Endocrinology Practice Questions

Q: Apparent mineralocorticoid excess is due to

11-β hydroxysteroid dehydrogenase. ***11-β hydroxysteroid dehydrogenase*** - Apparent mineralocorticoid excess (AME) is caused by a deficiency of **11-β-hydroxysteroid dehydrogenase type 2 (11β-HSD2)**, which is responsible for inactivating **cortisol** to **cortisone** [1]. - Without proper inactivation, elevated cortisol levels can then **bind to and activate mineralocorticoid receptors (MR)** in the kidney, leading to symptoms mimicking hyperaldosteronism [1]. *Sgk gene* - The **SGK1 gene** encodes for **serum and glucocorticoid-regulated kinase 1**, which plays a role in renal sodium absorption, but not directly in the cause of AME [1]. - While **SGK1** is involved in epithelial sodium channel (ENaC) regulation, its overactivity is a downstream effect, not the primary cause of AME [1]. *CYP 11B2* - **CYP11B2** (aldosterone synthase) is responsible for the final step in **aldosterone synthesis** [1]. - While it's crucial for mineralocorticoid production, a deficiency in **11β-HSD2** causes **cortisol-induced mineralocorticoid effects**, not issues with aldosterone synthesis itself. *CYP11A* - **CYP11A** (cholesterol side-chain cleavage enzyme) initiates the synthesis of all steroid hormones from **cholesterol** [1]. - Defects in **CYP11A** would lead to a more severe and broad deficiency in steroid production, not specifically apparent mineralocorticoid excess.

Q: Hypocalcemia is characterized by all except

Shortening of Q-T interval in ECG. ***Shortening of Q-T interval in ECG*** - Hypocalcemia typically causes **prolongation of the QT interval** on an ECG due to delayed repolarization of ventricular myocardial cells. - A **shortened QT interval** is usually associated with hypercalcemia or conditions like short QT syndrome. *Carpopedal spasm* - This is a classic sign of hypocalcemia, known as **Trousseau's sign**, elicited by inflating a blood pressure cuff above systolic pressure, which causes spasm of the hand and foot. - It results from increased neuromuscular irritability due to lower calcium levels. *Hyperactive tendon reflexes* - Hypocalcemia leads to **increased neuromuscular excitability**, which manifests as hyperactive or brisk deep tendon reflexes. - This heightened reflex activity is a common neurological symptom of low calcium. *Numbness and tingling of circumoral region* - This symptom, known as **paresthesia**, is a very common and early manifestation of hypocalcemia. - It occurs due to the increased excitability of peripheral nerves caused by reduced extracellular calcium.

Q: A 10 day old male pseudohermaphrodite child with 46 XY karyotype presents with BP of 110/80 mmHg. Most likely enzyme deficiency is:

17 hydroxylase. ***17-hydroxylase*** - Deficiency of **17α-hydroxylase** leads to impaired synthesis of androgens and estrogens, resulting in **male pseudohermaphroditism** (46 XY DSD) [1]. - The block in cortisol and sex steroid synthesis shunts precursors toward mineralocorticoid production (e.g., **corticosterone, deoxycorticosterone**), causing **hypertension** and **hypokalemia** [1]. *3-beta hydroxysteroid dehydrogenase* - This deficiency affects the synthesis of all three classes of adrenal steroids (glucocorticoids, mineralocorticoids, and androgens). - It would typically lead to **salt wasting**, **hypotension**, and severe **masculinization in females** or **pseudohermaphroditism in males**, but without hypertension. *11-hydroxylase* - Deficiency of **11β-hydroxylase** leads to accumulation of **11-deoxycorticosterone** (DOC) and **11-deoxycortisol**, which have mineralocorticoid activity. - This causes **hypertension** and **virilization** (overproduction of weak androgens), but it does not cause male pseudohermaphroditism. *21-hydroxylase* - This is the most common form of **congenital adrenal hyperplasia** (CAH) and results in impaired synthesis of cortisol and aldosterone, leading to an accumulation of androgen precursors. - Clinical features include **virilization in females**, **salt wasting** (due to aldosterone deficiency), and **hypotension** rather than hypertension in the severe forms, and no DSD in males.

