Endocrinology — MCQs

A 48-year-old woman presents with complaints of moderate weight loss over the past 6 months, heat intolerance, palpitations, and fine tremors in the hands. Physical examination reveals the presence of a diffuse goiter and exophthalmos. Which of the following laboratory findings would be expected in this individual?

Q1194Medium

A 65-year-old male patient complains of loss of libido and is found to have low free and total testosterone levels. Treatment is commenced with testosterone supplemental therapy. What is the next step in management after testosterone administration?

Q1195Easy

What is the most common paroxysmal symptom of pheochromocytoma?

Q1196Medium

Which laboratory test is the investigation of choice for confirming myxedema coma?

Q1197Medium

A 30-year-old male presents with fatigue, muscle weakness, headache, hypertension (170/120 mm Hg), and tachycardia (100/min). Laboratory findings include hypokalemia, metabolic alkalosis, and decreased plasma renin activity. A CT scan reveals a mass on the left suprarenal gland. After a few weeks of treatment with a specific medication, his symptoms resolved, and laboratory values and blood pressure normalized. What is the likely medication prescribed?

Q1198Easy

Hyperparathyroidism (in 80% cases), pancreatic islet cell tumors, and pituitary adenomas are seen in which of the following conditions?

Q1199Medium

In a patient experiencing thyroid crisis, characterized by hyperpyrexia, tachycardia, vomiting, dehydration, and shock, which of the following interventions is usually indicated?

Q1200Easy

Diabetes mellitus is diagnosed if fasting blood glucose is?

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1191: An 18-year-old girl presents with amenorrhoea, milk discharge, and weight loss. What is the most likely diagnosis?

A. Pituitary tumor (Correct Answer)
B. Anorexia nervosa
C. Hypothyroidism
D. Hypothalamic dysfunction

Explanation: The clinical triad of **amenorrhoea** (absence of menses), **galactorrhoea** (milk discharge), and **weight loss** in a young female strongly suggests a **Prolactinoma** (a type of Pituitary Tumor) [1]. 1. **Why Pituitary Tumor is correct:** High levels of prolactin (hyperprolactinaemia) inhibit the pulsatile release of GnRH from the hypothalamus. This leads to decreased FSH and LH, resulting in hypogonadotropic hypogonadism (amenorrhoea) [1]. Prolactin also directly stimulates mammary tissue to produce milk (galactorrhoea) [1]. While prolactinomas are often associated with weight gain, a large macroadenoma can cause weight loss due to compression of other pituitary axes (e.g., secondary adrenal insufficiency or GH deficiency) or systemic stress [1]. 2. **Why other options are incorrect:** * **Anorexia Nervosa:** While it causes amenorrhoea and significant weight loss, it is typically associated with *suppressed* lactation, not galactorrhoea [1]. * **Hypothyroidism:** Primary hypothyroidism causes hyperprolactinaemia (via increased TRH stimulating prolactin release), leading to amenorrhoea and galactorrhoea [1]. However, it is characteristically associated with **weight gain**, not weight loss [1]. * **Hypothalamic Dysfunction:** This can cause amenorrhoea (e.g., functional hypothalamic amenorrhoea due to stress/exercise), but it usually results in *low* prolactin levels, making galactorrhoea unlikely [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Drug-induced hyperprolactinaemia:** The most common cause of non-physiological prolactin elevation (especially Antipsychotics/Metoclopramide) [1]. * **Hook Effect:** In extremely high prolactin levels, lab assays may show falsely low results; serial dilution is required for diagnosis. * **Treatment of Choice:** Dopamine agonists (**Cabergoline** is preferred over Bromocriptine) are the first-line treatment for prolactinomas, even for large macroprolactinomas [1]. Surgery is reserved for refractory cases.

