Endocrinology Practice Questions

Q: In prolactinoma, what is the most common symptom other than galactorrhea?

Amenorrhea. The correct answer is **Amenorrhea**. Prolactinomas are the most common secretory tumors of the pituitary gland [1]. In premenopausal women, the clinical presentation is dominated by the effects of hyperprolactinemia on the hypothalamic-pituitary-gonadal axis [1]. **Why Amenorrhea is correct:** Excess prolactin inhibits the pulsatile secretion of **GnRH** (Gonadotropin-Releasing Hormone) from the hypothalamus [1]. This leads to decreased levels of LH and FSH, resulting in hypogonadotropic hypogonadism. Clinically, this manifests most frequently as **amenorrhea** (or oligomenorrhea) and infertility [1]. While galactorrhea is a classic sign, it is present in only about 30-80% of cases; menstrual irregularities are often the primary reason patients seek medical attention [1]. **Analysis of Incorrect Options:** * **A. Bitemporal hemianopia:** This occurs due to compression of the optic chiasm [1]. It is a feature of **macroadenomas** (>10mm) [2]. Since most prolactinomas in women are microadenomas, visual field defects are less common than hormonal symptoms [1]. * **C. Thyroid dysfunction:** While large pituitary tumors can cause secondary hypothyroidism by compressing thyrotrophs, it is not a primary or common feature of prolactinoma. * **D. Headache:** This is a non-specific symptom caused by the mass effect of a large tumor. It is less common than endocrine dysfunction in the overall population of prolactinoma patients. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Dopamine agonists, specifically **Cabergoline** (preferred over Bromocriptine due to higher efficacy and fewer side effects) [3]. * **Hook Effect:** In cases of extremely high prolactin, lab assays may show falsely low levels; a serum dilution is required for diagnosis [4]. * **Male Presentation:** Men usually present late with **macroadenomas**, showing symptoms of mass effect (headache, visual loss) or erectile dysfunction/decreased libido [1].

Q: Which one of the following clinical features is NOT typically seen in pheochromocytoma?

Diarrhea. **Explanation** Pheochromocytoma is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla. The clinical presentation is primarily driven by the excessive release of epinephrine and norepinephrine, which stimulate the sympathetic nervous system. **Why "Diarrhea" is the correct answer:** Catecholamines stimulate **alpha-adrenergic receptors** in the gastrointestinal tract, which leads to **decreased intestinal motility** and contraction of sphincters. Consequently, patients with pheochromocytoma typically experience **constipation**, not diarrhea. If a patient presents with a neuroendocrine tumor and diarrhea, clinicians should instead suspect Medullary Thyroid Carcinoma (secreting calcitonin) or Carcinoid Syndrome (secreting serotonin) [1]. **Why the other options are incorrect:** * **Hypertension (A):** The most common clinical sign. It can be sustained or paroxysmal due to alpha-1 mediated vasoconstriction. * **Episodic Palpitations (B):** Part of the classic triad (Headache, Sweating, Palpitations). It is caused by the beta-1 adrenergic effect on the heart, increasing heart rate and contractility. * **Weight Loss (C):** Catecholamines are catabolic; they increase the basal metabolic rate and promote glycogenolysis and lipolysis, leading to weight loss despite a normal appetite. **High-Yield Clinical Pearls for NEET-PG:** * **The Rule of 10s:** 10% are bilateral, 10% are extra-adrenal (Paragangliomas), 10% are malignant, and 10% occur in children. * **Diagnosis:** Best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. * **Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) for 10–14 days before Beta-blockers to avoid a hypertensive crisis (unopposed alpha-stimulation). * **Associations:** MEN 2A and 2B, von Hippel-Ludlau (VHL) syndrome, and NF-1.

Q: What is the most common cause of hypothyroidism in adults?

Primary hypothyroidism. Hypothyroidism is a common endocrine disorder characterized by a deficiency of thyroid hormones. The correct answer is **Primary Hypothyroidism**, which refers to a failure of the thyroid gland itself to produce sufficient hormones [1]. **1. Why Primary Hypothyroidism is correct:** Primary hypothyroidism accounts for over 95% of all clinical cases. In iodine-sufficient regions (like most urban populations), the most common specific cause of primary hypothyroidism is **Hashimoto’s Thyroiditis** (an autoimmune destruction of the gland) [1]. Globally, however, **iodine deficiency** remains the most common cause of primary hypothyroidism. **2. Why other options are incorrect:** * **Trauma (A):** Direct physical trauma to the neck rarely results in permanent hypothyroidism as the gland is well-protected and has a high compensatory capacity. * **Radioactive Iodine Ingestion (B):** While I-131 therapy (used for Graves' disease or thyroid cancer) causes "iatrogenic" primary hypothyroidism, it is a specific medical intervention and not the most common cause in the general adult population. * **Parathyroid Surgery (D):** Hypothyroidism is a risk during a total thyroidectomy, but isolated parathyroid surgery typically spares the thyroid gland. The most common complication of parathyroid surgery is hypocalcemia, not hypothyroidism. **Clinical Pearls for NEET-PG:** * **Most common cause worldwide:** Iodine deficiency. * **Most common cause in iodine-replete areas:** Hashimoto’s Thyroiditis (associated with anti-TPO and anti-TG antibodies) [1]. * **Screening:** Serum **TSH** is the most sensitive initial test for primary hypothyroidism (TSH will be elevated) [1]. * **Secondary Hypothyroidism:** Refers to pituitary failure (low TSH, low T4), which is much rarer than primary causes [1].

