Endocrinology Practice Questions

Q: Conn's Syndrome is characterized by increased synthesis of which hormone?

Aldosterone. **Explanation:** **Conn’s Syndrome**, also known as **Primary Hyperaldosteronism**, is a clinical condition caused by the autonomous overproduction of **Aldosterone** from the adrenal cortex [3]. It most commonly results from an aldosterone-secreting adrenal adenoma (approx. 60-70% of cases) [4] or bilateral adrenal hyperplasia. 1. **Why Aldosterone is correct:** Aldosterone is a mineralocorticoid produced in the **Zona Glomerulosa** of the adrenal gland [3]. In Conn’s Syndrome, the excess aldosterone acts on the distal renal tubules to increase sodium reabsorption and potassium excretion [1]. This leads to the classic triad of **Hypertension, Hypokalemia, and Metabolic Alkalosis.** 2. **Why other options are incorrect:** * **Adrenaline:** Produced by the adrenal medulla [2]. Excess production is seen in **Pheochromocytoma**, not Conn’s Syndrome. * **Corticosteroids (Cortisol):** Produced in the Zona Fasciculata [3]. Excess cortisol leads to **Cushing’s Syndrome**. While both involve the adrenal cortex, the clinical presentations are distinct. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Test:** The most reliable screening tool is the **Aldosterone-to-Renin Ratio (ARR)**. In Conn’s Syndrome, aldosterone is high while plasma renin activity (PRA) is suppressed. * **Confirmatory Test:** Saline infusion test or Oral salt loading test. * **Classic Presentation:** A patient with resistant hypertension and unexplained hypokalemia (though many patients are normokalemic). * **Management:** Surgical excision for unilateral adenoma [4]; **Spironolactone** or Eplerenone (Aldosterone antagonists) for bilateral hyperplasia.

Q: A 17-year-old girl presents with weight gain, hair loss, constipation, and weakness. Her free T4 level is low and TSH is increased. Which of the following is the most likely diagnosis?

Hashimoto's thyroiditis. ### Explanation **1. Why Hashimoto’s Thyroiditis is Correct:** The clinical presentation of weight gain, hair loss, constipation, and weakness is classic for **hypothyroidism** [1]. The laboratory findings of a **low free T4** and an **increased TSH** confirm **primary hypothyroidism**. In a 17-year-old female, the most common cause of primary hypothyroidism is Hashimoto’s thyroiditis (Chronic Lymphocytic Thyroiditis). It is an autoimmune destruction of the thyroid gland, often characterized by the presence of anti-TPO and anti-thyroglobulin antibodies. **2. Why the Other Options are Incorrect:** * **Graves' Disease:** This is the most common cause of *hyperthyroidism*. Patients typically present with weight loss, tachycardia, heat intolerance, and low TSH levels [1]. * **McCune-Albright Syndrome:** This is a triad of polyostotic fibrous dysplasia, café-au-lait spots, and autonomous endocrine hyperfunction (most commonly **precocious puberty**, not hypothyroidism). * **TSH-secreting Pituitary Adenoma:** This is a rare cause of *secondary hyperthyroidism*. It would present with **elevated** free T4 levels and an inappropriately normal or elevated TSH. **3. High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Histopathology showing **Hurthle cells** (Askanazy cells) and lymphocytic infiltration with germinal centers. * **Antibody Profile:** Anti-TPO (Antimicrosomal) antibodies are the most sensitive marker (found in >90% of cases). * **Associated Risk:** Hashimoto’s thyroiditis increases the risk of **Primary Thyroid B-cell Lymphoma**. * **Wolff-Chaikoff Effect:** Hashimoto’s patients are uniquely sensitive to iodine loads, which can precipitate or worsen hypothyroidism.

Q: What is the recommended target HbA1c to minimize the risk of vascular complications in a diabetic individual?