Question 1192: Multiple endocrine neoplasia type 1 (MEN-1) includes all except:

A. Prolactinomas
B. Parathyroid hyperplasia
C. Pancreatic endocrine tumors
D. Medullary carcinoma of the thyroid (Correct Answer)

Explanation: Multiple Endocrine Neoplasia type 1 (MEN-1), also known as **Wermer’s Syndrome**, is an autosomal dominant disorder caused by a mutation in the *MEN1* gene (encoding the protein Menin). It is classically characterized by the **"3 Ps"**: **P**arathyroid, **P**ancreas, and **P**ituitary [1]. * **Why Option D is correct:** **Medullary Carcinoma of the Thyroid (MCT)** is the hallmark feature of **MEN-2A and MEN-2B**, not MEN-1 [1]. MCT arises from the parafollicular C-cells and is associated with mutations in the *RET* proto-oncogene [1]. Its presence in a clinical vignette should immediately point towards MEN-2. * **Why other options are incorrect:** * **Parathyroid Hyperplasia (Option B):** This is the most common manifestation of MEN-1 (occurring in >95% of patients), usually presenting as primary hyperparathyroidism due to multiglandular hyperplasia [1]. * **Pancreatic Endocrine Tumors (Option C):** These occur in about 40-70% of cases [1]. Gastrinomas (Zollinger-Ellison Syndrome) are the most common, followed by Insulinomas. * **Prolactinomas (Option A):** Pituitary adenomas occur in about 30-40% of MEN-1 patients [1]. Prolactinoma is the most frequent subtype, followed by GH-secreting tumors (Acromegaly) [1]. **High-Yield Clinical Pearls for NEET-PG:** 1. **MEN-1 (Wermer’s):** Parathyroid (95%), Pancreas (Gastrinoma most common), Pituitary (Prolactinoma most common). Also associated with facial angiofibromas and lipomas. 2. **MEN-2A (Sipple’s):** Medullary Thyroid CA (100%), Pheochromocytoma, Parathyroid hyperplasia [1]. 3. **MEN-2B (Williams):** Medullary Thyroid CA, Pheochromocytoma, Mucosal neuromas, and Marfanoid habitus (No parathyroid involvement) [1]. 4. **Screening:** The first biochemical abnormality usually detected in MEN-1 is hypercalcemia due to hyperparathyroidism [1].

Question 1193: A 48-year-old woman presents with complaints of moderate weight loss over the past 6 months, heat intolerance, palpitations, and fine tremors in the hands. Physical examination reveals the presence of a diffuse goiter and exophthalmos. Which of the following laboratory findings would be expected in this individual?

A. Decreased serum T4
B. Decreased radioactive iodine uptake
C. Decreased resin T3 uptake
D. Increased plasma concentration of thyroglobulin (Correct Answer)

Explanation: The clinical presentation of weight loss, heat intolerance, tremors, diffuse goiter, and **exophthalmos** is pathognomonic for **Graves' Disease** (hyperthyroidism) [1], [3]. **Why Option D is Correct:** Thyroglobulin (Tg) is a large glycoprotein synthesized by follicular cells and stored within the thyroid colloid. In Graves' Disease, the thyroid gland is hyperactive due to stimulation by Thyroid Stimulating Immunoglobulins (TSI) [3]. This hyperfunction, along with increased glandular vascularity and follicular cell turnover, leads to an **increased leakage of thyroglobulin into the plasma**. Therefore, plasma Tg levels are elevated in almost all forms of hyperthyroidism (except factitious thyrotoxicosis) [2]. **Analysis of Incorrect Options:** * **A. Decreased serum T4:** In hyperthyroidism, serum T4 (and T3) levels are characteristically **increased** due to overproduction by the thyroid gland [1]. * **B. Decreased radioactive iodine uptake (RAIU):** Graves' Disease is characterized by **increased (diffuse) RAIU** because the gland is actively synthesizing thyroid hormones [2]. Decreased uptake is seen in thyroiditis or factitious ingestion [2]. * **C. Decreased resin T3 uptake:** Resin T3 uptake measures the saturation of Thyroid Binding Globulin (TBG). In hyperthyroidism, high levels of endogenous T4 saturate the TBG binding sites, leaving fewer sites available for the resin test. This results in an **increased resin T3 uptake**. **NEET-PG High-Yield Pearls:** * **Graves' Disease Triad:** Hyperthyroidism + Diffuse Goiter + Exophthalmos (Ophthalmopathy) +/- Pretibial Myxedema [3]. * **Thyroglobulin (Tg) Marker:** It is a crucial marker to differentiate **Factitious Thyrotoxicosis** (low Tg due to exogenous hormone suppressing the gland) from **Graves' or Thyroiditis** (high Tg) [2]. * **Antibody:** The most specific antibody for Graves' is **TSH-receptor antibody (TRAb/TSI)** [3].