Q: A 40-year-old woman with hypertension presents with excessive thirst, excessive urination, constipation, and a depressed mood. Her medications include hydrochlorothiazide. Laboratory studies show a serum calcium level of 11.0 mg/dL. Which of the following underlying disorders is most likely?

Parathyroid adenoma. **Explanation:** The patient presents with the classic "stones, bones, abdominal groans, and psychic overtones" of **hypercalcemia** (thirst, polyuria, constipation, and depressed mood). In an outpatient setting, the most common cause of asymptomatic or mildly symptomatic hypercalcemia is **Primary Hyperparathyroidism (PHPT)**, usually caused by a solitary **parathyroid adenoma** (85% of cases) [1]. 1. **Why Parathyroid Adenoma is correct:** PHPT leads to autonomous secretion of Parathyroid Hormone (PTH), which increases bone resorption and renal calcium reabsorption [2]. While hydrochlorothiazide can cause mild hypercalcemia, it often unmasks underlying PHPT [1]. The combination of chronic symptoms and a calcium level of 11.0 mg/dL strongly points toward an adenoma [3]. 2. **Why other options are incorrect:** * **Medullary carcinoma of the thyroid:** This secretes **calcitonin**, which typically lowers serum calcium levels [1]. It is associated with MEN 2A/2B, but the cancer itself does not cause hypercalcemia. * **Multiple myeloma:** While it causes hypercalcemia via osteoclast activation, it usually presents with "CRAB" features: Calcium elevation, Renal failure, Anemia, and Bone (lytic) lesions [1]. It is less likely in a 40-year-old with a mild, chronic presentation [3]. * **Porphyria:** Acute intermittent porphyria presents with abdominal pain and neuropsychiatric symptoms, but it is **not** associated with hypercalcemia. **NEET-PG High-Yield Pearls:** * **Most common cause of hypercalcemia:** Outpatient = PHPT; Inpatient = Malignancy [1]. * **EKG finding in hypercalcemia:** Shortened QT interval. * **Thiazide Diuretics:** These decrease urinary calcium excretion ("Thiazides throw sodium but save calcium"), which can unmask PHPT [1]. * **Diagnosis of PHPT:** Elevated Serum Calcium + Elevated/Inappropriately Normal PTH [1][3].

Q: What is the most common sign or symptom of pheochromocytoma?

Hypertension. **Explanation:** **Pheochromocytoma** is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla. Understanding its presentation is crucial for NEET-PG, as it is often referred to as the "10% tumor." **Why Hypertension is the Correct Answer:** **Hypertension** is the **most common clinical sign**, occurring in approximately 90% of patients [1]. It results from the excessive secretion of norepinephrine and epinephrine, which cause potent vasoconstriction and increased cardiac output. The hypertension can be **sustained** (more common) or **paroxysmal** (classic "spells"). While the "classic triad" (Headache, Sweating, Palpitations) is highly specific when all three are present, hypertension remains the most frequent finding overall. **Analysis of Incorrect Options:** * **B, C, and D (Headache, Sweating, Palpitation):** These constitute the **Classic Triad**. While they are the most common *symptoms* during a paroxysmal attack, they occur less frequently than hypertension. Among the triad, **Headache** is the most common symptom (approx. 80%), followed by generalized sweating (65%) and palpitations (60%). **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s:** 10% are bilateral, 10% are extra-adrenal (Paragangliomas), 10% are malignant, and 10% are familial. * **Best Screening Test:** Plasma free metanephrines (High sensitivity). * **Best Confirmatory Test:** 24-hour urinary fractionated metanephrines and catecholamines (High specificity). * **Pre-operative Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) followed by Beta-blockers to avoid a hypertensive crisis (unopposed alpha-stimulation). * **Associated Syndromes:** MEN 2A, MEN 2B, von Hippel-Lindau (VHL), and NF-1.

Q: Insulin resistance syndrome includes which of the following?

Dyslipidemia. **Explanation:** Insulin Resistance Syndrome, also known as **Metabolic Syndrome** or Syndrome X, is a cluster of metabolic abnormalities that significantly increase the risk of cardiovascular disease and Type 2 Diabetes Mellitus. **Why Dyslipidemia is correct:** In the state of insulin resistance, there is an increased flux of free fatty acids to the liver and impaired suppression of lipolysis in adipose tissue. This leads to a characteristic **atherogenic dyslipidemia** triad: 1. **Hypertriglyceridemia** (Elevated VLDL) 2. **Low HDL levels** [1] 3. **Small, dense LDL particles** [1] **Analysis of Options:** * **A. Dyslipidemia (Correct):** This is a hallmark feature. Specifically, high triglycerides and low HDL are diagnostic criteria. * **B & C. Hypertension and Hyperuricemia:** While both are frequently *associated* with insulin resistance, they are often considered secondary manifestations or associated findings rather than the core metabolic definition used in standard diagnostic criteria (like NCEP ATP III or IDF). In many MCQ formats, if "Dyslipidemia" is an option, it is prioritized as a primary metabolic component. * **D. High HDL (Incorrect):** Insulin resistance is characterized by **Low HDL** (typically 102cm M, >88cm F) 2. Triglycerides ≥150 mg/dL [1] 3. HDL <40 mg/dL (M) or <50 mg/dL (F) 4. Blood Pressure ≥130/85 mmHg 5. Fasting Glucose ≥100 mg/dL * **Acanthosis Nigricans:** A key clinical sign of insulin resistance. * **PCOS:** Strongly linked with insulin resistance syndrome in women.

