nodes can occur.

Question 1662: Osteitis fibrosa cystica is associated with which of the following conditions?

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

Explanation: ***Hyperparathyroidism*** - **Osteitis fibrosa cystica** is a classic bone manifestation of severe, chronic **hyperparathyroidism**, characterized by increased osteoclastic activity. - This condition results in the replacement of normal bone with **fibrous tissue** and **cysts**, often leading to bone pain, fractures, and deformities. *Hypoparathyroidism* - **Hypoparathyroidism** is characterized by low parathyroid hormone (PTH) levels and **hypocalcemia**, which typically leads to increased bone density, not bone degradation. - Its manifestations include muscle cramps, seizures, and tetany, without the bone lesions seen in osteitis fibrosa cystica. *Hypothyroidism* - **Hypothyroidism** is a state of thyroid hormone deficiency, affecting metabolism and growth but not directly causing osteitis fibrosa cystica. - It can lead to slowed bone turnover and delayed growth in children, but not the specific bone lesions associated with parathyroid dysfunction. *Hyperthyroidism* - **Hyperthyroidism** can cause increased bone turnover and **osteoporosis** due to accelerated bone resorption, but it does not lead to the distinct fibrous and cystic bone changes of osteitis fibrosa cystica. - Its effects on bone are generally a diffuse reduction in bone mineral density rather than specific lytic lesions or brown tumors.

Question 1663: Which of the following is NOT a criterion for primary hyperaldosteronism? a) Diastolic hypertension, b) Metabolic alkalosis, c) Low renin secretion, d) High aldosterone secretion.

A. Low renin secretion
B. High aldosterone secretion
C. Diastolic hypertension (Correct Answer)
D. Metabolic alkalosis

Explanation: ***Diastolic hypertension*** - While hypertension, including diastolic hypertension, is a common manifestation of primary hyperaldosteronism due to **sodium and water retention**, it is a *result* of the condition, not a direct diagnostic criterion or physiological hallmark [2]. - The core diagnostic criteria focus on the **renin-aldosterone axis** and metabolic derangements indicative of excessive mineralocorticoid activity. *Low renin secretion* - This is a key diagnostic feature of **primary hyperaldosteronism**, as high aldosterone levels suppress renin release through a negative feedback loop [2]. - The **aldosterone-to-renin ratio** is a crucial screening test for this condition. *High aldosterone secretion* - This is the **defining characteristic** of primary hyperaldosteronism, driven by an adrenal adenoma or bilateral adrenal hyperplasia. - Elevated aldosterone levels lead to increased **sodium reabsorption** and **potassium excretion** [1]. *Metabolic alkalosis* - This often develops due to increased **potassium and hydrogen ion excretion** in the renal tubules, spurred by high aldosterone levels [1]. - The resulting **hypokalemia** and alkalosis contribute to the clinical picture; primary hyperaldosteronism (Conn's syndrome) is a classical cause of normovolaemic metabolic alkalosis [3].

Question 1664: Which of the following hormones are raised in Prader-Willi syndrome?

A. Follicle Stimulating Hormone (FSH)
B. Ghrelin (Correct Answer)
C. Luteinizing Hormone (LH)
D. Growth Hormone (GH)

Explanation: Ghrelin - Ghrelin levels are typically elevated in patients with Prader-Willi syndrome, contributing to their characteristic hyperphagia and obesity. - This increased ghrelin secretion leads to a perpetual feeling of hunger and an insatiable appetite. Luteinizing Hormone (LH) - LH levels are often low in individuals with Prader-Willi syndrome, contributing to hypogonadism [1]. - This deficiency is part of the broader endocrine dysfunction seen in the syndrome. Follicle Stimulating Hormone (FSH) - FSH levels are generally low in Prader-Willi syndrome, mirroring the low LH levels and indicating hypogonadotropic hypogonadism [1]. - This hormonal imbalance leads to incomplete sexual development and infertility. Growth Hormone (GH) - Growth hormone levels are typically low or deficient in Prader-Willi syndrome, contributing to short stature and abnormal body composition. - GH deficiency is a common feature, often necessitating exogenous growth hormone therapy.

Question 1665: A known patient with renal stone disease, who developed a pathological fracture, abdominal pain, and certain psychiatric symptoms, should be investigated for.