Question 1194: A 65-year-old male patient complains of loss of libido and is found to have low free and total testosterone levels. Treatment is commenced with testosterone supplemental therapy. What is the next step in management after testosterone administration?

A. Check PSA levels (Correct Answer)
B. Testosterone levels are decreased
C. Decrease in size of benign prostatic tissue lesions occurs
D. Decrease in size of prostatic cancer occurs

Explanation: ### Explanation **Correct Option: A. Check PSA levels** The primary concern when initiating Testosterone Replacement Therapy (TRT) in an elderly male is the potential stimulation of androgen-dependent tissues, specifically the prostate. While TRT does not *cause* prostate cancer, it can stimulate the growth of an existing occult malignancy. According to standard guidelines (such as the Endocrine Society), patients over the age of 40–50 should undergo a baseline Digital Rectal Examination (DRE) and Prostate-Specific Antigen (PSA) testing before starting TRT [2]. Once therapy commences, **PSA levels must be monitored** (typically at 3–6 months and then annually) to screen for any significant rise that might indicate the development or progression of prostate cancer. **Analysis of Incorrect Options:** * **B. Testosterone levels are decreased:** This is incorrect as the goal of therapy is to normalize testosterone levels. If levels remain low, the dose is typically titrated upwards [1]. * **C. Decrease in size of benign prostatic tissue lesions:** TRT does not shrink the prostate; in fact, it may cause a slight increase in prostate volume or worsen symptoms of Benign Prostatic Hyperplasia (BPH) in some patients [2]. * **D. Decrease in size of prostatic cancer:** Testosterone is a growth factor for prostate cancer [2]. Exogenous administration would likely cause the cancer to grow or progress, which is why active prostate cancer is an absolute contraindication for TRT. **Clinical Pearls for NEET-PG:** * **Absolute Contraindications for TRT:** Metastatic prostate cancer, breast cancer in men, unevaluated prostate nodules, PSA >4 ng/mL (or >3 ng/mL in high-risk patients), and severe untreated obstructive sleep apnea. * **Monitoring Hematocrit:** TRT stimulates erythropoiesis. Monitor hematocrit levels; if it exceeds 54%, therapy should be held to prevent polycythemia and thromboembolic events. * **Target Level:** The goal of TRT is to achieve testosterone levels in the mid-normal range (approx. 400–700 ng/dL) [3].

Question 1195: What is the most common paroxysmal symptom of pheochromocytoma?

A. Headache (Correct Answer)
B. Palpitations
C. Abdominal pain
D. Hypotension

Explanation: Explanation: Pheochromocytoma is a catecholamine-secreting tumor arising from chromaffin cells of the adrenal medulla. The classic presentation involves paroxysmal episodes (spells) caused by the sudden release of epinephrine and norepinephrine. Why Headache is Correct: Headache is the most common symptom during a paroxysmal attack, occurring in up to 90% of symptomatic patients. It is typically sudden in onset, severe, and throbbing in nature, resulting from acute hypertensive surges and cerebral vasodilation. Analysis of Incorrect Options: * B. Palpitations: While very common (occurring in ~50-70% of cases), palpitations are statistically less frequent than headaches. The classic triad of pheochromocytoma consists of Headache, Perspiration (Diaphoresis), and Palpitations. * C. Abdominal pain: This is a less common symptom, usually occurring due to mesenteric vasoconstriction or associated complications like intestinal ischemia, but it is not a hallmark paroxysmal feature. * D. Hypotension: Pheochromocytoma typically causes hypertension (either sustained or paroxysmal). Orthostatic hypotension can occur due to low plasma volume, but it is not a primary paroxysmal symptom. NEET-PG High-Yield Pearls: * The Rule of 10s: 10% bilateral, 10% malignant, 10% pediatric, 10% extra-adrenal (Paragangliomas), and 10% familial. * Diagnosis: The most sensitive initial screening test is 24-hour urinary fractionated metanephrines or plasma free metanephrines. * Management: Always start Alpha-blockade (e.g., Phenoxybenzamine) before Beta-blockade to avoid an unopposed alpha-mediated hypertensive crisis. * Genetic Associations: MEN 2A, MEN 2B, von Hippel-Lindau (VHL) syndrome, and Neurofibromatosis type 1 (NF1).

