Endocrinology — MCQs

A patient with diabetes mellitus for the past 5 years presents with vomiting and abdominal pain. She is non-compliant with medication and appears dehydrated. Investigations revealed a blood sugar value of 500 mg/dl and the presence of ketone bodies. What is the next best step in management of this patient?

Q1558

A 32-year-old woman complains of amenorrhea since the delivery of a baby 15 months previously, despite the fact that she did not breastfeed her baby. The delivery was complicated by excessive hemorrhage that required a transfusion of 2.5 liters of blood. She has also been fatigued and has gained an additional 4.5Kg since the baby was born. Laboratory data show the following: Serum LH < 1 IU/L (normal, 4-24 IU/L) Serum estradiol 5 pg/mL (normal, 20 - 100 pg/mL) Serum TSH 0.1 mU/L (normal, 0.5 - 5 mU/L) Serum GH 3 ng/mL (normal, < 5 ng/mL) Serum ACTH 28 pg/mL (normal, 10 - 50 pg/mL) Serum prolactin 2 ng/mL (normal, < 20 ng/mL). Injection of 500 μg of TRH failed to produce the expected rise in both serum TSH and prolactin. Which of the following diagnoses most likely explains the findings in this patient?

Q1559

Patient has fatigue but is not gaining weight. Body was warm. Which investigation is most likely to be informative?

Q1560

A 55-year-old postmenopausal woman presents with chronic low backache of 6 months duration. She has no history of trauma. What is the most likely diagnosis?

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1551: At what age is prophylactic thyroidectomy recommended for children with MEN 2A?

A. By 1 year for MEN 2B
B. 5 years for MEN 2A (Correct Answer)
C. When detected for MEN 2B
D. Any time for MEN 2

Explanation: ***5 years for MEN 2A*** - For **MEN 2A**, prophylactic thyroidectomy is generally recommended by **5 years of age** to prevent the development of medullary thyroid carcinoma (MTC). - This timing allows for careful planning and minimizes the risks associated with surgery in very young children, while still being early enough to be effectively prophylactic. *By 1 year for MEN 2B* - This option is incorrect because **MEN 2B** has a more aggressive form of **medullary thyroid carcinoma (MTC)**, requiring earlier intervention. - Prophylactic thyroidectomy for **MEN 2B** is recommended **within the first year of life**, preferably in the first few months, not necessarily "by" 1 year. *When detected for MEN 2B* - While prompt action upon detection of **RET mutations** is critical, simply stating "when detected" is too broad for **MEN 2B**, where the disease is rapid and age-specific guidelines are crucial. - For **MEN 2B**, prophylactic thyroidectomy should be performed as early as possible, ideally **within the first few months of life**, to prevent highly aggressive MTC. *Any time for MEN 2* - This option is incorrect because the timing of prophylactic thyroidectomy **varies significantly between MEN 2A and MEN 2B** due to differing aggressiveness of MTC. - **MEN 2A** generally allows for an intervention around **age 5**, whereas **MEN 2B** necessitates surgery much earlier, within the **first year of life**, typically within the **first few months**.

Question 1552: The Z score measures bone mineral density compared to the average of which group of individuals?

A. Individuals matched for age, race, and sex (Correct Answer)
B. Individuals matched for race and sex
C. Individuals matched for sex
D. None of the options

Explanation: ***Individuals matched for age, race, and sex*** - A **Z-score** compares a patient's **bone mineral density (BMD)** to the average BMD of a healthy, age-matched, sex-matched, and race-matched population. - It is particularly useful in premenopausal women, men under 50 years of age, and children to help diagnose **secondary osteoporosis**. *Individuals matched for race and sex* - This definition is incomplete as it omits matching for **age**, which is a crucial demographic factor influencing bone density. - Without age-matching, the comparison would not accurately reflect expected bone density for the patient's specific life stage. *Individuals matched for sex* - This is an insufficient comparison for **bone mineral density**, as it excludes critical demographic factors like **age** and **race**. - Bone density naturally varies significantly with age and can also differ across racial groups. *None of the options* - This option is incorrect because the first option accurately describes the reference population for a **Z-score**. - The **Z-score** is a clearly defined metric in bone densitometry with a specific reference group.

Question 1553: In which condition are hung-up reflexes typically observed?

