Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1371: A 17-year-old woman presents with symptoms of a fine tremor of her hands. The tremor is best seen when her hands are stretched out. She is not on any medications and reports no alcohol use. Which of the following is the most likely diagnosis?

A. marijuana use
B. myxedema
C. hyperthyroidism (Correct Answer)
D. hypopituitarism

Explanation: ### Hyperthyroidism - A **fine tremor** that is best observed with **action (postural tremor)**, such as outstretched hands, is a classic feature of hyperthyroidism due to increased adrenergic tone. - Other common symptoms of hyperthyroidism often include **tachycardia**, **anxiety**, **weight loss**, and **heat intolerance** [1], which should be investigated further. *Marijuana use* - While marijuana use can cause tremors, they are typically more related to **intoxication** and less specifically described as a fine postural tremor in an otherwise healthy individual. - Tremors from cannabis are often less sustained and associated with other signs of impairment, such as **altered perception** and **impaired coordination**. *Myxedema* - Myxedema refers to severe **hypothyroidism**, which typically causes a **slowing of motor functions** and can sometimes result in a fine tremor, but this is less common and often less prominent than in hyperthyroidism. - Patients with myxedema usually present with **fatigue**, **weight gain**, **cold intolerance**, and **bradycardia** [1], which are symptoms opposite to those associated with a fine postural tremor dueoved. *Hypopituitarism* - Hypopituitarism involves a **deficiency in multiple pituitary hormones** and generally does not present with a primary symptom of fine hand tremor. - Symptoms vary widely depending on the hormones affected but typically include **fatigue**, **weakness**, **menstrual irregularities**, and **hypotension**, rather than a distinct tremor.

Question 1372: Most common tumour of the pituitary is -

A. ACTH secreting adenoma
B. Prolactinoma (Correct Answer)
C. TSH secreting adenoma
D. GH secreting adenoma

Explanation: ***Prolactinoma*** - **Prolactinomas** are the most frequently occurring type of pituitary adenoma, accounting for approximately **40-50%** of all pituitary tumors [1]. - They are characterized by the **overproduction of prolactin**, leading to symptoms like **galactorrhea**, **amenorrhea**, and **infertility** [1]. *ACTH secreting adenoma* - This type of adenoma leads to **Cushing's disease** due to excessive **ACTH production**, stimulating adrenal cortisol synthesis [2]. - While significant, **ACTH-secreting adenomas** are less common than prolactinomas, accounting for about **15-20%** of pituitary tumors. *TSH secreting adenoma* - **TSH-secreting adenomas** are extremely rare, making up less than **1%** of all pituitary tumors. - They cause secondary hyperthyroidism due to excessive **thyroid-stimulating hormone (TSH)** secretion. *GH secreting adenoma* - **Growth hormone (GH) secreting adenomas** cause **acromegaly** in adults and **gigantism** in children [1]. - These tumors are less common than prolactinomas, constituting about **15-20%** of pituitary adenomas.

Question 1373: Hormone replacement therapy (HRT) is indicated in:

A. Osteoporosis (Correct Answer)
B. previous history of thromboembolic episode
C. women with uterine cancer
D. women with breast cancer

Explanation: ### Osteoporosis - **Hormone replacement therapy (HRT)** is indicated for the prevention and treatment of **osteoporosis** in postmenopausal women, especially when other therapies are unsuitable [1]. - Estrogen, a component of HRT, helps maintain **bone mineral density** by decreasing bone resorption and increasing bone formation. *previous history of thromboembolic episode* - A previous history of **thromboembolic events**, such as deep vein thrombosis or pulmonary embolism, is a **contraindication** for HRT. - HRT can increase the risk of **blood clot formation**, making it unsafe for individuals with such a history. *women with uterine cancer* - Women with **uterine cancer**, particularly **endometrial cancer**, should generally avoid HRT containing estrogen. - Estrogen can stimulate the growth of **endometrial cells**, potentially worsening uterine cancer or increasing its recurrence risk [1]. *women with breast cancer* - **Breast cancer** is a strong **contraindication** for HRT, especially estrogen-containing regimens [1]. - Estrogen can promote the growth of **hormone-sensitive breast cancer cells**, increasing the risk of recurrence or progression.