Question 1196: Which laboratory test is the investigation of choice for confirming myxedema coma?

A. Thyroid stimulating hormone (TSH) (Correct Answer)
B. Thyrotropin releasing hormone (TRH)
C. Triiodothyronine (T3)
D. Tetraiodothyronine (T4)

Explanation: **Explanation:** **Myxedema coma** is a life-threatening complication of severe, long-standing hypothyroidism. The diagnosis is primarily **clinical**, based on the triad of altered mental status, hypothermia, and a precipitating event. However, laboratory confirmation is essential. 1. **Why TSH is the Investigation of Choice (Option A):** In the vast majority of cases (>95%), myxedema coma results from primary thyroid failure. **Serum TSH** is the most sensitive and reliable marker to confirm primary hypothyroidism [1]. It will be significantly elevated in primary cases. While a low Free T4 is also present, the TSH level is the definitive test to establish the etiology and confirm the diagnosis in the context of clinical symptoms. 2. **Why other options are incorrect:** * **TRH (Option B):** TRH stimulation tests are obsolete in acute settings and are not used to diagnose myxedema coma [1]. * **T3 (Option C):** Serum T3 levels are often the last to fall and can be low in non-thyroidal illness (Sick Euthyroid Syndrome); therefore, T3 is unreliable for diagnosing hypothyroidism [2]. * **T4 (Option D):** While Free T4 will be low in myxedema coma, it cannot differentiate between primary and secondary (central) causes without a concurrent TSH [2]. TSH remains the primary screening and confirmatory tool. **NEET-PG High-Yield Pearls:** * **Treatment Priority:** Do NOT wait for lab results to start treatment if clinical suspicion is high. * **Management:** The treatment of choice is **IV Levothyroxine (T4)**, often supplemented with **IV Liothyronine (T3)**. * **Steroid Rule:** Always administer **IV Hydrocortisone** before thyroid hormone replacement to prevent an adrenal crisis (as the patient may have co-existing adrenal insufficiency). * **Commonest Precipitant:** Infection (e.g., pneumonia, UTI) or discontinuation of thyroid medication.

Question 1197: A 30-year-old male presents with fatigue, muscle weakness, headache, hypertension (170/120 mm Hg), and tachycardia (100/min). Laboratory findings include hypokalemia, metabolic alkalosis, and decreased plasma renin activity. A CT scan reveals a mass on the left suprarenal gland. After a few weeks of treatment with a specific medication, his symptoms resolved, and laboratory values and blood pressure normalized. What is the likely medication prescribed?