A. Polycystic kidney disease
B. Renal tubular acidosis (RTA)
C. Primary hyperparathyroidism (Correct Answer)
D. Paget's disease of bone (osteitis deformans)

Explanation: ***Primary hyperparathyroidism*** - The combination of **renal stones** ("stones"), **pathological fractures** ("bones"), and **psychiatric symptoms** ("groans" and "moans") is a classic presentation of **primary hyperparathyroidism** due to hypercalcemia [1], [2]. - **Elevated parathyroid hormone (PTH)** leads to increased calcium resorption from bones and reabsorption in the kidneys, causing the described symptoms [1], [2]. *Polycystic kidney disease* - This genetic disorder is characterized by **cysts in the kidneys**, which can lead to renal failure and hypertension, but typically not pathological fractures or hypercalcemia-related psychiatric symptoms. - While **renal stones can occur**, the other systemic features point away from this diagnosis. *Renal tubular acidosis (RTA)* - RTA is a group of disorders where the kidneys fail to reabsorb or secrete acids properly, leading to **metabolic acidosis** and sometimes **nephrocalcinosis** (renal stones). - It does not typically cause hypercalcemia-related pathological fractures or psychiatric symptoms. *Paget's disease of bone (osteitis deformans)* - This disorder is characterized by **disorganized bone remodeling**, leading to localized areas of enlarged and weakened bone, which can cause fractures and bone pain. - While it affects bones, it does not typically cause **renal stones** or the **hypercalcemia-related psychiatric symptoms** seen in this patient [1].

Question 1666: A 56-year-old man presents with increased thirst, increased urinary volume, and frequency, along with new symptoms of constipation and generalized aches and pains. He has no significant past medical history and a normal physical examination. Initial investigations reveal a normal complete blood count, fasting blood glucose, and urinalysis, with normal sodium, urea, and creatinine levels, but an elevated calcium level of 12.4 mg/dL (8.4-10.2 mg/dL). Further testing shows an elevated PTH level. What is the most likely cause of the patient's polyuria?

A. Renal tubular acidosis due to hypercalcemia
B. Chronic renal failure secondary to hypercalcemia
C. Nephrogenic diabetes insipidus due to hypercalcemia (Correct Answer)
D. Increased renal excretion of water due to PTH action

Explanation: ***Nephrogenic diabetes insipidus due to hypercalcemia*** - **Hypercalcemia** can induce **nephrogenic diabetes insipidus** by impairing the kidney's ability to respond to **vasopressin (ADH)** [3], leading to increased urinary volume and frequency. - The elevated **PTH** confirms **primary hyperparathyroidism** [1], a common cause of hypercalcemia [4], which then drives the polyuria through this mechanism. *Renal tubular acidosis due to hypercalcemia* - While hypercalcemia can sometimes be associated with **renal tubular acidosis**, the primary symptom of **polyuria** is more directly explained by impaired ADH action rather than a specific acid-base disorder. - Renal tubular acidosis typically involves systemic **acid-base imbalances** and is not the most direct cause for the osmotic diuresis seen with polyuria in hypercalcemia. *Chronic renal failure secondary to hypercalcemia* - While severe and prolonged hypercalcemia can eventually lead to **chronic kidney disease** and **renal insufficiency** [2], the symptoms presented, particularly the prominent **polyuria** (increased urinary volume), suggest an immediate functional impairment of water reabsorption, rather than significant structural damage indicated by chronic renal failure. - The normal **creatinine** and **urea** levels argue against established chronic renal failure. *Increased renal excretion of water due to PTH action* - **PTH** primarily regulates **calcium** and **phosphate** metabolism, and its direct action does not significantly increase renal water excretion [4]. - The polyuria observed is an indirect effect of **PTH-induced hypercalcemia**, which then compromises the renal concentrating ability, not a direct action of PTH on water excretion.

Question 1667: Which is the most common cause of death in type 1 diabetes mellitus?

A. Infections
B. Myocardial disease (Correct Answer)
C. Stroke
D. Kidney disease

Explanation: ***Myocardial disease*** - **Cardiovascular disease**, particularly **myocardial infarction** and **heart failure**, is the leading cause of death in both type 1 and type 2 diabetes due to accelerated atherosclerosis. - This increased risk stems from chronic hyperglycemia, dyslipidemia, hypertension, and inflammation associated with uncontrolled diabetes. *Kidney disease* - While **diabetic nephropathy** is a serious long-term complication of type 1 diabetes and can lead to end-stage renal disease, it is not the most common direct cause of death. - Patients with kidney disease often eventually succumb to **cardiovascular complications** that are often exacerbated by renal dysfunction. *Stroke* - **Ischemic stroke** is a significant complication of diabetes due to increased risk of atherosclerosis affecting cerebral vessels, but it occurs less frequently than myocardial disease. - Stroke is a critical cause of **morbidity** and **disability** but ranks below myocardial disease in overall mortality in diabetic patients. *Infections* - Individuals with diabetes are more susceptible to severe and atypical infections due to impaired immune function. - While infections can lead to significant illness and death, they are not the leading cause of mortality compared to macrovascular complications like myocardial disease.