Question 1374: Hypocalcemia with hypophosphatemia is seen in:

A. Vitamin D deficiency rickets (Correct Answer)
B. Rhabdomyolysis
C. Crush injury
D. Renal failure

Explanation: ***Vitamin D deficiency rickets*** - **Vitamin D deficiency** impairs intestinal **calcium** and **phosphate** absorption, leading to both hypocalcemia and hypophosphatemia [1], [2]. - The body attempts to compensate by increasing parathyroid hormone (PTH) secretion, but the primary defect in vitamin D leads to low serum levels of both electrolytes [2], [3]. *Rhabdomyolysis* - **Rhabdomyolysis** primarily causes **hyperkalemia**, **hyperphosphatemia**, and **hypocalcemia** due to the release of intracellular contents from damaged muscle and calcium deposition in injured muscle. - While it causes hypocalcemia, it typically leads to **hyperphosphatemia**, not hypophosphatemia. *Crush injury* - Similar to rhabdomyolysis, **crush injury** involves massive muscle breakdown, leading to the release of intracellular components. - This typically results in **hyperkalemia**, **hyperphosphatemia**, and **hypocalcemia**, not hypophosphatemia. *Renal failure* - **Chronic renal failure** often leads to **hyperphosphatemia** due to impaired phosphate excretion and **hypocalcemia** due to reduced renal activation of vitamin D and impaired phosphate handling [2]. - While hypocalcemia is common, the presence of **hyperphosphatemia** differentiates it from vitamin D deficiency rickets [2], [3].

Question 1375: Treatment of choice for SIADH is:

A. Hypotonic Saline
B. Demeclocycline (Correct Answer)
C. Lithium carbonate
D. Vasopressin

Explanation: ***Demeclocycline*** - **Demeclocycline** is a tetracycline antibiotic that acts as an **ADH antagonist**, inhibiting its effect on the renal tubules. [1] - This leads to increased free water excretion and a reduction in **hyponatremia** associated with SIADH, making it a treatment of choice, especially for chronic cases. [1] *Hypotonic Saline* - Administering **hypotonic saline** to a patient with SIADH would further dilute serum sodium levels and worsen the **hyponatremia**, which is the opposite of the desired effect. - SIADH is characterized by **excess free water** retention, and adding more free water would exacerbate the underlying pathology. *Lithium carbonate* - While **lithium** can cause nephrogenic diabetes insipidus (a condition of impaired ADH action), it is not the primary or preferred treatment for SIADH. - Its mechanism of action is different, and **demeclocycline** is more specifically targeted at blocking ADH effects in the kidney. *Vasopressin* - **Vasopressin** (ADH) is the hormone that is already in excess or acting excessively in **SIADH**. - Administering more vasopressin would worsen the condition by increasing water reabsorption and further decreasing serum sodium.

Question 1376: Which of the following clinical findings is characteristic of both osteomalacia and rickets?

A. frontal bossing in the skull
B. defects in tooth enamel
C. muscle weakness (Correct Answer)
D. prominent costochondral junctions

Explanation: ***Muscle weakness*** - **Muscle weakness** is a common symptom in both rickets (in children) and osteomalacia (in adults) due to **impaired mineralization of bone matrix** and compromised muscle function [1]. - This weakness often presents as **difficulty walking**, standing, or performing daily activities. *Frontal bossing in the skull* - **Frontal bossing** (prominent forehead) is a specific sign of **rickets** in children, resulting from excessive unmineralized osteoid on the skull [1]. - It is not typically seen in adult **osteomalacia**, as the skull bones are already formed. *Defects in tooth enamel* - **Defects in tooth enamel** are primarily associated with a prolonged and severe deficiency of **vitamin D or calcium during tooth development**, which is characteristic of childhood **rickets**. - While vitamin D and calcium are crucial for overall bone health, enamel defects are less common or severe in adult-onset **osteomalacia**. *Prominent costochondral junctions* - **Prominent costochondral junctions** (rachitic rosary) are a classic sign of **rickets** in children, caused by the enlargement of the cartilage at the ends of the ribs due to defective mineralization [1]. - This finding is specific to growing children and is not observed in adults with **osteomalacia**.

Question 1377: Minimum fasting BGL for diagnosis of diabetes mellitus is:

A. 114 mg/dl
B. 120 mg/dl
C. 132 mg/dl
D. 126 mg/dl (Correct Answer)

Explanation: ***126 mg/dl*** - A **fasting plasma glucose (FPG)** of **126 mg/dL (7.0 mmol/L)** or higher is diagnostic of diabetes mellitus. - This value indicates sustained hyperglycemia that meets the criteria set by major health organizations. *114 mg/dl* - An FPG of **114 mg/dL** falls within the range for **prediabetes** (100-125 mg/dL) or impaired fasting glucose, not diabetes. - While it indicates a higher risk for developing diabetes, it does not meet the diagnostic threshold for the disease itself. *120 mg/dl* - An FPG of **120 mg/dL** is also considered **prediabetes** or impaired fasting glucose, as it is below the diagnostic threshold for diabetes. - Patients in this range should monitor their glucose levels and adopt lifestyle changes to prevent progression to diabetes. *132 mg/dl* - While **132 mg/dL** certainly indicates diabetes, the question asks for the **minimum** fasting BGL for diagnosis. - The threshold of **126 mg/dL** is the widely accepted minimum diagnostic value.