A. Clonidine
B. Propranolol
C. Hydrochlorothiazide
D. Spironolactone (Correct Answer)

Explanation: ### Explanation **Diagnosis: Primary Hyperaldosteronism (Conn’s Syndrome)** The patient presents with the classic triad of **hypertension, hypokalemia, and metabolic alkalosis**, coupled with **suppressed plasma renin activity** [2] and a suprarenal (adrenal) mass [1]. This clinical picture is diagnostic of Primary Hyperaldosteronism. Excess aldosterone causes sodium retention (leading to hypertension) and potassium/hydrogen ion excretion in the distal nephron [3]. **Why Spironolactone is the Correct Answer:** Spironolactone is a **competitive aldosterone receptor antagonist** [2]. It directly blocks the action of aldosterone at the mineralocorticoid receptors in the cortical collecting duct. This reverses the sodium retention and potassium wasting, thereby normalizing blood pressure and correcting hypokalemia and alkalosis. It is the medical treatment of choice for bilateral adrenal hyperplasia and is used pre-operatively for adrenal adenomas [2]. **Why Incorrect Options are Wrong:** * **A. Clonidine:** A centrally acting alpha-2 agonist. While it lowers blood pressure, it does not address the underlying mineralocorticoid excess or hypokalemia. * **B. Propranolol:** A non-selective beta-blocker. It may control tachycardia but can further suppress renin, which is already low in this patient, and does not correct the electrolyte imbalance. * **C. Hydrochlorothiazide:** A thiazide diuretic. It would worsen the patient's condition by further exacerbating **hypokalemia and metabolic alkalosis**. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Test:** Plasma Aldosterone Concentration (PAC) to Plasma Renin Activity (PRA) ratio. A ratio **>20–30** is highly suggestive. * **Confirmatory Test:** Saline infusion test (failure to suppress aldosterone) or Oral Salt Loading test. * **Side Effects:** Spironolactone can cause **gynecomastia** in males due to its non-specific anti-androgenic effects. **Eplerenone** is a more selective alternative with fewer endocrine side effects [2]. * **Muscle Weakness:** In these patients, weakness is a direct clinical manifestation of profound hypokalemia.

Question 1198: Hyperparathyroidism (in 80% cases), pancreatic islet cell tumors, and pituitary adenomas are seen in which of the following conditions?

A. Multiple Endocrine Neoplasia type 1 (Wermer syndrome) (Correct Answer)
B. Multiple Endocrine Neoplasia type 2A (Sipple syndrome)
C. Multiple Endocrine Neoplasia type 2B
D. All of the above

Explanation: The correct answer is **Multiple Endocrine Neoplasia type 1 (MEN 1)**, also known as **Wermer syndrome**. [1] ### 1. Why Option A is Correct MEN 1 is an autosomal dominant disorder caused by a mutation in the *MEN1* gene (encoding the protein menin). It is classically characterized by the **"3 Ps"**: * **Parathyroid Hyperplasia:** The most common feature (occurring in >90% of cases), leading to primary hyperparathyroidism. * **Pancreatic Islet Cell Tumors:** Most commonly Gastrinomas (Zollinger-Ellison Syndrome) or Insulinomas. * **Pituitary Adenomas:** Most commonly Prolactinomas. ### 2. Why Other Options are Incorrect * **MEN 2A (Sipple Syndrome):** Characterized by Medullary Thyroid Carcinoma (MTC), Pheochromocytoma, and Parathyroid hyperplasia. [1] While it shares the parathyroid component, it lacks pancreatic and pituitary involvement. * **MEN 2B:** Characterized by MTC, Pheochromocytoma, Mucosal neuromas, and Marfanoid habitus. It notably lacks parathyroid involvement. [1] * **Note:** Both MEN 2A and 2B are associated with mutations in the ***RET* proto-oncogene**. ### 3. NEET-PG High-Yield Pearls * **Screening:** The first biochemical sign of MEN 1 is often hypercalcemia due to hyperparathyroidism. Genetic testing and surveillance for mutation carriers include monitoring serum calcium, gastrointestinal hormones, and prolactin. [1] * **Order of Frequency:** Parathyroid > Pancreatic > Pituitary. * **Associated Tumors in MEN 1:** Adrenal cortical tumors, carcinoid tumors (thymic/bronchial), and cutaneous lipomas/angiofibromas. * **Mnemonic for MEN 1:** **P**arathyroid, **P**ancreas, **P**ituitary (**3 Ps**). * **Mnemonic for MEN 2A:** **M**edullary thyroid, **P**heochromocytoma, **P**arathyroid (**1 M, 2 Ps**). * **Mnemonic for MEN 2B:** **M**edullary thyroid, **M**arfanoid, **M**ucosal neuroma, **P**heochromocytoma (**3 Ms, 1 P**).

Question 1199: In a patient experiencing thyroid crisis, characterized by hyperpyrexia, tachycardia, vomiting, dehydration, and shock, which of the following interventions is usually indicated?

