Endocrinology Practice Questions

Q: A patient with IDDM presents to the emergency room in a coma due to diabetic ketoacidosis. Insulin therapy is initiated promptly. Which of the following electrolyte supplements should also be administered immediately?

Potassium supplementation. ### Explanation **Correct Option: D. Potassium supplementation** In Diabetic Ketoacidosis (DKA), patients typically have a **total body potassium deficit** due to osmotic diuresis and vomiting [1]. However, initial serum potassium levels may appear normal or even elevated because of the shift of potassium from the intracellular to the extracellular compartment (caused by insulin deficiency and acidemia) [4]. Once **insulin therapy** is initiated, potassium levels drop rapidly due to two main mechanisms: 1. **Intracellular Shift:** Insulin stimulates the Na+/K+-ATPase pump, driving potassium back into the cells [4]. 2. **Correction of Acidosis:** As pH improves, hydrogen ions move out of the cells in exchange for potassium moving in. Failure to supplement potassium early can lead to life-threatening **hypokalemia**, resulting in cardiac arrhythmias or respiratory muscle paralysis [3]. **Why other options are incorrect:** * **A. Calcium supplementation:** Routine calcium replacement is not indicated in DKA unless there is a specific symptomatic deficiency. * **B. Creatinine supplementation:** Creatinine is a waste product of muscle metabolism; it is never supplemented. * **C. Magnesium supplementation:** While magnesium may be depleted in DKA, it is not the priority electrolyte. It is only replaced if levels are significantly low (<1.2 mg/dL) or if the patient is symptomatic. **NEET-PG High-Yield Pearls:** * **The "Potassium Rule":** If the initial serum potassium is **<3.3 mEq/L**, hold insulin and replace potassium first. If it is between **3.3–5.2 mEq/L**, give potassium along with insulin [2]. * **Most common cause of death** in children with DKA is **Cerebral Edema**; in adults, it is often the underlying precipitant (e.g., MI or Sepsis) or electrolyte imbalances [3]. * **Bicarbonate therapy** is generally avoided unless the arterial pH is **<6.9**.

Q: According to ADA guidelines, what is the fasting blood glucose level that indicates a diagnosis of diabetes?

126 mg/dl. According to the **American Diabetes Association (ADA)** guidelines, the diagnosis of Diabetes Mellitus is established based on specific glycemic thresholds [1]. The correct threshold for **Fasting Plasma Glucose (FPG)** is **≥126 mg/dl (7.0 mmol/L)** [1]. Fasting is defined as no caloric intake for at least 8 hours. This value is chosen because it correlates with a significantly increased risk of developing microvascular complications, particularly diabetic retinopathy [1]. **Analysis of Options:** * **Option A (126 mg/dl):** The diagnostic cutoff for diabetes. A repeat test is usually required for confirmation unless unequivocal symptoms of hyperglycemia are present. * **Option B (100 mg/dl):** This is the upper limit of "Normal." Values between **100–125 mg/dl** are categorized as **Impaired Fasting Glucose (IFG)** or Prediabetes. * **Option C (140 mg/dl):** This is the threshold for **Impaired Glucose Tolerance (IGT)** when measured 2 hours after a 75g Oral Glucose Tolerance Test (OGTT). Values between 140–199 mg/dl indicate prediabetes. * **Option D (200 mg/dl):** This is the diagnostic threshold for diabetes if measured as a **Random Plasma Glucose** (in a symptomatic patient) or as a **2-hour post-OGTT** value. **High-Yield Clinical Pearls for NEET-PG:** 1. **HbA1c Criteria:** ≥6.5% is diagnostic for diabetes; 5.7%–6.4% indicates prediabetes. 2. **Gold Standard:** While FPG is common, the **75g OGTT** is considered the most sensitive diagnostic tool. 3. **Screening:** In asymptomatic adults, screening should begin at age 35 (revised from 45). 4. **Diagnosis Confirmation:** Unless there is a clear clinical diagnosis (e.g., patient in hyperglycemic crisis), two abnormal test results from the same sample or two separate test samples are required.

Q: What is the most common cause of hirsutism?