A. Cerebral palsy
B. Chorea
C. Cerebellar ataxia
D. Hypothyroidism (Correct Answer)

Explanation: ***Hypothyroidism*** - **Hung-up reflexes** (or **Woltman's sign**) are characterized by a **slow relaxation phase** of deep tendon reflexes, a classic finding in hypothyroidism. - This delayed relaxation is due to altered muscle contraction and relaxation kinetics caused by **deficient thyroid hormones**. *Chorea* - Chorea is characterized by **brief, abrupt, irregular, unpredictable, non-stereotyped movements** that flow from one body part to another [1]. - Reflexes themselves are not typically "hung up" but may be difficult to elicit or appear irregular due to the involuntary movements. *Cerebral palsy* - Cerebral palsy is a group of permanent movement disorders that appear in early childhood and are typically characterized by **spasticity**, **ataxia**, or **dystonia**. - While reflex abnormalities are common, including **hyperreflexia** and sustained clonus, the specific finding of "hung-up reflexes" (slow relaxation) is not typical. *Cerebellar ataxia* - Cerebellar ataxia primarily affects **coordination, balance, and gait**, leading to dysmetria, dysdiadochokinesia, and intention tremor [2]. - Reflexes in cerebellar ataxia are often **normal** or can exhibit **pendular reflexes**, where the limb swings back and forth several times after being struck, rather than a delayed relaxation.

Question 1554: In congenital adrenal hyperplasia, which enzyme deficiency is primarily responsible for precocious puberty in males?

A. 21-hydroxylase deficiency (Correct Answer)
B. 11-beta-hydroxylase deficiency
C. Both
D. Neither

Explanation: ***21-hydroxylase deficiency*** - This is the **most common form** of congenital adrenal hyperplasia (CAH) and leads to a **deficiency in cortisol and aldosterone** production [1]. - The accumulation of precursors shunts metabolic pathways towards **androgen production**, causing precocious puberty in males due to **excessive adrenal androgens** [1]. *11-beta-hydroxylase deficiency* - This deficiency also leads to **decreased cortisol** and an accumulation of precursors, but it specifically causes an increase in **deoxycorticosterone (DOC)**, which has mineralocorticoid activity. - While it also causes **androgen excess** (leading to precocious puberty in males), it is **less common** than 21-hydroxylase deficiency as the primary cause. *Both* - While both deficiencies can cause androgen excess and precocious puberty, **21-hydroxylase deficiency** is by far the more frequent and significant cause of these symptoms in CAH. - Attributing it equally to both would overlook the **prevalence** and primary impact of 21-hydroxylase deficiency. *Neither* - This option is incorrect because both 21-hydroxylase deficiency and 11-beta-hydroxylase deficiency can lead to **androgen excess**, which is the underlying cause of precocious puberty in CAH. - The condition is characterized by a defect in steroid synthesis, which inevitably results in a **hormonal imbalance**.

Question 1555: Poorly controlled diabetes with blood sugar of 450 mg% is associated with:

A. Hyponatremia
B. Hypokalemia (Correct Answer)
C. Hypernatremia
D. Hypomagnesemia

Explanation: **Hypokalemia** - **Insulin deficiency** in uncontrolled diabetes leads to an **extracellular shift of potassium** because insulin facilitates potassium entry into cells [1]. - **Diabetic ketoacidosis (DKA)**, a common complication of uncontrolled diabetes, causes significant **renal potassium loss** due to osmotic diuresis and vomiting, even if serum potassium appears normal or high initially [1], [2]. *Hyponatremia* - **Hyperglycemia** can cause **pseudohyponatremia** due to the osmotic effect of high glucose drawing water from cells into the extracellular space, diluting serum sodium [1]. - In severe cases, the true sodium might be low, but the initial effect is dilutional, not a deficit of sodium [1]. *Hypernatremia* - Mild hypernatremia can occur due to **osmotic diuresis** causing significant water loss, but this is less common than dilutional hyponatremia or normal sodium levels. - The primary effect of hyperglycemia on sodium is usually related to dilution rather than an absolute increase in sodium concentration. *Hypomagnesemia* - While diabetic patients can develop **hypomagnesemia** over time due to increased urinary excretion, it is not the most immediate or direct metabolic derangement associated with acute, poorly controlled hyperglycemia (blood sugar 450 mg/dL). - **Hypomagnesemia** is often a chronic complication due to long-term renal losses rather than an acute consequence of severe hyperglycemia.

Question 1556: A patient presents with polyuria following total hypophysectomy. Laboratory results show Na+ levels at 155 mEq/L and urine osmolarity at 200 mOsm/L. What is the definitive management for this patient?