Q: Most common endocrine complication of intracranial radiotherapy is

Growth hormone deficiency. **Growth hormone deficiency** - **Growth hormone (GH)-producing cells** in the pituitary are highly sensitive to radiation, making GH deficiency the earliest and most common endocrine complication after intracranial radiotherapy [1]. - This deficiency can manifest years after radiation and cause growth failure in children and reduced bone mineral density or fatigue in adults. *TSH deficiency* - While **TSH deficiency** (central hypothyroidism) can occur, it typically manifests later than GH deficiency and is less common [1]. - It indicates damage to the **thyrotrophs** of the pituitary, which are generally more resistant to radiation than somatotrophs. *Addison's disease* - **Addison's disease** is primary adrenal insufficiency, where the adrenal glands fail to produce enough cortisol and aldosterone. It is not caused by intracranial radiotherapy [1]. - Intracranial radiotherapy can lead to **central adrenal insufficiency** due to ACTH deficiency, but not primary Addison's. *Cushing's syndrome* - **Cushing's syndrome** is caused by prolonged exposure to high levels of cortisol, often due to an **ACTH-producing pituitary adenoma** (Cushing's disease) or adrenal tumor [2]. It is not a complication of intracranial radiotherapy itself. - Radiotherapy may be used **to treat** Cushing's disease, but it does not cause the condition.

Q: Hypophosphatemia is caused by-

Primary hyperparathyroidism. ***Primary hyperparathyroidism*** - In **primary hyperparathyroidism**, excessive parathyroid hormone (PTH) leads to increased **renal phosphate excretion** and inhibition of its reabsorption, resulting in hypophosphatemia [1][2]. - PTH's primary role is to raise **serum calcium**, but it indirectly lowers phosphate by acting on the kidneys and bones [3]. *Primary hyperthyroidism* - **Hyperthyroidism** typically causes an increase in **bone turnover**, but does not directly lead to **hypophosphatemia** as a primary feature. - While high thyroid hormone levels can affect calcium and phosphate metabolism, it's more commonly associated with hypercalcemia rather than hypophosphatemia. *Primary hypothyroidism* - **Hypothyroidism** can lead to altered bone metabolism, but it does not directly cause **hypophosphatemia**. - Renal phosphate handling is generally not significantly impaired in a way that would lead to low serum phosphate levels. *Hypoparathyroidism* - **Hypoparathyroidism** is characterized by deficient PTH production, which leads to **decreased renal phosphate excretion**, resulting in **hyperphosphatemia**, not hypophosphatemia [4]. - The lack of PTH also causes hypocalcemia due to reduced bone resorption and impaired renal calcium reabsorption.

Q: A 65-year-old woman with type 2 diabetes is on hemodialysis for chronic kidney disease. She now presents to the clinic with symptoms of pain in the hands. The symptoms started many months age and are now getting worse. She does not recall any injury to the hands and has not noticed any swelling or redness in the joints.On examination, the joints are normal with no inflammation or tenderness on palpation. There is full range of motion of the fingers and wrists.Lab investigations: calcium (7.2 mg/dL), phosphate (5.5 mg/dL), and PTH level (710 ng/L). (See Figure below) What is the most likely diagnosis?

secondary hyperparathyroidism. ***Secondary hyperparathyroidism*** - The patient's history of **CKD on hemodialysis**, coupled with **low calcium (7.2 mg/dL), high phosphate (5.5 mg/dL), and markedly elevated PTH (710 ng/L)**, is highly indicative of secondary hyperparathyroidism. - While joint pain is nonspecific, **bone and joint pain** are common symptoms of this condition due to **renal osteodystrophy**, which includes osteitis fibrosa cystica caused by chronic PTH elevation. *pseudogout* - Pseudogout typically involves **acute, inflammatory arthritis** with warmth, swelling, and redness, which is not described in this patient. - It is caused by **calcium pyrophosphate dihydrate crystal deposition**, usually seen in older adults (often with hyperparathyroidism, but not the primary cause of pain here). *gout* - Gout presents as **acute, severe pain and inflammation** (redness, swelling, tenderness) in a single joint, often the big toe, which is not consistent with the patient's presentation of gradual, non-inflammatory hand pain. - It results from **monosodium urate crystal deposition**, and while CKD can be a risk factor for hyperuricemia, the clinical picture here does not fit gout. *scleroderma* - Scleroderma (systemic sclerosis) involves **skin thickening and hardening**, Raynaud's phenomenon, and internal organ involvement, none of which are mentioned in the patient's symptoms or examination findings. - While **arthralgias** can occur, the prominent laboratory findings of abnormal calcium, phosphate, and PTH point away from scleroderma as the primary diagnosis for the presenting pain.

