Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1541: Which of the following is NOT a cause of fasting hypoglycemia?

A. Pentamidine therapy
B. Renal insufficiency
C. Chronic pancreatitis (Correct Answer)
D. Alcohol intake

Explanation: ***Chronic pancreatitis*** - This condition primarily affects the **exocrine function of the pancreas**, leading to malabsorption and, in later stages, often **diabetes mellitus** due to islet cell destruction [1]. - While it can lead to **pancreatic insufficiency**, it is not typically a cause of **fasting hypoglycemia**; rather, it often causes hyperglycemia [1]. *Alcohol intake* - **Ethanol metabolism** can inhibit gluconeogenesis in the liver, especially when **glycogen stores are depleted**, leading to **hypoglycemia**. - This is a common cause of **fasting hypoglycemia**, particularly in individuals with poor nutrition. *Pentamidine therapy* - **Pentamidine**, used to treat *Pneumocystis jiroveci* pneumonia, can cause **direct toxicity to pancreatic beta cells**, leading to acute **insulin release** and subsequent hypoglycemia. - While long-term use can lead to **beta-cell destruction** and diabetes, its acute effect is often **severe hypoglycemia**. *Renal insufficiency* - **Kidney failure** can lead to hypoglycemia through several mechanisms, including **reduced renal gluconeogenesis** and decreased insulin clearance. - The kidneys play a significant role in **insulin degradation** and glucose production, so impaired function can result in **prolonged insulin levels** and lower blood glucose.

Question 1542: Metabolic syndrome diagnosis in men based on NCEP ATP III criteria includes the following except:

A. Fasting glucose > 110 mg/dL
B. Abdominal obesity > 40 inches
C. BP >/= 130/85 mm Hg
D. HDL < 50 mg / dL (Correct Answer)

Explanation: ***HDL < 50 mg / dL*** - According to NCEP ATP III criteria for metabolic syndrome in men, **HDL cholesterol** should be **less than 40 mg/dL** to meet this specific criterion. Thus, an HDL of < 50 mg/dL is not the precise cutoff. - The threshold of **< 50 mg/dL** is the cutoff for **women**, not men. *Abdominal obesity > 40 inches* - **Abdominal obesity**, defined as a **waist circumference > 40 inches (102 cm)** in men, is indeed one of the NCEP ATP III criteria for metabolic syndrome. - This criterion reflects **visceral adiposity**, which is strongly associated with insulin resistance and cardiovascular risk. *BP >/= 130/85 mm Hg* - This **blood pressure** threshold is a correct criterion for diagnosing metabolic syndrome in both men and women by NCEP ATP III. - It signifies **elevated blood pressure**, a key component of the syndrome contributing to cardiovascular risk. *Fasting glucose > 110 mg/dL* - An **elevated fasting plasma glucose** of **≥ 110 mg/dL** is a correct NCEP ATP III criterion for metabolic syndrome. - This indicates **impaired fasting glucose** or **insulin resistance**, a core feature of metabolic syndrome.

Question 1543: In case of hypothyroidism, which investigation is most informative and commonly used?

A. Serum TSH Level (Correct Answer)
B. Serum T3, T4 Level
C. Serum Calcitonin assay
D. Serum T3 level

Explanation: ***Serum TSH Level*** - **Thyroid-stimulating hormone (TSH)** is the most sensitive and specific biomarker for primary hypothyroidism, as even small changes in thyroid hormone levels cause significant reciprocal changes in TSH [1]. - A **high TSH level** indicates that the pituitary gland is working harder to stimulate a underactive thyroid gland [1]. *Serum T3, T4 Level* - While **low T3 and T4 levels** are characteristic of hypothyroidism, TSH is a more reliable initial test due to its greater sensitivity as a first-line screen [1]. - T4 levels may be affected by various conditions like malnutrition, non-thyroidal illness, and medication, which might complicate interpretation. *Serum Calcitonin assay* - **Calcitonin** is a hormone involved in calcium regulation and is primarily used as a tumor marker for medullary thyroid cancer. - It has no role in diagnosing hypothyroidism. *Serum T3 level* - **Triiodothyronine (T3)** levels can be maintained within the normal range even in early hypothyroidism due to increased peripheral conversion of T4 to T3 [1]. - T3 measurement is generally more useful in **hyperthyroidism** diagnosis or in assessing the severity of thyrotoxicosis rather than hypothyroidism [1].

Question 1544: Which of the following is a common presentation of acute adrenal insufficiency?