A. Lifelong DDAVP supplementation (Correct Answer)
B. No treatment required as receptors are upset
C. Thiazides for a limited duration of 2 weeks
D. DDAVP for a limited duration of 2 weeks

Explanation: ### Lifelong DDAVP supplementation - The patient's **polyuria** after **total hypophysectomy**, coupled with **hypernatremia (Na+ 155 mEq/L)** and **low urine osmolarity (200 mOsm/L)**, strongly indicates **central diabetes insipidus (DI)** due to **ADH deficiency** [1]. - **Desmopressin (DDAVP)** is a synthetic analog of **ADH** and is the definitive treatment for central DI, replacing the missing hormone, and addressing the lifelong deficiency [1]. ### No treatment required as receptors are upset - This is incorrect as untreated **diabetes insipidus** can lead to severe **dehydration, hypernatremia, and neurological complications**, making intervention critical [2]. - The symptoms and lab findings indicate a clear deficiency, not merely "upset" receptors, which requires definitive management to prevent life-threatening complications. ### Thiazides for a limited duration of 2 weeks - **Thiazide diuretics** are used in **nephrogenic diabetes insipidus** to induce mild volume depletion, which can increase water reabsorption in the proximal tubule [1]. - However, they are not the definitive treatment for **central DI** where the primary problem is a lack of **ADH**, and using them for a *limited duration* would not address a lifelong condition. ### DDAVP for a limited duration of 2 weeks - While **DDAVP** is the correct treatment for **central DI**, the condition resulting from a total hypophysectomy is **permanent**. - Therefore, treatment for only a *limited duration* would lead to the recurrence of symptoms, and potentially life-threatening complications, making lifelong management essential.

Question 1557: A patient with diabetes mellitus for the past 5 years presents with vomiting and abdominal pain. She is non-compliant with medication and appears dehydrated. Investigations revealed a blood sugar value of 500 mg/dl and the presence of ketone bodies. What is the next best step in management of this patient?

A. Intravenous fluids
B. Intravenous insulin
C. Intravenous fluids with regular insulin (Correct Answer)
D. Intravenous fluids with long-acting insulin

Explanation: Detailed management of diabetic ketoacidosis (DKA) requires both fluid resuscitation and insulin therapy. ***Intravenous fluids with regular insulin*** - The patient presents with classic signs of **diabetic ketoacidosis (DKA)**: hyperglycemia (blood sugar 500 mg/dl), ketone bodies, dehydration, and a history of diabetes non-compliance [1]. - Initial management for DKA involves aggressive **intravenous fluid resuscitation** to correct dehydration and then **intravenous regular insulin** to lower blood glucose and resolve ketosis [2]. *Intravenous fluids with long-acting insulin* - While fluids are essential, **long-acting insulin** is not appropriate for the acute management of DKA because its slow onset of action makes it inefficient for rapidly correcting hyperglycemia and ketosis. - **Regular insulin** is preferred as it has a quicker onset and shorter duration, allowing for more precise titration in an acute setting [2]. *Intravenous fluids* - Although crucial for correcting **dehydration** and improving renal perfusion, fluids alone will not address the underlying **insulin deficiency** and **ketosis** that define DKA. - Without insulin, the body will continue to produce ketones, exacerbating acidosis [3]. *Intravenous insulin* - Giving intravenous insulin without prior or concomitant **fluid resuscitation** can be dangerous, as it can worsen **hypovolemia** and potentially lead to circulatory collapse by shifting glucose and potassium into cells. - It is critical to first restore **circulating volume** before initiating insulin therapy [2].

Question 1558: A 32-year-old woman complains of amenorrhea since the delivery of a baby 15 months previously, despite the fact that she did not breastfeed her baby. The delivery was complicated by excessive hemorrhage that required a transfusion of 2.5 liters of blood. She has also been fatigued and has gained an additional 4.5Kg since the baby was born. Laboratory data show the following: Serum LH < 1 IU/L (normal, 4-24 IU/L) Serum estradiol 5 pg/mL (normal, 20 - 100 pg/mL) Serum TSH 0.1 mU/L (normal, 0.5 - 5 mU/L) Serum GH 3 ng/mL (normal, < 5 ng/mL) Serum ACTH 28 pg/mL (normal, 10 - 50 pg/mL) Serum prolactin 2 ng/mL (normal, < 20 ng/mL). Injection of 500 μg of TRH failed to produce the expected rise in both serum TSH and prolactin. Which of the following diagnoses most likely explains the findings in this patient?

A. Pituitary apoplexy
B. Isolated gonadotropin deficiency
C. Hashimoto's thyroiditis
D. Primary amenorrhea
E. Hypopituitarism due to Sheehan's syndrome (Correct Answer)