Q: Gigantism is most commonly caused by:

Pituitary adenomas. Pituitary adenomas - Gigantism is characterized by excessive growth and height, primarily caused by hypersecretion of growth hormone (GH) before the fusion of epiphyseal plates [1]. - The most common cause of sustained GH hypersecretion leading to gigantism is a pituitary adenoma, a benign tumor of the pituitary gland's somatotroph cells [2], [3]. Chromosomal abnormalities - While some genetic conditions can cause tall stature (e.g., Klinefelter syndrome), they are not the primary cause of gigantism, which is specifically related to excessive GH production. - Conditions like Marfan syndrome may cause tall stature but do not involve GH excess or pituitary adenomas. Parathyroid disorders - These primarily affect calcium and phosphate metabolism, leading to conditions like hypercalcemia or hypocalcemia. - They do not directly cause excessive growth hormone secretion or gigantism. Thyroid disorders - Hyperthyroidism can cause increased metabolic rate and weight loss, but it does not lead to the massive skeletal overgrowth seen in gigantism. - Hypothyroidism in childhood can cause dwarfism or stunted growth, which is the opposite of gigantism.

Q: Mr. Murali has 126 mg/dl of fasting plasma glucose. His venous plasma glucose 2h after ingestion of 75g oral glucose load is 149 mg/dl. This patient comes under which stage of WHO diagnostic criteria of diabetes & intermediate hyperglycemia?

Diagnosis of diabetes. **Diagnosis of diabetes** - The **fasting plasma glucose (FPG)** of 126 mg/dL meets the WHO criterion for **diabetes**, which is FPG ≥ 126 mg/dL [1]. - Although the 2-hour post-glucose load (149 mg/dL) falls within the **impaired glucose tolerance (IGT)** range (140-199 mg/dL), the elevated fasting glucose alone is sufficient for a diabetes diagnosis according to WHO guidelines. *Decreased glucose resistance* - This term is not a standard diagnostic category recognized by the WHO for glucose metabolism disorders. - Glucose resistance is more commonly associated with conditions like **insulin resistance** rather than a specific diagnostic stage [1]. *IFG - Impaired fasting glucose* - **Impaired fasting glucose (IFG)** is defined by a fasting plasma glucose level between 100 mg/dL and 125 mg/dL. - Mr. Murali's fasting glucose of 126 mg/dL is higher than the upper limit for IFG [1]. *Impaired glucose tolerance* - **Impaired glucose tolerance (IGT)** is defined by a 2-hour post-glucose load plasma glucose level between 140 mg/dL and 199 mg/dL. - While Mr. Murali's 2-hour reading of 149 mg/dL falls within this range, the elevated fasting glucose level takes precedence for the overall diagnosis [1].

Q: Short 4th metacarpal is a feature of

Pseudohypoparathyroidism. ***Pseudohypoparathyroidism*** - **Short 4th metacarpal** is a classic skeletal feature, often referred to as **Albright's hereditary osteodystrophy**, which is pathognomonic for pseudohypoparathyroidism type 1A [2]. - This condition results from **end-organ resistance to parathyroid hormone (PTH)**, leading to hypocalcemia and hyperphosphatemia despite elevated PTH levels [2]. *Achondroplasia* - Characterized by **short limbs** due to abnormal endochondral ossification, but typically affects all long bones symmetrically and does not specifically cause a short 4th metacarpal as a distinct feature [1]. - While patients have short hands, the **overall hand structure** is disproportionate rather than a specific short metacarpal [1]. *Scleroderma* - This is a **connective tissue disease** characterized by fibrosis of the skin and internal organs; it does not typically cause skeletal abnormalities like a short 4th metacarpal. - Skeletal manifestations usually involve **erosions** and **joint contractures** due to skin tightening, not developmental bone anomalies. *Turner syndrome* - Patients with Turner syndrome often have **short stature** and various skeletal findings, including **short 4th metacarpals** in some cases [3]. - However, pseudohypoparathyroidism is more specifically and consistently associated with the **Albright's hereditary osteodystrophy phenotype**, which includes the short 4th metacarpal.