A. Abdominal pain, fatigue, and hypotension (Correct Answer)
B. Severe fatigue and weakness
C. Hypotension and shock
D. None of the options

Explanation: ***Abdominal pain, fatigue, and hypotension*** - **Acute adrenal insufficiency** often presents with a constellation of symptoms including **severe abdominal pain**, profound **fatigue**, and **hypotension** due to the sudden lack of cortisol and aldosterone [1]. - The abdominal pain can be mimic an **acute abdomen**, while profound fatigue and **hypotension** are directly linked to the body's inability to maintain vascular tone and electrolyte balance without proper adrenal hormones [1]. *Severe fatigue and weakness* - While **severe fatigue** and **weakness** are prominent symptoms of adrenal insufficiency, this option is incomplete as it misses other critical clinical signs like **hypotension** and **GI symptoms** that characterize the acute presentation. - These symptoms alone could be indicative of numerous other conditions, making them not specific enough for **acute adrenal insufficiency** compared to the more comprehensive answer choice. *Hypotension and shock* - **Hypotension** and progression to **shock** are indeed critical and life-threatening features of **acute adrenal insufficiency** [1]. - However, this option does not include other key clinical manifestations such as **abdominal pain** and **fatigue**, which are commonly present and help in diagnosis before full shock develops [1]. *None of the options* - This option is incorrect because the first option accurately describes the **common and critical presentation** of acute adrenal insufficiency by including the most salient symptoms. - The combination of **abdominal pain**, **fatigue**, and **hypotension** is highly characteristic of this medical emergency [1].

Question 1545: What is the average time period that HbA1c reflects blood glucose control?

A. 3 - 4 months
B. 2 - 3 months (Correct Answer)
C. 4 - 5 months
D. 1 - 2 months

Explanation: ***2 - 3 months*** - **Hemoglobin A1c (HbA1c)** reflects the average blood glucose levels over the preceding **2-3 months** due to the typical lifespan of red blood cells [1]. - Glucose molecules bind irreversibly to hemoglobin within red blood cells, and the level of glycosylation directly correlates with the average plasma glucose concentration during and after the red cell's formation [1], [2]. *1 - 2 months* - This timeframe is too short to accurately represent the full lifespan of red blood cells, which is the basis for HbA1c measurement. - While some red blood cells are younger, a significant portion reflecting the earlier part of the 3-month period would be missed, providing an incomplete picture. *3 - 4 months* - This period is generally considered too long, as the contribution of red blood cells older than approximately 3 months to the overall HbA1c value becomes negligible due to their natural turnover [1]. - Focusing on this longer duration might incorporate data from red blood cells that have already been replaced, potentially overestimating or underestimating recent glucose control. *4 - 5 months* - This timeframe would be significantly inaccurate for HbA1c measurement. - The vast majority of red blood cells from 4-5 months prior would have been replaced, leading to a poor reflection of actual blood glucose control.

Question 1546: What is the HbA1C criteria for a patient to be diagnosed with diabetes mellitus?

A. 5.5%
B. 6.5% (Correct Answer)
C. 4.5%
D. 7.5%

Explanation: ***6.5%*** - An HbA1C level of **6.5% or higher** is the diagnostic threshold for **diabetes mellitus** according to major international guidelines [1]. - This value reflects an average blood glucose level over the preceding **two to three months**, indicating chronic hyperglycemia [1]. *5.5%* - An HbA1C of 5.5% falls within the **normal range** for individuals without diabetes or prediabetes [1]. - It does not indicate impaired glucose regulation or diabetes. *4.5%* - An HbA1C of 4.5% is considered a **very good** or **low-normal** value, indicating excellent blood glucose control. - This level is far below the threshold for diagnosing diabetes. *7.5%* - While 7.5% is indicative of diabetes, it is **higher** than the diagnostic cutoff. - An HbA1C of 7.5% or more would suggest **poorly controlled diabetes** rather than just meeting the diagnostic criteria.

Question 1547: Which of the following causes of hypercalcemia is not associated with high bone turnover?

A. Hyperthyroidism
B. Thiazides (Correct Answer)
C. Vitamin D intoxication
D. Vitamin A intoxication

Explanation: ***Thiazides*** - Thiazide diuretics cause hypercalcemia by increasing **renal reabsorption of calcium** in the distal tubule [1], not by stimulating bone breakdown. - This effect leads to a higher serum calcium concentration without an increase in **bone turnover markers**. *Hyperthyroidism* - Excessive thyroid hormone can directly stimulate **osteoclast activity**, leading to increased bone resorption and high bone turnover. - This results in a net release of calcium from the bone into the bloodstream, contributing to hypercalcemia. *Vitamin D intoxication* - Excess vitamin D drastically increases intestinal absorption of calcium and phosphate [1], as well as stimulating **osteoclastic bone resorption** [3], thereby increasing bone turnover. - This leads to significant elevation of serum calcium levels [3]. *Vitamin A intoxication* - Chronic excessive intake of Vitamin A can lead to bone toxicity, promoting **osteoclastogenesis** and osteoclastic bone resorption [2]. - This process directly contributes to increased bone turnover and subsequent hypercalcemia [2].