7% or less. The primary goal of diabetes management is to prevent chronic complications. Large-scale clinical trials (such as **UKPDS** for Type 2 DM and **DCCT** for Type 1 DM) have conclusively demonstrated that maintaining an **HbA1c of ≤ 7%** significantly reduces the risk of **microvascular complications** (retinopathy, nephropathy, and neuropathy) [1]. While the impact on macrovascular outcomes (stroke, MI) is more evident over long-term follow-up (the "legacy effect"), the 7% threshold remains the standard recommendation for most non-pregnant adults [2]. **Analysis of Options:** * **Option C (Correct):** An HbA1c < 7% balances the benefits of complication prevention with the risks of hypoglycemia. * **Options A, B, and D (Incorrect):** HbA1c levels of 8%, 9%, or 10% are associated with a progressive and exponential increase in the risk of tissue damage due to advanced glycation end-products (AGEs) and oxidative stress. **Clinical Pearls for NEET-PG:** 1. **Individualization:** While < 7% is the general target, a more stringent goal (**< 6.5%**) may be suggested for young patients with short disease duration and no CVD [1]. Conversely, a less stringent goal (**< 8%**) is preferred for elderly patients, those with limited life expectancy, or those with a history of severe hypoglycemia. 2. **Diagnosis:** An HbA1c **≥ 6.5%** is diagnostic of Diabetes Mellitus. 3. **The 3-Month Rule:** HbA1c reflects average glycemia over the preceding 8–12 weeks (the lifespan of an RBC). 4. **False Lows:** HbA1c may be falsely low in conditions with high RBC turnover (e.g., hemolytic anemia, pregnancy, or recent blood transfusion).

Q: A 3cm adrenal mass is found incidentally on CT scan. Which of the following investigations is NOT indicated?

Adrenalectomy. ### Explanation The management of an **Adrenal Incidentaloma** (an adrenal mass ≥1 cm found incidentally on imaging) follows a strict protocol: first, determine if the mass is **hormonally active**, and second, assess its **malignant potential** [1]. **Why Adrenalectomy is the correct answer:** Surgery is a **treatment**, not an investigation. An adrenalectomy is only indicated if the mass is functional (hormone-secreting), shows suspicious radiological features (e.g., size >4 cm, high Hounsfield units), or shows significant growth on follow-up [1]. A 3 cm non-functional mass with benign imaging characteristics is typically managed with observation, not immediate surgery. **Why the other options are incorrect (Investigations that ARE indicated):** * **Dexamethasone Suppression Test (1 mg overnight):** This is the primary screening tool to rule out **Autonomous Cortisol Secretion (Subclinical Cushing’s)** [3]. * **Urinary or Plasma Catecholamines/Metanephrines:** Essential to rule out **Pheochromocytoma**, even in asymptomatic patients, as a biopsy or surgery on an undiagnosed pheochromocytoma can trigger a lethal hypertensive crisis [1], [4]. * **Midnight Plasma/Salivary Cortisol:** Along with 24-hour urinary free cortisol, these are alternative or confirmatory tests for hypercortisolism [3]. **High-Yield Clinical Pearls for NEET-PG:** 1. **Size Cut-off:** Masses **>4 cm** are generally considered for resection due to increased risk of adrenocortical carcinoma [1]. 2. **Hounsfield Units (HU):** On non-contrast CT, **<10 HU** suggests a lipid-rich benign adenoma [1]. 3. **Hypertension Screening:** If the patient is hypertensive, you must also check the **Aldosterone-to-Renin Ratio (ARR)** to rule out Primary Aldosteronism [2]. 4. **Biopsy Rule:** Never biopsy an adrenal mass until a Pheochromocytoma has been biochemically ruled out [1].

Q: A 27-year-old man and his 24-year-old wife have been trying to conceive a child for 6 years. Physical examination shows he has bilateral gynecomastia, reduced testicular size, reduced body hair, and increased length between the soles of his feet and the pubic bone. A semen analysis indicates oligospermia. Laboratory studies show increased follicle-stimulating hormone level and slightly decreased testosterone level. Which of the following karyotypes is this man most likely to have?