Q: Excess of calcium intake leads to?

Milk alkali syndrome. ***Milk alkali syndrome*** - **Milk-alkali syndrome** is caused by excessive intake of calcium (especially in the form of calcium carbonate) and absorbable alkali, leading to **hypercalcemia**, metabolic alkalosis, and acute kidney injury. - The combination of abnormally high calcium intake, often from supplements, and the use of antacids or milk, drives this condition. *Cardiomyopathy* - **Cardiomyopathy** refers to diseases of the heart muscle that make it harder for the heart to pump blood, and it is not directly caused by excess calcium intake. - While severe hypercalcemia can affect cardiac function, it typically causes arrhythmias or altered contractility, not a primary **cardiomyopathy**. *Osteomalacia* - **Osteomalacia** is a softening of the bones, typically due to **vitamin D deficiency** or impaired metabolism, leading to inadequate mineralization of new bone matrix. - This condition is caused by insufficient calcium and phosphate for normal bone formation, not by an **excess of calcium intake**. *Osteoporosis* - **Osteoporosis** is a disease where bones become weak and brittle due to **loss of bone mass** and microarchitectural deterioration. [1] - Chronic excess calcium intake does not cause osteoporosis; in fact, adequate calcium intake is crucial for **bone health** and preventing osteoporosis. [1]

Question 1

Apparent mineralocorticoid excess is due to

Accepted Answer

11-β hydroxysteroid dehydrogenase

Answer

Sgk gene

Answer

CYP 11B2

Answer

CYP11A

Question 2

Hypocalcemia is characterized by all except

Accepted Answer

Shortening of Q-T interval in ECG

Answer

Carpopedal spasm

Answer

Hyperactive tendon reflexes

Answer

Numbness and tingling of circumoral region

Question 3

A 10 day old male pseudohermaphrodite child with 46 XY karyotype presents with BP of 110/80 mmHg. Most likely enzyme deficiency is:

Accepted Answer

17 hydroxylase

Answer

3-beta hydroxylase

Answer

11 hydroxylase

Answer

21 hydroxylase

Question 4

Most common endocrine complication of intracranial radiotherapy is

Accepted Answer

Growth hormone deficiency

Answer

TSH deficiency

Answer

Addison's disease

Answer

Cushing's syndrome

Question 5

Hypophosphatemia is caused by-

Accepted Answer

Primary hyperparathyroidism

Answer

Primary hyperthyroidism

Answer

Primary hypothyroidism

Answer

Hypoparathyroidism

Question 6

A 65-year-old woman with type 2 diabetes is on hemodialysis for chronic kidney disease. She now presents to the clinic with symptoms of pain in the hands. The symptoms started many months age and are now getting worse. She does not recall any injury to the hands and has not noticed any swelling or redness in the joints.On examination, the joints are normal with no inflammation or tenderness on palpation. There is full range of motion of the fingers and wrists.Lab investigations: calcium (7.2 mg/dL), phosphate (5.5 mg/dL), and PTH level (710 ng/L). (See Figure below) What is the most likely diagnosis?

Accepted Answer

secondary hyperparathyroidism

Answer

pseudogout

Answer

gout

Answer

scleroderma

Question 7

Gigantism is most commonly caused by:

Accepted Answer

Pituitary adenomas

Answer

Chromosomal abnormalities

Answer

Parathyroid disorders

Answer

Thyroid disorders

Question 8

Mr. Murali has 126 mg/dl of fasting plasma glucose. His venous plasma glucose 2h after ingestion of 75g oral glucose load is 149 mg/dl. This patient comes under which stage of WHO diagnostic criteria of diabetes & intermediate hyperglycemia?

Accepted Answer

Diagnosis of diabetes

Answer

Decreased glucose resistance

Answer

IFG - Impaired fasting glucose

Answer

Impaired glucose tolerance

Question 9

Short 4th metacarpal is a feature of

Accepted Answer

Pseudohypoparathyroidism

Answer

Achondroplasia

Answer

Scleroderma

Answer

Turner syndrome

Question 10

Excess of calcium intake leads to?

Accepted Answer

Milk alkali syndrome

Answer

Cardiomyopathy

Answer

Osteomalacia

Answer

Osteoporosis

Endocrinology — MCQs

Endocrinology — MCQs

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