Q: Factitious hyperinsulinemia is differentiated from insulinoma by which of the following?

C-peptide levels. The differentiation between **Insulinoma** (an endogenous insulin-secreting tumor) and **Factitious Hyperinsulinemia** (exogenous administration of insulin) is a classic high-yield topic in endocrinology. **1. Why C-peptide levels are correct:** Insulin is synthesized in the pancreatic beta cells as **proinsulin**, which is then cleaved into equimolar amounts of **Insulin** and **C-peptide**. [1] * In **Insulinoma**, there is autonomous endogenous production, leading to **elevated** levels of both Insulin and C-peptide. [1] * In **Factitious Hyperinsulinemia** (exogenous insulin injection), the patient has high serum insulin, but because exogenous insulin does not contain C-peptide, the body’s endogenous production is suppressed via negative feedback. This results in **low/suppressed C-peptide** levels. [1] **2. Why other options are incorrect:** * **Insulin antibodies:** While these can be present in patients using older insulin formulations or those with Insulin Autoimmune Syndrome (Hirata disease), they are not the primary diagnostic tool to differentiate between these two specific conditions. * **Serum glucose level:** Both conditions present with profound **hypoglycemia**. [2] Therefore, blood glucose cannot distinguish the source of the excess insulin. **Clinical Pearls for NEET-PG:** * **Whipple’s Triad:** Essential for diagnosing insulinoma (Symptoms of hypoglycemia, low plasma glucose, and relief of symptoms after glucose administration). * **Sulfonylurea Screening:** If a patient has high insulin and high C-peptide, you must screen the urine/serum for oral hypoglycemic agents (Sulfonylureas) to rule out factitious ingestion of pills, which mimics an insulinoma. [1] * **Proinsulin:** Usually elevated (>25%) in patients with insulinoma.

Question 1

In prolactinoma, what is the most common symptom other than galactorrhea?

Accepted Answer

Amenorrhea

Answer

Bitemporal hemianopia

Answer

Thyroid dysfunction

Answer

Headache

Question 2

Which one of the following clinical features is NOT typically seen in pheochromocytoma?

Accepted Answer

Diarrhea

Answer

Hypertension

Answer

Episodic palpitations

Answer

Weight loss

Question 3

What is the most common cause of hypothyroidism in adults?

Accepted Answer

Primary hypothyroidism

Answer

Trauma

Answer

Radioactive iodine ingestion

Answer

Parathyroid surgery

Question 4

A 40-year-old woman with hypertension presents with excessive thirst, excessive urination, constipation, and a depressed mood. Her medications include hydrochlorothiazide. Laboratory studies show a serum calcium level of 11.0 mg/dL. Which of the following underlying disorders is most likely?

Accepted Answer

Parathyroid adenoma

Answer

Medullary carcinoma of the thyroid

Answer

Multiple myeloma

Answer

Porphyria

Question 5

What is the most common sign or symptom of pheochromocytoma?

Accepted Answer

Hypertension

Answer

Headache

Answer

Sweating

Answer

Palpitation

Question 6

What is the most common cause of euvolemic hyponatremia?

Accepted Answer

Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)

Answer

Hypothyroidism

Answer

Hypoadrenalism

Answer

Hyperthyroidism

Question 7

Insulin resistance syndrome includes which of the following?

Accepted Answer

Dyslipidemia

Answer

Hypertension

Answer

Hyperuricemia

Answer

High HDL

Question 8

Autonomic Polyglandular syndrome 2 is associated with Adrenocortical insufficiency and which of the following?

Accepted Answer

Type 1 diabetes mellitus

Answer

Primary Gastric Adenocarcinoma

Answer

Hashimoto's thyroiditis

Answer

Islet cell adenoma

Question 9

A 28-year-old male presents with ophthalmoplegic signs of thyrotoxicosis. All of the following can be considered in the differential diagnosis of the case, EXCEPT:

Accepted Answer

Riedel's Thyroiditis

Answer

Diffuse thyroid goiter

Answer

Hashimoto's Thyroiditis

Answer

Adenomatous goiter

Question 10

Factitious hyperinsulinemia is differentiated from insulinoma by which of the following?

Accepted Answer

C-peptide levels

Answer

Insulin antibodies

Answer

Serum glucose level

Answer

None of the above

Endocrinology — MCQs

Endocrinology — MCQs

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