Question 1668: All of the following statements regarding diabetes mellitus are true, except one:

A. Insulin levels may be decreased in patients with Type II Diabetes mellitus
B. Insulin is essential to reverse Diabetic Ketoacidosis
C. Intravenous Insulin is administered as a sliding scale in the hospital setting
D. Insulin is never used in Type II Diabetes mellitus (Correct Answer)

Explanation: ***Insulin is never used in Type II Diabetes mellitus*** - This statement is incorrect because insulin therapy is a common treatment for Type II Diabetes mellitus, particularly when **oral medications** and **lifestyle modifications** are insufficient to control blood glucose levels. [1] - Many patients with Type II DM eventually experience pancreatic beta-cell dysfunction, necessitating **exogenous insulin** to achieve glycemic targets. [1] [2] *Insulin levels may be decreased in patients with Type II Diabetes mellitus* - While Type II DM is initially characterized by **insulin resistance** and compensatory hyperinsulinemia, over time the **pancreatic beta cells** can fail, leading to reduced insulin production. [2] - This decline in insulin secretion necessitates insulin therapy in later stages of the disease. *Insulin is essential to reverse Diabetic Ketoacidosis* - **Diabetic Ketoacidosis (DKA)** is a life-threatening complication primarily of Type 1 DM (but can occur in Type 2 DM) characterized by **severe insulin deficiency**, hyperglycemia, ketosis, and acidosis. [2] [3] - **Insulin therapy** is critical to stop ketogenesis, promote glucose uptake, and correct metabolic acidosis. *Intravenous Insulin is administered as a sliding scale in the hospital setting* - A **sliding scale insulin regimen** involves administering insulin doses based on current blood glucose readings, often used in hospital settings for both Type 1 and Type 2 DM patients. - While often used, it is increasingly being replaced by **basal-bolus regimens** for better glycemic control. [1]

Question 1669: Which condition is primarily associated with tetany?

A. None of the options
B. Hyperparathyroidism
C. Hypercalcemia
D. Hypocalcemia (Correct Answer)

Explanation: ***Hypocalcemia*** - **Tetany** is a neuromuscular hyperexcitability state resulting from critically low levels of **ionized calcium** in the extracellular fluid [2]. - Reduced extracellular calcium increases neuronal membrane excitability, leading to spontaneous and repetitive nerve discharges and muscle contractions. *Hypercalcemia* - **Hypercalcemia** refers to elevated calcium levels, which *decreases* neuromuscular excitability. - Symptoms typically involve **fatigue, weakness, constipation, and kidney stones**, rather than tetany [1]. *Hyperparathyroidism* - **Primary hyperparathyroidism** is a common cause of **hypercalcemia** due to increased PTH secretion [3]. - Therefore, it leads to symptoms associated with high calcium, not low calcium and tetany. *None of the options* - This option is incorrect because **hypocalcemia** is a well-established cause of tetany.

Question 1670: Among the following, which is a feature of testicular feminization syndrome?

A. XX pattern
B. Commonly reared as male
C. Well formed female internal genitalia
D. High testosterone levels (Correct Answer)

Explanation: High testosterone levels - Individuals with testicular feminization syndrome (also known as androgen insensitivity syndrome) have testes that produce normal to high levels of testosterone. [1] - However, due to a lack of functional androgen receptors, the body cannot respond to this testosterone, leading to feminization. [1] XX pattern - Testicular feminization syndrome is characterized by a 46,XY karyotype, meaning individuals have male chromosomes. - The XX pattern refers to female chromosomal makeup, which is not present in this syndrome. Commonly reared as male - Due to their female external phenotype and development, individuals with testicular feminization syndrome are almost invariably reared as females. - Their condition is often diagnosed when they present with primary amenorrhea or lack of pubertal feminization. Well formed female internal genitalia - Individuals with this syndrome have undescended testes but lack a uterus and fallopian tubes because the testes produce Müllerian Inhibiting Substance (MIS), which causes regression of Müllerian structures. - They typically have a shortened or blind-ended vagina but no other internal female reproductive organs.

Practice by Chapter

Diabetes Mellitus

Practice Questions

Thyroid Disorders

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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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