47, XXY. The clinical presentation of infertility, bilateral gynecomastia, small testes, and eunuchoid body habitus (increased sole-to-pubis length) is classic for **Klinefelter Syndrome (47, XXY)** [1]. **Why 47, XXY is correct:** Klinefelter syndrome is the most common cause of primary hypogonadism in males. The extra X chromosome leads to **dysgenesis of seminiferous tubules** (causing low inhibin and high FSH) and **atrophy of Leydig cells** (causing low testosterone and high LH) [1]. The high LH/FSH ratio and peripheral conversion of androgens to estrogens result in gynecomastia [3]. The "eunuchoid" habitus occurs because testosterone is required to close the epiphyseal plates; its deficiency leads to delayed closure and disproportionately long limbs [1]. **Analysis of Incorrect Options:** * **46, X, i(Xq):** This represents an isochromosome X, a variant of **Turner Syndrome** [2]. This would present in a phenotypic female with short stature and primary amenorrhea. * **47, XYY:** Known as **Jacob’s Syndrome**. These individuals are usually phenotypically normal, very tall, and may have severe acne or behavioral issues, but they typically have normal fertility and testosterone levels. * **46, XX/47, XX, +21:** This is a mosaic form of **Down Syndrome**. While it can cause hypogonadism, it is characterized by distinct facies, intellectual disability, and Simian creases, which are absent here. **High-Yield Clinical Pearls for NEET-PG:** * **Most common genotype:** 47, XXY (due to maternal meiotic non-disjunction). * **Key Lab Findings:** ↑ FSH, ↑ LH, ↓ Testosterone, ↑ Estrogen [1]. * **Histology:** Hyalinization and fibrosis of seminiferous tubules [1]. * **Increased Risks:** Breast cancer (20x higher than normal males), extragonadal germ cell tumors, and autoimmune diseases (SLE) [3]. * **Semen Analysis:** Usually shows **azoospermia** (complete absence) or severe oligospermia [1].

Q: Weight gain is seen in all of the following conditions except:

Pheochromocytoma. **Explanation:** The correct answer is **Pheochromocytoma**. This condition is characterized by the hypersecretion of catecholamines (epinephrine and norepinephrine), which are potent catabolic hormones. Catecholamines increase the basal metabolic rate (BMR) and promote glycogenolysis and lipolysis [2]. Furthermore, they inhibit insulin secretion, leading to a hypermetabolic state that typically results in **weight loss**, despite a normal or increased appetite [5]. **Analysis of Incorrect Options:** * **Cushing’s Syndrome:** Characterized by hypercortisolism, which promotes adipogenesis and redistribution of fat. This leads to progressive weight gain and "centripetal obesity" (moon facies, buffalo hump, and truncal obesity) [3]. * **Hypothyroidism:** A deficiency in thyroid hormones leads to a significant decrease in BMR and the accumulation of glycosaminoglycans (myxedema), which causes water retention and weight gain [1]. * **Insulinoma:** This beta-cell tumor secretes excessive insulin, leading to recurrent hypoglycemia. Patients often experience weight gain due to the anabolic effects of insulin and "defensive eating" (frequent snacking to prevent or treat hypoglycemic symptoms). **NEET-PG High-Yield Pearls:** * **Pheochromocytoma Triad:** Episodic headache, sweating, and tachycardia (often associated with hypertension). * **Rule of 10s:** Historically associated with Pheochromocytoma (10% bilateral, 10% malignant, 10% extra-adrenal, 10% pediatric). * **Weight Gain Differential:** Always consider PCOS, Metabolic Syndrome, and drugs (Steroids, Sulfonylureas, TCAs, and Valproate) in clinical vignettes [4].

Q: Food-dependent Cushing's syndrome is a result of the aberrant expression of which of the following?