Question 1378: What is normal range of glycosylated haemoglobin (HbA1c) for adequate glycaemic control in diabetic patient-

A. 10 % to 12 %
B. 8 % to 10 %
C. 4 % to 6 % (Correct Answer)
D. 6% to 8 %

Explanation: ***4% to 6%*** - This range represents **excellent glycemic control** and is closest to the recommended target of **less than 7%** for adequate diabetes management [1]. - While it requires careful monitoring for **hypoglycemia risk**, it significantly reduces the risk of **microvascular** and **macrovascular complications** [1]. *10% to 12%* - This range indicates very **poor glycemic control** and significantly increases the risk of both acute and chronic diabetes complications. - An HbA1c in this range suggests that the patient's blood glucose levels have been consistently high over several months. *8% to 10%* - While better than 10-12%, an HbA1c in this range still indicates **suboptimal glycemic control** for most diabetic patients. - It suggests a need for adjustments in treatment, diet, or lifestyle to prevent long-term complications. *6% to 8%* - This range is **too broad** for adequate glycemic control, with the upper limit of 8% being acceptable only for **elderly patients** or those with **significant comorbidities** [1]. - For most diabetic patients seeking adequate control, this range exceeds the recommended target of **less than 7%** [1].

Question 1379: Sirtuin is associated with?

A. Diabetes
B. Aging
C. Cancer
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - **Sirtuins** are a family of protein deacetylases and ADP-ribosyltransferases that play crucial roles in regulating various cellular processes, including **metabolism**, gene expression, and DNA repair. - Their involvement in these fundamental processes links them to the pathogenesis and progression of **diabetes**, **aging-related diseases**, and **cancer**. *Diabetes* - Sirtuins, particularly **SIRT1**, influence **insulin sensitivity** and glucose metabolism. - Dysregulation of sirtuin activity has been implicated in the development and progression of **type 2 diabetes**. *Aging* - Sirtuins are often referred to as **"longevity genes"** due to their role in regulating cellular responses to stress and extending lifespan in various organisms. - They are involved in pathways that maintain cellular integrity and function, thereby impacting the **aging process**. *Cancer* - The role of sirtuins in **cancer** is complex and can be either tumor-suppressive or oncogenic depending on the specific sirtuin, cancer type, and cellular context. - They regulate pathways involved in **cell proliferation**, apoptosis, and DNA repair, making them potential targets for cancer therapy.

Question 1380: A 14-year-old male presents with type I diabetes mellitus. His mother wants to know if the boy's brother might also have an increased risk of getting the disease. Which of the following genotypes, if present in the brother, would be associated with the greatest risk of developing diabetes?

A. DR2/DR4
B. DR3/DR4 (Correct Answer)
C. DR2/DR2
D. B27/B27

Explanation: ***DR3/DR4*** - The combination of **HLA-DR3** and **HLA-DR4** is the strongest genetic risk factor for **Type 1 diabetes mellitus (T1DM)**, particularly in individuals of European descent. - These alleles are associated with increased susceptibility to autoimmune destruction of pancreatic beta cells [1]. *DR2/DR4* - While **DR4** is a risk allele for Type 1 diabetes, **DR2 (specifically DRB1*1501)** is generally considered to be protective against the disease. - The presence of the protective DR2 allele would likely mitigate the increased risk conferred by DR4. *DR2/DR2* - **HLA-DR2 (DRB1*1501)** is largely recognized as a protective allele against **Type 1 diabetes**, meaning individuals with this genotype have a lower risk of developing the disease [1]. - Its presence is associated with a reduced susceptibility to autoimmune conditions like T1DM. *B27/B27* - **HLA-B27** is primarily associated with **seronegative spondyloarthropathies** such as ankylosing spondylitis and reactive arthritis, and not directly with an increased risk of Type 1 diabetes mellitus. - This allele is involved in different autoimmune pathways than those implicated in T1DM.

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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