Polycystic ovary disease. ### Explanation **1. Why Polycystic Ovary Syndrome (PCOS) is Correct:** PCOS is the most common cause of hirsutism, accounting for approximately **70–80% of all cases**. The underlying pathophysiology involves a combination of insulin resistance and an imbalance in the hypothalamic-pituitary-ovarian axis. This leads to increased LH secretion, which stimulates the ovarian theca cells to produce excess androgens (primarily androstenedione and testosterone). These circulating androgens are converted to dihydrotestosterone (DHT) in the hair follicles, leading to the transformation of fine vellus hair into coarse terminal hair in male-pattern areas. **2. Why the Other Options are Incorrect:** * **Arrhenoblastoma (Sertoli-Leydig Cell Tumor):** While these are potent androgen-secreting ovarian tumors, they are **extremely rare**. They typically present with rapid-onset virilization (clitoromegaly, voice deepening) rather than isolated, gradual hirsutism. * **Cushing Syndrome:** Excess cortisol can lead to hirsutism due to the co-secretion of adrenal androgens. However, it is a much less frequent cause than PCOS and is usually accompanied by systemic features like moon facies, striae, and proximal muscle weakness. * **Congenital Adrenal Hyperplasia (CAH):** Specifically, Non-Classic (Late-onset) CAH is a common differential for PCOS. While it is a significant cause of hyperandrogenism, its prevalence is much lower (approx. 1–5%) compared to PCOS. **3. NEET-PG High-Yield Pearls:** * **Ferriman-Gallwey Score:** The clinical tool used to quantify hirsutism (Score ≥8 is usually significant). * **Idiopathic Hirsutism:** The second most common cause; characterized by normal androgen levels and regular menses. * **First-line Treatment:** Combined Oral Contraceptive Pills (OCPs) are the mainstay for PCOS-related hirsutism. * **Drug of Choice for Hair Reduction:** Spironolactone (anti-androgen) or Eflornithine cream (topical).

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 of the following conditions is associated with peripheral artery disease, coronary heart disease, and stroke?

Insulin deficiency. The correct answer is **Insulin deficiency**, which is the hallmark of Diabetes Mellitus (DM). DM is a major systemic metabolic disorder and a potent independent risk factor for **Atherosclerosis**. **1. Why Insulin Deficiency is Correct:** Insulin deficiency (or resistance) leads to chronic hyperglycemia [2], which triggers a cascade of vascular damage: * **Endothelial Dysfunction:** Increased oxidative stress and advanced glycation end-products (AGEs) damage the vessel walls. * **Dyslipidemia:** Insulin deficiency promotes the production of small dense LDL and reduces HDL, accelerating plaque formation [1]. * **Pro-thrombotic State:** It increases platelet aggregation and impairs fibrinolysis. These processes lead to **Macrovascular complications**, which manifest clinically as Peripheral Artery Disease (PAD), Coronary Heart Disease (CHD), and Ischemic Stroke [1]. **2. Why Other Options are Incorrect:** * **Hyperestrogenemia:** Estrogen generally has a protective effect on the cardiovascular system in premenopausal women by improving lipid profiles and promoting vasodilation. * **Hypothyroidism:** While hypothyroidism can cause hypercholesterolemia (increasing CHD risk), it is not as strongly or classically associated with the triad of PAD, CHD, and stroke as insulin deficiency is. * **Hyperprogesteronemia:** Progesterone does not have a primary, direct role in the pathogenesis of systemic atherosclerosis. **Clinical Pearls for NEET-PG:** * **DM is considered a "CHD Equivalent":** A patient with DM but no history of MI has the same cardiovascular risk as a non-diabetic patient who has already had an MI [2]. * **PAD in DM:** Usually involves infra-popliteal (distal) arteries and is often multisegmental. * **Metabolic Syndrome:** Remember the "Deadly Quartet": Upper body obesity, glucose intolerance, hypertriglyceridemia, and hypertension.

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: 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: 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

A patient with IDDM presents to the emergency room in a coma due to diabetic ketoacidosis. Insulin therapy is initiated promptly. Which of the following electrolyte supplements should also be administered immediately?

Accepted Answer

Potassium supplementation

Answer

Calcium supplementation

Answer

Creatinine supplementation

Answer

Magnesium supplementation

Question 2

According to ADA guidelines, what is the fasting blood glucose level that indicates a diagnosis of diabetes?

Accepted Answer

126 mg/dl

Answer

100 mg/dl

Answer

140 mg/dl

Answer

200 mg/dl

Question 3

What is the most common cause of hirsutism?

Accepted Answer

Polycystic ovary disease

Answer

Arrhenoblastoma

Answer

Cushing syndrome

Answer

Congenital adrenal hyperplasia

Question 4

Which of the following is true about Hyperglycemic hyperosmolar state?

Accepted Answer

Kussmaul respirations are characteristic.

Answer

It is more common in young patients with type 1 diabetes mellitus.

Answer

Mental status is not altered in any case.

Answer

There is associated hypertension and tachycardia.

Question 5

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

Accepted Answer

Amenorrhea

Answer

Bitemporal hemianopia

Answer

Thyroid dysfunction

Answer

Headache

Question 6

Which of the following conditions is associated with peripheral artery disease, coronary heart disease, and stroke?

Accepted Answer

Insulin deficiency

Answer

Hyperestrogenemia

Answer

Hypothyroidism

Answer

Hyperprogesteronemia

Question 7

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 8

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 9

What is the most common sign or symptom of pheochromocytoma?

Accepted Answer

Hypertension

Answer

Headache

Answer

Sweating

Answer

Palpitation

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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