Gastric inhibitory polypeptide. **Explanation:** **Food-dependent Cushing’s syndrome** is a rare form of ACTH-independent macronodular adrenal hyperplasia (AIMAH). The underlying pathophysiology involves the **aberrant expression of receptors for Gastric Inhibitory Polypeptide (GIP)** on the adrenal cortex [1]. 1. **Why GIP is correct:** Normally, GIP is a hormone secreted by the K-cells of the small intestine in response to food intake. In this pathological state, the adrenal glands ectopically express GIP receptors. Consequently, every time the patient eats, the postprandial rise in GIP stimulates the adrenal glands to secrete cortisol, leading to hypercortisolism that is specifically triggered by meals [1]. 2. **Why other options are incorrect:** * **Somatostatin:** Generally acts as an inhibitory hormone in the endocrine system; its receptors are often targets for treatment (e.g., octreotide), not the cause of food-dependent Cushing’s. * **Substance P and Tachykinins:** These are neuropeptides involved in pain transmission and smooth muscle contraction; they do not have a recognized role in the postprandial regulation of adrenal cortisol secretion. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Characterized by low morning (fasting) cortisol levels and high postprandial cortisol levels. * **ACTH Levels:** ACTH will be suppressed (ACTH-independent) because the cortisol excess is driven by GIP, not the pituitary [1]. * **Other Ectopic Receptors:** Besides GIP, AIMAH can also be caused by aberrant expression of receptors for **Beta-adrenergic agonists**, **Vasopressin (V1)**, or **LH/hCG** [1]. * **Treatment:** Often involves bilateral adrenalectomy or, in some GIP-dependent cases, octreotide to suppress GIP release.

Question 1

Conn's Syndrome is characterized by increased synthesis of which hormone?

Accepted Answer

Aldosterone

Answer

Adrenaline

Answer

Corticosteroids

Answer

None of the above

Question 2

A 17-year-old girl presents with weight gain, hair loss, constipation, and weakness. Her free T4 level is low and TSH is increased. Which of the following is the most likely diagnosis?

Accepted Answer

Hashimoto's thyroiditis

Answer

Graves' disease

Answer

McCune-Albright syndrome

Answer

TSH-secreting pituitary adenoma

Question 3

What is the recommended target HbA1c to minimize the risk of vascular complications in a diabetic individual?

Accepted Answer

7% or less

Answer

10% or more

Answer

8%

Answer

9%

Question 4

A 3cm adrenal mass is found incidentally on CT scan. Which of the following investigations is NOT indicated?

Accepted Answer

Adrenalectomy

Answer

Dexamethasone suppression test

Answer

Measurement of urinary or plasma catecholamines

Answer

Midnight plasma cortisol measurement

Question 5

A diabetic patient in hypoglycemia does not regain consciousness despite blood glucose restoration to normal. Which one of the following is a not likely condition or explanation?

Accepted Answer

Alcohol intoxication

Answer

Cerebral edema

Answer

Post-ictal state

Answer

Cerebral haemorrhage

Question 6

A 17-year-old female patient presents with hirsutism, hyperglycemia, obesity, muscle wasting, and increased circulating levels of ACTH. What is the most likely cause of her symptoms?

Accepted Answer

Primary overproduction of ACTH

Answer

Primary adrenocortical insufficiency

Answer

Exogenous steroids

Answer

Hypophysectomy

Question 7

A 27-year-old man and his 24-year-old wife have been trying to conceive a child for 6 years. Physical examination shows he has bilateral gynecomastia, reduced testicular size, reduced body hair, and increased length between the soles of his feet and the pubic bone. A semen analysis indicates oligospermia. Laboratory studies show increased follicle-stimulating hormone level and slightly decreased testosterone level. Which of the following karyotypes is this man most likely to have?

Accepted Answer

47, XXY

Answer

46, X, i(Xq)

Answer

47, XYY

Answer

46, XX/47, XX, +21

Question 8

Weight gain is seen in all of the following conditions except:

Accepted Answer

Pheochromocytoma

Answer

Cushing's syndrome

Answer

Hypothyroidism

Answer

Insulinoma

Question 9

Food-dependent Cushing's syndrome is a result of the aberrant expression of which of the following?

Accepted Answer

Gastric inhibitory polypeptide

Answer

Somatostatin

Answer

Substance P

Answer

Tachykinins

Question 10

A 54-year-old man presents with 7 weeks of facial flushing and diarrhea. His symptoms began intermittently but are becoming more constant. A 24-hour urine collection reveals an elevated level of 5-hydroxyindoleacetic acid (5-HIAA), a metabolite of serotonin. An abdominal CT scan shows a 2-cm mesenteric mass in the ileum and likely metastatic tumors in the liver. What is the likely diagnosis?

Accepted Answer

Malignant carcinoid syndrome

Answer

Serotonin syndrome

Answer

Cushing syndrome

Answer

Phaeochromocytoma

Endocrinology — MCQs

Endocrinology — MCQs

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