A. Metaraminol
B. Glucocorticoids
C. Intravenous saline
D. Propranolol (Correct Answer)

Explanation: ### Explanation **Thyroid Storm (Thyrotoxic Crisis)** is a life-threatening hypermetabolic state. The management follows a specific hierarchy: blocking the peripheral effects of catecholamines, inhibiting thyroid hormone synthesis, and preventing peripheral conversion of T4 to T3. **Why Propranolol is the Correct Answer:** Propranolol (a non-selective beta-blocker) is the initial drug of choice. It rapidly controls the life-threatening cardiovascular symptoms (tachycardia, palpitations, and arrhythmias) and tremors. Crucially, in high doses, propranolol also **inhibits the peripheral conversion of T4 to T3**, which is the more biologically active form of the hormone. **Analysis of Incorrect Options:** * **A. Metaraminol:** This is a sympathomimetic amine used to treat hypotension. In thyroid storm, the shock is often distributive or high-output; using a sympathomimetic would dangerously worsen the tachycardia and cardiac workload. * **B. Glucocorticoids:** While IV Hydrocortisone or Dexamethasone is indicated in thyroid storm (to treat relative adrenal insufficiency and inhibit T4 to T3 conversion), it is secondary to beta-blockade and antithyroid drugs. * **C. Intravenous Saline:** While rehydration is necessary to treat dehydration and shock, it is supportive therapy. It does not address the underlying pathophysiology of the crisis. **NEET-PG High-Yield Pearls:** 1. **Burch-Wartofsky Point Scale:** Used clinically to diagnose Thyroid Storm (Score >45 is highly suggestive). 2. **Order of Treatment:** * **1st:** Beta-blockers (Propranolol/Esmolol). * **2nd:** Thionamides (PTU is preferred over Methimazole because it also inhibits peripheral T4→T3 conversion). * **3rd:** Iodine (Lugol’s iodine/SSKI)—must be given **at least 1 hour after** thionamides to prevent the iodine from being used as substrate for new hormone synthesis (Wolff-Chaikoff effect). * **4th:** Glucocorticoids. 3. **Aspirin is Contraindicated:** It displaces thyroid hormones from Thyroid Binding Globulin (TBG), increasing free T4 levels. Use Acetaminophen for hyperpyrexia instead.

Question 1200: Diabetes mellitus is diagnosed if fasting blood glucose is?

A. >100 mg/dL
B. >126 mg/dL (Correct Answer)
C. >110 mg/dL
D. >116 mg/dL

Explanation: The diagnosis of Diabetes Mellitus (DM) is based on standardized glycemic thresholds established by the American Diabetes Association (ADA) and WHO. [1] ### **Explanation of the Correct Answer** **Option B (>126 mg/dL)** is the correct diagnostic threshold for fasting plasma glucose (FPG). Fasting is defined as no caloric intake for at least 8 hours. A value of **≥126 mg/dL (7.0 mmol/L)** on two separate occasions (unless symptomatic with random glucose ≥200 mg/dL) confirms the diagnosis of Diabetes Mellitus. [1] This specific cutoff is used because it correlates with a significantly increased risk of developing microvascular complications, particularly diabetic retinopathy. [1] ### **Analysis of Incorrect Options** * **Option A (>100 mg/dL):** 100 mg/dL is the upper limit of "Normal." Values between **100–125 mg/dL** are classified as **Impaired Fasting Glucose (IFG)**, a state of pre-diabetes. [1] * **Options C & D:** These values (110 and 116 mg/dL) fall within the range of Impaired Fasting Glucose (Pre-diabetes) and do not meet the criteria for a definitive diagnosis of Diabetes Mellitus. [1] ### **NEET-PG High-Yield Pearls** To excel in NEET-PG, remember the four diagnostic criteria for Diabetes: 1. **Fasting Plasma Glucose (FPG):** ≥126 mg/dL. [1] 2. **2-hour Post-Prandial (75g OGTT):** ≥200 mg/dL. 3. **HbA1c:** ≥6.5% (using a standardized assay). 4. **Random Plasma Glucose:** ≥200 mg/dL in a patient with classic symptoms of hyperglycemia (polyuria, polydipsia, weight loss). [1] **Note:** For **Gestational Diabetes (GDM)**, the O'Sullivan criteria or IADPSG criteria (Fasting ≥92 mg/dL) are used, which differ from the standard adult diagnostic thresholds.

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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