Explanation: ### Hypopituitarism due to Sheehan's syndrome - The patient's history of **postpartum hemorrhage** followed by amenorrhea, fatigue, and weight gain, along with low levels of **LH**, **estradiol**, **TSH**, and **prolactin**, despite normal ACTH and GH, points towards anterior pituitary dysfunction due to **ischemic necrosis** caused by Sheehan's syndrome [1]. - The failure of **TRH stimulation** to increase TSH and prolactin further supports a pituitary origin, as the pituitary is unable to respond due to damage. ### Hashimoto's thyroiditis - This condition primarily causes **hypothyroidism**, characterized by elevated TSH and low thyroid hormones, which is inconsistent with the patient's low TSH. - It does not explain the **gonadotropin deficiency** (low LH and estradiol) or the history of postpartum hemorrhage leading to multi-hormone deficiencies. ### Isolated gonadotropin deficiency - While the patient exhibits **amenorrhea** and low LH and estradiol, this diagnosis does not account for the **low TSH** [3] or the historical context of a severe postpartum hemorrhage. - Isolated gonadotropin deficiency does not explain the lack of TSH and prolactin response to TRH. ### Primary amenorrhea - This refers to the absence of menstruation by age 15 (with breast development) or 13 (without breast development) in a patient who has never menstruated, which is not applicable to a 32-year-old woman who has delivered a baby. - The patient's presentation is secondary amenorrhea, occurring after menarche and delivery, and is associated with other pan-hypopituitary features [4]. ### Pituitary apoplexy - Pituitary apoplexy typically presents with the **sudden onset** of severe headache, visual disturbances, and ophthalmoplegia due to acute hemorrhage or infarction of a pituitary adenoma. - This patient's symptoms are more chronic and progressive, evolving over 15 months, and lack the acute, severe presentation typical of apoplexy [2].

Question 1559: Patient has fatigue but is not gaining weight. Body was warm. Which investigation is most likely to be informative?

A. Low TSH with elevated T3 and T4 (Correct Answer)
B. High TSH with normal T3 and T4
C. High TSH with euthyroid status
D. Increased T3 with decreased T4 levels

Explanation: ***Low TSH with elevated T3 and T4*** - This pattern is indicative of **hyperthyroidism**, which aligns with symptoms of **fatigue** (despite increased metabolic rate due to catabolic effects), not gaining weight, and feeling warm, as thyroid hormones regulate metabolism and body temperature [1]. - An elevated **Free T4** and **Free T3** with a suppressed **TSH** confirms a diagnosis of primary hyperthyroidism [1]. *High TSH with normal T3 and T4* - This suggests **subclinical hypothyroidism** (also known as latent hypothyroidism), where the thyroid gland is beginning to fail, but **peripheral thyroid hormone levels** are still within the normal range due to thyroid compensatory mechanisms [1]. - Patients with subclinical hypothyroidism are usually asymptomatic (as the body has compensated to produce sufficient amounts of T3 and T4), but when symptoms do emerge, they are those of **hypothyroidism**, such as weight gain and cold intolerance, which contradict the patient's presentation [1]. *High TSH with euthyroid status* - **Euthyroid** means having normal thyroid function, therefore this option is practically identical to "High TSH with normal T3 and T4". - This implies **subclinical hypothyroidism**, which typically presents with normal body temperature and potential for weight gain, not fatigue without weight gain alongside a warm body [1]. *Increased T3 with decreased T4 levels* - This specific pattern is rare and could be indicative of certain conditions affecting thyroid hormone metabolism, such as **T4 to T3 conversion issues** or specific forms of **thyroiditis**, but is not typical of a primary thyroid disorder presenting with the given symptoms. - While an elevated T3 might suggest some hyperthyroid features, the decreased T4 complicates the picture and does not directly support the clinical presentation of *unexplained fatigue* and *warm body* in typical thyroid disease.

Question 1560: A 55-year-old postmenopausal woman presents with chronic low backache of 6 months duration. She has no history of trauma. What is the most likely diagnosis?

A. Osteoporosis (Correct Answer)
B. Hurler's syndrome
C. Paget’s disease
D. Renal osteodystrophy

Explanation: ***Osteoporosis*** - **Postmenopausal women** are at a high risk of developing osteoporosis due to **estrogen deficiency**, which leads to accelerated bone loss [1]. - **Chronic low backache** without trauma in this demographic suggests **vertebral compression fractures**, a common complication of osteoporosis [1]. *Hurler's syndrome* - This is a **lysosomal storage disorder** (mucopolysaccharidosis type I) that manifests in **childhood** with skeletal deformities, coarse facial features, and developmental delays. - It would not present as new-onset chronic low backache in a 55-year-old adult. *Paget’s disease* - Paget's disease involves **localized abnormal bone remodeling**, leading to enlarged and weakened bones [2]. - While it can cause bone pain, it's characterized by elevated **alkaline phosphatase** and often affects the pelvis, skull, or long bones, and a simple low backache presentation in a postmenopausal woman points more strongly to osteoporosis [2], [3]. *Renal osteodystrophy* - This condition is a complication of **chronic kidney disease**, resulting from imbalances in calcium, phosphate, parathyroid hormone, and vitamin D metabolism. - It would require a history of **renal dysfunction** and the low backache would likely be accompanied by other symptoms of kidney failure or bone pain related to specific lesions, which are not mentioned.

Practice by Chapter

Diabetes Mellitus

Practice Questions

Thyroid Disorders

Practice Questions

Adrenal Gland Disorders

Practice Questions

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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