Question 1548: In which condition is a hypotonic solution administered for correction?

A. Hyperosmolar hyperglycemic state (HHS) (Correct Answer)
B. Dehydration secondary to diuretic therapy
C. Hypotonic dehydration
D. Diabetic ketoacidosis

Explanation: ***Hyperosmolar hyperglycemic state (HHS)*** - In **HHS**, patients have severe **hyperglycemia** and **hyperosmolality**, leading to significant dehydration and intracellular fluid shifts. - Administering a **hypotonic solution** (e.g., 0.45% saline) helps to gradually lower serum osmolality and **rehydrate cells**, correcting both the fluid deficit and the hypertonic state [2], [4]. *Dehydration secondary to diuretic therapy* - This typically involves **isotonic or hypotonic fluid loss**, and administering a hypotonic solution could exacerbate **hyponatremia** or fluid overload. - Treatment usually focuses on replacing lost volume with **isotonic fluids** and addressing the underlying electrolyte imbalances. *Diabetic ketoacidosis (DKA)* - Initial fluid resuscitation in **DKA** typically involves **isotonic saline** (e.g., 0.9% NaCl) to expand the extracellular volume and restore perfusion [1], [2]. - While DKA eventually requires free water, a hypotonic solution is not the initial or primary fluid for correction of the acute phase due to significant fluid and electrolyte deficits [1]. *Hypotonic dehydration* - In **hypotonic dehydration**, there's a greater loss of sodium than water, leading to **hyponatremia** [3]. - Administering a **hypotonic solution** would worsen the already low serum sodium concentration, which can be dangerous [3].

Question 1549: Sheehan syndrome is?

A. Pituitary adenoma
B. Pituitary necrosis (Correct Answer)
C. Adrenal necrosis
D. Adrenal adenoma

Explanation: ### Pituitary necrosis - Sheehan syndrome is characterized by **pituitary gland necrosis** due to severe blood loss or low blood pressure during or after childbirth [1]. - This condition leads to **hypopituitarism**, affecting hormone secretion crucial for various bodily functions [1], [2]. *Adrenal necrosis* - Refers to the death of adrenal gland tissue, but is not specifically related to Sheehan syndrome's etiology. - Symptoms may include **adrenal insufficiency**, which is not the primary feature of Sheehan syndrome. *Adrenal adenoma* - This is a benign tumor of the adrenal gland, typically associated with hormonal excess (like Cushing's syndrome) [3]. - Unlike Sheehan syndrome, it does not involve **ischemic damage** to the pituitary gland. *Pituitary adenoma* - A tumor of the pituitary gland that often causes **hypersecretion** of hormones rather than necrosis. - While it may affect pituitary function, it does not occur due to blood loss during childbirth, unlike Sheehan syndrome.

Question 1550: Tufting of the distal phalanx is characteristically seen in which of the following conditions?

A. Hyperkalemia
B. Hypoparathyroidism
C. Gout
D. Hyperparathyroidism (Correct Answer)

Explanation: ***Hyperparathyroidism*** - Tufting of the distal phalanx is a classic radiological feature associated with **hyperparathyroidism**, due to increased bone resorption. - This condition leads to **subperiosteal bone resorption**, especially noticeable in the phalangeal tufts of the fingers [2]. *Gout* - Gout is characterized by the **deposition of uric acid crystals**, typically affecting the **metatarsophalangeal** joint [1]. - It does not exhibit the specific bony changes such as tufting seen in hyperparathyroidism. *Hypoparathyroidism* - Hypoparathyroidism leads to **hypocalcemia** and symptoms such as tetany, but does not cause tufting of the distal phalanx. - This condition is marked by **bone density increases**, contrary to the resorption seen in hyperparathyroidism. *Hyperkalemia* - Hyperkalemia refers to abnormally high **potassium levels** and is primarily associated with renal issues and cardiac symptoms. - It has no direct connection to bony changes or tufting of the phalanges.

Practice by Chapter

Diabetes Mellitus

Practice Questions

Thyroid Disorders

Practice Questions

Adrenal Gland Disorders

Practice Questions

Pituitary Disorders

Practice Questions

Calcium and Bone Metabolism

Practice Questions

Reproductive Endocrinology

Practice Questions

Lipid Disorders

Practice Questions

Endocrine Hypertension

Practice Questions

Multiple Endocrine Neoplasia

Practice Questions

Obesity and Metabolic Syndrome

Practice Questions

Neuroendocrine Tumors

Practice Questions

Endocrine Emergencies

Practice Questions

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